| | | | | ll | | | til | || CO— GIN ARO | | | THS | LIBRARY Michigan State University MSU LIBRARIES a — RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date Stamped below. Le SOME POLLINATION STUDIES. Since Darwin announced in 1°62? his law that Nature abhors perpetual self-fertilization, more interest has centered on pollination work, We find many other more remarkable characteristics in plants than even Darwin dared to announce, The investigation of the various effects of | cross pollination, improvement of varieties through ‘known ancestorage, the planting of varieties be- cause of pre patesy of one variety over another, the increased productivity of certain plants and certain parts of plants as increased fibre, increased prain production and increased hardiness, have all brought forth other questions for investigation, Among these questions are those relating to the effect of certain acts in the methods of polli- nation, and the time of performing some of these operations, The primary purposes of the investigations re- corded herein are to determine: list - The best method of emasculation of the blossom, 2nd - The best time for the application of the pollen to the stigma of the emasculated blossom, Of secondary imrortarnce 103917 | “THE< i. -°. the question as to whether a pistil will produce a fruit without the intervention of the male element, through the influence of mechanical irritation or application of some substance other than nollen, This work was planned by Prof, S. W. Fletcher and A. T. Stevens, and executed by A, T. Stevens as- sisted by Moses Craip, at the Michigan Apricultural College in the season of 1907, The fruits selected to work uron were Rartlett pears, Northern Svny anples and YWontmorency cherry, The pear trees were all of about the same age, all had the same cultivation, and all had nractically the same condition of soil, air, and water drainage, and and were healthy, vigorous trees, Part Qne:- Methods of Emasculation. On Saturday, May 18th, I emasculated 910 blossoms, following three methods, In division A, 3805 blossoms were emasculated by cutting just above the ovary, into the nectaries, and sacked with cloth sacks, In divi- Sion B, 300 blossoms were emasculated by cutting just above the point of insertion and sacked with cloth sacks, UA In diviston C, 305 blossoms were emasculated by pulling off the anthers with tweezers, thus doing no cuttingof the blossom, These were also sacked with cloth sacks. All the blossoms of these three divisions were asc nearly in the same condition of develorment; viz., the pink, as could possibly be selected, The Weather Conditions. The day on which the emasculation was done, was warm and pleasart, Many insects were flying about the trees, None of the buds on the pear trees were yet oren, On the Nonday following the weather had changed to very cold and windy. Some rain had fallen in the time intervening and the cloth sacks had become con- Siderably twisted, Pollination = All the stipmas which rematned in condition were pollinated with Anjou rollen on May °3, five days. following emasculation, Whether because of severe cold and rain, or because of the chaf ing of the sacks against the pistils, while awaiting their rnrorer development, I cannot say, however few ristils remaired uninjured, Those remaining uniniured were in the dest of candition for reception of rollen, On June 4th, I removed the sacks and found only a few fruits developing, Wany fruits had nade no develon- ment whatever, some had partially develoned and withered, Those developing were not so larpre as those untreated on the same tree, The results might be represented in the following wy tabular statement so far as can be accounted for, Division A. Number Number Fruits de- Number Number ¥ruits de- Emascu=- Pollin= veloned and Fmascu=- Pollin= veloned and lated. ated. collected lated. ated, collected Sent .4&, 1907, Sent ,F,j0°",. 3 4 One poor frost 5 0 No fruit. belted nubbin, o 4 One larre re- puler pear, 5 p " " 5 Zz One small, 5 z " " frost belted, distorted pear. o e One large, re- 5 4 " t pular rear, 10 2 One larre, re- 5 Z ft " pular pear, 9 6 One medium, 5 9 i" " Slightly irre- rular rear, 4 4 One small, ire 5 0 " " rerular scabby pear, o 3 No fruit. 