Euclidean Distance Analysis for Genetic Divergence in Biochemical Characters amongst Promising Bold Grain Rice (Oryza sativa L.) Genotypes of Barak Valley

In Barak valley zone of Assam the physically hard working people prefer bold type rice grains with good taste as these are slowly digested and give a feeling of fullness in the stomach for a longer time. But most of the modern high yielding rice varieties are medium and fine grain type. Keeping the need of rural people in mind, the present experiment was conducted with 49 genotypes/varieties including 47 bold grain rice genotypes and two recommended high yielding check varieties namely Ranjit and Monohar Sali of Barak valley, Assam. The mean values of fourteen biochemical characters of these 49 genotypes were evaluated. Crude protein content (%) and total soluble protein content (g/100g of oven dry sample) varied from 7.09 to 13.10 and 4.10 to 6.69, respectively. The amino acids lysine and tryptophan varied from 3.20 to 4.45 and 0.56 to 1.10 g/16g N, respectively. The starch, amylose and amylopectin contents varied from 79.78 to 65.63%, 25.56 to 15.25 and 84.75 to 74.44% of starch, respectively. Total soluble sugar, total reducing sugar and total non-reducing sugar content ranged from 1.14 to 0.35%, 0.363 to 0.103% and 0.935 to 0.279%, respectively in the bold grain rice genotypes. The ash content and the phosphorus content varied from 0.88 to 1.50% and 0.213 to 0.430%, respectively. Calcium and iron content ranged from 16.59 to 37.98 mg and 1.11 to 3.92 mg/100g, respectively in the bold grain rice genotypes. Euclidean distance, based on fourteen biochemical characters was studied among 49 rice genotypes in all combinations. The highest coefficient of dissimilarity or Euclidean distance (10.541) was observed between the genotypic pair Shem Sail (G43) and Chandmoni (G20) indicating highest genetic divergence between them. The lowest coefficient of dissimilarity [1.721] was observed between the pair Latha Sail (G34) and Kamal Bhog (G15) followed by the pair Hacha Lath (G31) and Baodun (G18) [1.920]. These pairs of genotypes showing low Euclidean distance were genetically more similar and, therefore, would not be very effective as parents in breeding superior pure lines for the biochemical characters.