Genetic Analysis And Initial Location Of Zebra-band Gene ZB9(t)in Rice (O.Sativa L.)

A natural zebra-band rice mutant HR15m was found in an Indica restorer line HR15. the phenotypic traits showed leaves of yellow and green zebra-band in the Seedling Stage The mutant was tentatively named HR15m and the mutant gene ZB9(t). In this study, chlorophyll content and main agronomic traits of the zebra-band mutant HR15m and the wild type HR15 were compared. Effects of factors including seedling stage, sowing date, and temperature on HR15m mutant expression were tested through the field and pot experiments. Meanwhile, initial location of the mutant gene was made using the existing and new developed SSR markers taking F2 and F3 group of the mutant and Nipponbare as the mapping population. The major results are as follows:1. Chlorophyll content of the mutant was significantly lower than that of the wild type during the mutant expression. Chlorophyll b had decreased more than chlorophyll a, while in other periods there were no significant differences in chlorophyll content.2. Analysis on main agronomic traits of both the mutant and the wild type indicated that the mutant were higher in tiller number and 1000 grain weight than the wild type but there were significantly differences in other agronomic traits.3. Mutant expression was directly related to transplantation, and it generally showed zebra-band leaf one week after transplanting. Mutant expression was affected by the seedling age when transplanting and too small or too big was unfavorable to mutant character.4. Sowing experiments and low temperature treatment showed that the mutant HR15m was different to temperature sensitive mutant 1103s, the expression of HR15m was not directly related to temperature changes.5. F1 and F2 generation were got from cross between the mutant and the Nipponbare. Observation showed that F1 performanced no zebra-band leaf and the segregation ratio of F2 was 3:1, indicating that the zebra-band mutant character was controlled by a single recessive gene.6. Taking F2 and F3 group from the japonica and indica cross as the mapping population, the mutant gene ZB9 (t) was located on the long arm of rice chromosome 12 using SSR markers. Linkage analysis showed that the gene was located between RM101 and RM277, with the genetic distances of 4.4cM and 5.4cM respectively. After increased the group the mutant gene ZB9 (t) was finally located between MM1296 and MM0948 with a physical region 477 kb.