Effect of timing of hand thinning on productivity of Moorpark apricots destined for drying

Abstract

Summary. Thinning at full bloom was compared with thinning at 3 stages of fruit development and the effects on size, total soluble solids level (TSS) and yield of apricots are reported. In 2 seasons separate branches of 9-year-old Moorpark apricot trees were hand-thinned to a density of 1 blossom or fruit per 50 mm of fruiting wood. Times of thinning were at full bloom, 5–15 mm size fruit, stone tip hardening and 21 days post stone tip hardening. These treatments were compared with an unthinned control. Experimentation was carried out at Loxton, South Australia. All thinning treatments reduced the yield of fresh fruit. Thinning reduced yield of dried fruit irrespective of timing in the first season but only at the 5–15 mm diameter fruit timing in the second season. Total soluble solids level of the fruit was increased by thinning which tended to improve drying ratio. Compared to the unthinned control all thinning treatments increased the size of fresh fruit. Mean fruit weight and diameter progressively decreased as thinning was delayed from full bloom till stone tip hardening. Thinning at full bloom produced higher yields of 35-mm-grade dried fruit than other treatments. To achieve the greatest benefit from thinning it should be carried out at blossoming.

Crop load and harvest maturity effects on consumer preferences for apricots

“…The effect of crop load on SSC has also been reported to differ in other trials. Chemical or hand thinning apricot trees to lower crop loads resulted in no effect on SSC in some trials, whereas it resulted in significant increases in SSC in other trials . In general, more severe thinning increased the difference in SSC.…”

“…Although the effects of maturity of fruit at harvest on consumer preferences have been previously examined, no studies were found on crop load affecting consumer liking of apricot fruit. Crop load has been shown to affect SSC and SSC to affect consumer liking so, intuitively, an increase in consumer liking for fruit from lower crop loads would be expected. In this study, fruit from lower crop load trees were preferred, but not always.…”

“…Chemical or hand thinning apricot trees to lower crop loads resulted in no effect on SSC in some trials, 28 whereas it resulted in significant increases in SSC in other trials. 17,18,29,30 In general, more severe thinning increased the difference in SSC. In year 1 of this trial, the different crop loads were established as a means to provide fruit of differing SSCs for consumer testing, rather than directly associating crop loads with consumer liking.…”

“…Orchard management practices have been shown to alter SSC, but have not been directly shown to affect consumer liking. Apricots accumulated more sugar when grown on trees that had lighter crop loads and also when fruit were located in high light positions within the tree …”

“…16 Orchard management practices have been shown to alter SSC, but have not been directly shown to affect consumer liking. Apricots accumulated more sugar when grown on trees that had lighter crop loads 17,18 and also when fruit were located in high light positions within the tree. 19 There have been no attempts to consider the effect of the interaction between sugar content and firmness on consumer acceptance of apricots, nor any attempt to change consumer acceptance through manipulation of tree management.…”