Improving micronutrient value of rice through breeding
A 10×10 complete diallel crosses were made in studying the genetics of high Fe trait in the grain. Genetic analysis showed the complexity of high-Fe trait inheritance. The combining ability analysis showed high significance of the general combining ability (GCA), suggesting that some parents are good combiners that, when crossed, could produce high-Fe trait in their progenies. Specific combining ability (SCA) was also significant, indicating that good specific combinations of parents could be selected that contain increased Fe concentration in the grain. The presence of reciprocal effects suggested the importance of the choice of paternal or maternal parent. Narrow-sense heritability was moderately low (43％). The large difference between narrow-sense and broad-sense heritability (88％) estimates confirmed the importance of a non- additive type of gene action responsible for the high-Fe trait. Thus, for breeding for high-Fe concentration in rice grain, selection should not be applied in the early segregating generation since dominance effect (unpredictable/urfixable genes) is still present. Selection should be delayed in the later generation, such as F<,5> where the dominance effect (unfixable genes) is not pronounced. There is a great potential for exploiting heterosis by developing hybrid rice with enhanced Fe accumulation in the grain. To increase the genetic variability of the trait, plants should be grown under optimum environmental conditions. Three important QTLs were detected for high-Fe traits. These were located on chromosomes 7, 8, and 9, with 30.3％, 21.3％, and 19.0％ phenotypic variation, respectively. Three QTLs were identified for aroma. These were located on chromosomes 5, 7 and 8, with 16.4％ to 38.3％ of the variation. Two QTLs in high-Fe trait and aroma were common in two chromosomes (7 and 8) but in different loci with 24.8 and 36.4cM between QTLs, respectively. These results indicated a slight linkage between aroma and the high-Fe trait. The use of biotechnological tools such as the molecular marker-assisted selection approach will significantly increase the prospects of breeding to improve the Fe concentration of rice.
rice micronutrient breeding genetics diallel QTL
G. B. Gregorio T. Htut
Plant Breeding, Genetics and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, Metro Manila, Philippines
国际会议
第九届痕量元素生物地球化学国际会议(9th International Conference on the Biogeochemistry of Trace Elements)
北京
英文
268-269
2007-07-15（万方平台首次上网日期，不代表论文的发表时间）