Heterosis in physicochemical grain quality characters in intervarietal hybrids in rice

Manifestation of heterosis for three physicochemical grain quality characters in 102 F₁ rice hybrids is reported. Average heterosis of 2.2% for amylose content, -1.3% for gelatinization temperature, and -45.2% for gel consistency was recorded ewer the midparent in the japonica x indica crosses, and -5.2%, 1.1% and -23.0%, respectively, in the indica x indica crosses. Significant negative heterosis over better parent (UP) for gel consistency was demonstrated by all the hybrids in the japonica X indica group and by 81.2% in the indica X indica group. 72.9% of the indica x indica and 44.4% japonica X indica hybrids had significant negative midparent (MP) heterosis for amylose content. While no hybrid was lower than the lower parent in amylose content, 79.6% japonica X indica and 60.4% indica X indica hybrids were so forget consistency. Correlations between the midparent mean and hybrid performance were highly significant for gelatinization temperature and amylose content, and were of sufficient magnitude for gelatinization temperature, which indicates that the MP values are an effective indicator of hybrid performance. The correlation coefficients between MP value and heterosis were also highly significant, of high magnitude, but negative.