THS THE EFFECT OF ARTEHCAL DRYING 0F HELD BORN IN DEFFERENT STAGES OF MATURXTY ON THE VITALITY OF THE SEED Thesis for the Degree of M. S. Anhur Russell Marston I 9 2 6 '. 7” “.3 ; 4K$Wiy . h ,1: ~ . .. , ‘ w" ‘ ‘ '”fi a; ‘ I “‘ “.v 4" A.*flw , , . . ,' ,, PM A}; V .- V“ W}~,¢3% 5‘; IL" ‘3; . . ,‘ " ‘2‘: a r A ‘g'. . ~ . . ‘ . . ,l «f, , f *0 ’1' «p, ‘ J ‘ ' ' " ' , ' at: . W .4_:.p;$5.?r£f‘ M; * 3,, f'— - - ‘ y .‘ -. . ., 5.0"” -;- .111“: - , ‘ ' ‘. , - '- - ~. ,- .‘.._" Jr" ‘1 "flak-3571,? fl'w . JrAu, : ' ti? ; 1 'J 1,.gm , v£”5%1 '«"-'i-: ‘1‘ *i “9% “H“ >-’ ‘i' - vi. L3 _!‘\ ., «.‘r . 1‘, :7; 'Ll’fir ; 1 ”fig W .1. saw?» 5; .,-, , a? ‘L‘EIN‘L‘V'! .i' “(9" t v_ G 1; v:- .. Mm i" -‘ ‘ ‘ Bk‘ifi‘ “J x A 'f lrfiumqg; J I uuurmnq’di- 35,“; 1 .' $114; .;...";.r.u :~ - V . . 4 - FEE EFFECT OF ARTIFICAL DRYING OF FIELD CORN IN DIFFERENT STAGES OF MURITY ON THE ViTALITY OF THE SEEI). H THE EFFECT OF ARTIFICAL DRYING 0F FIELD CORN IN DIFFERENT STAGES OF EATUFITY ON THE VITNLITY OF THE SEED. L Thesis Prepared. by ARTHUR RUSSELL WON 1n Partial Ful- fillment of the Requirements Eartha Degree of Master of Seienee,Departnent of ram Grosz . MICHIGAN STATE COLLEGE or AGEICULTDRE AND APPLIED .- 1.925. 1 .V a Hisva ACKN O‘v'JLEDGI‘IEN T The author of this thesis is indebted to Professor J. R. Duncan for assistance proffered and advice given in the conducting of this experiment. To Professor Cox and Megee the author also acknowledges valuable assistance tendered by them and to Professor Down and Pettigrove appreciation for the method of compilation of statistics thereby aiding materially in the writing of the manuscript. The experimental equipment and laboratories of the Farm Crops Department were used and for their use the author is deeply indebted. For the Catalase experiment, appara- tus was given by the courtesy of the Horticultural Depart- ment for'which the author tenders "thanks". For advice in methods used in the Catalase experiment Dr. Grist and Mr. Ezell wh5leheartedly are resPonSible and appreciation is hereby expressed to them. Hearty coOperation made possible the findings for which the author appreciatively acknowledges. .3- (:01st , - Page lgmmtOOOOOOOOOOOOOOOO00.000.00.000 1.8%: of naturity............. amnion Ming.........._..... 3Jater Absorption of Seeds and . _ Permeability of Seed-Coats. .. 9 mural-entail. ler......................... 10 6M1”: of Experimental Data............. 16 mm... utiuty........................... so mausolusion.................................. 64 Lumecem...“........................... 68 1‘ O'. 9.69... 00.0000 ‘00.... 6.0.0....OOIIOOOOIC'. ' Q . ICOOOIOOIODCOIUIOOOOIOt'I...'-— ‘\‘\ a: . 5.. oeee-oeeeeeeOOe'eeeeeeee -'~ "-'+-'--~ . n u. ’7 v "‘n - \ ‘ -.' "-(“. ‘ v 0.... ‘1 ‘ ' . 00006.. ‘ e - CH .'. a ‘ s“. s. . . 1'}. ‘ '3, 3—- “' , ‘ . eeeveeeoeeeeeeoee ' -- . O .0. . ' I! g‘ ’. eeeeo~l ~-~ - , - ‘ ~" eoleoeeoe’eOeOeeeeOO, .. ‘ - . eeooe000000~noose-oeeesaeo~'- ., ‘ . . eeeeoeeeeeeeeeeeooevoeoe7 - ,---‘»'-"‘ -3- INTRODUCTION Field corn is one of the important craps to Michigan farmers. Each year its yield is equivalent to approximately 66,796,000 bushels. An important question in corn growing arises, however, - Is it possible for every farmer in Mich- igan to grow the seed corn that he plants? We immediately answer ”yes", but the quality of that seed corn cannot be guaranteed to be of high vitality in every case. If weather conditions for all years were the same, and we had the choosing of that particular kind of a year, I feel sure we would choose a year in which no frosts were earlier than November, with as little rainfall as was necessary. As we are handicapped in this respect, we natur- ally have to take what is givm us and plan to meet whatever conditions may prevail. We must admit that in years of high precipitation, cool weather and early frosts, we do not have the corn maturing and drying on the stalk fast enough for us to select seed that would be high in (vitality. Would it be possible for us to select our seed in an earlier stage of mt- urityufor example, in the milk or soft dough-wand, by some drying process, evaporate off the excess moisture and store it in conditions where that moisture could be kept as constant as possible and, in this ww, obtain seed corn of high vitality and able to produce a yield equal to that of seed corn that was left to mature and dry on the stalk? The object of the investigations in this thesis has -a '. -4- been to determine the effect of artificial drying of field corn.harvested in different stages of maturity on the vitality of seed. -5- REVIEW OF LITERATURE 1- Stages of Maturity Kidd, r and West, C (I) state that the most ob- vious categories under which we may deal with conditions affecting the potentiality of the seed, measuring by this the capacity of the resulting plant growth and yield are as follows-41) Parental conditions, (2) Harvesting con- dit ions, (3) Conditions during Ol‘ imediately preceeding germination or in the early stages of the seedling. 1 con- sideration of the results reviewed above makes it clear that the quest ion as to whether differences in the resulting plant are predetermined by the use of seeds differing in degree of ripeness cannot be regarded as satisfactorily answered in the case of any single Species. This is due to the fact that all the recorded comparisons between plants grown from immature seeds and plants grown from mature seeds appear to have been complicated by some period of storage. Immature seeds are less tolerant of storage in the dry condition than mature seeds 80 that in comparisons which have been made the total yields from immature seeds are usually less than those from mature seeds owing to the fact that a 8:19.11 percentage of the immature seed germinate. From the point of view of the grower, seed harvested at a stage somwhat previous to mat- urity may, under certain conditions give a better yield than seed allowed to become dead-ripe upon the parent plant, but it must be borne in mind that immature seed does not with- -5- stand storage as well as seed which has been allowed to become fully ripe. Dungon D. H. (2) states seed corn harvested before complete maturity absorbed water more rapidly and also pos- sessed a greater water absorptive capacity than corn that had been allowed to nature on the stalk. Although early harvested seed corn absorbs water more rapidly than corn that is allowed to nature on the stalk, the nature corn is distinctly the better from the standpoint of seedling vigor. The corn harvested in the milk stage began germinat- ing earlier than that harvested in the dent stage. The dent stage likewise produced a higher percentage genuination dur- ing the first three days than the com gathered after it had become nature. Soon, however, the "milk stage" seed showed evidmce of lack of vigor. The corn in the 30°C chamber par- ticularly that harvested at the milk stage was soon overrun by molds and for that reason the germ emergence was abnormal. {Phieopus Sp, Penicillium sp, and depergillus Sp.) Hughes B. D. and Stanfield w. w. (s). l. The more immature seed corn picked at weekly inter- vals and cured and stored in the seed house with articicial hear gave 65% strong ears, the closed shed 14% and the Open shed 10%. Several of the early selections showed practically perfect germination when stored in the seed house and cured with artificial heat. Hughes B. D. (4) states Those ears which produced the most rapid growth when -7- planted in the field have unifomly given the most satis- factory yields. Arny A.C. (5) Correlation between weight of seed sown and result- ant plant characters at maturity is not high in any instance and may be 80 modified by enviroment conditions that the re- lation may be slight or obliterated entirely. Cracker, William 8: Harrington, George TJG) The catalase activity of'the grains of grasses is determined to a large degree by their maturity at the time of harvest. The immature grains have much higher activity than nature ones. Test with Sudan grass showed that the higher activity of immature grains is not lost with thorough drying, but it is maintained after years of dry storage. 