Genetic Control of Resistance to Anthracnose Crown Rot of Strawberry in Florida and North Carolina

Anthracnose crown rot is an economically important disease of strawberry in the southeastern United States and is primarily caused by Colletotrichum gloeosporioides in that region.  However, no information on genetic control of resistance to this pathogen is currently available to guide breeding efforts. Our objectives were to estimate genetic parameters and gains for resistance, and to examine the effects of locations (Florida and North Carolina) and transplant types (plugs grown from seed and bare-root runner plants) on the estimates.  An incomplete diallel mating design generated 42 full-sib families. Both seedling plugs and bare-root runner plants were established in field locations at Castle Hayne, NC, and Wimauma, FL.  Conidia of Colletotrichum gloeosporioides were sprayed directly into the crowns, and plant collapse was recorded biweekly during the 2010–11 season. Heritabilities were higher in North Carolina (h² = 0.34–0.58 and H² = 0.35–0.70) than in Florida (h² = 0.11–0.16 and H² = 0.25–0.26). Likewise, the seedling tests showed higher genetic control than the runner plant (clonal) tests at both locations. Genotype by environment interactions were low, with few rank changes in parental performance across locations. ‘Pelican’ was the most resistant parent at both locations, and NCH09-68 was comparable to ‘Pelican’ at the North Carolina location but conferred less resistance at the Florida location. Selection and clonal deployment of the most resistant genotype within each of the five best families is estimated to produce average genetic gains of 37.4 % and 34.9% in North Carolina and Florida, respectively.