Comparative studies on growth and grain yield of some F1 rice (Oryza sativa L.) hybrids and parents [Philippines]
1983
Ponnuthurai, S.
Hybrids and parents yielded higher in dry season (DS) than in wet season (WS) cropping. In the DS, difference in yield in F1 hybrids compared with the better parent and check variety was positive and significant. Higher gross yields and heterosis for the trait in DS could be attributed to higher solar radiation and to a lower difference between the maximum and minimum temperatures. In the DS, hybrids expressed positive and significant differences compared to the parents and check varieties for plant weight and harvest index (HI). Increase in plant weight was attributed to an increase in leaf area index (source activity). Higher crop growth rate was apparent in the hybrids compared with the parents following the partitioning of relatively more dry matter for leaf growth rather than stem growth. Hybrids expressed superiority in yield compared with the parents consequent to a higher HI. Hybrids showed simultaneous increase in plant weight and HI, resulting in higher gross yields and heterosis for the trait. Heterosis for yield, therefore could be attributed to simultaneous heterosis for plant weight and HI. Expression of these traits is greatly influenced by environment as evidenced by the differential response in the two seasons. Choice of parents based on plant weight and HI would be useful in developing superior F1, hybrids to explore heterosis for grain yield
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