2019 ASHS Annual Conference

Harvest process in almond is commonly done in several steps starting from shaking the trees, drying nuts on the orchard floor followed by blowing, sweeping and final harvesting by pickup machines. Sweepers and blowers create significant amount of airborne particles and drying nuts on the orchard floor has several environmental and food safety issues. Therefore, the main goal of this study is to facilitate using over-the-canopy harvester for almond varieties with more vertical structure and to understand how they differ in growth habit in response to different types of training systems. Trees of four almond cultivars, Monterey, Wood Colony, Nonpareil and Shasta, were planted in Fresno, CA in February 2018 and the trees were trained to either traditional open center (P1 and P2) or central leader training system (CL1 and CL2). P1 trees were subjected to a heading cut plus trimming of side branches in the nursery and no further pruning; while P2 trees received a narrow “palmette” pruning in the field in second year, in addition to P1 treatment at planting. CL1 trees received no heading cut or trimming in the nursery and no further pruning, while CL2 trees also received no heading cut in the nursery, but their side branches were trimmed at the nursery to produce a “bare pole”. Results of full bloom data showed significant differences among both the cultivars and training treatments, with Non-pareil, Shasta and Monterey blooming significantly earlier than Wood Colony. P2 trees showed significant bloom earliness in comparison with P1 and CL1, followed by CL2. Tree height was also significantly different among cultivars and pruning treatments. On average among the cultivars, the tallest cultivar was Shasta (268.6 cm) and the shortest was Monterey (250.3 cm) while the CL2 treatment was tallest among training treatments (287.0 cm) and P2 the shortest (239.8 cm). Data showed significant difference for all measured parameters for cultivar effect but bloom number and fruit number also showed significant differences among pruning treatments.