Genetic Mapping And Gene Localization Of Main Agronomic Characters Of Sorghum×Sudan Grass

Genetic map of sorghum × sudan grass (314A X ZKSD) were constructed based on AFLP and RAPD markers with F2:3 population . The field experiments were designed with randomized blocks of 3 replications in 2 areas and involved 248 families of F2:3 . 10main agronomic characters (including yield) were tested . The Quantitative Trait Loci (QTL) and gene effects of 10 characters were analyzed with composite interval mapping (CIM) based on the Genetic Segregant Analysis. The main results were as follow : 1. The linkage map of sorghum x sudan included 158 AFLP markers and 8 RAPD markers. It covered 836 cM of the genome. The average interval was 5.03 cM among the markers . 2. 136 loci from 166 loci (158 loci based on AFLP markers and 8 loci based on RAPD markers) were significantly expressing the segregation ratio of 3:1 through X-square test. The fitness was 81.9% and the deviation rate was 18.1% . 3. 48 QTL related to the 10 agronomic characters . In detail ,that is , 5 QTLs related to height , 5 QTLs related to tiller number , 5QTLs related to stem diameter , 4 QTLs related to leaf number , 6 QTLs related to leaf length , 5 QTLs related to fresh weight of individual , 5QTLs related to dry weight of individual , 4QTLs relalated to weight ratio of stem / leaf . The loci were located on 10 Linkage populations separately . 4. From 98 QTLs Detected in the materials come from 2 areas (48 QTLs from one area , 50 QTLs from the other area), 6.1% QTLs (that was 6 loci) express additive effect ; 36.8% QTLs (that was 36 loci) expressed partly dominance effect; 17.3% QTLs (that was 17 loci) expressed dominance effect; 39.8% QTLs (that was 39 loci) expressed superdominance effect. The superdominance effect and the dominance effect took the main function in the genetic basis of heterois of sorghum x sudan grass. 5. The estimate of genetic parameters and correlation of 10 agronomic characters proved , the differences among the F2:3 families were extremely significant . The correlations among most characters were significant (P=0.05 orP=0.01). 6. The 10characters of 5 progeny populations were analyzed with the Quantitative Character main gene + polygene mixed genetic model , the genetics of the characters , such as yield of individual , height, stem diameter , leaf number , leaf length and ear length , was according to double-gene style of main gene + polygene mixed genetic model ; that of the characters , such as tiller number , leaf width and weight ratio of stem / leaf , was according to one-gene style of main gene + ploygene mixed genetic model .