THE EFFECT OF SUMMER PRUNING TREATMENTS ON GROWTH AND TRUITFULNESS IN THE RED RASPBERRY Thesis for the Degree of M. S. J. R. van Haarlem I 9 2 7 means \Akk .Lr»t|.‘l :71 quTLL I: flu“...».u«..: ... ; . T 5 vii: It... :1 . .T .. .w‘.-A»¢r1hs VI; 5:. liziatt .. n .~ 4. «...-o,..... . 7.. L. .h’uuflb‘a'n 4 ‘l T.R.>fih.’ll[ J 4’ s. “.9"; 5 V “:15“. I . . 5,3», I 3“" . 333% «52:. 2; ‘l-l .l Eli. TA Etua‘ ,rT‘fl TT‘T' THE.EFFECT 0F SUMIER PhUHING TREATKENTS ON GROWTH AND FRUITFULNESS IN THE RED RASPBERRY by J. R. van Haarlem M A THESIS Submitted to the Faculty of the Michigan State College of Agriculture and Applied Science in partial fulfillment of the require- ments for the Degree of Master of Science \\ ”f. DEPARTMENT OF HORTICULTUhE \ EAST LANSING, MICHIGAN 1 9 2 7 INTRODUCTION. Many early writers on red raspberry growing mention the practice of summer pruning; some commend it and others disapprove of it. Perhaps this is not to be wondered at since little or no eyperimental evidence dealing with the problem has been published. Baker (1) in 1866 wrote the following sunnary of the method recommended in summer pruning, then in common use: " Sumner pruning consists in cutting out the old canes after they have fruited, and the superfluous weak shoots. This strengthens the buds upon the new canes. By a judic- ious winter pruning the season can be extended through six weeks." Probably the statenent regarding the renoval of old canes cannot be classed as a method of summer pruning. However the mention of sup rfluous and weak shoots can (T) certainly be thus applied. Beadle (3) in speaking of pruning at the tins of old cane renoval says,- " - and of those young canes that have come up, if any of then should be weak and slender, it is always advisable 'to out them away at this time leaving only those that are vigorous and capable of supporting a crOp of fruit." In defending the practice of summer pruning bullerTS) says:- " - because no other pruning is generally practiced fi5331(}{3 1L it is "no sufficient reason why it is not necessary, or that it would not be beneficial." Card (4), Lewis (7), Riehl (8), Roe (10), and Taylor (12) affirm that no benefits can be found with summer pruning and therefore do not advocate it. Thornber (l3) recommends the thinning and selection of next year's canes throughout the summer. Thomas (11) claims that suckering sorts to bear well must have the suckers hoed away when they first appear above the ground. - Patrick Barry (2) understands that summer pruning is the pinching of the new shoots when they are from 2% - 3 feet high and later pinching the resulting shoots or laterals when they attain a length of one foot. It will be seen from the foregoing that summer pruning has been a much discussed question. However, discussion and recommendations apparently have been based on observation alone or on theoretical considerations for in no instance are the results of carefully conducted trials given. MATERIALS AND METHODS. A Cuthbert red raspberry plantation on the grounds Of the Horticultural Experiment Station, Vineland Station, Ontario, Canada, was used for the field trials employed in this experiment. The portion of the field that was used consisted of seven rows, sixty feet long and eight feet apart, running North and South, in which the plants were trained to the hedgerow system. The soil was of an apparently uniform sandy loam, well underdrained. Previous to this experiment the plot had received the usual cultural and pruning treatments consisting of: l. Pruning out of the old wood in August, after the crop had been removed. 2. Dormant pruning in early April consisting of the thinning out of the canes to the required number and tipping the whole plot at approx- imately four feet in height. 3. Consistent and regular summer cultivation up to picking time, with a light discing of the runways after each picking to break up the packed crust. 