2018 ASHS Annual Conference

The predominant harvest method of blueberries, is hand harvesting. Production of southern highbush blueberries (SHB) by southern states (FL, GA and NC) makes up 26% of U.S. planted acreage and 20% of blueberry production. Hand harvesting blueberries increases production cost and risk of disease, lowering producer profit margins. In addition, hand picking is slower and more laborious than mechanical harvest (MH). These attributes in conjunction with competition among southern states for labor forces necessitates new strategies for blueberry production and harvest. Our objective was to evaluate advanced selections for MH by simulating blueberry growers’ conditions using a mechanical harvester and sorting the fruit using color and soft sorter packing line. Thirteen five-year-old SHB advanced selections (NC4360, NC4385, NC4622, NC4638, NC4671, NC4676, NC4982, NC4984, NC4992, NC4994, NC4995, NC4996, and NC4998) and control SHB cv. ‘Reveille’ were used in a replicated trial from 2015-16. Fruit were harvested up to four times during the harvest season via Little Blue BEI harvester. Harvester efficiency was evaluated for fruit ground-waste, plant debris, and yield of acceptable fruit. Fruit quality was measured for berry weight, firmness, color, and appearance. Post-harvest storage amenability was evaluated after a week at 4 °C. Yield evaluations of consumer acceptable fruit after MH, showed that NC4360 had significantly higher yield than eleven other cultivars; NC4994 was not significantly different from the lowest yielding accession. NC4994 had the greatest average berry weight over the two years of study, followed by NC4360, both were significantly greater than nine other accessions. Further, NC4994 and NC4360 had the largest berry latitudinal diameter. The relation of berry weight and diameter to percentage of acceptable berries after MH is an important consideration for suitability of cultivar for MH. Interestingly, fresh fruit firmness was negatively correlated with fruit softness after storage; berries of accession NC4992 had significantly greater fresh fruit firmness and had significantly higher quality berries and least weight loss post-storage. In 2017, hyperspectral transmittance imaging showed NC4992 had the least bruising index compared with Reveille and 30 other described firm accessions. Harvester performance evaluation indicated that the average ratio of harvested consumer-quality-fruit to green or soft fruit was 3:1. NC4996 had significantly less soft and immature fruit to acceptable berries harvested at 1:7.5, all other accessions were less than 1:5. Accession evaluations show promise in cultivar adaptability to MH. Overall, accession 4992 has potential of being named as a new cultivar suitable to MH and storage.