Inheritance of seed weight in Cucumis sativus (L.) var. sativus and var. hardwickii (Royle) Kitamura

A series of experiments was conducted to determine the inheritance of seed weight in cucumber. Matings between a Cucumis sativus var. sativus (Cs) L. inbred line (USDA WI 1606; P1) and a C. sativus var. hardwickii (Royle) Kitamura (Ch) collection (PI 215589; P2) were made to produce seed of reciprocal F1, F2, and BC1 families. Families were grown under field and greenhouse conditions, and seeds were extracted from fruit 55 to 60 days post-pollination. Seed of F1 and F2 families was obtained using the Cs inbred WI2808 (P12) and the Ch collection LJ 90430 (P10), and seed of F1 families were produced using a North Carolina Design II mating scheme in which three Cs (P3= GY-14; P4=WI 1379; P5=WI 1909) inbreds were used as maternal parents and seven Ch collections (P2; P6= PI462369; P7=486336; P8=LJ91176; P9=273469; P10= 2590430; P11=PI187367) were used as paternal parents. Mean seed weights of F1 progeny reflected the dominance of genes of the C. sativus var. sativus parent. Transformation to number of seeds per unit weight resulted in increased variance homogeneity within generations and a broad-sense heritability ranging between 26% to 56%. Additive and dominance effects were important in the expression of seed weight in P1×P2 progeny produced in the greenhouse and additive effects were important in field grown progeny resulting from P1×P2 and P10×P12 matings. The estimated number of factors or loci involved ranged between 10 to 13, depending on the method of calculation.