2. Artificial Drying Hughes H. D. and Stanfield w. w. (3) The mature ears of corn picked at weekly intervals throughout the fall and stored in seed houses with continuous heat 74% gave strong germination, the same quantity of ears picked at the same time but stored in a closed shed with no artificial heat gave 35%, while that stored in an open shed showed only 11% of strong cars. In many cases, however, it is well worth while to provide some artificial heat. This is practically true with corn which contains considerable mois- ture when picked. Kienhol (5) finds in an elaborate study of the ef- fect of high temperatures on seed corn that air dry corn was -3- killed by exposure to 80°C for 25 minutes and to 90°C for 10 minutes and injured by exposure to 70°C, 80°C, 90°C for 80, 10 and 5 minutes reSpectively. Resistance to heat waned inversely as to water content. Ewart A. J. (8) in working with seeds of wheat, corn, barley, peas, artichokes, hemp, Squash, rape and sunflower which he dried in a vacuum desiccator at 37° to 30°C conclu- dad that it was impossible to reduce the % water held by even the most resistant seeds to lower than 2% or 3% of their dry weight without affecting their vitality. Ewarts hypothesis was that excessive drying so changed the dormant protoplasm that upon being remoistened it was unable to re-establish the molecular groupings essential for normal vital activity. Harrington G. T. 8: Cracker William (6) in an essay des- cribing experiments to determine the effect on the vitality of certain seeds when dried under varying conditions and for vary- ing lengths of time, it was found that the percentage of ger- mination was not materially changed whm seed of wheat, barley, Sudan grass, Kentucky bluegrass and Johnson grass was dried to less than 1% moisture. The percentages of germinati on of Ken- tucky bluegrass and Johnson grass was not affected when the moisture was further reduced to .1% although the vigor of the Kentucky bluegrass seed was further dried in a vacuum oven for 6 hours at 100°C, the vigor'of the seedling was further reduced, but the percentage of germination was not materially affected. All this controverts Ewarts (a) statements as to the degree of drying which seeds are capable of withstanding and -9- remaining viable so far as the seeds used in this experi- ment are concerned. Waggoner H. D. (9) in a study of radish seeds (Raph- onus Sativus L.) as affected by high temperatures says that by drying first at 60°C and later at 100°C reduced the mois- ture content of radish seeds to 4% without affecting subse- quent germination. Crocker Wm. (10) The changes involved in rapid loss of vitality by seeds that;will not withstand drying are still more obscure. The nature of the injury produced by drying is also entirely un- knmwn. Montgomery E. G. (11) states experimental work has shown that grain insects exposed to a temperature of 120°! for 15 or 20 minuteSIwill be killed. This temperature also kills the eggs, larvae and pupae. 3. Water Absorption of Seeds and Permeability of Seed Coats Shull, Charles A. (12) The main chemical changes with rise of temperature are believed to occur in the colloids of the seed, and semipermea- bility, as such, is thought not to be an important factor in determining the rate of water absorption. Greater amounts of oxygen absorbed‘with seed coats reunved. Oxygen accelerates germination, Ianthium glabrutum. Rose D. H. (22) Ebr two varieties of lettuce it is shown that the seed improves in viability as it grows older, up to the end of at -10- least the fourth year. This improvement is probably due to increased permeability of the inner seed coat to water. Dixon H. H. (23) Prot0plasmic permeability is greatly increased by rise in temperature. Syringe vulgari and Hedera helix used. Cracker Wm. and Davis, Wilmer E. (24) Dormancy in the akmes of alisma Plantago is due to the mechanical restraint of the seed coat. This restraint enables the seed to lie in water for years without germin- ation. Cracker Wm. (10) Delayed germination is reported in the seeds of many plants, and exactly opposite to the common view, its cause generally lies in the seed coats rather than in the embryo's; but in hawthornes as perhaps in some other seeds it is due to embryo characters. Seed coats which exclude water are much better adapted to securing delays than are seed coats which exclude oxygen, because of the much greater reduction of reapiration in the first case. In nature growth of the delayed seeds comes about through the disintegration of the seed coat structures by a larger or shorter exposure to ger- mination conditions and the length of the delay depends upon the persistence of the structure securing it. 4. Catalase Cracker William.& Harrington, George (5) states that Catalase is an enzyme capable of Splitting hydrogen peroxide into water and oxygen. It is universally present in living -11- matter and was supposed to be a property of all enzymes until Loew (20) mowed it to be a distinct body. There is some question arising as to its real enzymic nature. Its functi on in the organism is not known. Catalase activity of seeds seemsto parallel phy- siological behavior much more generally than does oxidase activity. Appleman, Chas. 0. (12) Catalase is prob ably the most widely distributed of any of the known enzymes. In fact, its occurence is so general that Loew (20) concluded that there did not exist a group of organisms or any organ or even a single vegeta- ble or animal cell that did not contain some catalase.(ll) There is no correlation between oxidase activity and the reSpiration in these organs (potato). Catalase activity in the potato Juice shows a very striking correlation with respiratory activity in the tubers. Heinke, Arthur John (13) Treatments tending to increase nitrogen content in many cases cause increase in catalase activity, condition causing increase in carbohydrates seem to produce decrease in catalase actiVity. Ne Mec Antonin and Duchon, Frantisck (14) Catalase activity consistent with viability. Hard coated seeds, like those of trees, diffiallt to germinate in laboratory. -12- Crocker, William and Harrington, George T. (6) 0n Johnson grass seed there seems uc‘be close corre- lation between catalase activity and reapiration intensity, but not any very close correlation between either of them and vitality of the seed or vigor of the seedling. Catalase activity decreases with age. In amaranthus, no correlation even with reSpiration. Oxidases as active in non-living as living organs. McHague, 3. S. (15) Peroxidase reaction may be used for seed.testing. Seeds of high, low and medium.viability. Vital property of seeds contained in substance (presumably oxyglucose) which has power to activate molecular oxygen in air, per- oxidase being found. This power lost when seed loses power to germinate. Peroxidases also determine rate of loss of viability. Vant T. Hoff (16-) The Vent Hoff velocity coefficient fbr potato catal- ase is 1.5 from.O°C--10°C. At higher ranges of’temperature there is an apparent progressive decrease in the velocity coefficient. This is due to actual destruction of the cat- alase which is not due in the main to impurities in the hy- drogen peroxide or to oxidation by the hydrogen peroxide. Bailey, 0. H. (17) Increasing temperatures accelerate