NATIONL CENTER OF PLANT GENE RESEARCH(WUHAN)
Relationship between molecular marker heterozygosity and hybrid performance in intra- and inter-subs
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Relationship between molecular marker heterozygosity and hybrid performance in intra- and inter-subspecific crosses of rice Zhao, M. F., X. H. Li, J. B. Yang, C. G. Xu, R. Y. Hu, D. J. Liu and Q. Zhang. 1999. Plant Breeding 118:139-144. ABSTRACT The objective of this study was to investigate the relationship between molecular marker diversity and heterosis in both intra- and inter-subspecific hybrids of rice to evaluate the feasibility of predicting hybrid performance using molecular markers. Eleven elite lines were intermated resulting in a diallel set including 10 indica by indica, 15 japonica by japonica and 30 indica by japonica crosses. The F1 hybrids and parents were evaluated for agronomic performance in a replicated field trial. The parental lines were surveyed for DNA polymorphisms with 113 RFLP probes covering the 12 rice chromosomes. Inter-subspecific crosses showed better performance and higher heterosis than intra-subspecific hybrids. Correlations of marker heterozygosity with hybrid performance and heterosis differed considerably between the two subspecies; they were higher in crosses within japonica subspecies than within indica subspecies. Very little correlation was detected in inter-subspecific crosses. It was concluded that relationships between marker heterozygosity and hybrid performance were complex due to germplasm diversity and the complexity of the genetic basis of heterosis. The implications of the results in predicting hybrid performance using molecular markers were discussed. Key words Oryza sativa, hybrid rice, predicting heterosis, restriction fragment length polymorphism (RFLP), wide-compatibility