Heterosis and combining abilities of 10 supersweet corn lines adapted to the humid tropics

A. H. Abdul Wahab and L. J. Wong

Abstract

A 10-parent diallel cross, excluding reciprocals and parents, of sweet corn Thai Supersweet (TSS) lines, was analysed for fresh cob yield, husk cover, disease rating, plant and ear heights as well as ear aspect. Highly significant differences were observed among the F₁ hybrids in both general combining ability (GCA) and specific combining ability (SCA) effects for husk cover, disease rating as well as plant and ear heights. The GCA effect was also highly significant for ear aspect while the SCA effect was also highly significant for fresh cob yield. A comparison of the relative magnitudes of GCA and SCA effects showed high GCA/SCA sum of square ratios for most of the characters investigated, except fresh cob yield, suggesting the importance of additive genes for most of the traits. In addition, six F₁ combinations showed very highly significant SCA effects for fresh cob yield, thus representing the best combinations for developing interline hybrids.

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