the rate of res- piration until 55°C is reached. As the temperature rises the diastatic action upon starch increases. A point is -13- reached, however, at which the enzyme activity deminishes. At 55°C the whole mess of wheat is of a mahogany color. At 65°C the resPiratory enzymes have been partially but not wholly inactivated while at 75°C this inactivation has pro- ceeded still further and some roasting of the grain has oc- curred. Appleman, Chas. O. (12) Catalases from different sources show considerable variation in temperature relations, the point of total des- truction in the cases reported ranging from 65°C to 80°C. In potato catalase,‘ however, destruction is complete when the temperature reaches 50°C. At 20°C a destruction of the catalase begins , which renders the accelerating effect of higher temperatures upon the peroxid decomposition, impos- sible of manifestation. Cracker, William 8: Harrington, George T. (6) Heating air dry seeds causes a fall in their vitality as well as in their catalase activity, but the denaturing of the substances connected with viability and of the catalase do not parallel each other. Heating Johnson grass seed to 81°C from half an hour to two hours reduces the catalase activity by a large percentage and improves the germination. Longer heating 4 hours at 81°C causes considerable additional reduction in the catalase activity and a very decided fall in germination. Still longer heating, 17 hours at 81°C reduces the catalase to from 10 to 16% of its original value and kills all the seeds. Heating to 100°C for 5 hours kills all the seeds and destroys all their catalase. In the early stages -14- of heat degeneration as in time degeneration the catalase falls faster than the viability, but some catalase activity persists after the seeds are all killed. schoenbein (18) Concluded that the power to decompose hydrbgen per- oxide (H202) and to blue gnaiacium thereby is intimately as- sociated with the specific activity of the unorganized fer- ments and with.such vital phenomena as the sprouting of seeds, etc., inasnuch as all of. these bioligio prOperties are lost by heating to 100°C by exposure U3 323 and also as shown in a later paper by exposure to hydrocyanic acid. Jones, E. A. (19) After a slight initial increase, catalase activity gradually decreases in the dessiccating seeds. Catalase activiw increases enormoufily during the early stages of germination. Shull, Chas. a. and Davis, Ward B. (21) Catalase activity is relatively stable in dry stored seeds for several months. Fig. No. l--Showing ears that had been selected in different stages of natal-ity and a germinated kernel from each. No.1 was selected in the hard dough; 150.: was selected in the soft dough; No.3 was selected in the milk stage. -15- EXPERIMENTAL METHOD In the fall of 1924 seed ears of dent corn (zea mays indentata) were harvested in different stages of maturity according to the classification (No.1). No. 1. Classification for stage of maturity Milk Stage--Vu'hal milk exudes by a slight pressure of the finger nail. Soft Dough Stage--When soft dough, which is rubbery in texture, fills the endosperm and the kernel begins to dent. Hard Dough Stage--When the endosperm is filled with firm dough and the kernel is fully dented. A sample of six ears of each was placed on a table in the laboratory at an approximte tenperature of 68°F, and allowed to dv out so shelling could be done. At the same time, sanples were placed in ovens (Fig. 2) under de- finite tanperatures for different lengths of time. These ovens could be kept at a constant temperature, as thq were electrically heated and thermostat controlled. It was nec- essary to have the temperature quite high in order to suc- cessfully free the corn of its excess moisture immediately. Soft dough and milk samples were left in a temperature of 112°? for eight sen hours while hard dough was left in the sane tenperature for twenty-four hours. The milk stage and soft dough stage were also subjected to a temperature of 95°! for a period of thirty-six hours, which was twice the former period of time. Germination tests were nade in a germinator(Fig.5) after a few months rest period had been given the sanples. In the spring of 1925, the residue of all these samples ,-17- 5‘? 75 it Effie}, 9IIEEEE 231E?!?i Fig. No. 2--Electric ovens used in drying corn samples. Notice electric fan in middle. This is used to force circulation at the inlet of the ovens. Pig. No. 5--Germinator used in making germinati on determinations. Kept at a constant temperature of 22°C. -19- was planted in the field where we could observe our plots in actual Operation under field conditions. The series were planted in triplicate, every fourth plot in each series being a check. In this way soil variation was takai care of as each row was compared to its check which was a standard sample of Duncan seed corn tint had been dried by means of nat- ural outdoor air circulation such as would be obtained in any good seed com drying house without the use of artificial heat. One-hundred and eighty kernels were planted in each plot and the plants counted whal they germinated, thus obtaining a record of the germinability of the seed in the field. All plots were handled and harves- ted in a like manner. The weight and number of the ears were takal. A sanple of ten ears from each plot was stored for the purpose of getting the moisture con- tent and shelling percentage when properly dry. These tel ears were weighed when harvested and re-weighed when shelled for the purpose of obtaining loss in moisture until the test could be made in the moisture tester (Brown Duvel Moisture Tester,Fig. 13). The yields were calculated by bringing all samples to 14% moisture and r. E. calculated on all samples by Bis Bell's modified method . In the fall of 1925, samples of seed corn were again harvested in different stages of maturity accor- ding to classification No. 1. These samples were put ihru the same form of ex- -20- Fig. No. 13--Brown Dureel Moisture Tester used in making moisture determinations. -21- periment as in the former year, but a greater number of different tanperatures were used in the artificial drying. All samples of each stage of maturity were held in temperatures of 90°F, 108°F, 125°r, 144°F,and 161°F for periods of 48 hours, 24 hours and 12 hours. A sample of 10 care was dried at each time and immed- iately after they were taken from the ovens,(Fig. 2) a sample of one ear was obtained, a moisture determin- ation being made on the sample by the Brown Duvel Mois- ture Tester (Fig. 15.)--0ne ear was kept for observa- tion and two ears of each sample were placed in differ- ent storage conditions. These storage conditions were the barn, laboratory, root cellar and greenhouse. Sanples were hung on wire hangers so that there were no ears touching each other. After a period of three months in these varying storage conditions, all samples were brought into the laboratory and hung up together. These were left for a period of one month in order that thq might all reach the same degree of moisture percent,-~The laboratory being approximately 85°F. 6 At the end of one month all samples were shelled and a germination test was made by the laboratory ger- minator(Fig. 5). In making the germination test, two samples of 100 kernels each were taken from each ear. Tests were nade of both ears stored because this was -22- necessary in order to eliminate any ear characteristics that might tend to give one ear more potentiality than another. These sanples were placed between wet blotters as shown in (Fig. 14) with all the kernels placed in a line manner. All kernels were placed so the embryo and was facing the same direction and the embryo side of the kernel was facing upward(Fig. 14). Due to variations of temperature within the germinator, (Fig. 5) samples of each car were placed both in the top portion of the ger- minator and in the bottom porticn of the germinator. Con- trol sanples were placed on every tray, each sanple being of the same variety of corn‘used in the eXperiment that had hem allowed to mature in the field, and had bew stored in a good outside, air circulated, drying house. All sanples were left in ‘lhe germinator for a period of five days. All saxnples upon removal from the germinator were counted for the number of viable and non-viable seeds. For a measure of vigor of the young seedlings, actual measurementsfli‘ig. 16) were made of plumule and radical of each seedling. These seedlings were then classified according to classification No. 11. -25- '9 9 n ovvwfinflnenon '0 90,906 eons. neon none Q o n CQQUBGON 9000.0 "009 0 a a. 0n no new no 9 0d: 0 an ,0. 