Profiling Bangladeshi rice diversity based on grain size and amylose content using molecular markers

Abstract

Bangladesh lies within the origin of rice biodiversity and is home to many genotypes with varying amylose content and grain size. There is however no precise data on their amylose content and correlation with grain size and type. Yet these classifications governs the taste, cooking and nutritional quality of rice, ultimately determining its consumer preference and market price. Correlating grain size with amylose content will be useful information for Diabetics, particularly due to the unproven assumption that long grains correlate with high amylose content and vice versa. In this study, 131 long, medium and short grain Bangladeshi rice cultivars were analyzed and classified into high, intermediate, low or very low (H, I, L or VL) amylose slender or bold grain types. Both short and medium grain cultivars have mostly H or I amylose. The maximum amount of L and VL amylose was found among the long grain cultivars which also contain H and I amylose-containing rice. Therefore we could clearly show that long grains are associated with L and VL amylose, rather than medium and short grain. The microsatellite marker (RM190) and CAPS marker (RM190F-GBSSW2R/AccI) are linked to the gene responsible for amylose content and can be used for distinguishing variants. Thirty-five cultivars with all grain sizes were found to have four RM190 alleles (1–4: 100, 110, 116 and 120bp). Cultivars having VL amylose were identified by RM190F-GBSSW2R/AccI cleavage pattern. High amylose-containing rice was found mostly associated with class 1 and 2 alleles. The intermediate amylose group was characterized by the absence of the class 1 allele. Therefore we could distinguish VL, H and I amylose rice with simple tests with the rest belonging to the L group. The study thus demonstrated the use of simple tests in the categorization of rice, based on amylose groups.