H“! N, HM I lh * ,H W [I I J N i r “IN > it) t‘ '3 C3 '2: l Jlel‘l WM -- NOSIHHVQ GROWTH STUDIES iN ALFALFA Thus-15 for 1116 Degree. of M. S. MICHIGAN FATE COLLEGE Cali“ .02? S. Car'isuz $938 9-H c,“ 2'5 g 1 I w 31*“. ‘n. r E .Wfihfi . GROWTH STUDIES IN ALFALFA A THESIS Submitted to the Faculty of’MiChigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the Degree of Master of Science 1 I. A‘ a“ i}? X Carlton S; garrison December, 1938 THE-TS!” I ACICNOWIEDGMENT The writer is very grateful to Mr. E. E. Down for invaluable advice and assistance in the pursuit of this work. To Mr. H. M. Brown whose interest and cooperation made this work possible, the writer wishes to express his sincere appreciation. CONTENTS Introduction Review of Literature Material and Methods Results and Discussions May Rating Number of Days to Observance of Secondary Shoots Yield Relationship Between May Rating and Number of Days to Observance of Secondary Shoots Relationship Between May Rating and Yield Relationship Between the Number of Days to Observance of Secondary Shoots and Yield Relationship Between May Rating, Number of Days to the Date of Cutting, and.Yield Conclusions Page \n \n i4 t4 10 15 18 19 20 13 GROWTH STUDIES IN ALFALFA INTRODUCTION It had been observed in the alfalfa breeding nursery that there were certain noticeable differences existing between the individual plants within a strain in the amount of growth made early in the spring, in the time of appearance of the secondary shoot growth.and in yielding ability. The purposes of the investigation here reported were: (1) to study (a) the amount of growth made by the individual plants by May 1, (b) the :number of days from.May l to the date when the secondary shoot growth was Observed to be one to two inches high, (c) the yield- ing ability, in green weight, of the plant at time of observance of secondary shoots, and (d) the relationShips between these characters; and (2) to determine whether the several strains differed from each other in regard to these characters. REVIEW OF LITERATURE Among all of the published material relating to growth studies in.alialfa no literature was found pertaining to this particular prdblem. MATERIAL AND METHODS The data for this study were secured from the alfalfa breeding nursery which was set out in JuIy, 1934, one plant in a place with the plants spaced 33 inches in the row and the rows 36 inches apart. The nursery was planted in four series of 101 rows each; each row of the north three series, A, B, and C, was 27 - 2 - plants long while the fourth series, D, was 29 plants long, Figure 1. Series B and D were the replications of Series A and C, respectively. The entire nursery consisted of 150 different strains plus the check. A check (designated by'x in tables) was planted in the east row and every fou'th row thereafter. The other 75 rows of a series were each the progeny of a high yielding plant of the previ- ous nursery. The systematic replications were such that a strain appeared in two adjacent series, that is plots 0-100 were in series A and B, and plots 10032- .