出版社：The International Institute for Science, Technology and Education (IISTE)
摘要：To study the effect of different sowing dates on rice nursery rising and to evaluate their effect on yield and yield components of rice genotypes, an experiment was conducted at Agriculture Research Institute (N) Mingora Swat, Pakistan, during summer 2011. The experiment was laid out in randomized complete block design with four replications. Seven genotypes (PARC 403, OM5627,IR64,IR8225-9-3-2-3, CIBOGO,GA-5015, and FakhreMalakand) and 5 sowing dates (D1= 25 th April, D2= 10 th May, D3= 25 th May, D4= 9 th June, and D5= 24 th June) were used. Each genotype was sown in six rows in dry bed nursery. The germination percentage was above 90%. The nursery reached its optimum size up to 30 days and was ready for transplantation.Sowing on either D5 (24 th June) or D4(9 th June)gave maximum leaf area(9.6 and 9.1 cm 2 ) followed by D3 (7.2 cm 2 ), maximum leaves seedling -1 produced by D3 (5.3) followed by D2 (5.0). Maximum seedling height was gave by sowing on D5 (23.5 cm) followed by D4 (19.9 cm), maximum biomass gave by sowing on D4 (15.3 gm) and D5 (13.8 gm) followed by D2 and D3 (12.8 and 12.2 gm), highest root number gave by D4 (13.0) followed by D2 and D3 (11.3 and 11.5) and highest root length gave by D1 and D2 (10.7 and 10.7 cm) followed by D3 (9.6 cm). Among the rice genotypes FakhreMalakand produced highest seedling height (21.9 cm), highest biomass (14.0 gm), highest root length (12.9 cm) followed by GA-5015 while maximum leaf area gave by genotype PARC 403 (9.8 cm 2 ) and number of leaves (4.9) followed by FakhreMalakand (8.3 cm 2 and 4.6) respectively. Later data showed that highest paddy yield (6.49 t ha -1 ) was produced by FakhreMalakand sown on either D2 or D3 while the other genotypes were at par valued in this order. On the basis of the above results, it is recommended that rice nursery rising should be either D2 or D3May10 th or 25 th in the agro-ecological conditions of swat valley. Key w ords: Rice (Oryza sativa L.), genotypes, sowing dates, biomass, seedling
