Combining Ability for Germination Traits in Jatropha curcas L.

Abstract

Six parents of Jatropha curcas were crossed in half diallel fashion, and the F1s were evaluated to determine the combining ability for nine germination parameters. The ratio between general combining ability (GCA) and specific combining ability (SCA) variances indicated preponderance of additive gene action for all the characters except germination percentage, time of 50% germination, seedling length, and seedling vigor index. The parents P1 and P2 were the best general combiner for most of the characters studied. The cross P1×P5 was the best specific combiner for speed of emergence, germination percentage, germination energy, germination index, and seedling vigor index, the cross P2×P5 for mean germination time, time of 50% germination, and seedling length, and the cross P4×P5 for number of days to first germination. The germination percentage varied from 58.06 to 92.76% among the parents and 53.43 to 98.96% among the hybrids. The highest germination (98.96%) was observed in hybrid P2×P4, and none of the hybrids or parents showed 100% germination. The highest germination index (GI) and seedling vigor index (SVI) were found in hybrid P1×P5 and P2×P5, respectively. The results of this study provide clue for the improvement of Jatropha variety through breeding program.