Development Of Introgression Lines Of Common Wild Rice (O.rufipogon Griff.) From Yanjiang In Yunnan Province And Identification Of Genetic Factors Controlling The Domestication-related Traits Of Rice

Common wild rice (Oryza rufipogon Griff.) is wild progentior of cultivated (Oryza sativa L.). Morphological characters, adaptation ability and genetic diversity have been tremendously changed during the process of evolution from common wild rice to cultivated rice. An advanced backcross population between an accession of Oryza rufipogon from Yuanjiang, Yunnan province in China, as the donor, and the elite Indica cultivar Teqing, as the recipient, was developed to identify genetic factors influencing the differentiation between cultivated rice and common wild rice. QTLs for 18 agronomic traits were also analyzed by the same population. The main results were as follows:1.The genetic analysis of the domestication-related traits (awn, hull color, panicle type, seed shattering habit, sheath color, growth habit and pericarp color) showed that all wild phenotypes are dominant and controlled by a single Mendelian factor. The genes for these traits, including awn, hull color, panicle type and seed shattering habit, were located on the long arm of chromosome 4. The genes for growth habit and pericarp color were located on the short arm of chromosome 7. These results may provide an explanation that the domestication-related traits were controlled by simple heredity and the genetic basis of the "domestication syndrome" (Harlan, 1975).2.The gene controlling growth habit which is a key characteristic of the genetic differentiation between common wild rice and cultivated rice was mapped on the short arm of chromosome 7.3.It was found that genes (QTLs) of the domestication-related traits detected in this study distributed mainly on the distal end of the long arm of chromosome 1, the long arm of chromosome 4, the short arm of chromosome 5, the short arm of chromosome 7 and the centromere region of chromosome 8. These chromosomal regions may be the hot point of the genetic differentiation from common wild rice and cultivate rice.4.Based on the genotypes of BC3F2 lines and the investigation of agronomical traits of BC3F2 lines and BC3F3 lines, a total of 100 putative QTLs influencing 19 traits were identified. Among the QTLs of yield traits, 46.5% of the alleles originating from O. rufipogon showed positive effect in the background of Teqing.5.A set of 106 introgression lines representing 97% of the genome of common wild rice (O.rufipogon Griff.) in genetic background of cultivated rice (O.sativa L.) were developed using 112 SSR markers. The mean number of donor segments per introgression line was 4.36. It is very important to construct introgression lines for exploring and utilizing beneficial genes from common wild rice and for fine mapping and cloning the genes controlling the domestication-related traits.