- 200 in series 0 and D. Around the entire nursery was a row of plants used as a border. It was decided that this exploratory study should be made on only a portion of the nursery rather than the whole nursery. The areas selected for this study consisted of the first 26 plots in series A and C and their replicates. All of the data presented was secured on the first cutting in 1936. Each plant in the alfalfa breeding nursery was given a rating according to the amount of growth made by May 1, 1936. Four ratings, based entirely on plant height, were used. Rating~"l" included all plants which.had made a growth of only a trace to two inches high. Rating "2" included those plants which.had made a growth of two to four inches. Rating "3" included those plants which had made a growth of 4 to 6 inches. Rating "4“ included all plants having made a growth greater than six inches. At various times during the last half of May, the nursery .haonass moaoooen omawmad one mo seamsan .H .mwm warez ethane 8E do“ . ‘eexlullttll-auaoou-lu-ln....nlaaall shun” t.“ ed ex 41 .wt it teflo . . _ .m‘l -UV" . _ _ . u _ . 4 . . . . . _ _ .7 .1 L n .2 .o} 9....» me" x...“ e4 Y J: Hebe .__o «Nadallalalaann nnnnnn 3.} Axeim . . .Tln IbV. . _ . _ _ . H . S m e _ a a _ b . _ 14m . _ t . _ a: 5n 1 lllllllllll 4N d\\ x. 4% oofllltlalla- IIIIIIIII but" 1? adx vex .wox ex \ ”0+0 _ TI- ..i m i w P i n u n . _ _ _ . n .7 . a.“ L _ .2 oflfi u: Aaxtwae..\.dl\ oJ: qt 4: maxim? 4&1“? QNN I '0 .ollllllllln oIllInN}\ axes: % . . _ "Ant: 31v" . _ . _ H _ a . _ . . . . _ u . . 6 . 1! . I 5 mebom moaaom - 4 - was examined to determine whether secondary shoots had begun to appear. During the last few days of May and the first days of June some plants were Observed to have their secondary shoots. On June 4 all plants so Observed were recorded, cut and weighed. On June 12 and 19 similar notes and cuttings were made. The plants remaining uncut on June 19 were so slow in showing secon- dary shoots that two weeks were allowed to elapse before the plants were again out on July 2. On the final date of cutting, July 16, all remaining plants, whether they had.yet formed secon- dary shoots or not, were out. This was done to allow ample time for the second crop to develop seed. The number of days to Observance of secondary growth (here— after, more briefly called date of cutting) was determined from May 1, the day the May ratings were taken. Green weights were taken immediately after cutting and were recorded in grams. The more detailed data are presented in two parts, by series A and B and by series 0 and D, as that formed a convenient method of dividing the otherwise long tables. However, in the statistical analysis for significance of differences between strain means the entire area was treated as a whole and plots 100% to 125 were con- sidered to be a continuation of plots 0 to 25. In the analysis of. variance there were assigned, therefore, 103 degrees of freedom to total, 1 to replication, 51 to strains, and 51 to error. - 5 - RESULTS AND DISCUSSIONS May Rating The May rating values were taken by two persons, one tak- ing those on plots 0 to 16 of series A, the other taking all of the other ratings. Table l, which is arranged according to plot number, shows the frequencies of the individual May ratings, the number of plants in each plot, the plot means, the strain means (average of series A and B), and the number and per cent of plants in each.May rat- ing group for plots 0 to 25. The strains varied in may rating from 2.20 to 3.11, giving a range of .91. The average for all strains was 2.57. The average May rating for series A was 2.26 and series B 2.89. The large difference of .63 between the two series averages may be partially explained