Indian Society of Genetics & Plant Breeding

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PHYSIOLOGICAL BASIS OF HETEROSIS FOR GRAIN YIELD IN RICE

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Eight CMS based rice hybrids of medium and mid-early duration were evaluated
along with their parents and three check varieties for various physiological parameters
like shoot and root dry matter accumulation at different growth stages of the plant,
spikelet fertility, panicle dry weight at harvest, harvest index and grain yield per plant.
Standard heterosis and heterobeltiosis for growth and yield parameters were computed
and hybrids were grouped into three categories based on heterosis for grain yield per
plant. The results indicate that yield heterosis in hybrids comes through heterosis for
total dry matter at different growth stages coupled with heterosis for panicle dry
weight without ~uch change in harvest index. Despite negative heterosis for spikelet
fertility, due to increased number of spikelets, three hybrids showed standard heterosis
for grain yield mainly due to increased number of filled grains. In all the CMS based
hybrids, sink is the major limitation rather than the source because of high spikelet
sterility, which may be related to restoration ability of the male parent.
 

Keywords: Heterosis, hybrid rice, source-sink relationship, physiological basis

Info

Year: 1999
Volume: 59
Issue: 4
Article DOI: NA
Print ISSN: 0019-5200
Online ISSN: 0975-6906

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