09000. 9 w e eeeeev v .09.... Q” ...' '0 .0 90.". .. O . ‘0' O .. As '00 0 e 00 ea c O. .0. e C . .0... lo. 0 O 0" . ' ..'. . . '0 . Q '0 "IOC‘COC Q.’ test. P. 6 °r. (a) Hard dough stage (J. R. Duncan's M. A. C. heated 48 hours c 161°F. ) (D) Soft dough stage heat- gh stage heated 12 hours 0 108 ) Milk stage heated 24 hours a 108°? (0) rol sample lacing in germinator for germination A ed for 24 hours 0 108 Hard dou (I) Cont standard variety ‘3 Fig. No. 14--Tray of 100 kernel samples of corn before Fig. No. l5--Trw of 100 kernel samples of corn as shown in Fig. after having been placed in germin- ator Fig. No.5) for a 6 day period. VV -25- No. 11 Classification for seedling vigor. Very Vigorous--Radica1 over 6 centimeters, Plumule l centimeter or over or Plumule over 4 centimeters. Semi Vigorous--Radical between 4 and 6 centimeters, Plumule é'to 1 centimeter, or Plumule 2 to 4 centimeters. Weak --Measurements less than above or any seedling that is without;either a Plumule or a Radical. Dead --No Emergence of both Plumule and Bad- ical. we then assumed that should all kernels be planted of a type similar to the W class trat we could ob- tain a 100% stani everything else being equal. For class V we could obtain a 90% stand and for class W we could obtain a 50% stand. Therefore, we gave the W class the value of 100 for vigor, V class 90 for vigor, W class 50 for vigor, and, of course, D class 0 for vigor. We then divided our total vigor by 100 in order to have it per average seedling. Ebr example, in calculating seedling vigor of a sam- ple of 100 kernels that had bem germinated would be as follows: Class 1 fi cati on Numb or Value Vigor W 59 x 100 _ . 59 00 V 22 x 90 _ 1980 -25- Classification W m 38.2.2 I 19 X 50 - 950 D o x o ___ ‘ Total Visor esso Vigor of average seedling ._ 8850 _ 88 .5 ‘3706 Calculations were nude in a like manner for control samples and their values compared to the sanple being tested by the use of students modified method for calcu- lati on of odds. -27- (I 3(813N In . 4 M u-c ,. "' " , 1 '2‘ Fig. No. l6--Measurirg plumule and radical of germinated kernel after 5 days in the germinator. -28- DISCUSSION OF EXPERIMENTAL DATA All samples which were harvested in 1924 in the immature stage after drying showed a partially wrinkled appearance, cape cially in the milk stage. This was evidently due to the evaporation of high percentage of moisture as found in the immature seed at time of havest. After dlying there was a dark- ed difference in the weight of seed in the milk stage and the seed in the hard dough stage. These weights are shown in Table I. All sanples also showed a de- crease in germinative power when planted in the field compared in the laboratory germination test. This decrease was not consistently increased as the stages of naturity from the hard dolgh stage to the milk stage. were reached. A greater variation, neverthe- less, was found in the germinability of the immature seed than in the nature seed. We do not find, however, direct correlation between the variation in the power to germinate and in the power to yield which results. -29- assess m m chHH m oosucoaen ow ” z . omnsHsmeHob H «HcHn we mHoe " mammc ” emawcumdsue . :chUH Hpuosmdoew m H H» vewoonecz u on u won m 0% «on QmHanmaHos.u H "EmassHmNI wwMHsmv WmsseHm was none . . mmoo osmow 0 H00 4» ma mHsm oH. EH58 H.m mmoH musH.Uosms HHm e - we sense aw sense Hoo me- am a a a H meow . a HHmom . ma . a a Hoo mm mm a a a H mace . . HHmom - we . aw . Hoo ma uH e e . H macs oseow Hoo mm em a a e H meow meme seems amoe - Has a a Hoo «H a» e a a m meow . . meow - ea sense a e Hoo an we a a a H macs . . amew - Has a . Hoo so am a a a H meow aseew Hoo me as a a a H mmom KHHN room i am Sousa m a mo no me a a a H mmHo e HHmoe - Hm sense Hm a so me me a a a H mmHH . amoe - Hoe m e Hoo mm as a a a H mmHm oscew Hoo on em a e a H maHm muse seems HHmoe . me sense a . Hoo me up a e a -H mmHe . a mace . Hoe aw a Hoo mm eH e a . H mmHm . a amoe - Hue » a Hoo . mm mm a a e H mmHm osmow . H00 00 am a a a H mch meme seems HHmem - Hm sessm mp e Hoo so me a a . H maHm . e mace - Hue mm . Hoo mm mm a a a m maHe a a each - Hoe aw . Hoo mm eH . e a m ammo aseew Hoo mH as e a a H mmmH aHHw mace - Hue m . Hoo me He . a a mama . ewes - Hoe Hw 3 H00 mm em a a a m some a HHmom - Hm sense m a mo Ha a e e a meme oseow Hoo on em a e a H mama mesa seems ewes - Hoe er a Hoo me me a a a H mama . e mace - Hoe em a Hoo mH em a a a H some a a each - Has a» 3 H00 as as a a r H mama oscew Hoo em as a a a H mums meme seems macs . era a . Hoo mH me a a a H memo . . mace - Hoe er 3 H00 me as a a a H mmmH . e HHmee - Hm sessm »w 3 H00 mm mm a a e w -mumm oscow Hoo mm 90 a a a meme sHHw mace . Has a a Hoo mm me e a a H meme e area. .. 58 new a H8 3 mm a a a H meme . amps . Hoe m 3 H00 me Hm a a a H mace osoow Hoo we as a a a H 0.... 00...... m‘OQmmmuOfim-QN'ONHQO’ONNQQOOIQ-dQO‘NG‘DdO-IUIO‘Q 00.0.00... 1 l -30- In comparing samples tabulated in Table II which were taken from the yield series in Table I, we will use the mean yield first. The mean yield was obtained by the use of students' method in averaging two, three or more values. We find, however, a higher yield for the soft dough than any other stage of maturity. This comparison was calculated by the use of students' method for determining a difference. 1. Soft Dough mean yield 40 plus-minus .8 Hard Dough mean yield 55,; " .7 Difference 6.8 " 1.0 2. Soft Dough mean yield 40 plus-minus .8 Milk mean yield ' 33,6 " .7 Difference 6.4 " 1.0 3. Soft Dough mean yield 40 plus—minus .8 Check(g1azed)mean yield 55.5 ' .6 Difference 4.5 " 1.0 As the difference, in every case, is greater than.5.5 1 PE, we, therefore, conclude that we have a significantly higher yielder in the Soft Dough Corn than any other stage of mat- uri ty. -31- TABLE 11. Stages Temperature Germination Germination Yield in of of 36 in % in Pounds at Maturity Storage Laboratory Field 14% Moisture Milk 68°F Lab. 100 92 57 plus-minus 2.8 Milk 68°F Lab. 100 65 17 7 .8 Milk 68°F Lab. 100 88 42 7 2.1 Milk 68°F Lab. 100 88 55 7 1.6 Milk 68°F Lab. 100 81 55 7 1.7 Milk 68°F Lab. 100 54 18 7 .9 Mean = Sing-minus .7 Soft Dough 68°F Lab. 100 71 52 plus-minus 2.6 Soft Dough 68°F Lab. 100 76 39 7 1.9 Soft Dough 68°F Lab. 100 92 45 7 2.2 Soft Dough 68°F Lab. 100 85 41 7 2.0 Soft Dough 68°F Lab. 100 91 27 7 1.5 Soft Dough 68°F Lab. 100 96 57 7 1.8 Mean " :gus-minus .81 Hard Dough 68°“. Lab. 100 92 51 plus-minus 1.5 Hard Dough 68°F. Lab. 100 92 39 7 1.9 Hard Dough 68°F. Lab. 100 8'7 24 " 1.2 Hard Dough 68°F. Lab. 100 91 35 7 1.7 Hard Dough 68°F. Lab. 100 97 57 7 1.8 Mean .. gifig-minus .7 -52.. TABLE II. (Continued) Stages Temperature Germination Germination Yield in of of in % in Pounds at Maturity Storage Laboratory Field 14%1Moisture check '0utside Seed House 100 72 57 plus-minus 1.8 Mature Check Mature Outside Seed House 100 88 55 " 1.7 Check Mature Outside Seed House 100 87 57 " 1.8 Check Mature Outside Seed House 100 95 55 " 1.7 Check Mature Outside Seed House 100 90 55 " 1.7 Check Mature Outside Seed House 100 91 54 " 1.6 Mean 55.5 " .6 -53- In comparison of the milk stage mean yields with the hard dough stage and check, we get a somewhat differ- ent result. 