Abstract:

To elucidate distribution of alleles, genotype composition and correlation between isozyme genotypes and enzyme activities of starch branching enzyme (SBE) in wheat (Triticum aestivum L.) grains, total activity of SBE was measured in seventy-one wheat cultivars with different provenances, including some typical hexaploid wheat from various province of China and some high-yielding modern varieties as well as eight exotic ones. The allele loci and genotypes of SBE isozymes were also investigated using native polyacrylamide gel electrophoresis (Native-PAGE). The results showed that there were two loci of starch branching enzyme, SBEⅠ and SBEⅡ. SBEⅡ failed to exhibit genetic polymorphism but SBEⅠmanifested genetic diversity. Four alleles were identified at SBEⅠ locus, that was A, B, D_ⅰ, and D_ⅱ, with frequency 9.9%, 76.1%, 95.8%, and 57.8%, respectively. Nine genotypes were determined, of them genotype D_ⅰD_ⅱB, D_ⅰB, and D_ⅰDⅱ took on high frequency with 45.1%, 28.2%, and 8.5%, respectively. From single locus analysis, starch branching enzyme activity correlated to SBEⅠ locus, but no significant correlation to SBEⅡ was observed. Therefore it indicated that different gene loci and genotypes of starch branching enzyme in wheat had different genetic impacts on enzyme activities.

Key words: Wheat (Triticum aestivum L), Starch branching enzyme, Allele, Genotype, Enzyme activity