LORAL BIOLOGY OF BASMATI AND NEPALI FINE RICE (Oryza sativa L.)

Abstract

The field experiment was conducted at the experimental field of Genetics and Plant Breeding department in Hajee Mohammad Danesh Science and Technology University, Dinajpur during December, 2008 to May, 2009 to study floral biology, character association and correlation provided by Basmati and Nepali fine rice. The results of the investigation revealed that the highest mean difference (0.7) for pairs of tillers/fill at vegetative and (4.1) for pairs of effective tillers/hill at maturity stage were observed at 2" 15 days interval of sowing. The results of paired ‘t’ test indicated that tillers/hill at vegetative and effective tillers/fill at maturity stage at 1* sowing period were highly significant and showed vast difference in between the genotypes. Leaf angle under the flag leaf (0°) showed higher mean difference at 24 sowing 15 days later and paired ‘t’ test indicated, 2"4 sowing 15 days later pairs showed highly significant difference among the three pairs. In case of leaves/tiller, paired ‘t’ test indicated that appropriate time gave the maximum leaves for contributing photosynthesis. Whereas paired ‘t’ test for panicle length (cm) and plant height (cm) showed highty significant difference between Basmati and Nepali rice. Rachillae/panicle and fertile grains/panicle were more yield increasing attributes at optimum period of sowing. Thousand grains/weight (g) and yield /hill (g) in Nepali and Basmati showed the highest mean (23.087 (g) and 38.702(g)) at 1% sowing followed by 2"4 15 days and 3 30 days interval of sowing. These indicated that 1% sowing time gave more yield than other sowing period. The maximum pollen fertility (%) and spikelet fertility (%) was observed in both varieties at 1% sowing period and the lowest at 3% 30 days interval of sowing. The range of maximum days required for flowers blooming and commence anthesis after panicle emergence were 2-4 and 7-9 days respectively in both Nepali and Basmati rice. The range of anthesis period was 7-10 a.m. in usual but the period of opening of spikelets was (2 fr. 50 min.) in Nepali and (2hr. 45 min.) in Basmati rice. Correlation coefficients of grain yield per hectare with fertile pollen, pollen fertility (%), spikelet fertility (%) and period of opening of spikelets were positive and highly significant. Whereas, correlation between grains yield per hectare with sterile pollen and period of blooming flower were negative and significant. Selection based on fertile pollens, pollen fertility (%), spikelet fertility (%) and period of opening spikelets would be effective for increasing grains yield.