Relationship Between AFLP And Yield Heterosis In Maize

Maize heterotic grouping and the relationship between genetic differentiation and yield heterosis were studied by using AFLP technique. The materials consisted of a set of 222 combinations among 34 maize inbred lines by unbiparental(16+18) cross mating design in field and 49 inbred lines of maize in lab. Following results were obtained:1. Combining abilities of 34 inbred lines are analysised using their 222 cross combinations. The results showed that general combining abilities of not less than one of parents are high in high-yield cross combinations, and their special combining abilities are generally high. But there is not identification relationship between the level of special combining ability and yield in the whole combinations.2. 34 inbred lines have been divided into 4 groups and the result is consistent with pedigree information using Fl yield performance of the cross combinations. And there are excellent cross combinations among the different groups, especially in group I+II, II+III,II+IV.3. 49 inbred lines were studied by using AFLP technique, and the result indicated that primer-combinations among 13 pair of primers amplified 846 bands, which include 487 polymorphic bands, 43 monomorphic bands. AFLP can detect greater number of loci than those detected by other DNA makers, and a cluster analysis revealed that these lines are divided into 5 groups in standard on the genetic distance 0.188, which mainly agreed with known pedigree information and the cluster by using SSR. These results showed that AFLP could be used to do heterosis grouping of maize. And there are more excellent cross combinations in group I+II,I+IV.4. Genetic distance was correlated with heterosis, yield performance and special combining ability, but their coefficients of correlation were low. Thus, AFLP may not be used to predict heterosis of yield in maize.5. There is high relevant relationship between each trait and m (m=y/x, y stand for each trait and x stand for genetic distance) and their coefficients of correlation were high. So genetic distance may be used to predict heterosis.