Identification of genetic factors controlling domestication-related traits of rice using an F2 ...
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Identification of genetic factors controlling domestication-related traits of rice using an F2 population of a cross between Oryza sativa and O. rufipogon Xiong, L. Z., K. D. Liu, X. K. Dai, C. G. Xu and Q. Zhang. 1999. Theor. Appl. Genet. 98:243-251. ABSTRACT Domesticated rice differs from the wild progenitor in large arrays of morphological and physiological traits. This study was conducted to identify the genetic factors controlling the differences between cultivated rice and its wild progenitor with the intention to assess the genetic basis of the changes associated with the processes of rice domestication. A total of 19 traits, including 7 qualitative and 12 quantitative traits, that are related to domestication were scored in an F2 population from a cross between a variety of Asia cultivated rice (Oryza sativa) and an accession of the common wild rice (O. rufipogon). Loci controlling the inheritance of these traits were determined making use of a molecular linkage map consisting of 348 molecular marker loci (313 RFLPs, 12 SSRs and 23 AFLPs) based on this F2 population. All the 7 qualitative traits were each controlled by a single Mendelian locus. Analysis of the 12 quantitative traits resolved a total of 44 putative QTLs with 3.7 QTLs per trait on the average. The amount of variation explained by individual QTLs ranged from a low of 6.9% to a high of 59.8%, and many of the QTLs accounted for more than 20% of the variation. Thus, genes of both major and minor effects were involved in the differences between wild and cultivated rice. The results also showed that most of the genetic factors (qualitative or QTLs) controlling the domestication related traits were concentrated in a few chromosomal blocks. Such clustered distribution of the genes may provide explanations for the genetic basis of "domestication syndrome" observed in evolutionary studies and also "linkage drag" than occurs in many breeding programs. The information on the genetic basis for some desirable traits possessed by the wild parent may also be useful for facilitating the utilization of these traits in rice breeding programs. Key words Common wild rice, Cultivated rice, Evolution, Genetic analysis, Molecular marker