1. Milk Stage mean yield 55.6 plus-minus .7 Hard Dough Stage mean yield 55.2 " .7 Difference . .4 " .9 2. Check mean yield 55.5 " .6 Milk Stage mean yield 55.6 " .7 Difference 1.9 " .9 As the difference in each case is not as great as 5.5 X P.E. we, therefore, conclude that there is no difference in the yield. We also find the same result when we compare the hard dough stage to the check. Check (Glazed) 55.5 plus-minus .6 Hard Dough Stage 55.2 " .7 Difference 2.4 " .9 Therefore taking the situation from a mean yield stand- point the soft dough stage of maturity is higher in yield than any other stage in the yield test. We also conclude as far as this eXperiment is concerned that there is no difference in the mean yield of any of the other stages of maturity; i.e. hard dough, milk, glazed. The question immediately rises, "Was the higher yield :offctiough seeddue to the immaturity of the corn?; if so, why was the milk corn not as high ibr higher than the soft dough stage? Taking the resulting yields from.individual yield stand- point, we do have individual plots that had been planted to milk -54.. Fig. No. 4--Showing plate in field after corn was above ground 6 inches high. Where the white stake is plot Ho. 2510 planted with seed that had been harvested in milk sta e and artificially dried for 18 hours at 112°F. lot No. 2509 which is directly to the right is also milk stage seed planted which had been dried for 56 hours at 75°F. Fig. No. 5--Showing plot No. 2522 with.white stake in the dis- tance had been planted to seed that had been har- vested in the milk stage and artificially dried for 18 hours at 1120?. -35- stage seed, yielding considerably higher than any other stage of maturity. Take for example plot No. 2511, Table I, which yielded considerably higher than any other plot in the series, the next highest plot, No. 2518, Table I, yielding 45 plus-minus 2.2. Plot No. 2511 Milk Stage 57 plus-minus 2.8 Plot No. 2518 Soft Dough Stage 45 ' 2.2 Significant Difference l2 " 5.5 Due to the high percentage of moisture in the milk stage. corn seed.it does not withstand storage conditions as well as the more mature corn.Kidd 8: West (l),which would tend to cause the variability in the power of the seed to yield. Even though it failed to withstand the storage as well as the more mature corn, we received equally as good a yield. The soft dough be- ing lower in percentage moisture was able to withstand storage conditions better than the milk stage seed. TABLE III. Results secured with seed com kiln dried at 112°F as compared to air-dried sample (Duncan standard variety) when planted for yield . 1:7 ""v- ‘ ""~"“‘i'h5§" , Fig No. 6--Shcwing plot No.’25l7 which had been planted with seed that had been harvested in the soft dough stage and artificially dried for 18 hrs. . at 112°F. Fig. No. 7--Showing plot No. 2515 which had been planted with seed that had been harvested in the hard dough gtage and artificially dried for 24 hrs. at 112 F. -57- W Time ex- Gcenninatf on Germination Yield in Lbs. Maturity posed to in in c 14% Moisture Temp . Laboratory Fie 1d Milk 18 hrs. 50 25 55 plus-minus 1.6 Milk 18 " 50 15 7 " .55 Mean Yield 20 " .9 Soft Dough 18 7 100 46 24 7 1.2 Soft Dough 18 " 100 85 55 " 1.6 Mean Yield 28 " 1.0 Hard Dough 24 " 100 87 55 " 1.8 Hard Dough 24 " 100 89 52 " 1.6 Mean Yield 55 " 1.2 *Oheck(clazed) Air Dried 100 72 57 7 1.8 *check(clazed) Air Dried 100 88 55 7 1.7 Mean Yield 56 " 1_.__2_ *Check is the air dried SMple of Duncan Corn when planted for yield. students' methods of comparison and a difference must be at least Comparisons in Table III were calculated according to 5.5 X P.E. in order to be significant. 1. Check mean yield 56 plus-minus 1.2 Hard Dough mean yield 55 " 1.2 Difference 5 " 1.9 2. Check mean yield 56 " 1.8 Soft Dough mean yield 28 " SL9. Difference (signifi cant) 8 " 1 . 7 5. Check mean yield 56 " 1.2 Milk mean yield 20 " .9 Difference M (81 gnifi cant ) Fig. No. 8--Showing relative amount of corn produced by plots in yield series. On the left plot No. 2512 which was the check(Duncan standard seed) dried without artificial heat yield 55 plus-minus 1.7 pounds. In the center plot No. 2511, seed used to plant was selected in milk stage with no artificial heat used but stored in laboratory yield 57 plus-minus 1.6 pounds. On the right plot No. 2510 seed used to plant was selected in the milk stage and was arti- ficially dried for 18 hours at 112 F. yield 55 plus- minus 1.6 pounds. We can immediately ob serve that the immature samples showed a significant decrease in yielding ability from that of the check yield. This shows tint they were damaged by that particular drying process. The hard dough stage did not show a significant difference in yielding ability from that of the check, even though it had been exposed to the same temperature as the immature sanples for 6 hours longer. TABLE IV. Results secured with seed corn kiln dried at 95°F when in immature stage as compared to air dried sanples (Duncan standard variety) when planted for yield. Check takal from Table III for comparison. Stage of Time Germination Germination Yield in lbs. Maturity exposed in in 0 14% Moisture to Temp. Labor atogy Field Milk 56 Hours 90 50 24 plusiminus 1.2 Soft Dough 56 ' 100 65 27 " 1.7 Comparisons in Table IV were calculated according to students' method of comparison and a difference must be at least 5.5 X P.E. in order to be significant. 1. Check mean yield 56 plus-minus 1.2 Soft Dough " 27 .‘ " 1.7 Difference(Significant) 9 ' 2.0 2. Check mean yield 56 " 1.2 Milk " " 24 " 1.2 Difference(Significant) 12 7 1.9 -40- 'd'e can, therefore, conclude again that the immature samples were damsged with this particular drying process even though not to such a great extent as in Table III. Possibly if a greater number of plots had been used in this case we would not have had a significant difference in the soft dough stage. -41- ‘ 1 «01.?- .. _,._....-sas..,..r. .88....- --.-:»-e.a.aeaw. .........---e..-.....a.. mam-reassar-wnec .. a. ass-amps... L‘s. mew...- 3 2.6.2.... The loose kernels are a sample of the milk stage corn that had been planted to produce these yield series when planted in the field. ears. Fig. No. 9--Five ears representing plot No. 2554 in the -43- 444.. {$414,941 m1440£3b ,\:Alrl.. , , .. .KYI 44444 23v~s4114o4Y 3;: a 2511 in No. the yield series as type harvested from kernels planted of the milk stage. was the hi ive ears representing plot '7‘ Fig. Ho. lO-- This ghest yielding plot in the ser- The loose kernels are a sample of the kernels planted to produce these ears. ies. -45- v». r. . Snag? \ a... flaws .:.........,;. a 4 - .... .. r :2... 