| The dwarf mutant was obtained from transgenic rice KMD with a crylAb gene. In order to apply it in rice improvement well and suitablely, the dwarf mutant was studied from the aspects of morphology, genetics, physiology and biochemistry. Results could be summarized as folio wings:Plant height of the dwarf mutant is about 29.40 cm on average. Dwarf traits were caused by the decrease in the number and the length of internodes. Compared with the Xiushui 11 (CK), the dwarf mutant is in short of 1.17 internodes and its length of first, second, third and fouth internodes below ear decreased in 56.64%, 71.51%, 68.90% and 73.46% respectively. The dwarf mutant has more tillers, similar weight of grain and seed-setting percentage to Xiushui 11, but orther important agromicall traints were not as good as Xiushui 11.The dwarf mutant was analysed genetically. Its dwarf character was controlled by 2 recessive genes, segregating freely in heritance. GUS activity bioassay in F2 population showed that the transgene carried by T-DNA in the dwarf mutant was integrated in single insertion. Among F2 519 plants, 3 dwarf plants showed GUS negative and 186 heigh plants showed GUS positive, which suggested that it was not caused by T-DNA insertion in transformation, rather than caused by somclonal variation in in vitro culture.The dwarf mutant and its CK (Xiushui 11) were also analysed by using SSR marker. Among the 414 pairs of SSR primers tested, 328 pairs showed amplifications, and 64 pairs revealed polymorphinism between the dwarf mutant and CK, accounting for 19.51% polymophoric frequency in the total primers used. The linkage relation of SSR marker RM405, RM592 and RM583 to dwarf genes was determined preliminarily. Among these markers, RM592 showed the close linkage to a dwarf mutant gene, while the genetic distance between RM405, RM 583 and the dwarf gene was 2.94cM and 1.47cM respectively. It has been known that RM405 and RM592 located at the short arm of rice chromosome 5 and RM583 at the the short arm ofchromosome 1, therefore the 2 dwarf genes in the dwarf mutant could be determinated at the short arm of chromosome 5 and 1.Seeds of the dwarf mutant were treated with GA solution and length of the second leaf sheath varied from -10.14% to 169.75% compared to the untreated under different concentration of GA. At tillering stage, spraying GA solution to the dwarf mutant could promote the elongation of the first and the second internode, but no significant effect on the length of the third internode. Thus the dwarf mutant belonged to the dwarf type sensitive to GA. After irradistion to y-ray (60Co) , the assay of seedling height displayed the dwarf mutant was more sensitive to radiation than Xiushui 11.Starch characteristics and key nutiritonal compositions in the dwarf mutang from transgenic rice with crylAb gene were compared with its original parent, Xiushuill. It was found that peak viscosity, hot paste viscosity and cool paste viscosity of RVA profile between the dwarf mutant and its parent were signigicantly different at 1% level, and crylAb protein only expressed in the dwarf mutant. Respectively, but apperance and milling quality charactertics, apparent amylose content, gel consistence and breakdown viscosity, setback viscosity of RVA profile were similar, and no significant differences existed in contents of crude protein, crude fat, ctotal ash, mineral compositions and amino acids. It was suggested that no notable changes in grain quality traits had been caused by integration of T-DNA in the dwarf mutant genome from transgenic rice.Results obtained in this research laid a theoretic foundation for application of the new dwarf mutant in rice breeding. |
PDF Full Text Request