by the fact that two persons took the May ratings for series A as mentioned above. The average for the two replications gave a more even dis- tribution between ratings 1 and 4, and 2 and 3 than was the case in the individual series. The average shows 7.3% and 10.4% in ratings 1 and 4, and 38.7% and 43.6% in ratings 2 and 3, respectively. Number of plants per plot classified according to lay - 6 - Table 1 rating, total number (N) of plants per plot, plot mean rating and strain mean rating. Order that of plot numbers in series A and Bo Plot Series A. Series B. Strain No A _ __ mean May rating lay rating 1:12 3 N Mean 1 fig; 3 i N. Mean 01 6 15 l 22 1.77 3 9 4 16 3.06 2.32 02 4 14 6 24 2.08 1 l 18 6 26 3.12 2.62 03 2 12 10 24 2.33 1 12 11 24 3.42 2.88 04: 6 15 4 25 1.92 6 12 3 21 2.86 2.351 05 4| 12 9 25 2.20 9 15 3 27 2.78 2.50 06 6 12 5 23 1.96 1 10 12 3 26 2.65 2.33 07 1 l8 6 25 2.20 1 11 13 25 3.48 2.84 09 5 14 3 1 23 2.00 1 4 11 3 19 2.84 2.38 10 l 16 8 25 2.28 1 I7 8 26 3.27 2.78 11 2 15 10 27 2.30 2 4 16 3 25 2.80 2.54 13 4, 17 4 25 2.00 2 15 4 21 3.10 2.50 14. 5 l7 4 26 1.96 3 3 l3 4 23 2.78 2.35 15 4 l6 3 23 1.96 2 6 9 l 18 2.50 2.20 16: 5 20 ‘ 25 1.80 l 9 14 2 26 2.65 2.2411 17 9 13 4 26 2.81 5 18 1 24 2.83 2.82 18 3 18 .4 25 3.04 4 14’ 7 25 3.12 3.08 19 l 10 11 2 24 2.58 3 19 1 23 2.91 2.74 21 l 8 12 4 25 2.76 6 9 4 19 2.89 2.82 22 1 7 12 5 25 2.84 2 1 14 3 20 2.90 2.87 23 1 4. 13 6 24 3.00 2 14 7 23 3.22 3.11 24:. 4 ll 9 2 26 2.35 7 13 2 22 2.77 2.541 25 1 15 9 l 26 2.38 3 10 7 2 22 2.36 2.38 Total No. 74 353 189 29 645 17 128 353 101 599 x 11.5 54.7 29.3 4.5 2.3 21.1. 53.9 16.9 Av. 2026 2.89 2057 Total, both series 91 481 542 130 1244 5 7.3 38.7 43.6 10.4 In this and all other tables the checks are marked with an x. - 7 -‘ In Table 2 are given the data on May ratings for series C and D similar to those in Table l for series A and B. The strains varied in May rating from 1.98 to 3.02, a range of 1.04. The average for all strains was 2.42. The average May rating for series 0 was 2.30 and fer series D was 2.53. The average of series C and D shows 12.2 , 43.1%, 35.7% and 9.0% for ratings 1, 2, 3, and.4, reapectively. As in series A and B, the greater numbers of plants were found in ratings 2 and 3 with a total of 78.8%. The totals for all four series are the following: Rating 1 2 3 4 Total No. of plants 251 1043 1008 248 2550 % 9.8 40.9 39.5 9.7 100 In Table 3 is given the average May rating of each strain with the check average inserted in its proper place. It is seen that there are many significant (5% point) differences and some highly significant (1% point) differences between Strains. -8... Table 2 Number of plants per plot classified according to May rating, total number (N) of plants per plot, plot mean rating and strain mean rating. Order that of plot numbers in series C and D. Plot Be as C p;§gg;g§:D Strain No. Hay rating F_’ lay rating mean 1 2 _3__44 ll lgyul 3;; .2 :1 N Is 100%: 9 12 5 1 27 1.93 I. 15 8 1 28 2.21 2.07:: 101 5 10 8 1 24 2.21 1 16 9 2 28 2.43 2.33 102 4 11 3 2 20 2.15 1 9 6 2 18 2.50 2.32 103 3 8 11 1 23 2.43 1 11 9 3 24 2.58 2.51 r1041, 9 14 3 1 27 1.85 16 10 2 28 2.50 2.18: 105 14 '7 3 24 2.54 3 9 10 4 26 2.58 2.56 106 10 9 6 25 2.84 1 7 12 6 26 2.88 2.86 107 2 9 8 7 26 2.77 3 7 12 5 27 2.70 2.74 1081 10 11 4 1 26 1.85 4 11 13 28 2.32 2.091 109 1 10 8 2 21 2.52 7 18 3 28 2.86 2.71 110 2 7 9 A 22 2.68 1 2 14 5 22 3.05 2.86 