5 4 " " oS z " tt 4 0 " o 5 9 " " 11 9 " " o 5 " " 5 0 " " 5 3 " tt 14 14 * '" 5 1 " "" Fe) 4 " " 5 4 t" " 5 4 tt 1" E 4 tt # =| O " " 6 4 iT) E 4 4 % t" t 9 9 " " 2 0 " " 6 5 "" " Thirty-nine were on a limb which had been broken off, This leaves 54 of the original number unaccounted for and must have been destroyed by teams working around the trees or labels destroyed in some manner, As will be seen by the table this matured seven nears, These seven pears weirhed 19 ounces, -5- Of the ®50 blossoms which were emasculated and accounted for, only 1°90 were nollinated, The 120° tren were either broken off by winds or destroved by the Cloth sacks or killed by freezing. It can readily be seen that in the event of cold weather, the cloth sacks would be of little or no nrotection, Of the seven fruits which matured, three were Jarre and of typical form; three showed what we termed frost belts and were otherwise inferior fruits, One was of medium grade, Division B, In this the cut was made above the point of insertion and sacked with cloth sacks, on the Sane tree as division A, Division B. Number Number Fruits de- Number Number Tollin-Fruits 3 Emascu= Pollinated veloned and "mascue ated, velored lated, collected lated, and col- Sent. 6. ~Tected sert. &, 5 4 No fruit 5 4 | No fruit 5 % "7 + 5 Zz a | " 5 4 ve UY 5 4 7] ) 5 4 iT 9 5 @) e " 5 4 "" " 5 2 " " 5 z iT) " 5 4 ¢ t 5 0 it] "7 5 z ee "" 5 4 " " 5 mR a] " 5 4 iT et 6 5 * " 5 @ iT eE 0 i] ¢ 5 4 9 et 4 9 * "" 4 1 _s - P One larre fine near, 4 2 " " 3 - One, one- sided near (Rested on : branch). 9 7 " " z - Two frost belted rea -6- Number Number Number Number Number Number fruits Emascu- Polline fruits Pmascu= Pollin=e- collected, lated, ated, collect=- lated. ated, ed, oe _ _ oe 15 11 “No fruit 5 2" One large frost 7 4 " " belted near, 16 13 of 5 Oné Jarpe, slirht- 4 3 _ ly irrepular rear, 10 1 " " 5 P One fair sized, 7 2 " " frost belted, 16 0 " " slightly irre- 4 " " : pular near, 3 noon 5 2 One slightly 4 " " trrerular, frost 0 tt . belted near, 0 "ON 7 5 One larre, irre- ooo oo polar near, The table shows nine nears develoned and collected, weirhing a total of 35 ounces, We have’ only °’69 of the 200 blossoms emasculated accounted for by the table, Of this number only 141 were pollinated, leaving 178 which were in some manner cestroy- ed, either by frost, sacks, or broken off, “rom the 141 pollinated, only 9 fruits were collected Sert,. €. Of this number only two were of rood size ard refulars one was large but frost injured, one larre but slirhtly irre- gular, while the remainder were more or less irrefrular, Division ¢. Of the 305 emasculated by nulling off anthers, 1°1 were on the same tree as those of A & B, and °94 were on a tree opposite in the next row. This tree was in all respects about the same as the other tree, Cloth sacks were also used on these, -7— The results of tris division are not easily rresented in tabular form, Twenty sacks containing 100 clusters ana 197 flowers, had no fruit, Qne sack, with six blossoms emasculated, and four rollinated, nrocuced one rear} another sack with Ff emasculated, and five rollinated, produced one fine rear$3 while another sack with & emas- culated, hed only one of the six pollinated, and nroduced one large frost belted near, We then have from the 305 blossoms emasculated in Division C, only ?15 accounted for, and but few of these pollinated, The nroduct being three nears, weiphing 14 ounces, I cannot see from these results that any rarticular influence is shown by any one method of emasculation, The only influence nossible would be in favor or the medium heiphnt cut, even in vreference to rulling off the anthers, Nine-huncred-sixteen Bartlett near blossoms, in the pink, were emasculated by cutting just above the roint of insertion, This was done on May 0, 1907, Division A. Three huncred fifteen of these were pollinated at once with Anjou nollen, by cutting blossoms from an Anjou tree and dabbing the anthers apainst the pistils of the emasculated blossoms, The blossoms were Qn then sacked with cloth sacks, The remaining Ff 1 blossoms were divided into two lots and sacked with cloth sarks, The weather on this date was very cold for the blocsoming reriod, No insects were observed flying about the trees, Livision B. On May end, the second 390 of these pistils were pollinated in the same manner as were the first and the sacks replaced, The weather on this date was cold, and a misty like rain was falling, The nistils in these sacks were found much injured, Probably not more than 1/4 were good, This might have resulted from severe cold, or handling blossoms when cold, or from the rubbing of the cloth sacks, It may be noted here that 95 of these blossoms were on another tree than the first 315. There was no apparent difference in the trees, Pivision ¢. The last 301 were pollinated May P4th, four days after emasculation, The nollen was applied in the same manner aS in the preceding two, The nollen was taken from the same tree as that of the two preceding. The pistils, that were left, were all well matured, Some were a little brownish in anpearance, but rollen adhered to them readily. On this date the weather was warm, The nectaries were well filled with nectar, May bees were on the wing. These blossoms were on the same tree -9- as the last 95 of division B, experiment No, °. When the sacks were removed, from these June 4th, two hundred thirty-five pollinations were accounted for in division A, and only 16 fruits had begun develonvment. On September 