Variation and heritability of economically important traits in black currant (Ribes nigrum L.) evaluated in a diallel cross design

Summary The inheritance of commercially important characters in black currant (Ribes nigrum L.) was investigated using a complete 5×5 varietal diallel cross. Estimates of the genetic components of variance and broad and narrow-sense heritabilities revealed that additive genetic effects were greater than nonadditive genetic effects for resistance to powdery mildew (Sphaerotheca mors-uvae Berk.), white pine blister rust (Cronartium ribicola Fisher) and leaf spot (Drepanopeziza ribis Kleb.) as well as for bush defoliation and length of strigs. Apart from resistance to leaf spot, narrow-sense heritabilities of these characters exceeded 0.5.Nonadditive genetic effects were greater than additive effects for plant habit, plant vigor, bush size, length of one-year-old shoots, uniformity of berry ripening and fruit yield per bush. Narrow-sense heritabilities of these characters were rather low (0.05–0.42).