Expression of hollow heart in segregating tetraploid potato families

Expression of hollow heart, a physiological disorder in potato, is controlled by both genotype and environment. Development of high levels of resistance in cultivars would reduce economic yield losses that occur under conditions that promote hollow heart. This experiment was conducted to study hollow heart in segregating populations from parents in a breeding program. Nine families were planted in a replicated trial under dryland conditions and five of those families were also grown at an irrigated location under conditions favoring the expression of hollow heart. As expected, positive correlations between hollow heart and both mean yield and tuber weight were detected; correlations between hollow heart and tuber number were negative. Hierarchical regression analysis was performed on these yield traits to determine the independent contribution of each to the overall results. The highest levels of hollow heart were found in families with susceptible parents, but susceptible clones were obtained in families with two resistant parents. Regardless of the type of cross, selection of clones with large tubers increased the probability of selecting for susceptibility to hollow heart.