Flower and leaf bud density manipulation affects fruit set, leaf-to-fruit ratio, and yield in southern highbush 'Misty' blueberry

Abstract

This study examined the influence of the different flower bud-to-leaf bud ratios on flowering, fruit set, leaf-to-fruit ratio, fruit quality, yield, and new flower bud production in southern highbush 'Misty' (Vaccinium corymbosum L. hybrid) blueberry. The flower bud-to-leaf bud (FB: LB) manipulations were as follows: in 2019, 1FB: OLB, 1FB: 1LB, 1FB: 2LB, 1FB: 3LB, 1FB: 4LB, 1FB: 5LB, 2FB: 1LB, 2FB: 2LB, 2FB: 3LB, 2FB: 4LB, and 2FB: 5LB; and in 2020, 2FB: 1LB, 2FB: 2LB, 2FB: 3LB, 2FB: 4LB, 2FB: 5LB, 4FB: 2LB, 4FB: 3LB, 4FB: 4LB, 4FB: 5LB, and 4FB: 6LB. The highest fruit-setting rate was observed with 1FB: 1LB (96.7 %) followed by 2FB: 3LB (88.8 %) in 2019, when the leaf-to-fruit ratios were 4.8 +/- 1.0 and 6.2 +/- 0.9, respectively. A 100 % fruit set was recorded for 2FB: 2LB followed by 4FB: 3LB (95.6 %) in 2020 with 1.1 +/- 0.4 and 0.4 +/- 0.2 leaf-to-fruit ratios, respectively. In contrast, all fruit quality parameters, including berry weight, size, and yield were highest for the 2FB: 3LB with a leaf-to fruit ratio of 6.2 +/- 0.9 and the 2FB: 4LB with a leaf-to fruit ratio of 2.9 +/- 0.6 in 2019 and 2020, respectively. Consequently, the two flower buds with three to four leaf buds per bearing shoot (2FB: 3LB or 2FB: 4LB) can be implemented in 'Misty' blueberry to enhance the productivity of blueberry plants.