4. Manuring and plowing in the fall. The plot as a whole was of uniform growth and fruitfulness and was six years old at the start of the experiment. In the spring of 1924 the plot was pruned in the usual way. Weak shoots and all surplus canes were removed. All the laterals were cut back half their length and the whole plantation tipped at four feet. PLAN OF THE EXPEEIILET. The patch was divided into seven plots, numbering from West to East with Plot 6 serving as Check. The various treatments employed were as follows: PLOT 1. The new shoots coming up after the crOp had been removed were cut out. PLOT 2. No new shoots were thinned from this plot during the season of 19a4. In 1935 the old canes were allowed to develop and fruit normally but a certain number of new shoots, enough for next year's fruiting canes, were pinched when about 24 inches high. The remaining new shoots were then removed. PLOT 5. For a period of eight weeks at the beginning of the growing season all the shoots coming up were removed. After that time all new shoots were allowed to grow. If the supposition that the early canes really are competitive with the fruiting canes largely for moisture supply, but also for plant nutrients to a lesser extent, this treatment should show marked benefit over those plots which were not so treated. All the new shoot growth, other than those new shoots that were retained for next year's fruiting canes, were removed for an eight week period. This plot was in effect the reverse of the pre- ceding plot in that it uses the early canes that come up for the following season's fruiting wood, while Plot 3 utilizes the late canes. PLOT 5. The plants were handled in the normal way until the blossoming season was over and the first berries were getting to be of good size but still showing no signs of ripening. Then all the shoots were removed except the comparatively small number which were left to serve as fruiting canes for the following year. This plot was included to throw light on the question of competition between the individual new shoots, those destined to become fruiting canes for the following year, during the latter part of the season. PLOT 6. Check. This plot was given the regular commercial treatment. No summer pruning of any kind was done. PLOT 7. Similar to plot 2. After the shoots required for the following year had been pinched, all the remaining shoots were left growing. In Plot 2 certain shoots were summer pinched and the remainder of the new shoots were cut out. Plot 7 therefore would indicate the effect of pinching accomp- anied by no removal of the remaining shoots. PROCEDURE. In the spring of 1924 each cane remaining after the dormant season pruning was tagged and numbered. Individual cane records were kept of all canes in the experiment. The records taken at picking time were as follows: 1. Date of picking. 2. Number of berries per cane by pickings. 3. Weight of berries, in grams, per cane by pickings. In 1925 each cane was labelled as in 1924 and the following measurements were made. 1. Diameter of cans in millimeters. 2. Length of cane in inches. 3. Number of laterals per cane. 4. Length of laterals per cans in inches. 5. Date of picking. 6. Number of berries per cane by pickings. 7. Height of berries per cane by pickings. SAMPLING FOR CHEMICAL ANALYSIS. On November 1st 1924, and 1925, samples were taken for chemical analysis. Three representative canes were chosen from each plot, weighed immediately, cut into thirds according to length, and dried for 72 hours at a temperature of 90° C. In 1925 it was necessary to take five canes from Plot 1 in order to obtain a sufficient amount of dried material for analysis. METHODS OF ANALYSIS. Three-gram samples of oven dried material were placed on filter paper and washed ten times with cold distilled water. The washings filtering into 250 cc. Volumetric flasks. The filtrate was cleared with dry ‘Lead Subacetate; made up to volume and filtered. 200 cc. of this filtrate was transfered to a 250 cc. Volumetric flask and de-leaded with dry Sodium Carbonate; made up to volume and filtered. §g§§_§§gggipg_§ggggg. - were obtained by taking a 50 cc. aliquot of the above filtrate and boiling for 2 min. with fiehlings solution made up as follows: 30 cc. Iehlings a, 50 cc. flehlings B, and 60 cc. distilled water. The boiled solution was then filtered through an asbestos mat in a dried and weighed Gooch crucible; then dried in the oven and weighed as Cuprous Oxide. TQI§1_§Bg§r§: - 50 cc. of the filtrate obtained after de-leading was transfered to a 100 cc. Volumetric flask and hydrolized with 5 cc. conc. HCl for fifteen minutes in a water bath at 700 C. It was cooled, neutralized with NaOH and made up to volume. 