Research Report: Evaluation Of The Cornell-Geneva Apple Rootstocks And Other Promising Apple Rootstocks.

Authors:

Terence Robinson, Dept. of Horticulture, New York State Ag. Exp. Station, Geneva, NY  14456-0462,  Phone: 315-787-2227,  Fax: 315-787-2216, E-mail:  tlr1@cornell.edu

Gennaro Fazio, USDA-ARS, Plant Genetic Resources Unit, New York State Ag. Exp. Station, Geneva, NY 14456, Phone:315-787-2480, Fax: 315-787-2216, E-mail: gf35@cornell.edu

Rootstock effects on mineral nutrient profile and bitter pit

      A field experiment with 31 rootstocks representing a genetically diverse group of rootstocks was planted in 2010 at Geneva, NY USA. Rootstocks included three from the Malling series (UK), nine from the Budagovsky series (Russia), 12 from the Cornell Geneva series (USA) and three from the Pillnitz series (Germany).  Over the first 8 years (2010-2017) we measured final tree size (trunk cross-sectional area: TCA) and cumulative yield. In the last 4 years we measured fruit soluble solids, bitter pit incidence, biennial bearing, and leaf zonal chlorosis. We also measured mineral nutrient concentrations in leaves, fruit flesh and fruit peel and identified relationships between nutrients in leaves and fruit of ‘Honeycrisp’ apple.  We also evaluated the constancy of rootstock influence on scion nutrient profiles over the four years. Boron concentration in both leaf and fruit was consistent in different seasons, with rootstocks M.9 (several clones), B.9, M.26EMLA, PiAu51-11 and B.71-7-22 resulting in consistently low boron levels, while G.935, CG.2034, CG.4004, G.222 and CG.5087 provided consistently high boron levels. Unlike boron, calcium concentration in scion tissues was somewhat variable in different seasons suggesting a role for climate and perhaps management factors in the rootstock induced absorption and translocation of calcium. We identified a group of rootstocks that yielded high calcium levels in scion tissues (G.214, B.10, G.41, B.9, G.935, G.11, CG.4003) while another group yielded low calcium levels (M.26, M.9-T337, G.202, CG.4004, G.814).