111 7 8 8 1 24 2.13 4 8 10 6 28 2.64 2.40 7112: 5 ll 6 3 25 2.28 5 15 7 1 28 2.14 2.21x 113 7 13 5 25 2.92 2 1 16 8 27 3.11 3.02 ”114 2 11 7 3 23 2.48 10 10 2 22 2.64 2.56 .115 11 9 1 21 2.52 7 17 4 28 2.89 2.73 .116: 7 13 '7 27 2.00 2 17 9 28 2.25 2.13: 117 2 15 6 23 2.17 4 9 12 2 27 2.44 2.32 .118 7 18 1 26 2.77 4 6 10 7 27 2.74 2.75 119 4 13 5 2 24 2.21 2 9 10 2 23 2.52 2.36 ,121 6 10 9 25 2.12 2 15 6 23 2.17 2.15 .122 6 13 5 24 1.96 7 9 7 23 2.00 1.98 123 4 12 7 2 25 2.28 3 10 12 3 28 2.54 2.42 .1241: 4 16 6 26 2.08 15 10 25 2.40 2.24: 925 6 16 3 1 26 1.96 3 11 8 2 24 2.38 2.16 otal No. 99 297 190 48 634 60 266 276 70 672 i 15.6 46.8 30.0 7.6 8.9 39.6 41.1 10.4 A70 2030 2053 204-2 otal, both series 159 563 466 118 306 S " " 12.2 43.1 35.7 9.0 - 9 _ Table 3 May ratings in ascending order of strain averages. Strain Rating Dif. Strain Rating Dif. 122 1.98 103 2.51 .17 .05 121 2.15 105 2.56 .01 .02 125 2.16 11 2.58 .04 .13 15 2.20 109 2.71 .04 .01 1 2.24 18 2.72 .04 . .01 Ch. 2.28 115 2.73 .04 .01 102 2.32 19 2.74 ‘ .00 .00 117 2.32 107 2.74 .01 .01 6 2.33 118 2.75 .00 .03 101 2.33 10 2.78 .02 .04 14 2.35 17 2.82 .01 .00 119 2.36 21 2.82 .02 .01 2 2.38 23 2.83 .00 .01 9 2.38 7 2.84 .00 .02 25 2.38 106 2.86 .01 , .00 13 2.39 110 2.86 .01 7 .01 111 2.40 23 2.87 .02 .01 123 2.42 3 2.88 .08 .14 5 2.50 113 3.02 .00 114 2.50 .01 Difference between two strain means must be at least .66 to be significant (5% point) or .88 to be highly significant (1% point). - 10 - Number of Days to Observance of Secondary Shoots Table 4 shows the plots arranged according to plot number for series A and B and gives the distribution of plants within a strain cut on the various dates when notes were taken on presence of secondary shoots. Also included in the table are the number of plants in each plot, the plot means, the strain means (average of series A and B), and the number and per cent of plants cut on each date within each series for plots 0 - 25. The strains varied in the average number of days to date of cutting from 37.2 to 45.1, a range of 7.9 days. The average for the 26 strains means was 39.7 days. The average number of days to the date of cutting for series A was 39.3 days, and for series B it was 39.9 days. Series B was very similar to A in the per cent of plants cut at the various cutting dates. The percentages for both series together were 62.8%, 26.4%, 7.1%, 5.3% and 0.2% for the five cutting dates of 35, 43, 50, 63 and 77 days, respectively, from.May 1. Table 5 gives the data on the number of days to date of cutting for series 0 and D similar to that in Table 4 on series A and B. The strains varied in the average number of days to the date of cutting from 37.6 to 47.0 days, a range of 10.6 days. The average number of days to the date of cutting for the 26 No Min 1N 05M 9M0 : = & m we we con Hm» noHnon neon .Hnwmm +N.mm m.mm m.mm .n»« 3 m. m. 0% Mme . m. mm m. mm mm L: H .nnanmquutaaimmamj m m“ a .HH .nuHmHan H mall NHuifinnws. Nb.bm e.pm H M NH o.wm N 6 NH neN o.He H.NH N e 6 HH o.oe N m «H «N H.He o.me H N N 8 HH m.mm H m m 8H NN o.He m.Ne N m a m N.He m a «H HN um.mm N.mm N m oN m.am H HH 8H uoN o.om o.mm N m 6H o.o< H «H oH mH N.mm N.on H e N mH N.bm a NH NH o.N< H.m< e m b m n.oe H m m «H pH aw.om n.0m m HN N.bm a NH neH m.am m.mm N H nH m.om N b «H mH o.H< m.N< m m m NH o.H< N e b mH «H H.me H.me N m m a p.6e H e m m 8 NH when Nam H 6 pH Ném a. «H “NH >.bm N.om N 0 pH «.om H n MN HH o.oe N.oe H e w mH N.om H N 6 6H oH m.H< N.oe H H s 0H N.n< H m H 0 NH mo 2H.