NC-140 peach rootstock testing in thirteen U.S. states

Eighteen Prunus rootstocks budded with 'Redhaven' peach were planted at 16 locations in North America in 2009. After four years at 14 locations, significant differences among rootstocks and sites were found for survival, root suckers, growth, bloom date, fruit maturity date, fruit size, cumulative yield, and yield efficiency. Tree survival was high (>96%) in the states MA, CA, SC and UT and low (<78%) in MO and NC (bacterial canker). Imperial California had the lowest overall survival (48%) followed by Fortuna and Krymsk®1. Rootstock suckering was excessive on Prunus americana seedlings with Krymsk®1 a distant second. The largest trees were in CA, NY, MO and SC, while the smallest trees were in CO and UT, both high elevation mountain states with calcareous soils. Tree TCSAs were largest on Bright's Hybrid #5, Guardian®, Viking, Krymsk®86 and Atlas, whereas TCSAs of trees on Krymsk®1, Controller 5, P. americana and Fortuna were the smallest. The earliest bloom by 1-2 days in both years occurred on Bright's Hybrid #5 and KV010127 rootstocks. Trees on P. americana and Fortuna bloomed 1-3 days later than the average in 2011 and 2012. Fruit maturity dates varied by 59 and 52 days across sites in 2011 and 2012, respectively. Among rootstocks and years, fruit maturity was advanced up to 2.5 days and delayed as much as 3.5 days, when compared to Lovell. Bright's Hybrid #5 and KV010127 advanced maturity, and Penta and HBOK 32 delayed maturity in both years. Fruit size was largest (192 to 231 g) in SC, UT and CA and smallest (117 to 154 g) in GA and NC for both years. Empyrean®3, Atlas, Empyrean®2, Bright's Hybrid #5, Guardian® and Viking produced the largest fruit and Fortuna the smallest. Cumulative yields were highest in CA, NY, MO and MA and lowest in CO and IL. The highest yields were on the vigorous peach and peach hybrid rootstocks. Also, rootstocks with the highest yield efficiency were Krymsk®1, HBOK 10, P. americana, HBOK 32, and Controller™ 5.