DEVELOPMENT OF AROMATIC FINE RICE (Oryza sativa L.) GENOTYPES FOR BANGLADESH

Abstract

At the beginning of the investigation 32 F4 lines derived from eight crosses including six aromatic fine rice varieties as parents were received from the Department of Genetics and Plant Breeding, HSTU, Dinajpur. The field experiments were conducted at Randomized Complete Block Design (RCBD) with three replications. The unit plot size was 3m x 2m and spacing was 20 cm x 20cm in every experiment. Field data were recorded on plant height (cm), productive tillers/hill, panicle length (cm), fertile grains/panicle, sterile grains/panicle, panicle weight (g), sterility percentage, lodging percentage, 1000-grain weight (g), days to 50% flowering, days to maturity, harvest index and grain yield/hill (g). Broad sense high heritabilities (h2b) were measured for all the characters except productive tillers/hill and genetic advances of the characters were in general low which suggest both additive and non-additive interactions of genes were envolved upon the expression of the characters. Genotypic and phenotypic associations among the characters were in same direction and panicle weight, 1000-grain weight and harvest index showed positive and significant correlation, whereas plant height, panicle length and sterility percentage were negatively associated with grain yield/hill. Hence, short stature plants to resist lodging with high spikelet fertility must be considered during selection. Thousand grain weight extorted maximum positive direct effect (0.843) followed by fertile grains/panicle (0.361), plant height and sterility percentage exercised maximum negative direct effects (-0.821) and (-0.965), respectively to build up association with grain yield. The negative direct effects of these two characters were not counter balanced by other grain yield enhancing characters. Therfore, panicle weight, 1000-grain weight and harvest index were the important characters for improving yield potential. Upon measuring the response to selection from F4 to F5, plant height, sterile grains/panicle, sterility percentage, panicle length and days to maturity exhibited negative direction, but high realized heritabilities were estimated for productive tillers/hill, grain yield/hill and harvest index. So, the latter three characters had high realized heritability might consider during advancing the generation. The thirty-two advanced lines (F4) were grouped into five clusters following Mahalanobis‘s D2 statistics and principal component analysis (PCA). Considering grain yield potential, aroma assessed from green leaves and powder grain and clustering pattern with cluster means, ten lines of F6 (PL1, PL2, PL12, PL13, PL15, PL16, PL17, PL22, PL24 and PL26) were forwarded to assess performance in three locations. Overall, the Plant Breeding Research Farm, HSTU, Dinajpur projected the highest environmental index (1.397), suggests superior to BADC Seed Multiplication Farms Nilphamari and Faridpur. Applying Eberhart and Russell model along with GGE biplot analysis, the stability and sensitivity of the advanced lines were evaluated over the three locations. The highest grain yield/hill was obtained from PL13 (18.85 gm/hill) followed by PL16 with 18.10 g/hill and Pl1 with 16.12 g/hill and both the lines had regression coefficients (bi) closed to unity and deviation from regression (s2di) very near to zero, suggest average stable with considerable yield potential across the three locations. The aroma contents in F5 and F6 were assessed by the sensory method with the help of a six members panel. The highest aroma contents were assessed in the lines, PL1 (Kalozira x Kataribgog) and PL13 (Kataribhog x Chinigura) from cooked rice. While other cooking qualities were considered, PL13 exhibited the maximum cooked rice expansion (5.87cm) and PL6 had resulted the minimum semi-liquid starch (348ml) during cooking. Therefore, considering all findings the advanced lines PL1 and PL13 appeared outstanding both for grain yield and aroma content, and the line PL16 was stable with average yield potential over three locations. Therefore, the advanced lines PL1, PL13 and PL16 (F6) might be forwarded for further utilization in aromatic rice breeding in the country.