io6 



Journal of Agricultural Research 



Vol. X\ai. No. 3 



stated that during both seasons conditions were unfavorable for insect 

 flight. The weather conditions at time of blooming for these two seasons 

 are shown in Plate 15. 



TablC I. — Comparison of fruit setting in an orchard of 226 Surprise seedlings during 



the two relatively unfavorable seasons of igij and igi8 ^ 



' The percentage set is based upon the total number of flowers borne. Each tree is placed in the table 

 with reference to the percentage of fruit set in 1917 compared with that in 1918. For instance, in 1917 there 

 were 78 trees in which 20 per cent of the flowers set, but in 1918 the set on these same trees ranged from o to 

 20 per cent. 



The data are presented in the form of a correlation table in order to 

 show the influence of heavy fruiting during one year upon the crop the 

 succeeding year. Accordingly, each tree is placed in the table with 

 reference to the percentage of fruit set in 191 7 compared with that set 

 in 1918. 



Three things are outstanding in Table I: (i) The heavy setting or 

 bearing of 191 7 was shown to have no distinct influence on the succeeding 

 crop in 1918; (2) there was a heavier setting in 1917 than in 1918, the 

 relative number of trees setting below 20 per cent being 109 and 189, 

 respectively; and (3) since by actual count it was determined in the 

 6-weeks period after blooming that only one pistil in four set or persisted 

 on those trees bearing what was arbitrarily regarded as a "full set," it 

 will be seen that many of the trees set an unusually small number of 

 fruits, too few, in fact, to produce a full crop after allowing for subse- 

 quent loss. This condition is not unusual in the plum when blooming 

 time is accompanied by unfavorable weather. The light set in those 

 trees which produced normal flowers in abundance presents a condition 

 quite similar to that which prevailed both seasons in a number of standard 

 varieties and other seedlings under cultivation. In Plate 13, A and B, 

 the contrast between the number of flowers borne and the fruit to set is 

 shown. 



