Morpho-physiological and biochemical characterization of a recombinant inbred line population of rice (Oryza sativa L.) under direct-seeded aerobic conditions
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Date
2014
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Punjab Agricultural University, Ludhiana
Abstract
Direct seeding of rice (Oryza sativa L.) is a resource conservation technology but at the cost of
reduction in yield. In the present study, recombinant inbred lines (RILs) obtained from a cross
between PR 120 x UPLRi 7 were sown as direct-seeded aerobic and conventional transplanted
crops respectively for two seasons. Various morpho-physiological, biochemical and yield related
traits were studied under the two conditions. In general, plant height, dry matter, crop growth rate,
relative growth rate, leaf area and chlorophyll content were lower under direct-seeded aerobic
conditions than under conventional transplanted conditions. Plant height and crop growth rate
showed a positive correlation with grain yield and had a direct effect on grain yield. Dry matter
accumulation did not show any significant correlation but had an indirect effect on grain yield.
Relative growth rate, leaf area and chlorophyll content did not show any correlation or effect on
grain yield. All the yield contributing traits viz., above ground biomass, total number of tillers per
0.5m row, number of fertile tillers per panicle per 0.5m row, spikelets per panicle, grain filling
percentage, grain yield per 0.5m row, harvest index, 1000 grain weight were lower and sterile
grain per panicle were higher in direct-seeded aerobic condition. Above ground biomass and
harvest index showed correlation with yield and had a direct effect on grain yield under both
direct-seeded aerobic and conventional transplanted conditions. In general, higher sugar, starch
and proline content were detected in leaves of direct-seeded aerobic crop. Out of twenty RILs
under study, Ae-RIL-B-158, showed highest proline and sugar contents. Interestingly, this RIL
showed least reduction in yield when sown under direct seeded-aerobic condition as against
conventional transplanted condition suggesting this RIL may be more tolerant to drought stress as
it accumulated highest proline and sugars under direct-seeded aerobic condition. The
development of aerenchyma was comparatively more in crop raised under conventional
transplanted conditions than under direct-seeded aerobic conditions. UPLRi7 (parent) showed
maximum aerenchyma under direct-seeded aerobic conditions while PR120 (parent) showed
maximum aerenchyma formation under conventional transplanted conditions. Under both the
sowing conditions, two high-yielding RILs (Ae-RIL-B-42 and Ae-RIL-B-44) had higher
aerenchyma than the two low-yielding RILs (Ae-RIL-B-7 and Ae-RIL-B-117). These characters
could be used as criteria for selecting RILs for incorporating into breeding programmes for yield
enhancement.
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