Genetic Analysis Of Grain Traits And Gene Mapping Of Grain Length In Rice(Oryza Sativa L.)

Rice grain characters are one of the most important economic traits of rice. A suitable grain shape and 1000-grain weight are not only related closely to the rice yield but also to the rice quality. In this research, the ~ and F2 of the crosses between a natural mutant 慪34?with super-minute grain and 慪38?with super-large grain, 慡huhui 881擲huhui 527?with middle grain size were carried out to study the inheritance of the grain shape (grain length, grain width, grain thickness and grain length/width ratio) and 1000-grain weight. The main results are summarized as below: ? The F1 grain length, grain width, grain thickness and 1000-grain weight of three crosses were lay between the two parents and tended to Y34, which indicated that those grain traits were all governed by the dominant effect of Y34 and influenced by both female and male parents. The differences of F1 grain length, grain width, grain thickness and 1000-grain weight of positive and negative crosses between Y38 and Y34 indicated the existence of cytogene effects. ? The broad heritabilities of major grain traits were calculated. The result showed that grain length, grain width and grain thickness had higher heritabilities. The grain length had the highest broad heritabilities, 95.94% and 98.02% in 881 and 527 populations, respectively. ? Studied on F2 populations indicated that except to significant superior-parent effect of grain width in 881, the grain length, grain width, grain thickness and 1000-grain weight were lay between the two parents and tended to Y34, which showed the characteristic of addictive-dominant effect. The studied on F2 also indicated that the minute grain trait of Y34 was mainly controlled by a short- grain dominant gene, which mainly affected grain length and thus affected the compound trait: grain length/width ratio and 1000-grain weight. In the 881 and 527 populations, the effect of the gene was very significant. In Y38 population, 3 the grain length, grain lengthlwidth ratio and 1000-grain weight of F2 show the characteristic of multi-genes distribution. Grain width and grain thickness were controlled by multi-genes with significant dominant effect. ? The straight line correlation analysis indicated that grain length and thickness had significant influence to 1000-grain weight, among them the grain thickness showed the most important influence and the correlation coefficient was 99.67, 128.06, 107.65 in Y38, 881, 527 populations, respectively. Partial correlation analysis of grain traits indicted that grain thickness had significant partial correlation relationships with other grain traits in the above 3 populations. The very significant partial correlation was also detected between grain length and grain width with the correlation coefficient of more than 0.90 in three populations. ? According to the result of genetic analysis, bulked segregant analysis and co- segregation analysis in the F2 of 881 and 527 populations were used to screen rice SSR molecular marker linked with the short-grain dominant gene. The result showed that the marker RM 16 in chromosome 3 is linked with the target gene, and the genetic distance is 7.76cM and 8.75cM in 881 and 527 populations, respectively. Even though there was a short-grain gene-Mi had been mapped on chromosome 3, it was just mapped on classic linkage map rather than on molecular...