The objective of this work was to estimate general (GCA) and specific combining ability (SCA) and heterosis of lines and populations of Japanese cucumber using a topcross. We obtained 16 experimental hybrids crossing two test populations (Yoshinari, T Y, and Natsusuzumi, T N, F2 population) and eight S5 lines obtained from Hokuho commercial hybrid. The Hokuho hybrid F1 was also evaluated, totalizing 27 treatments. The experimental design used was randomized block, with four replicates and four plants per plot. Weight of total and commercial fruits, total number of fruits, number of commercial fruits, percentage of commercial fruits and average weight of commercial fruits were evaluated. Yoshinari population (T Y) presented, on average, better combining ability with lines of Hokuho. Line L7 presented the highest positive values of GCA for most of evaluated characteristics. Hybrids H1Y and H1N, with line L1 as one parental, showed higher values for SCA with the test populations for most of evaluated characteristics, while the hybrids with line L5 (H5Y and H5N) showed the smallest values. Population Yoshinari F2 showed greater potential to obtain lines for crossings with lines of Hokuho, in order to obtain hybrid with high yielding potential. Heterosis was positive for most evaluated characteristics.
Cucumis sativus L.; diallel; gene effects; plant breeding