5.5... .8 as 553 5.9.5395. .3 5.355;“. ‘- rr-oncmcrccvl... , sissy. ===§=¢n .a .. «a. w 2519 in the yield series as type of ear harvested from LJOSS kernels corn planted from seed that had been harvest- is a sample of the seed that had been plant- . o N to 08 1%. pas mean he Huse nunsv mmh e t rt Pfe emm med 0 h at? an eim v i dd Vlee _ - l 1 O N Fig. -44- FCHP? ' n ““ mi. | mm .1 “MM'L 2." a {J- ~ Fig. No. 12--Five ears representing plot No. 2506 in the yield series as type of ears harvested from corn planted with seed that had been harvest- ed in the soft dough stage. Loose kernels are a sample of the seed that had been plant- ed to produce these ears 5 Was artificially dried for 56 hours at 95 F. -45- TABLE NO . V. Corn harvested in milk stage, artificially dried and stored in Laboratory Date Treatment Moisture Germ Germ Vigor Vigor Odds after Sample Control Sample Control Treatment Aug.19 aor. 12 Hrs. 66% as 99 as 79.2 4.3-1 Aug.19 90F. 24 " 59% 71 99 46.7 90.8 144 -1 Aug.19 90F. 48 " 55% 16 99 11.1 89.6 624 -1 Table No. V shows When corn is harvested in the milk stage and dried with Artificial Heat at a.Temperature of 90°F for the per- iods of 12 hours, 24 hours, and 48 hours. There is a decrease in Germination power and also in Seedling Vigor as the period of time is increased. It is evident that there has been no dam- age done when the sample is only held for the period of 12 hours by the Odds of 4.3-1, Which is not high enough to shmw a signi- ficant difference from the Control. On the other hand there is a marked difference between the samples that were held for the periods of 24 and 48 hours as compared to their Controls giving Odds of 144-1 and 624-1 reSpectively, which are shgnificmutly high.$howymgkthat there has been.damage done by this particular dry ing pro cess . -45- TABLE NO . VI. Corn harvested in the Soft Dough Stage, artificially dried and stored in the Laboratory. Date Treatment Moisture 'féGerm Germ Vigor Vigor Odds after Sample Control Sample Control F. Hrs. Treatment Sept.2 108°F 12 42% 13 97 7.3 62.3 322-1 Sept.2 108 24 40.3% 56 98 30.0 71.0 23.9-1 Sept.2 108 24 37% 63 97 41.5 51.6 6.7-1 Aug.29 125 12 42.3% 84 98 60.0 60.0 1.29-1 Aug.29 126 24 13% 39 100 17.3 93.7 322-1 Aug.29 125 48 11.2% 15 99 6.0 94.8 9999-1 Sept.5 144 12 32% 41 99 13.3 81.9 624-1 Table No. VI shows When corn is harvested in the Soft Dough stage and dried with Artificial Heat at a temperature of 108 degrees F. for the periods of 12, 24 and 48 hours, that there is an increase in the Germination and also in the Seedling Vigor in the sample as the length of the period of eXposure to that particular temper- ature is increased. This was evidently caused by molds as they were more abundant in the 12 hour and 24 hour than in the 48 hour period. Therefore, damage has been caused by this particular pro- cess in the 12 hour and 24 hour period when exposed to 108°? as the Odds are significantly high gheting a difference from the Control. This is not apparent, however, in the 48 hour period as the Odds which are 6.7-1, which are significantly low enough that there is no difference from the Control. When the corn.was orposed to 125°F'f0r the period of 12 hours, 24 hours, and 48 hours we notice a decrease in the Germination.power and Seedling Vigor in the sample as the period of time of eXposure increases. -47- When the corn was left in the heat of 125°F’for 12 hours, there was no difference in Germination Power or Seedling Vigor from that of the Control according to the Odds 1.29-1 which are not high enough to show a significant difference. In the case of the 24 hour and 48 hour periods at 125°F the Odds 522-1 and 9999-1 are high and therefore show a signifi- cant difference from the Control giving evidmce of a deter- ioration in vitality. Although we got a Germination and Seedling Vigor result when the samples were dried at 144% for 12 hours and stored in the Laboratory, the Odds were so high that a significant difference from the Control was the result, thus showing great damage was done from this parti- cular process of drying. The sanples dried at 144°3'ror the periods of 24 hours and 48 hours did not show any germination so were evidently killed. for 12, 24 and 48 hour periods. Table N0. m Com Harvested in the Hard Dough stage, artificially dried and stored in the Laboratory. This was also the case for the temperature of 161°F Date Treatment Moisture 35 Germination Vigor Temp. after P Hrs. Treatment Sample ControlSalee Control Odds Sept.16 90 12 38% 99 99 93.3 93.6 1.29-1 Sept.16 90 24 36.2% 99 99 93.7 93.3 1.29-1 Sept.16 90 48 19.5% 99 99 67.9 96.1 20.3-1 Sept.14 108 12 36.3% 88 99 82.9 98.9 20.3-1 Sept.14 108 24 25.9% 37 99 44.4 92.9 61.9-1 Sept.14 108 48 14% 95 98 82.9 95.6 14.5-1 -48- Table No. VII shows when corn is harvested in the Hard Dough stage and dried with Artificial Heat at a temperature of 90? for 12 hours, 24 hours and 48 hours and stored in the Laboratory, that it is equal- ly as good in Gernnnative Power and Seedling Vigor as the Control, the Odds being 1.29-1 and 20.3-1, which are too low to show any significant difference from the Control. In the case of the samples which were dried at 125F for the periods of’l2 hours, 24 hours, and 48 hours, one sample showed a difference from the Control, this being the sample dried at 1253' for 24 hours, with Odds of 61.9-1 which were 111511.: 12.. The samples dried at the same temperature but for the periods of 12 hours and 48 hours show no difference from their controls. All samples dried at 1253‘, 1443‘ and 161 failed to show any germination. -49- TABLE NO.VIII. Corn harvested in the Milk Stage, artificially dried and stored in the Barn Date Treatment moisture Germination Vigor Odds Trzgtmgnt Sample Contr61* Sample Control Aug.19 90F. 12 Hrs. 66% 39 98 31.3 98.4 118-1 Aug.19 902. 24 Hrs. 54% 12 98 9.3 97.4 9999-1 Aug.19 N0.Treatment 84.5% 42 99 30.9 99.1 54.9-1 Table No. VIII shows that of all the samples which were artifically dried at 90F, 108E, 125F, 144?, and 161E for 12 hours, 24 hours and 48 hours, there‘were only two samples, 90? at 12 hours and 24 hours that germinated. The Odds were so high that it shows that these samples were damaged by the storage in the barn, because the corn that had the same treatment and stored in the Laboratory gave good results, according to Table No.V. TABLE No.11. Corn harvested in the Soft Dough stage, artificially dried and stored in the Barn Date Treatment Moisture Germination Vigor after Treatment Sampie COntrol Simple Control Odds Sept.2 108E lzhrs. 42% 26 97 21.9 98.5 1999-1 Sept.2 108? 24Hrs. 40.2% 94 97 86.7 98.1 34.5-1 Sept.2 108E 48Hrs. 37% 88 100 71.1 99.1 23.9-1 Aug.29 1253 lZHrs. 43.3% 44 99 40.9 99.7 4999-1 Aug.29 125s 24Hrs. 13% 60 99 49.8 98.0 131-1 -50- Table No. IX snows when corn.is harvested in the Soft Dough Stage and stored in the barn, that although.we get a higher germination and vigor result than in Table No. V1. we have damage done to our samples shown by the Odds, which are so high that they show a significant difference from the Con- trol. This difference indicates damage done by this parti- cular drying and storage pnacess. All samples dried at 125E for 48 hours and.144F, 161E for 12 hours, 24 hours and 48 hours, were totally destroyed.and failed to germinate in each case as a result of this process. TABLE NO. x. Corn harvested in the Hard Dough stage, artificially \ dried and stored in the barn Date Treatment Moisture Germination Vigor ‘ after ’ Treatment Sample Control Sample Control Odds Sept.16 903 12Hrs. 38% 95 98 74.1 73.6 6.7-1 Sept.16 903 24Hrs. 36.2% 100 98 97.6 94.6 10-1 Sept.16 902 48Hrs.‘ 19.5% 99 99 90.7 94.5 98.3-1 Sept.14 108E l2Hrs. 36.3% 78 99 71.6 99.1 108-1 Sept.14 1082 24Hrs. 25.9% 71 99 63.4 97.7 118-1 qut.14 108E 48Hrs. 14.0% 74 98 72.5 96.3 10-1 sept.14 1253 12Hrs. 23% 6 99 4.1 99.0 9999-1 Sept.14 125F 48Hrs. 8% 13 99 11.2 98.2 9999-1 Sept.16 144p 12Hrs. 18% 14 97 12.1 97.7 9999-1 Sept.16 Ho Heat Treatment 100 99 99 99 1.66-1 Table No..l shows that corn harvested in the Hard Dough stage and stored in the barn without any artificial drying, gave bet- ter results than corn.artificially dried, as it gave practically -51- perfect germination and vigor results with Odds 1.66-1, which are so low'that it is very significant that there is no difference from the Control. 