Heterosis and combining abilities in a diallel cross of seven CIMMYT corn inbred lines in Malaysian conditions

A. H. Abdul Wahab

Abstract

Twenty-one hybrids and seven parental lines were evaluated for heterosis in yield. Mean performance of hybrids was superior to that of the parental inbreds in all the crosses. All the hybrids outyielded their better parents and their midparent values. However, compared against Suwan 3, the best commercial variety, only five F₁ combinations showed positive heterosis, the values of which ranged from 0.1% to 8%. The diallel analysis for combining ability indicated that a large part of the total genetic variance observed for 50% tasseling, plant and ear heights was associated with significant general combining ability effects, indicating the importance of additive genes in the genetic determination of these characters. Yield and ear aspect, however, were largely controlled by non-additive genes as reflected by the significant specific combining ability effects.

Full Text ( 34 KB )