Molecular design breeding is one of straightforward approaches to break yield barriers in rice. In this study, GW6 gene for grain length and width from Baodali was transferred into an indica recurrent parent 9311 and ...Molecular design breeding is one of straightforward approaches to break yield barriers in rice. In this study, GW6 gene for grain length and width from Baodali was transferred into an indica recurrent parent 9311 and a japonica variety Zhonghua 11 （ZH11） using marker-assisted backcross （MAB）. One and three introgression lines were selected for phenotypic analysis from 9311 and ZH11 genetic backgrounds, respectively. SSL-1, an improved 9311 near isogenic line with GW6 performed 11%, 19% and 6.7%higher of grain length, 1000-grain weight and single plant yield, respectively, as compared with 9311. All the three improved ZH11-GW6 lines, R1, R2 and R3, had more than 30% increase in grain weight and about 7%higher in grain yield. Seed plumpness of R1, R2 and R3 was improved synchronously because the three ZH11-GW6 lines contained GIF1 （Grain Incomplete Filling 1）, a dominant grain filling gene. Thus, GW6 has high potential in increasing the yield of inbred lines through MAB, making it an important genetic resource in super hybrid rice breeding. This study provides insights in the utilization of GW6 for large grain and high yield rice breeding via molecular design breeding.展开更多
Genetic diversity of 36 rice entries from the United States Department of Agriculture （USDA） rice collection was assessed using 103 ILP （intron length polymorphism） and 54 SSR （simple sequence repeats） markers. ...Genetic diversity of 36 rice entries from the United States Department of Agriculture （USDA） rice collection was assessed using 103 ILP （intron length polymorphism） and 54 SSR （simple sequence repeats） markers. A total of 236 and 332 alleles were detected by the ILP and SSR markers, respectively. On average, the SSR markers produced higher polymorphism information content value and number of alleles than the ILP markers. Whereas the Nei＇s genetic distance measured using the SSR markers was much higher than that measured using the ILP markers. Manters test indicated that there was a statistically significant correlation （r=0.827, P〈0.001 ） between the two marker systems. UPGMA clustering based on the ILP and SSR markers resulted in consensus dendrograms. The cophenetic correlation coefficient （r=0.918, 0.878 and 0.924, P〈0.001 for the ILP, SSR and combined markers, respectively） showed a highly accurate dendrogram represented the genetic distance among these entries. The 36 entries were divided into four groups. Four African Oryza glaberrima accessions were clustered within a distinct group （I）, and the remaining entries were separated into three groups （11, III and IV）. All the entries could be also clustered into two main groups： One was composed of III and IV, considered as indica group, and the other was composed of I （O. glaberrima） and II （japonica-like）. Model-based cluster analysis revealed that the japonica-like group maintained very pure ancestry while the indica group shared mixed ancestry, especially for group III, which had seven admixtures sharing from 19.5% to 30.0% of ancestry with group IV （based on SSR markers）. It is suggested that ILP and SSR markers could be very useful for the genetic study and breeding in rice.展开更多
基金supported by grants from the National Science Foundation of China (Grant No. 31271700)National Basic Research Program of China (Grant No. 2013CBA01405)
文摘Molecular design breeding is one of straightforward approaches to break yield barriers in rice. In this study, GW6 gene for grain length and width from Baodali was transferred into an indica recurrent parent 9311 and a japonica variety Zhonghua 11 （ZH11） using marker-assisted backcross （MAB）. One and three introgression lines were selected for phenotypic analysis from 9311 and ZH11 genetic backgrounds, respectively. SSL-1, an improved 9311 near isogenic line with GW6 performed 11%, 19% and 6.7%higher of grain length, 1000-grain weight and single plant yield, respectively, as compared with 9311. All the three improved ZH11-GW6 lines, R1, R2 and R3, had more than 30% increase in grain weight and about 7%higher in grain yield. Seed plumpness of R1, R2 and R3 was improved synchronously because the three ZH11-GW6 lines contained GIF1 （Grain Incomplete Filling 1）, a dominant grain filling gene. Thus, GW6 has high potential in increasing the yield of inbred lines through MAB, making it an important genetic resource in super hybrid rice breeding. This study provides insights in the utilization of GW6 for large grain and high yield rice breeding via molecular design breeding.
基金supported by the China Scholarship Council(CSC)(Grant No.2008100568)
文摘Genetic diversity of 36 rice entries from the United States Department of Agriculture （USDA） rice collection was assessed using 103 ILP （intron length polymorphism） and 54 SSR （simple sequence repeats） markers. A total of 236 and 332 alleles were detected by the ILP and SSR markers, respectively. On average, the SSR markers produced higher polymorphism information content value and number of alleles than the ILP markers. Whereas the Nei＇s genetic distance measured using the SSR markers was much higher than that measured using the ILP markers. Manters test indicated that there was a statistically significant correlation （r=0.827, P〈0.001 ） between the two marker systems. UPGMA clustering based on the ILP and SSR markers resulted in consensus dendrograms. The cophenetic correlation coefficient （r=0.918, 0.878 and 0.924, P〈0.001 for the ILP, SSR and combined markers, respectively） showed a highly accurate dendrogram represented the genetic distance among these entries. The 36 entries were divided into four groups. Four African Oryza glaberrima accessions were clustered within a distinct group （I）, and the remaining entries were separated into three groups （11, III and IV）. All the entries could be also clustered into two main groups： One was composed of III and IV, considered as indica group, and the other was composed of I （O. glaberrima） and II （japonica-like）. Model-based cluster analysis revealed that the japonica-like group maintained very pure ancestry while the indica group shared mixed ancestry, especially for group III, which had seven admixtures sharing from 19.5% to 30.0% of ancestry with group IV （based on SSR markers）. It is suggested that ILP and SSR markers could be very useful for the genetic study and breeding in rice.
