Location: Plant Genetic Resources Unit (PGRU)
2020 Annual Report
Accomplishments
1. Ten-year rootstock field experiment with Red Delicious Scion is completed. The primary role of our breeding program is to produce new apple rootstock that are commercially viable. In order to realize their commercial potential, it important to test this material in an “apple grower” field setting and compare it to existing commercial material. These types of field experiments sometimes include other components like orchard system design to understand how such rootstocks behave in different systems. Cornell University and USDA ARS investigators concluded and reported on a 2-acre field experiment planted in 2007 in the Hudson Valley apple growing region (New York) to test orchard systems and apple rootstocks, using Super Chief Delicious apple as cultivar. This research compared six Geneva® rootstocks (G.11, G.16, G.210, G.30, G.41 and G.935) with one Budagovsky (B.118) and three Malling rootstocks (M.7EMLA, M.9T337 and M.26EMLA). Trees on each rootstock were trained to four high-density systems: Super Spindle (SS) (5,382 apple trees/ha), Tall Spindle (TS) (3,262 trees/ha), Triple Axis Spindle (TAS) (2,243 trees/ha), and Vertical Axis (VA) (1,656 trees/ha). Analysis of yield and fruit quality data showed that rootstock and training system interacted to influence tree growth, productivity, and fruit quality. When comparing orchard systems, SS trees were the least vigorous but much more productive than any other system on a per-acre basis. The lowest yield values were for all training systems with B.118 and M.7EMLA and very often, apple growers are tempted to plant weak growing “spur-type” apples like Red Delicious on vigorous rootstocks like M.7 and B.118 – a choice that would likely result in disastrous yields. The outcome of this experiment gives viable rootstock alternatives than traditional commercial options and shows that the type of orchard system can be leveraged to achieve optimal commercial yields.