3.th the Temperature of 903' is used we have a decrease in vigor whai eacposed for 48 hours, although the germin- ation results are perfect, the Odds are too high, thus showmémage done by that particular drying process. In the case, however, of the 12 hours and 24 hours we have no difference from the Control according to the Odds 6.7-1 and 10-1. Possibly this was due to the permeability of the seed-coat and the heat did not have time to penetrate to the inner layers of the kernel and whereforedid’netzdlsturb the enzymes and cell structures. When the temperature of 108}? was used only the 48 hour period gave good results showing no difference from the Control by the Odds of 10-1. The other two periods of time, 12 hours and.24 hours, show a significant differ- ence from the Control by the Odds of 108-1 and 118-1 res- pectively. This was possibly due to an evaporation of the moisture into steam within.the kernel, but due to the impermeability of the seed cost in this stage of maturity, all of the stean failed to be liberated and we have an activation of the Enzymes Which are later des- troyed by the extreme ccmditi one of the barn storage. In the remainder of the Table we have some samples giving a smell germination and vigor result but the Odds are so very high that they show a significant difference from -52- the Control as the result of the damage done by the drying process used in this case. The samples dried at 1253' for 24 hours and 1443‘, 1613' for 12 hours, 24 hours,and 48 hours, failed to germin- ate. -53- TABLE NO. 11. Corn.harvested in the Milk Stage, artificially dried and stored in the Greenhouse Date Treatment Moisture Germination Vigor after Treatment Sample Control Sample—ControT'Odds Aug.l9 90? 12Hrs. 66% 78 97 62.8 95 131-1 Aug.19 909 24Hrs. 59% 1 100 .5 95.7 9999-1 Aug.19 90? 48Hrs. 55% 18 100 15 93.3 9999-1 Table No. XI shows when corn is harvested in the Milk stage and stored in the Greenhouse that all the sanples were destroy- ed by this process, giving a low germination and vigor result with Odds 131-1, 9999-1, and 9999-1, Which are all very signi- ficantly high, thus proving them different from the Control. The remainder of the samples which were dried at 108?, 125?, 144?, and 161E at 12 hours, 24 hours, and 48 hours, gave no gerndnation and showed no seedling vigor. TABLE NO.XII. Corn harvested in the Soft Dough stage, artificially dried and stored in the Greenhouse Date. Treatment Moisture Germination Vigor after Treatment Sample Control Sample Control Odds Sept.14 108F 12Hrs. 42% 39 100 8.8 91.1 172-1 Sept.14 108F 24Hrs. 40.2% 97 99 86.8 90.6 10-1 Sept.14 108? 48Hrs. 37% 32 99 21.7 86.2 624-1 Table No. III shows when corn is harvested in the Soft Dough stage, artificially dried and stored in the Greenhouse it be- -54- comes very moldy, giving out of all the samples when dried at 108E, 125E, 144? and 161F for 12 hours, 24 hours and 48 hours, only one sample that was not damaged by this process, this one being 108? for 24 hours, with Odds 10-1 which are not high enough to show a significant difference from the Control. -55- TABLE NO .XIII . Corn harvested in the Hard Dough stage, artificially dried and stored in the Greenhouse Date Treatment Moisture Germination Vigor after 1 Treatment Sample Control Sample Control Odds Sept.16 90? 12Hrs. 38% 98 97 79.6 85.5 32.2-1 Sept.16 90F 24Hrs. 36.2% 99 98 88.1 90.2 1.9-1 Sept.16 aor 48Hrs. 19.5% 100 99 84.7 85.7 8.22-1 Sept.14 108? 12Hrs. 36.3% 93 99 86.5 96.5 118-1 sept.14 108? 24Hrs. 25.9% 76 99 74.6 97.0 1249-1 sept.14 108s 48Hrs. 14% 72 99 65.5 97.4 999-1 Sept.l4 No Treatment 96 99 83.4 97.4 10-1 Table No. XIII shows when corn.is harvested in the Hard Dough stage, artificially dried, and stored in the Greenhouse, it will give equally as good results when certain tauperatures are used as when stored without drying, in fact, gives better results ac- cording to this data. When the temperature 9015‘ is used for the period of either 24 hours or 48 hours we get equally as good.a germination and vigor result as the Control, thus showing no damage done by the drying and storage used in this case. With the same tenperature, however, but only an exposure of 12 hours, we do not get as good results as in the former case, but rather have Odds which are so high that they show a significant dif- ference from the Control. This is due to the molds which.were quite obvious in this case. The temperature 108? is used also in this table, but the Odds are so high that they show a marked difference from.the Control, indicating damage done by the stor- age. By the tenperatures 125F, 144F, and 161? for 12 hours,24 O hours and 48 hours, we do not get any germination what- soevere With the corn stored without any artificial heat treat- ment we get results equally as good as the Control. Fill/f Fig. No. 17--Good kerne1(1ei’t) versus destroyed kernel (right) with the use of too high temperature. -58- TABLE NO .XIV. Corn rmrvested in the Milk Stage, artificially dried stored in the Cellar. Only one ear of each survived, so no Odds calculated Date Treatment Moisture Germination Vigor after Treatment Sample Control Sample Control Odds Aug.19 902 12Hrs. ,66% 100 96 90.4 94.9 0 Aug.l9 902 24Hrs. 59% 16 100 11.2 99.5 0 Aug.19 90F 48Hra. 55% 96 100 95.6 96.1 0 Aug.19 No heat treatment 8 96 8.0 94.9 0 Table No. XIV does not show very much because only one ear of each survived the storage conditions, therefore, no Odds could be calculated and the results are not very dependable. By mere observation it appears that the corn artificially cured at 90! gave considerably better results than the corn that had no heat treatment at harvest. All sanples that were stored in the Cel- lar showed an abundance of Mold as a result of the damp condi- tions and the lack of circulation when stored in an unheated Cellar. These were the only samples tint survived the condi- tions out of thirty sanples stored which had been treated 90F, 108E, 126?, 144? and 1613' for the periods of 12 hours, 24 hours, and 48 hours. TABLE NO.XV. Corn harvested in the Soft Dough stage, artificially dried and stored in the Cellar Date Treatment Moisture Germination Vigor after Treatment Sample Controf Sample ControT Odds EEpt.2 108? 24Hrs. 40.2% 88 100 83.6 96.1 0 Table No. IV shows that corn that had been artificially dried at 903', 1083', 1251', 1443' and 1613‘ at 12 hours, 24 hours, and 48 hours, there was only one ear survived the storage. This sample also shows damage by this treatment. Molds were very abundant in all sanples. TABLE NOJVI. Corn when harvested in the Hard Dough stage, artifi- cially dried and stored in the Cellar. Date Treatment Moisture Germination Vigor after Treatment Tample Control Sample Control Odds Sept.16 908 lZHrs. 38% 92 97 87.3 96.4 17-1 Sept.16 908 24Hrs. 36.2% 100 98 94.4 95.5 10-1 Sept.16 903 488rs. , 19.5% 96 98 80.2 95.5 10-1 Sept.l4 108F 18Hr8. 