2017 ASHS Annual Conference

New practices to improve quality and size of fresh market ‘Wonderful’ pomegranate fruit are needed. A previous study indicated that younger wood was more likely to produce staminate flowers and early-produced flowers produced higher quality fruit. Therefore, the objective of this project was to investigate pruning and flower removal protocols to increase production of high-value, fresh market pomegranates. A combination of three pruning strategies with or without late season flower removal was applied to mature ‘Wonderful’ pomegranate trees in a commercial California orchard. Treatments were replicated four times within seven blocks using a randomized complete block design (168 data trees). Pruning treatments included Mechanically Topped (MT), with data trees pruned using industry standards by mechanically topping and hand pruning to skirt, sucker and remove branches that extend outside tree row width. Cut to Lateral Branches (CLB) data trees were pruned by the MT method followed by hand pruning to a lateral branch to remove stumps left by heading cuts. Thinning One-Year-Old Wood (TOW) data trees were pruned using the CLB method and one-third of remaining 1-year-old wood was removed by thinning cuts. Mechanically Topped with Flower Removal (MT+FR), Cut to Lateral Branches with Flower Removal (CLB + FR) and Thinning One-Year-Old Wood with Flower Removal (TOW + FR) data trees were pruned by the respective method and flowers produced after peak bloom were removed every 7-17 days until flowering ended. Removed hermaphroditic flowers were quantified and characterized. At harvest, trees were strip picked and total fruit mass from each data tree was recorded. A subsample of 20 fruit from each data tree was measured to determine individual fruit mass and diameter. Aril mass and mass of 100 arils were measured for 10 randomly selected fruit from each subsample. Pruning treatments did not result in statistically significant differences in any measured parameter. There was a statistically significant relationship between flower removal and fruit size, with flower removal resulting in fruit that were on average 4 mm larger in diameter and 47 g heavier than fruit from trees from which flowers were not removed. Such fruit had higher aril number and larger arils. Annual CLB and/or TOW treatments might increase fruit quality as tree architecture changes. Removal of late season flowers improved fruit size and quality, suggesting that cultural or chemical control measures that decrease late-season flower and/or fruit production should be investigated to improve production of high-value, fresh market pomegranates.