Yield of new rice varieties as influenced by nitrogen level and seedling age
2000
Comadug, A.I. (Mindanao State Univ., Marawi City, Lanao del Sur (Philippines))
The experiment was conducted during the 1994 wet season at PhilRice [Philippine Rice Research Institute], Maligaya, Munoz, Nueva Ecija [Philippines] to study the yield performance of new varieties as influenced by nitrogen (N) level and seedling age and to determine the interaction effect between the N level and seedling age on the yield of three varieties. The experiment involved three factors in split-split plot design with three replications-N level (0,40, 80, and 120 kg N/ha) as main plot, seedling age (15, 20, 30, and 40-day-old) as subplot, and varieties (PSB Rc12, PSB Rc18, and PSB Rc22) as sub-sub plot. Seedlings were raised by ordinary wetbed method and transplanted with 3-4 seedlings per hill at a spacing of 20 x 20 cm. Results showed that different N levels and seedling age significantly affected the grain yield. Thirty-day-old seedlings of PSB Rc22 with 80 kg N/ha yielded highest (6.7 t/ha) among the three varieties at different N levels because of the greater number of grains/sq m and lower spikelet sterility. However, there were no significant varietal differences in grain yield. The lower yield at 120 kg N/ha indicates that N enhances more vegetative growth thereby more photosynthates for straw production, straw yield significantly increased with increasing N level up to 120 kg N/ha
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