>m m.am H m mH 0.8m H a oN uwo N.em 6.0m H m HN m.bm N m NH so H.oe m.Ne N e oH OH m.bm m H oH no H.oq m.HH m H o «H b.wm m 0H mo us.em H.8m H N NH m.om e HN nee o.oe o.He H a 8 NH N.oe «N m 0H HH no o.am 0.0m H a q pH m.wm «N N o oH No o.om m.mm H a HH H.mm NN H e «H Ho aNfim m.om H q oN «.5m 0N H 0 0H aoo nan» W L L 9 9 9 W WW H . / / / / / e In In 9 9 9.. . mm w gas 2... . newsman.“ O as we, oww new, mm, wen. owa‘ wee. new m mmdhmm 4 mmdhmm Java—=5 no.3 o... mangoes... cements $5350 mo 3.3 on» 8. H has sohm who“. no pepsin owdnebd Q 0.3.8.. 1:, H. a.N N.N1 N.NN N.NN: g g N N 8N NNH ooN OHN annNn anon .HaNmms H«q«n N.o ‘wN.oN, .sa 0 N.N N.N N.HN m.oN m.o «.« o.N o.«N N.NN u NaN 0 an em >«H oo« «NN N NN Hm NNH Ho« Hupoa lmlflé [5.81% N qHF N NH .0 NM «7 NH. NH mNH NN.Nm N.sN NN H a NH N.NN NN N NN n«NH N.H« N.N« NN N N «H N.N« mN H m N b NH NNH N.N« N.N« NN N o N m N.N« «N N « oH N NNH N.H« N.NN NN H 0H NH N.N« NN « « N «H HNH UhH.R N.Nm NN N NH N.NN NN H N HN NONH N.N« «.H« NN N « « NH «.«« «N N N 8 NH oHH N.H« N.N« aN N H 8 NH N.NN NN N N mH NHH . H.H« N.N« 6N m 8 NH N.Nm NN H N N «H bHH xN.Nm N.Nm NN N N NH N.NN 5N H 0H NH U"NHH N.H« N.N« NN m N N mH N.N« HN H N « NH NHH N.Nm N.NN NN N N «H N.NN NN H N NH «HH N.Nm N.NN NN H N m NH N.am mN H a pH NHH NN.NN N.NN NN N m m oN N.NN NN H H n NH NNHH N.H« o.H« NN N m N pH s.N« «N N « N NH HHH «.NN o.o« NN N N m mH N.NN NN H H m NH NHH N.Nm H.H« NN m « mH o.Nm HN H N «H 00H am.em H.Nm NN « «N N.NN NN H H N NH NNOH H.mm N.N« NN N N 8 NH m.>m NN H H « oN 80H N.NN N.NN NN N H N oN N.NN NN H H N 8H NNH N.H« N.N« NN « « N NH N.o« «N H « m «H moH NH.>N «.Nm NN N H mN N.N« bN m « ON N«0H «.NN N.NN «N N N NH 5.5m NN H N NH moH o.s« N.N« NH N « N m N.«« 0N m N a a NNH N.N« N.N« NN N m HH oH N.Nm «N N a ,NH HNH u«.bm N.NN NN H N HN N.NN 8N H N HN NNOOH N S N d N N d N 8 a... 8 .L O L L 9 9 0/ 8 T. O In In 9 0/ .d . / / / / / . / / / / 9 T. mm a ma... N, a N a v a T. N a a a w N N“ uwNNn NN on, NNH mm aw NN on, ‘m«, mm 9 mmfihmm Ollmfimflhww newness No.3 on 932003 Nemfihfim mfipfié no 3.3 68.. op H has seen whee mo .HensHE $225 a .Hn.a - 13 - strain means was 40.1. The average number of days to the date of cutting for series 0 was 39.4 days and for series D it was 40.6 days. The results in series D were very similar to those of series 0. The percentages for both series together were 62.0%, 22.9%, 6.7% and .l% for the five successive cutting dates resPectively. Considering all four series together, the number of plants cut on each date and the percentage that number was of the total are as follows: Date Cut . June 4 June 12 June 19 July 2 July 16 Total Number of days after may 1 35 43 50 63 77 Number or plants 1591 605 196 153 5 2550 % of total 162.4. 23.7 7.7 6.0 .2 100 In Table 6 are given the strain averages of the number of days to the cutting date. It is seen that there are some significant (5% point) and a few highly significant (1% point) differences between strains in number of days after May 1 until secondary shoots emerge. - 14 - Table 6 Number of days from May 1 to the date secondary shoots ‘were observed (date of cutting) arranged in ascending order of strain averages. Strain Days Dif. Strain Days Dif. 7 37.2 , 23 1.1.0 .2 .0 Ck. 37.4 117 41.0 .2 ‘ .1 114 37.6 19 1.1.1 .2 .2 11 37.8 103 41.3 .4 .0 18 38.2 121 41.3 .1 .3 .1 .0 103 38.4 118 41.6 .5 .2 106 38.9 111 41.8 .1 ' .1 1 39.0 9 41.9 .1 .0 107 39.1 21 41.9 .3 .1 110 39.4 14 42.0 .4 .6 109 39.8 17 42.6 01 04. 