2. 



THE 1961 HARVEST SEASON 



We've just passed through a rather unusual growing season and it may be 

 worthwhile, now that we can look back on it, to try to determine what happened 

 that caused our Mcintosh to mature and color so late, produce so heavily, size so 

 well, and drop so little even though we experienced above normal temperatures 

 from mid- August to November. 



Mcintosh blossomed perhaps 3 to 7 days later than usual. May had an average 

 daily mean temperature about 3 degrees below normal but June, July and August had 

 normal mean temperatures and September averaged about 6 degrees above the average 

 daily mean. The puzzling question is why Mcintosh were so immature by mid- 

 September and made it possible to pick so many, good, firm Mcintosh in early 

 October. The prime harvest date for Mcintosh was about two weeks later than 

 usual this year and the reason for this is not fully explainable on the basis of 

 a bloom period that was somewhat later than usual. Frankly, we haven't got a 

 suitable explanation for the late ripening of our Mcintosh this year. However, 

 it does seem reasonable that this late ripening of our Mcintosh did inhibit red 

 color development to some extent and reduce the tendency of fruit to drop 

 seriously. This lack of preharvest drjp surprised me considerably since the 

 trees bore extremely heavy crops and unusually high temperatures prevailed during 

 most of September and October. In one block, where over 40 trees averaged 56 

 boxes of Mcintosh per tree, only 10 per cent of the crop had dropped by October 9 

 when the second picking completed the harvest. 



As growers in this area finally began to harvest the crop, many began to 

 find that they had many more apples than boxes. The volume of the harvested crop 

 markedly surpassed expectations in some cases and individual tree yields in ex- 

 cess of 80 boxes per tree occurred occasionally. With yields of this size we 

 generally expect relatively large percentages of apples under 2-1/2 inches In 

 diameter but in spite of exceptionally large crops the proportion of Mcintosh 

 over 3 inches in diameter is the problem. 



The marked increase in tree production and fruit size can be explained in 

 large part on the basis of adequate moisture, above normal temperatures and a 

 harvest period about two weeks later than usual. 



In Figure 1 are shown some typical growth curves for apples plotted on the 

 basis of cross sectional fruit diameter and volume (assuming the fruit to be a 

 perfect sphere). It can be seen that when one plots the growth curve on the 

 basis of diameter that it appears that the rate of apple fruit growth tends to 

 slow down as the fruit approaches maturity. This apparent slackening of growth 

 rate is more pronounced for the later maturing Golden Delicious than for the 

 earlier maturing Early Mcintosh. If the data are calculated on the basis of 

 volume increase, however, it is apparent that the growth rate actually accelerates 

 in July and may not taper off appreciably for early apples and only slightly be- 

 fore harvest for late varieties. These data merely show that fruit volume 

 increases more rapidly with each regular diameter increment as the fruit gets 

 larger. This is shown more readily in Table 1 where it can be seen, for example, 

 that an increase in diameter of 0.1 inch on a 2.60 inch apple represents a volume 

 increase of 18.51 cubic centimeters as compared to a 17.19 cubic centimeter 

 increase in volume of a 1.50 inch apple that has grown another 0.25 inch in 

 diameter. Also, a 0.25 inch increase on a 3.00 inch apple represents an increase 

 in volumealmost equivalent to the entire cubic contents of a 2.00 inch apple. 



Since Mcintosh may grow at the rate of 0.07 to 0.10 inch per week in 



