Genetic diversity based on isozyme pattern of rice germplasm in China

摘要

Genetic diversity was studied in 4,408 cultivars of core germplasm selected from 56,220 Chinese rice accessions on the basis of 12 isozyme loci, Pgi-1, Pgi-2, Amp-1, Amp-2, Amp-3, Amp-4, Sdh-1, Adh-1, Est-1, Est-2, Est-5, and Est-9, analyzed through starch gel electrophoresis. Among the materials examined, 431 different genotypes were detected; genotypic diversity was 3,845. The average gene diversity index in all tested loci was 0,248. Based on isozyme allele pattern, there was clear concordance toidentify materials as indica (Hs/en), japonica (Keng), and intermediate groups, with the ratios of 68.7%, 30.3%, and 0.98%, respectively. These figures matched well with 67.0% indica and 32.1% japonica based on the classification of morphological characters. The average genetic diversity of indica rice was 0.193, which was much higher than that of japonica (0.092). Amp-2 had the highest coefficient of genetic differentiation (Gst = 0.847) between indica and japonica, followed by Pgi-1, Pgi-2, and Est-2.It was found that in six rice ecoregions in China, the cuitivars in the southwest ecoregion had the highest average genetic diversity (Ht = 0.266), followed by the south and central ecoregions. A new allele was identified in only four indica cultivars (Makezhan, Jibianzi, Changmaodao, and Jiefan 16) out of the 4,408 genotypes analyzed. This was designated Pgi-1~5.