Root pulling resistance in rice: Inheritance and association with drought tolerance |
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| Authors: | I J Ekanayake D P Garrity T M Masajo J C O'Toole |
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| Institution: | (1) Department of Agronomy, The International Rice Research Institute, P.O. Box 933, Manila, Philippines;(2) University of the Philippines, Los Baños, Naguna, Philippines |
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| Abstract: | Summary Avoidance of drought stress is commonly associated with root system characteristics and root development. The inheritance of root pulling resistance in rice (Oryza sativa L.) was investigated and its relationship with visual field scores for drought tolerance was studied. Transgressive segregation for high root pulling resistance was observed in 3 crosses (high x high, low x high, and intermediate x intermediate). Both dominant and additive genes control the variation. F1 superiority for high root pulling resistance was observed and could be exploited in an F1 hybrid breeding program. F2 distribution curves indicated that plants highly resistant to root pulling can be obtained not only from low x high and high x high crosses, but also from intermediate x intermediate crosses. Root pulling resistance in rice has a low heritability (39 to 47%). Thus, breeding for a high root pulling resistance may best be accomplished by selection based on line means rather than individual plant selection. Field screening showed significant differences in leaf water potential among random F3 lines. F3 lines with higher leaf water potential had better visual scores for drought tolerance. Visual drought tolerance scores were correlated with root pulling resistance. Plants with high root pulling resistance had the ability to maintain higher leaf water potentials under severe drought stress. The usefulness of the root pulling technique in selecting drought tolerant genotypes was confirmed. |
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| Keywords: | Orvza sativa L rice drought tolerance genetics leaf water potential root pulling resistance |
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