6th the fruits were collected and only 11 were then accounted for and were described by Mr, Moses Craig, who collected them,as follows: One One One One One One One One One One One The medium pear frost injured. small frost belted pear. small regular pear, fair sized, nearly regular pear, small frost injured pear, fair sized, frost belted, regular near, small frost belted pear, fair sized, slightly irregular, frost injured near. small, regular, pear, medium sized, regular pear, small regular pear, total weight of the eleven pears was 20 ounces, In Division No, 2, B, when the sacks were removed June 4th, 296 pollinations were accounted for, and only 58 fruits were developing. September 6th, seven fruits were collected and de- scribed as follows: One small regular pear, One small regular pear, One regular pear, One -10- small, slightly irregular, frost injured pear. One medium sized, regular pear, One The small, dead, pear on a dead branch. total weight of the seven pears was ?1 ounces, Division Ne._<. G. on June 4th, when the sacks were removed, nearly all the blossoms which had been emasculated, had also been pollinated and many of the fruits were developing. Sept, 6th, 27 pears were picked and described as follows: One One One One One One One One One One One One One One One One frost belted rear. small pear, medium pear, small, irregular pear, small, one-sided pear, nearly regular pear. small, frost belted pear. small, frost belted pear, small, frost injured pear, Small pear. pear, regular pear, large, frost belted pear, fairly regular pear, one-sided pear, one-sided, frost injured rear, One, one-sided, frost injured pear. One medium, regular pear, -)1- One very small, regular pear. One frost injured pear. One regular vear. One regular near, One fairly regular pear. One frost belted near. One regular pear, One medium sized, regular vear, One slightly distorted, medium sized pear, The total weight of the 27 vears was 55 ounces, These figures would indicate that the later polli- nation was somewhat more successful than the earlier ones, There are so many unusual factors, however, which enter into this that I should not care to accent these results as final, These same investigations were duplicated on the apple, A Nothern Spy tree, about 40 years old, but apparently in good health, was used for the female parent. Division A. On May 28th, after a bright cold night, of freezing temperature, S03 blossoms were emasculated by cutting in- to the nectaries, and sacked with yellow manilla paver sacks, These were pollinated June 1st, with Baldwin pollen, The pistils were found in good condition, save a few which had been broken in the process of handling. On the day of pollination, there was plenty of nectar, though the weather was cool and cloudy, Rain followed -1]?P- in the afternoon, On June 17th the sacks were removed and all the fruits were found dead and undeveloped, No. ts 8. May 28th, three-hundred-one blossoms were emascu- lated by cutting just above the insertion of the stamens, then cutting the filaments, These were sacked with the same kind of paper sacks as in No, l, A, June ist, these were pollinated with Baldwin pollen from the same tree as in l, A. The pistils were in good cgéndittion, Very few had been broken in handling. When the sacks were removed, June 17th, all the fruits were dead and dried, There had been no develonment, Now ds Ce, On the same date as the preceding two and with blossoms in the same condition, viz., the pink, 300 blossoms were emasculated by opening the petals and null- ing off anthers with small tweezers, These were then sacked with paper sacks, June lst, these were pollinated with Baldwin pollen from the same source as the previous two. The pistils were in unusually good condition, When these sacks were removed, June 17th, all fruits were found dead with no indication of development, The very fact, that of this more than 900 blossoms, not one fruit had developed, would lead one to believe something must be wrong with the pollen, The pollen had been examined with a microscope, and to all aprneare -13- ances, waS normal and healthy. So far as determining the relative value of the different positions of making the emasculation, these results are valueless, It may be noted, however, that though the night preceding this work was cold, even to freezing, anc while very severe storms of wind and rain took place within the four days intervening emasculatiton and pollination, few pistils were injured, The sacks withstood the storms well, and very few were torn away, Experiment No, 2 of the apple was the duplicate of No, 2 on the pear, The work was performed on the same Spy tree as mentioned in No, 1. The blossoms were all in the pink, The work of emasculation was done by the assistance of three stucents, All were emasculated by twisting off anthers with smajl tweezers, All were sack- ed with