15 .39.9 119 43.0 .0 03 5 40.1 22 43.3 .0 1.8 6 40.1 13 45.1 .0 .2 .1 .7 2 40.2 122 46.0 .3 .9 123 40.5 102 46.9 .1 3 40.6 .3 101 40.9 .0 125 40.9 .1 Difference between two strains must be at least 3.3 days to be significant (5% point) or 4.4 days to be highly significant (1% point). - 15 - Yield In Table 7 are given the plot and the strain means for ‘the yield (green weight in grams) per plant of series A and B, and of series 0 and D, arranged according to plot number. The strain means for series A and B varied from 467 to 840 grams per plot, a range of 373 grams. The average of the 26 strain means was 673 grams. The average yield per plot for series A was 646 grams and for series B it was 671 grams. The strain means for series 0 and D varied in yield from 520 to 907 grams per plot, a range of 387 grams. The average of the 26 strains means was 756 grams. The average yield per plot for series 0 was 743 grams, and for series D it was 769 grams. In Table 8 is given the average plant yield of hay per strain. It can be seen that there are some significant (5% point) and several highly significant (1% point) differ- ences between strains. -16... Table 7 Mean yield of hay per plant arranged according to plot number. Plot Series Strain Plot Series Strain No. A _ B mean N 0. C D mean 00: 702 772 737: 100;: 800 775 787: 01 533 526 530 101 745 795 775 02 693 722 780 102 831 805 819 03 765 817 791 103 773 909 842 041 612 759 679: 101.: 707 953 8323: 05 . 637 640 639 105 875 937 907 06 ' 600 520 558 106 861 928 895 07 687 796 742 107 822 827 825 08:. 598 760 6771 108: 735 890 815: 09 463 546 501 109 831 831 831 10 851 689 768 110 836 847 842 11 687 590 640 111 659 704 683 12:: 660 621 641: 1121 648 674 662:: 13 688 839 757 113 750 767 759 14 590 667 626 114 770 697 734 15 460 477 467 115 892 911 903 161. 620 671 646x 116x 747 660 703: 17 877 800 840 117 674 647 659 18 758 806 782 118 947 785 864 19 766 712 740 119 498 676 585 20: 575 683 628: 1201 702 633 666: 21 646 616 633 121 626 532 581 22 647 667 671 122 578 654 615 23 584 601 592 123 818 850 835 241 541 693 611: 124:. 676 772 723: 25 527 512 520 125 519 522 520 Av. 646 671 673 743 769 756 - 17 - Table 8 Green weight per plant arranged in ascending order of strain averages. Strain Grams Dif. Strain Grams Dif. 15 467 19 740 34 2 9 501 7 742 19 15 25 520 13 757 0 2 125 520 113 759 10 9 l 530 10 768 28 7 6 558 101 775 23 7 121 581 18 782 4 9 119 585 3 791 8 13 23 593 103 804 23 14 122 616 102 818 10 7 14 626 107 825 7 6 ‘21 633 109 831 5 4 5 638 123 835 3 5 11 641 17 840 19 1 117 660 110 841 ll 23 22 671 118 864 ’ 12 30 111 683 106 894 18 9 Ck. 701 115 903 3 4 2 704 105 907 30 114 734 6 Differences between two strains must be at least 123 grams to be significant (5% point) or 164 grams to be highly significant (1% point). - 13 - Relationship Between May Rating and Number of Days to Observance of Secondary Shoots Not all the plants in any one of the May rating groups were observed to have their secondary shoots by the same date of cutting, Table 9, although rating groups (3 and 4) showed more than 90% of their plants with secondary shoots at the first two dates of cutting. Table 9 The number and per cent of plants of each May rating group harvested on the various cutting