50 cc. of this solution was used for a determination. §tgrgh§g. The residues from the first washings were washed into 250 cc. beakers and gelatinized by heating. After cooling .03 gram Taka Diastase in 3 cc. distilled water was added to each sample and allowed to incubate for 24 hours. This solution was then washsi into 500 cc. Pyrex Erlenmeyer flasks, 8 cc. conc. HCl added, and hydrolysed for two and one half hours. After cooling it was neutral- ized with NaOH and washed into 250 cc. Volumetric flasks. The solution was then treated as for free Reducing Sugars. T91gl_§91y§§gghggijgg. Three grams of the original dried sample were placed on filter paper and washed with 200 cc. distilled water to remove all free reducing substances. The residue was washed into 500 cc. Pyrex Erlenmeyer flasks and treated as for starch where it was washed into a similar flask. The dextrose reading was con- verted to polysaccharides by the factor 0.90. All the weights were calculated on an oven dry basis. Weights of Cuprous Oxide were converted to dextrose by means of Allihn's Tables. EKPERIAENTAL DATA WEATHER DATA Records of temperature, sunshine, and precipitation.were taken for the two fruiting seasons, 1924 and 1925. These are presented in tables 1 and 2. Table 1.-Weather data for the summer of 1924 " TEMPERATURE W. Houfly Hours‘f Precipitation ‘ ' Date 0F. F. gean Sunshine (Inches) F. July 16 81 67 70.2 5.0 . 17 67 54 61.4 11. 5 0.60 18 77 53 61.6 10.6 19 69 53 62. 7 13.0 20 74 58 63. 6 12.2 21 75 60 65. 4 12.8 22 81 79 74.7 6.5 23 85 68 76.3 12.9 f 24 87 73 76.1 3.6 25 79 61 66. 3 9.8 0.56 26 73 57 63.5 8.9 27 78 63 70.2 12.9 # 28 84 71 77.0 6.9 29 88 69 76.3 9.7 30 80 70 72.6 3.1 0.22 31 72 61 62.2 4.2 1.23 August 1 66 55 59.7 11.7 2 65 53 59.7 12.8 3 68 65 62.4 9.8 4 79 70 74.3 2.2 0.62 5 76 64 70.3 10.0 0.21 6 84 76 75.3 6.1 0.30 7 83 69 71.6 10.7 0.67 8 80 64 72.1 6.6 9 76 68 69.2 10.3 # 10 73 62 66.6 8.9 0.75 11 75 56 64.0 10.4 12 74 60 65.5 11.6 13 72 59 61. 3 1.8 0.51 g 14 64 55 61.2 12.3 15 73 57 65.9 11.8 Averages 76.0 62.9 67.7 9.0 Total 5.67 # 2 Picking Dates. V . _ . '~.‘~ v. .,.. ., v Table 2.-Weather data for the summer of 1925 fV vfivfif vvv—v—jw v’VV—‘VVVVfifivv fi v TEMPERATURE Date gax. gin. Hourly Hours of Precipitation . gean Sunshine (Inches) F. July 16 86 73 70.9 5.8 0.32 17 74 55 59.4 3.3 18 80 54 65.6 10.0 19 84 52 68.5 12.3 20 84 62' 72.2 2.5 # 21 82 70 71.2 2.4 0.08 22 80 63 64.1 9.0 2.05 23 76 60 65.1 11.4 24 84 54 66.2 9.7 25 80 64 65.7 3.1 26 72 62 64.4 4.6 27 77 60' 65.5 7.7 0.08 28 67 60 61.9 3.5 0.81 # 29 70 49 59.2 8.9 0.05 30 75 50 61.0 11.8 31 54 55 60.6 .6 August 1 66 56, 60.2 2.1 2.78 2 80 58 64.4 9.9 # 3 82 58 66. 9 11.3 0.38 4 82 58 65.9 11.9 5 74 62 66.2 3.6 6 76 63 66.9 4.3 0.19 7 75 60 66.0 6.4 . 8 78 66. 68 .1 0.03 ?9 78 68 68.2 4.5 0.10 # 10 84 68 71.3 9.1 11 80 61 67.2 12.5 12 76 56 64.6 2.4 13 73 64 66.5 2.0 0.21 14 74 66 65.8 5.2 0.21 15 80 60 67.7 12.1 Ayerage 77. 5 60.2 65.7 6.5 Total 7.29 vfiivfi‘vv—v # Picking Dates. The tables show that during the period of July 16th to August 15th, inclusive, the daily mean temperature was fairly high in both 1924 and 1925 vfivv—wfivvfifi II W'fi In 1924 we had a daily mean of 67.70 F with an average of 9.0 hours of sunshine per day. In 1925 the daily mean was 65.70 and the average daily sunshine 6.5 hours. During the same period there was a total rain- fall of 7.29 inches in 1925, as compared with a total of 5.67 inches in 1924. In no instance was there any apparent response in all plots to the heavy rains between pickings in 1925, either in yields of fruit or in the size of the berry. This indicates that probably at no time either year was moisture supply during the fruiting season a limiting factor to production. FRUIT RECORDS. While it was assumed that all the plots at the start of the experiment were fairly uniform as Judged by outward appearances, it is quite apparent from tables 3 and 4 that such was not the case. That they were not entirely uniform is indicated by the fact that, though plots 1 and 6 received identical treatment until after the fruiting season of 1924, the difference in their average yields per cane was almost as great that year as between any two plots receiving different treatments early in the season. While this might be due to small unnoted differences in the cane diameters .336 «Win 26.562. who. 23mg“ on Hui—m 6N 33mg“? #5 Mmgmuuwmmm 1“ ‘11‘1‘4‘1 11“ ‘1“ ‘4‘ 4‘ ‘1 ‘ 1‘{‘ EM .0.» 