2014 ASHS Annual Conference

Peach production acreage in Central Florida is steadily expanding with the availability of new, high-quality, and low-chill requirement peach cultivars adapted to the region’s subtropical climate. Florida’s well-drained sandy soils are ideal for peach production except that they are also inhabited by plant pathogenic nematodes. ‘Flordaguard’ peach rootstock is recommended for commercial utilization because it is well-adapted to Florida’s acidic soils and exhibits good resistance to the endemic peach root-knot nematode, Meloidogyne floridensis (Mf).  Additional nematode-resistant rootstocks are being identified to diversify the panel of improved rootstocks for the expanding peach industry.  Two new rootstocks, ‘MP-29’ and ‘P-22’ (T. G. Beckman, USDA-ARS Byron, GA) offer potential for peach production in Central Florida. ‘MP-29’ is “pleach”, a hybrid between a red-leafed peach rootstock breeding selection and ‘Edible Sloe’ plum.  The rootstock selection ‘P-22’ is a hybrid of ‘Guardian’ and ‘Flordaguard’ peach and is under consideration for release.  A rootstock trial was planted at Citra, FL during the Spring of 2012 to test horticultural performance of these rootstocks with ‘Flordaguard’ in the presence of Mf.  ‘Okinawa’ peach and ‘Barton’ peach rootstocks were included as susceptible and resistant controls, respectively.  A commercial quality, low-chill peach scion, ‘UFSun’ was budded on all rootstocks to evaluate fruit quality. ‘MP-29’ clonal and ‘Barton’ seedling rootstocks were field-budded in 2012. ‘P-22’ clonal, ‘Okinawa’ seedling, and ‘Flordaguard’ seedling rootstocks were budded a year prior to field-transplanting in 2012.  Scion growth was monitored one year after budding and fruits were harvested in the second season after establishment.  Preliminary data indicate that the two new clonal rootstocks ‘MP-29’ and ‘P-22’ are promising alternatives to ‘Flordaguard’. During the two growing seasons, stem circumferences (2 inches below and above graft union) were significantly greater in ‘Okinawa’ and ‘P-22’ rootstocks.  The relative growth rates of the scion were higher on field-budded ‘Barton’ and ‘MP-29’ rootstocks than those budded the previous year.  ‘MP-29’ produced trees with yield efficiency and fruit size comparable to other tested rootstocks despite its smaller tree size – a characteristic useful for high-density planting systems. ‘Barton’ rootstock also demonstrates significant promise in terms of vigor (pruning weight and tree size) in the initial years of orchard establishment.  Further evaluation is required to validate the effect of rootstocks on yield efficiency and resistance to Mf.