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ARS Home » Research » Publications at this Location » Publication #121532
Title: INHERITANCE OF SEED DORMANCY IN WEEDY RICE (ORYZA SATIVA L.)

Author
item GU, XINGYOU - NORTH DAKOTA STATE UNIV.
item FOLEY, MICHAEL

Submitted to: American Society of Plant Physiologists Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/12/2001
Publication Date: 7/21/2001
Citation: Gu, X., Foley, M.E. 2001. Inheritance of seed dormancy in weedy rice (Oryza sativa L.). [Abstract]. American Society of Plant Physiologists Meeting. Providence, RI. p. 67.

Interpretive Summary: To clone dormancy genes from rice we have identified some weedy rice strains with very strong dormancy. Three pairs of dormant and non-dormant parents and their F1, F2 or backcross BC1 and BC2 generations were used in the present research to characterize the inheritance of the trait in weedy rice strains and to identify the candidate population(s) for mapping of major genes or quantitative trait loci (QTL). The dormancy was measured in terms of percent germination rate at 30 C at 7 days after imbibition. Germination tests using intact seeds, hull- and pericarp/testa-removed caryopses, and excised embryos demonstrated that dormancy in the weedy strains was imposed through its diploid maternal tissues such as the hull and pericarp/testa. The degree of dominance for seeds from F1 plants changed from complete to partial dominance for dormancy within 60 days after harvest (DAH). Germination data were collected from all the generations at 0, 20, 40 and 60 DAH. Genetic analysis revealed that the germinability in the crosses had a lower broad-sense heritability (h2b) for freshly harvested seeds and a high h2b for partially afterripened seeds. The maximum genetic variance (h2b > 90%) occurred between 20 and 40 DAH. The most significant gene non-additive and genotype-by-environment interaction effects were presented at 0 DAH. The bimodal uninterrupted distributions appeared in all F2 populations from 20 to 60 DAH manifested the presence of major genes for dormancy in weedy strains.

Technical Abstract: To clone dormancy genes from rice we have identified some weedy rice strains with very strong dormancy. Three pairs of dormant and non-dormant parents and their F1, F2 or backcross BC1 and BC2 generations were used in the present research to characterize the inheritance of the trait in weedy rice strains and to identify the candidate population(s) for mapping of major genes or quantitative trait loci (QTL). The dormancy was measured in terms of percent germination rate at 30 C at 7 days after imbibition. Germination tests using intact seeds, hull- and pericarp/testa-removed caryopses, and excised embryos demonstrated that dormancy in the weedy strains was imposed through its diploid maternal tissues such as the hull and pericarp/testa. The degree of dominance for seeds from F1 plants changed from complete to partial dominance for dormancy within 60 days after harvest (DAH). Germination data were collected from all the generations at 0, 20, 40 and 60 DAH. Genetic analysis revealed that the germinability in the crosses had a lower broad-sense heritability (h2b) for freshly harvested seeds and a high h2b for partially afterripened seeds. The maximum genetic variance (h2b > 90%) occurred between 20 and 40 DAH. The most significant gene non-additive and genotype-by-environment interaction effects were presented at 0 DAH. The bimodal uninterrupted distributions appeared in all F2 populations from 20 to 60 DAH manifested the presence of major genes for dormancy in weedy strains.