36.3% 100 100 99.2 96.1 10-1 qut.l4 1088 24Hrs. 25.9% 24 100 16.9 96.1 999-1 Sept.l4 1088 48Hrs. 14.0% 56 100 49.0 97.8 37-1 Table No.1VI shows all the samples were able to withstand the storage conditions of the Cellar except the samples that had been dried at 1083' for 24 hours and 48 hours. The remainder of the samples shown in the Table show no difference in ger- minative power and Seedling Vigor from that of the Control as indicated by the Odds which are so low that there is no signi- ficant difference. The remainder of the samples dried at 1259‘, 144]? and 1611‘ for 12 hours, 24 hours and 48 hours failed to give any Germination results, when stored in the Cellar. CATALASE ACTIVITY Catalase is an Enzyme which is capable of Splitting Hydrogen Peroxide (3202) into Oxygen (O) and Water (320). It is found in practically all living matter according to Loew (20). It is found in Germinating Seeds to a great extent. For the purpose of determining whether or not the Seeds that were harvested in an immature stage of mat- urity, and also those that were treated with different temperatures, differed from the seed that was mature and dried by natural air circulation, we performed a short eXperiment. Heinicke’s water diaplacanent method as des- cribed in Cornell Memoir.No. 62 was used in the experiment. A constant water bath was used where the temperature could be kept within 1°C. Hydrogen Peroxide, and which was neu- tralized with Sodium Carbonate. The seeds were ground up so they could be passed thru a 100 mesh seive. Two grams of the powdered material was placed in one side of the Y tube and 5 cc. of Hydrogen Per- oxide in the other. This tube was placed in the water bath and left for 5 minutes until it came to the temperature of the bath which was at 35°C. After this period the stirring began which brought the seed powder in contact with the Hy- drogen Peroxide and thus the activation began. The dis- placement of the water was then recorded in cubic centi- meters, a count being made at the end of the period of 6 minut es . -61- Fig. 18--Apparatus used in making Catalase Activity determinations. Notice the Heinicke water displacemnt apparatus on the Left. -52- TABLE N 0 .XVII . Catalase Activity of corn sanples that have been treated with Heat, compared to the Control which was dried with natural air circulation.without any artificial drying. Stage of Maturity Treatment of Sample Germination Activity Milk Stage 90°F for 24 hours 71% 10.0 cc Milk Stage 108°]? for 48 hours 0 9.2 cc Milk Stage 125°F for 24 hours 0 8.1 cc Milk Stage 161°F for 48 hours 0 6.0 cc Milk Stage No Heat Treatment 99% 9.5 cc Hard Dough Stage 90°F for 24 hours 99%; 6.0 cc Hard Dough Stage 12538 for 24 hours 0 5.2 00 Hard Dougi Stage 144 F for 48 hours 0 5.0500 Hard Dough Stage 161°}? for 48 hours 0 5.0500 Hard Dough Stage No Heat Treatment 99% 4.4 cc Catalase Activity as expressed in Table No. XVIII shows a higher activity throughout in the Immature Seed than in the more Mature Seed. There seems to be no Correlation between the Catalase Activity and the Germination of the Seed. It is noticed that even when the Seed failed to Germinate there was still a Cat- alase Activity result greater than the more mature corn. There is a decrease in Catalase Activity as the Temper- ature of the Heat is increased. This decrease is more rapid in the case of the Immature Seed possibly due to the thickness of the Seed-Coat, which would be thinner and more permeable than thatfthe Mature Seed and thus allow the heat to penetrate more readily When Drying. As it was quite evident that the Catalase Activity was -53- not affected to any very great extent, further research was considered unnecessary so far as this Experiment was concerned. 1. 2. 6. 7. 8. -64- - CONCLUS ION- Immature seed corn yields higher than mature seed corn. There is no correlation between the variation in the power to germinate and the resulting yield. There is greater variation in the germinability of the immature seed than in the mature seed. Seed in the Soft Dough stage when natural air dried gives a higher yield than either Milk stage seed or Hard Dough stage seed. Milk stage seed does not withstand storage when natural air dried as well as either seed in the Soft Dough or Hard Dough stages, therefore, when planted in the field it does not give as high a germination as mature seed. The earlier the stage of maturity ani the higher the tanperature when drying the greaterphleoss in germina- tion. Soft Dough stage and Milk stage seedskai lamina vim- ing ability dried with temperature of 112°? for 18 hours, whereas Hard Dough stage seed is not affected by an ex- posure to the same tanpe rature for 24 hours. Corn harvested in the immature stages of maturity and dried slowly in a moderate temperature (68°F) will re- tain its germinability and yield equally as well as mat- ure corn dried in any good seed corn dryirg house with- out the use of artificial heat. Corn harvested in the milk stage and dried moderately at 90°F for 12 hours and stored in the 1aboretory(68°r) -65- will give equally as good a germination percent and show sgtrongd vitality as corn harvest ed in the nature stage and dried by mtural air drying. 10. Corn harvested in the Milk stage and dried at 90°F, 108°r, 125°F, 144°r, 161% for the period of 12, 24 and 48 hours and stored in the gremhouse, barn or root cellar shows a decrease in viability. 11. Com harvested in the milk stage and artificially dried at 90°F for 24 and 48 hours at 108°r, 125°r, 144°r and 161°]? for 12, 24 and 48 hours and stored in the laboratoiy(68°r) is lowered in viability as the temperature is increased. 12. Corn harvested in the soft dough stage and artifi- cially dried at 108°}? for 24 hours and 125 or for 12 hours aid stored in the laboratory showed equal- 1y as good in viability of seedling as mature corn dried by natural air drying. This holds true for corn dried at 108°? for 24 hours and stored in the greenhouse.- 13. Corn harvested in the soft dougi stage and artifi- cially dried at 90°F, 108°F, 125°1v, 144°r, and 161°? for 12 hours, 24 hours and 48 hours, stored in the cellar or barn will be damged and therefore not be as viable as mature seed dried by natural air dry- ing. 14. Corn mrvested in the soft dough stage and artifi- ci ally dried at 108°F. for 12’ and 24 hours. 125°? 15. 16. 17. 18. ~66- for 24 hours, 48 hours and at 144°F, 161°F, for 12, 24 and 48 hours, stored in the laboratory will be damaged and, therefore, it will not give as good results as mamre corn, naturally air dried. Corn harvested in the soft dough and artificially dried at 108°F for 12 hours and 48 hours, 125°F, 144°F and 161°F for 12, 24 and 48 hours and stored in the green- house will be damaged and, therefore, lowered in via- biliw and vitality. Corn harvested in tne hard dough stage and artificial- ly dried at 90°F for 12 hours, 24 hours and 48 hours, 108°}? for 12 hours aid 48 hours and stored in the lab- oratory, dried at 90°F for 12 hours, 24 hours, or 48 hours and stored in the greenhouse, dried at 90°F for 12, 24 and 48 hours, and stored in the cellar gives equally as good results as mature wrn naturally air dried, thus showing no damage done by these drying processes. Corn Iarvested in the hard dough stage and artificially dried at 10898 flir 24 hours, 125°F, 144°? and 161°F for 12, 24 and 48 hours, dried at 108°F, 125°F, 144°F and 161°? for 12, 24 and 48 hours stored in the cellar; dried at 90°F for 48 hours, 108°}? for 12 and. 24 hours, 125°F, 144°}? and 161°F for 12, 24 and 48 hours, stored in the barn, all showed damage done by the process of drying and thus were lowered in vitality and viability. All other methods of drying with the hard dough stage other than those shown above showed evidence of damage. 19. 20. 21. 22. 23. 24. -57- Corn harvested in the hard dough stage, artificially dried at 108°F for 24 hours, stored in.the laboratory, greenhouse, barn and cellar Showed evidence of damage and thus must be a critical period in.the drying pro— cess. Laboratory stored samples after artificial.i drying was used showed evidence of better results than barn, greenhouse orcellar stored samples. Samples stored in.the greenhouse and cellar show dame age by mold more readily than samples stored in the laboratory or barn. Good circulation of air is necessary in artificial drying of seed corn. Catalase activity is not affected by the degrees of heat used in 0118 experiment. Catalase activity is greater in immature seeds than in mature seeds. 1. 2. 3. 4. 5. 6. -43. BIBLIOGRAPHY Kidd, F. and West C. The potentiality of the seed as influenced by the time of harvest. 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