dates. May' Number and per cent of plants harvested Total Rating June 4 June 12 7 June 19 July 2 July 16 No. % No. % No. % No. % No. % No. %‘ 77 30.7 74 29.5‘ 32 112.7 66 26.3 586 56.2 2961 28.4 99 9.5 60 l 5.8 .7 251 100 .2 1043 100 2 2 O I-‘UNH 223 89.91 23 9.3 1 .4 k 1 .4‘ 0 248’ 100‘ ( _ Total 1591 62.4 605 23.7 196 7.7 153 6.0 5 .2 2550 100 The coefficient of correlation, -.326, between May rating and date of cutting on an individual plant basis, is highly significant statistically though not very great biologically - the squared variability in May rating accounting for only 10.6 per cent of the squared variability in date of cutting. The coefficient indicates _ 19 - that there is a tendency for the more vigorous plants on May 1 to produce their secondary shoots early. When the plot averages were compared and the covariance due to series and strains eliminated, the correlation co- efficient was found to be -.154, a non-significant value. Even though the coefficient is not significant it may be noted that it has the same sign as does the coefficient ob- tained from the individual plants. RelationshiplBetween May Rating and Yield The plants which received a rating of 3 or 4 on May 1 gave higher yields than did the plants which received ratings of 1 and 2, Table 10. Ratings 3 and 4 gave an average yield of 849 grams and 1005 grams, respectively, while ratings 1 and 2 gave average yields of 328 grams and 599 grams respectively. Table 10 The average yield of plants when grouped according to their May ratings. May Number of Per cent of Per cent of Average Eating plants plants in each total yield yield group» <__' in each group ‘ 1 251‘ 9.8% , _ 4.5% 328 .12 g 1043 i 403% 34.5% 599 _ 3 i008 39.55% 421%....Jn___8.49__, ._._41 ZA§_ 9.78 13.8% =11): Totalfi, 2550 General Ayerage 711 i - 20 - While the plants were grouped by ratings quite symmetri- cally, the average yield tended to vary in the direction of the plants receiving the higher ratings. Rating 1 with 9.8% of the total number of plants included only 4.5% of the total yield; rating 2 with 40.9% of the plants included only 34.5% of the total yield; rating 3 with 39.5% of the plants included 47.2% of the total.yield, while rating 4 with only 9.7% of the plants included 13.8% of the total yield. After the covariance due to series and strains was elimi- nated, the coefficient of correlation was .209, a non-significant value, indicating that though within a strain there was little relationship between plot average May rating and green weight of plant, yet the relationship was in the positive direction. Relationship Between the Number of Days To Observance of Secondary Shoots and Yield The results given in Table 11 show that as the number of days to the observance of secondary shoots (date of cutting) in- creased the average yield per plant decreased. The increase in the average yield of the July 16 cutting over that of July 2 can be explained as due to the small number of plants, five, which were cut on the later date. The per cent of plants cut on the various cutting dates corresponds very closely to the per cent of the total yield in each of the groups, indicating a fairly close relationship be- tween earliness of secondary shoot Observance and yield. - 21 - Table 11 Average yield per plant on the various cutting dates. Cutting ‘fiSL of days P.5“Eéht of Per cent of Average Date to cutting plants cut total yield Yield ._