Author
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JOHNSON, O - CORNELL UNIV |
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XU, Y - CORNELL UNIV |
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CHEN, X - CORNELL UNIV |
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PARK, W - TAMU |
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BEACHELL, H - RICETEC |
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Dilday, Robert |
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GOTO, M - CORNELL UNIV |
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MCCOUCH, S - CORNELL UNIV |
Submitted to: Genome
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/4/1997 Publication Date: N/A Citation: N/A Interpretive Summary: There is not an effective and efficient method of detecting within-cultivar variation in rice varieties. Our objective was to determine an efficient way of detecting within-cultivar variation in rice varieties obtained from national and international germplasm collections. Variation between individuals within an accession and between duplicate accessions within a cultivar was detected even in cultivars that had been purified by phenotypic evaluation. Landrace cultivars were more heterogeneous and displayed a larger number of both RFLP and SSLP alleles than did modern cultivars. Microsatellite markers detected a greater number of alleles and were able to discriminate between even closer related individuals more efficiently than RFLPs. Single markers revealed 5.6-61.1% of the total variation detected by the ten SSLP markers. Several combinations of four SSLP markers detected as high as 94% of the total within-cultivar variation ndetected by the ten SSLP markers. The results suggest that the use of fou well-chosen microsatellites would be an efficient method for evaluating the heterogeneity of rice accessions. The results will be used by other scientists especially rice breeders and geneticist in rice variety development. Technical Abstract: The objective of this study was to determine an efficient way of detecting within-cultivar variation in rice varieties obtained from national and international germplasm collections. Seventy one rice cultivars were evaluated for within-cultivar variation using a combination of phenotypic, RFLP and microsatellite or simple sequence length polymorphism (SSLP). Variation between individuals within an accession and between duplicate accessions within a cultivar was detected even in cultivars that had been purified by phenotypic evaluation. Landrace cultivars were more heterogeneous and displayed a larger number of both RFLP and SSLP alleles than did modern cultivars. Microsatellite markers detected a greater number of alleles and were able to discriminate between even closely related individuals more efficiently than RFLPs. Some microsatellite markers were more informative than others for assessing genetic diversity. Single markers revealed 5.6-61.1% of the total variation detected by the ten SSLP markers. Some marker combinations were complementary, providing more information than others. Several combinations of four SSLP markers detected as high as 94% of the total within-cultivar variation detected by the ten SSLP markers. These results suggest that the use of four well- chosen microsatellites would be an efficient method for evaluating the heterogeneity of rice accessions. |