Sensitive event at rice flowering stage of drought resistance lines with QTL 12.1 under water deficit
2008
Oane, R.H. | Bernier, J. | Malabanan, P.B. | Estenor, L. | Enriquez, B. | Kumar, A. | Bennett, J., International Rice Research Inst., Los Banos, Laguna (Philippines). Plant Breeding, Genetics and Biotechnology Div. | Somayenda, I. | Serraj, R., International Rice Research Inst., Los Banos, Laguna (Philippines). Crop and Environmental Sciences Div.
Drought stress at the reproductive stage causes a major contribution to the decrease in spikelet fertility in rice, which translates into a significant yield decline. The lack of proper understanding of sensitive events leading to failure in grain formation is one of the constraints to improving rice traits for drought tolerance. Preliminary screening in the greenhouse showed that most sterile spikelets from popular varieties are sensitive to the event just after another exsertion. Majority of the sterile spikelets under drought stress have exserted anthers but no ovule enlargement, which may be due to failure of the anther to dehisce and/or failure of pollen to enlongate and reached the microphyle due to heading delay. In this experiment, the anthers present results from a field experiment using selected lines from Vandana/Way Rarem population with quantitative trait loci (QTL) conferring grater yield under drought stress (qtl 12.1). The authors analyzed at least 3,500 spikelets per line of plants grown in field condition under well-irrigated and extreme drought stress environment at maturity stage. Dissection of sterile spikelets showed that majority of sterile spikelets from both well-watered and drought stress environment showed similar pattern of sterility to those of popular varieties grown in the greenhouse inthe + QTL, - QTL and the parental lines, which may indicate that the Way Rarem allele qtl 12.1 that confers greater yield under drought stress did not influence the event happening at flowering stage. To account for the increase in yield under drought stress, the analysis of root biomass and leaf morphology will be discussed to explain a possible influence on these traits by qtl 12.1
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