Identification and molecular characterization of zinc biofortified rice(Oryza sativa L.)
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Date
2020
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Department of Agricultural Biotechnology, OUAT, Bhubaneswar
Abstract
Rice is the major staple food of more than half of the world population. Malnutrition seems to be a chronic problem affecting three billion people including death of 3.1 million children each year. Developing countries are worst affected and in India, Odisha being one of the poorest state in the country, nutritional deficiency and zinc in particular is alarming causing loss of immunity to diseases, stunted growth, impaired learning ability, wound healing and reproduction; and increased risk of infection, DNA damage and cancer. Feeding hungry with nutritious rice seems to be a lasting solution to food and nutritional security. Therefore, a quest for identification of zinc rich rice genotypes and exploring the genetic loci determing grain Zn content in selected donors using gene specific marker(s) was attempted as a step forward for development of zinc biofortified varieties in rice . In the present investigation, a set of 26 test genotypes including 11 promising land races, four zinc biofortified released varieties (BRRI Dhan 64, BRRI Dhan 72, CGZR-1 and DRR Dhan 45), nine Zn-dense advance breeding lines, one zinc dense check variety (Chittimatyalu) and one low zinc mega variety of rice (Swarna) as yield check were characterized for morpho-economic traits, physical quality traits and grain zinc content. One advance breeding line of IRRI e.g., IR128773-4-4-2-2-B and three land races of Odisha e.g., Nikipankhia, Tikimahsuri, and Mallipullajhuli harbour Zn content more than 40 ppm in rice grain. Among these, IR128773-4-4-2-2-B revealed high yield potential (≥ 45.0qtl/ha), while the zinc rich land race Nikipankhia yielded 39.20q/ha. Number of effective ear bearing tillers and grain number/panicle had significant positive correlation with seed yield, but plant height correlated
negatively with yield per se. Tiller number indirectly contributed to seed yield via its strong correlation with grain number and fertility percentage; and inverse relationship with plant height. Grain number/panicle though negatively correlated with 100-grain weight, grain breadth and kernel breadth, but directly contributed to yield by its strong positive association with tiller number. However, grain Zn content seems to have feeble negative association with grain yield although there was significant positive correlation with plant height and grain length. 100-grain weight negatively correlated with grain number/panicle, but positive association with grain breadth and kernel breadth. The present set of material was distributed into eight distinct clusters. Swarna, Karhani and Nikipankhia formed monogenotypic clusters (Cluster I, III and IV), while Nagina 22 and Chittimatyalu constitute Cluster II. These were highly divergent from rest of the clusters. Swarna being most divergent with semidwarf plant type and high yield potential, may be considered for hybridization with Nikipankhia - a highly divergent land race with higher grain Zn content than even Karhani, Nagina 22 and Chittimatyalu. Besides, the present set of 25 core high zinc test genotypes along with Swarna (Check) were screened for presence of genetic locus for the zinc transporter gene osZIP 1 that functions at rhizosphere. A 720bp amplicon was revealed in BG 102, BRRI Dhan 64, BRRI Dhan 72, Dudh Kandar, DRR Dhan 45, IR 95133:1-B-16-14-10-GBS P1-2-3, IR 85850-AC-157-1, IR 91143-AC239-1, Kalanamak, CGZR 1, R-RHZ-7, Nikipankhia, Tikimahsuri, Bishnupriya, Hundar, Karhani, MI 127, Malliphulajhuli and Padmavati using gene-specific primer in PCR analysis indicating the presence of the above candidate gene. Such a marker assisted selection of donors for presence of Zn transporter gene(s) can pave the way for gene.
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TH - 6117