Development Of Introgression Lines Of Common Wild Rice (O.rufipogon Griff.) From Gaozhou In Guangdong Province And Mapping Of QTLs For Yield-related Traits

Cultivar rice (Oryza sativa L.) has a narrow genetic base for most of the agronomic traits. A backcross BC3 population developed from an inter-specific cross between Yuexiangzhan (Oryza sativa) and Gaozhou wild rice (O.rufipogon) was used for QTL analysis to identify 17 agronomic traits, and the primary introgression lines were constructed. The main results were as follows:1. Based on the investigated results of field agronomic traits and yield-related traits, the elementary descriptive stastistics,Pearson correlation coefficients,Regression analysis, and Principal component analysis were used to analyse the BC₃F₁ population. The results indicated that seven traits of the investigated seventeen traits including grain number per panicle, productive panicle number, grain length,1000 grain weight, seed set percentage, days to heading, spikelet density have the most contribution for the yield.Based on the ranking of BC₃F₁ families in terms of the seven traits, 33.20% of the BC₃F₁ lines were better than Yuexiangzhan in some traits. These results and the statistic method to form a good way for selection in backcross breeding.2. BC₃F₁ families were used to analyse the introgression segment, and results indicated that the proportion of segment introgression from O.rupogon ranged from 2.80%⁴3.60%, with an average introgression of 21.14 % in BC₃F₁ families. The range of introgression segments of 10%-30% were obtanted in BC₃F₁ families (about 82.57%). Three thousand two hundred and nineteen heterozygous introgressed segments were detected on all 12 chromosomes. The introgression segment length ranged from 11.10⁴6.62cM with an average length 25.56cM.3. Based on the genotypes of 241 BC₃F₁ families and 120 BC3F3 lines and the investigation of agronomic traits in two years, a total of 84 putative QTLs for 17 traits were identified by using AB-QTL analysis. Among these QTLs, 59 loci (70.24%) were from O.rufipogon. Two QTLs (qGYP-2-1 and qGYP-3-1)on chromosome 2 and 3 from Gaozhou wild rice could increase the yield of"Yuexiangzhan"by 40.05% and 49.04%.4. A set of 60 introgression lines cover with 93.9% of the genome of common wild rice (O.rufipogon Griff.) in genetic background of cultivated rice (Oryza sativa L.) were constructed using 115 SSR markers. The average number of donor segments per lines was 8.12.