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Researchers find a new possibility to improve rice productivity

By Sunderarajan Padmanabhan New Delhi, May 27 (India Science Wire): Rice is one of the main staple foods across the world as it has high carbohydrate content and provides instant energy. In Southeast Asia, where it is consumed more than in other parts of the world, it accounts for more than 75% of the calorie intake. India has the largest area under rice crop cultivation; almost all states grow rice. However, it suffers from a problem of low productivity. To meet the demand of the growing population of India and the world, production of rice needs to increase significantly, say by about 50% of current production. Traits like the number of grains per plant and weight of the grain mainly determine the yield in rice. Thus, one of the main aims of researchers and breeders has been to develop superior rice varieties with heavier grains, which can give higher yield and better nutrition. In a new study, researchers from the Department of Biotechnology’s National Institute of Plant Genome Research (DBT-NIPGR); ICAR-Indian Agricultural Research Institute (ICAR-IARI); ICAR-National Rice Research Institute (ICAR-NRRI), Cuttack; and University of Delhi South Campus (UDSC) have identified a region in the genome of rice, which seems to have the potential for improving productivity. The scientists conducted their study by sequencing the genomes of four Indian genotypes (LGR, PB 1121, Sonasal & Bindli) that show contrasting phenotype in seed size/weight. After analyzing their genomic variations, they found that the Indian rice germplasms had much more genomic diversity than that estimated so far. They then studied the DNA from 3000 rice accessions from across the world along with the four Indian genotypes sequenced in the study. They identified one long (~6 Mb) genomic region, which had an unusually suppressed nucleotide diversity region across the centromere of chromosome 5. They named it a `low diversity region’ or LDR in short. An in-depth multidimensional analysis of this region revealed that it had played an important role during domestication of rice varieties as it was present in most of the cultivated rice genotypes and absent in wild varieties. Most of the modern…