1 HER mm v bfimdma » bfimavub hfimfimn H» ”be i i Eden. vamolwumwsialwfilwam‘u Mommwmiadadoml ‘sophwa zgdou 1 songs wisdom. ivshumww H mam mama Haw» Hmmp mama ammo Home mmou was was m mmm mmm Hmme pomp mmom ammo Hmum Hope saw sea a use as» mass mseo mama seem Heme mmam am» as» a was muo as» Home moms moaa Hyeu pomp mam amp a mum um» Haas mama psmo moms Hpmm Home use pas a amm mam Hemp mmpm Homo mmem mes Hpmm amp mmm q mam .amm may Hume Ham» mmmm Homo Hume mow mac 1 I adeo ».dlfififipdwbm,m¢3£mmk Hon Hmmw 111“1 1‘1“ {‘11“ {1“ 1“! j { ‘ A.‘ ‘1‘ mace aoemw uneven aoemw sopms« adadou 0H m pdmaaumwa on ><.uo.ow coeeuom >4.aowmua A. on douuuom‘11.,mMWwwuuppmv 1mmbom ‘J anfipmmwmw fimbollwmw ammo thvosMNl H. awaa mesa no Hem.m Awmm.m H.»m m mmum mmou ma Huo.m mm.u H.uH a mupq Hommu mm Ham.w Hmm.» H.aw » pawn mayo #9 \ Huo.u Hoe.» H.»o m memo ammw up was.» mu.u H.»m a 09mm «awe pm Hop.» HHm.o H.uw a pump mmoo pa Hmm.p mm.m H.uu this same statement may be made regarding the figures for the size of berry in 1924. This makes it impossible to accept the figures for any two plots which differed in their early summer treatment and therefore no interpretations of this sort are attempted. It is significant, however, that where the average fruiting records for those plots in which the early summer shoot growth was removed entirely or thinned out are considered together and compared with the records for those plots in which the early summer shoots were left undisturbed, there appears to be no advantage in favor of such an early reduction of shoots. In other words there is no evidence of their being parasitic on or detri- mental to the growth and fruit production of the fruiting canes. Indeed, if anything, they seem to help; and on this point the evidence is clear. Tables 5 and 6 present data on fruit production for the 1925 season. More canes were used per plot in 1924 than in 1925 because it was found that the larger number of canes required more than one day to pick the fruit. Therefore it was deemed advisable to reduce the number of canes so that the fruit could all be gathered the Same day. If the records of 1924 are difficult of interpretation those of 1925 are even more so, for, in addition to any possible plant Variation, there is still the possible re- sidual effect of the treatments applied the previous season as registered through their effect on the new shoot growth amdwo awe ammumh map aopmra ow wucua um wuoanmm. up mumsmauwmmu Hawk MNJ, ti HHWN,NH Hmwmrwm hmmmmdmm Pfimfima Ho wfiww, szdoH soumww, apadou ampmfia grades Sonmwa adsdcu Soumun asadou acumW¢ H 0mm mpq Hpmo quo pomp HHmp um» app N mam mqo Hpmm Homo Hpmm qum mum Houm a mum moo poo mwm Hqu Haas Homo Hpmw mom map a mmo «aw Huoo Hmpm Hopm quw mum qmm a mac pmq mmm Hmwm Hoop qum mam was 0 mqu mmm mHoo mama mwmo wuom Howm Hqu q mmm mqq Humm Hume puma Hag» qmo qpu amdwoim.umuduauum msssmmw Hon Hmmm eocmw assume mommy aoumfid assume on ><.aoum:« on ><.zo.ow douuuom bd.£o»®#¢ mace ow cesspom ow doneuom omsom waspm1Weu ombo tWeu ammo 0H douwkl H amqo popm ma Ham.» Ham.m H.mu m pwom meow um Hmo.o HuH.o H.NH u ammo mwam um Hpq.u Hop.q H.Ho m mmoa away up HaH.m ku.o H.mm u mmuw ammo ma Hm».o mm.H H.mm m mmum ammo on Hoq.m mm.o H.NH a umuu «ma» um mm.m mu.H H.0m of that season. Generally 1925 was a less favorable season than 1924 from the standpoint both of yield and size of berry. all plots except #2 showed decreases. However, since the check plot showed the greatest decrease, it might be taken that all the pruning treatments of the previous season had some beneficial effects, although the differences are not significant. It is quite apparent in table 6 that the early canes are the best to leave for subsequent fruiting, Plot 1 standing ahead of the remainder of the treatments. It would also appear that these new shoots are not competitive with the fruiting canes - rather they are more of a benefit than a detriment. Plot 3 which contained only late formed canes had no influence on bettering the total yield of the plot, while Plot 1 having early canes did give a better yield. I Pinching the young growth accompanied by the removal of the surplus shoots helped to increase the yield per cane, while pinching with no surplus cane removal proved fatal to the plot. This contrast is well brought out by plots 2 & 7. It might also be added that where there was no removal of canes, as in Plot 6, the check plot, the yield was decreased. Tables 7a and VB give the fruiting record by pickings for the two seasons with respect to average number of berries per cane and average weight of berry. amvwo q.uh