the same kind of paper sacks used in No, 1, The work of emasculation was done May 29th, My notes show the weather was warm , Many insects were flying. Nine hundred fifteen blossoms were emasculated anddivided into three divisions, visi ; Three hundred three were pollinated at the time of emasculation, with R. I. Greening potten,. which had been secured from the same orchard as had been the Balcwin pollen, and from a tree opnosite the Raldwin tree, When the sacks were removed, June 17th, only 235 blossoms could ~14- be accounted for, Teams working under the trees may have broken some which hung low, Of the number saved, lf were developing fruit. The final reports show no fruits from this pollination, as for some rezson the branch contain- ing the blossoms died, No, c, B. June lst, $03 9° the blossoms which had been emascu- lated May 29th, and sacked, were pollinated with R. I. Greening pollen, T he pistils were found in excellent condition, Nectar was plentiful, though the weather was cool anc cloudy, No insects were flying. When the sacks were removed, June 17th, I found 88 fruits developing, These were not so large as the fruits outside, throughout the tree, This was no doubt due to the shade of the colored sacks and the partial shutting off of air by them, The total number of fruits matured from this division was seven which weighed 26 ounces, They were described es follows: One sack, 10 pollinated, and produced ore medium sized apple, ‘In another sack 13 were pollinated and pave one mediur Sized fruit. In the third, 12 were pollinated and two small apples matured. In a fourth sack 10 were pollinated and one medium sized arple resulted, In a fifth, 15 pistilis were pollinated and gave one fair sized apple, In a sixth, 10 pollinations gave one medium sized apple. No, 2.0. -15- On June 5th the remaining @C2 blossoms were pollinated with R. I. Greening pollen as before, The weather was warm, Some stigmas were quite brown, yet there was an abundance of nectar in the nectaries, A few stigmas were yet preen and fresh, When the sacts were removed, June 17th, orly four fruits were developing. The records show, however, that none of these matured fruit, From the 1814 pollinations made on the Spy aprile, in these two sets of treatments, only seven small aprles were obtained, This record I consider too small for any definite conclusions. as to the best methods of emascu- lation or the proper time of pollination. We may note one fact of considerable imrortance, however On the 909 emasculations in the first division of this in- vestigation, a large percent of which were rollinated with Baldwin pollen, not one fruit showed the least development. In the second division 905 emasculations were made and a large per cent were pollinated, June 17th, on the re- moval of the sacks 58 fruits were developing ,though not so large as those outside the sacks. The pollen had rer- formed its function, however, though only a few fruits matured, This failure to mature the fruit may be at- tributable to other causes than non-fertilization, These being on the same tree as in division one, where no fruits showed any indication of development ard all conditions -16- being the same would indicate that Greening rollen is prepotent in fertilizing the Spy pistils, and that the Spy utterly rerused to accept the Baldwin pollen. Development of fruit without polien. In this investigation,the plan was to emasculate blossoms of cherry and pear, One portion to be sacked and nothing further done, A second portion was to have common dry earth dust pressed upon the stipmas, The third portion was to have stigmas brushed, thus testing the theory of mechanical irritation, A strong, vigorous, Montmorency tree was selected for the cherry test, On May 16th and 17th, I emasculated 36° blossoms by pulling off the anthers, No blossoms were selected which would have been fully open for several hours, Division A. One hundred twenty-two of these blossoms were covered with cloth sacks and nothing more done with them, The re- maining £40 were sacked with cloth sacks to await further treatment, The air at this time was warm anéd a mist like rain was falling. Division B, On May e3rd, dry dust was pressed upon the stipmas of 120 blossoms, Division ¢C, On the same date as above,the stigmas of the remaining 120 blossoms were brushed with a fine cawel hair brush, -17~- which had been thorourhly cleansed to insure it against any poscibility of foreign nollen, or other substance coming in contact with the stigmas, Both divisions were resacked as the processes were completed, Many pistils Showed injury from either cold or sacks, Many nistits in blossoms which were stil] onening were also injured, In fact, not more than 10% of the blossoms at the time of emasculation, presented rnerfect pistils, On June 10th the sacks were removed and in Division A, five ovaries had apparently developed