Genetic Research And SSR Analysis To Dwarf Gene In Germplasm N0238D

The wide application of dwarf and semi-dwarf wheat varieties in the mid-20th century improved the world wheat yield significantly. Dwarf breeding depended on the discovery of the dwarfing sources and the dwarfing genes have become a major path for high-yield and sup-high yield breeding. Most of the dwarf varieties were from Daruma and Akagomugi.26 dwarfing genes which have been identified were not used sufficiently, besides breeding only focusde on few of them. So the genetic base of dwarfing wheat was narrow. Thus it is important for wheat breeding that keeping on discovering new dwarfing sources and enriching their diversity.The dwarfing inheritance and the location of the dwarfing gene in N0238D was studied by morphology and molecular technique. The results are showed as follows:1 N0238D have good field characters with dwarf (54.00cm), big ear, disease resistance, early maturity characteristics, and grain white, horny. The height of the plants of F1 which were created by crossing between the dwarfing germplasm N0238D and two high material (ChineseSpring and Abbondanza) were close to the value of medium parents.And then the genetic character of dwarfing gene in N0238D was analyzed in F2 population and BC1 population.The results were showed that the proportion of the dwarf, semi-dwarf and high individuals in the F2 segregating population was 1:2:1, the proportion of the dwarf and semi-dwarf in the BC1 population was 1:1.In a word the dwarfing character of N0238D was controlled by a major recessive gene and minor genes.2 The GA-insensitivity of the germplasm N0238D was detected by treating seedlings with low concentrations of exogenous GA.3 Four genomic SSR markers (xgwm251, Xwmc 59, xgwm 272 and xgwm 337) which were identified polymorphic in parents DNA and Bulked segregating analysis(BSA) by SSR analysis with 243 SSR primer pairs were used to screen in 143 (N0238D/ChineseSpring) and 166 (N0238D/Abbondanza) individuals F2 population, coming to a conclusion that polymorphic marker xgwm251 on 4B was linked to the dwarfing gene. The genetic distance between Rht gene and microsatellite marker xgwm251 was 14.5 cM. The dwarfing gene may be a new gene and the remaining three SSR markers Xwmc 59, xgwm 272 and xgwm 337 may be minor genes.