a little, but were of small size; while fruits outside were half grown, on the same date I removed the sacks from Division B, and found one fruit with slight development. YeY In Division © I found, on removing the sacks, two small fruits, On this date there were yet blossoms with stipmas in receptive condition, On July 15th I made another examination and found all the fruits which I supposed had become fertilized, had dis- appeared, so that from the cherry I cannot at rresent say that either of these three treatments will develov a fruit. This was duplicated on a Bartlett pear tree which was in healthy condition, On May 2l1st, four-hundred-one blossoms were emascu-~ lated by opening the blossoms and pulling off the anthers, as I had in the cherry, Division A. -1R- One-hundred-forty-seven of these were sacked with yellow manilla paper sacks ard no further treatment piven them, The remaining 254 were sacked with the naper sacks for further treatment, | Division B. On May 24th, three days later dust was pressed on the stigmas of 127, All were found in good condition, The sacks were then replaced, | Division ¢. On the same date as last mentioned I brushed the stigmas of the remaining 127 with the same brush which had been used on the cherry ,and then replaced the sacks, All these pistils were in splendid condition, The day was warm, . Many insects were in the air and about the tree, On June 14th the sacks were removed from all these, and to all appearances one fruit was developing under each treatment. From notes made September 17th, 1907, I find that only one fruit of the three had matured, and that was on that portion which was sacked... No treat- ment further than emasculation, This fact alone leads me to believe there must have been some pollen from some source come in contact with the stipma, Either an anther had been lost in the emasculated blossom, and developed pollen, or some insect come in contact, and thus intro- duced pollen, So far as these investigations go, I cannot say that fruit will develop without the intervention of Nature's -19- male element, the pollen. In all these investigations this year it is exceed- ingly difficult to draw any concluSions, The weather conditions were so extremely unfavorable that but little is known of what results might have been obtained had the conditions been more favorable, In many different fruits, late severe freezes had destroyed the pistils entirely. Cold continued rains, accompanied with high winds ,so twisted the cloth sacks that there certainly must have been injury resulting. We hore to continue these in- vestigations when more favorable corditions will give us better foundation for some more definite conclusion, In discussing the causes for so many failures of pistils to become fertile in cross pollination work, the question arose, are we not pollinating too many pistils in a cluster in many of our fruits. As a rule not mary varieties of apples or pears bear more than about two on a spur from near the same axis. To study this matter I took a Ben Davis tree, in my yard, which was vigorous ard healthy. On the mornings of May 2end, 23rd, and 24th, I emasculated, by opening the petals and pulling off anthers, 78 blossoms, one in a place, none of which was the center blossom of a cluster. These were sacked with paper sacks, The mornings were cold, cloudy, and windy. One June lst, these were rol- linated with Spy pollen. Many of the pistils were quite -20 = brown and seemed almost past the receptive stare, On June 15th, when I removed the parer sacks, I found 16 fruits developing, cr 20% of the numter pollinated, In a second set of blossoms, on the same tree, on May esth, I emasculated 1C8 blossoms with four or more in a cluster, These were sacked with parer sacks, and on June lst pollinated with Spy rollen, A few of these pistils seemed too old when pollinated but in much better econdition than those in the first division, June l1Sth I found °0 fruits developing and a small branch having 12 which had been emasculated was broken ,so that the chance of develoring any of these pistils was im- possible, Deducting this 12 from the number emasculated we have 20% of the emasculated in this developing fruit. There are two factors to be considered in this how- ever, First, the blossoms emasculated (those of the Single blossom) were left too long before pollinating, Second, I observe that probably few varieties of apples ripen so many fruits in a cluster as do the Ben Davis. While collecting apples at the Connecticut State Agr'l College in December, '07, I found it not uncommon for this veriety to produce four good sized aprles in a cluster , while five are frequently found, I am still of the belief that had I not waited so long before pollinatingyor had I have chosen some other variety to work with, I should have obtained very different results, A. T. Stevens, THEA aii