Growth and yield of five irrigated spring wheat varieties as influenced by seeding rate in Old Himalayan Piedmont Plain of Bangladesh

摘要

Farmers in Bangladesh are always seeking an optimal seed rate to reduce production costs and increase wheat yield.The Wheat Research Centre (WRC) of Bangladesh has developed new wheat varieties over several years. To reduce productioncosts and obtain higher grain yield (GY) from these varieties, optimum seeding rates are needed. In this context, a two-year fieldexperiment was conducted with five newly released wheat varieties (‘BARI Gom 24’, ‘BARI Gom 25’, ‘BARI Gom 26’, ‘BARIGom 27’ and ‘BARI Gom 28’) and three seeding rates (100, 120 and 140 kg ha─1). These treatments were performed underirrigation in the WRC research field in Northern Bangladesh to determine the optimum seeding rates for these varieties.Significantly higher GY (p≤0.05) was obtained with a seeding rate of 140 kg ha─1 for all varieties, compared to other rates. Aseeding rate less than the recommended rate (120 kg ha─1) for all varieties failed to produce comparable GY in both years.Among all varieties, ‘BARI Gom 26’ had the highest GY while ‘BARI Gom 25’ had the lowest GY in both years. Although theinteraction effect of variety and seeding rate on GY did not vary significantly (p≤0.05) in both years, surplus GY was 467 and233 kg ha─1, respectively for ‘BARI Gom 24’, 63 and 75 kg ha─1 for ‘BARI Gom 25’, 81 and 93 kg ha─1 for ‘BARI Gom 26’, 23and 66 kg ha─1 for ‘BARI Gom 27’, and 152 and 220 kg ha─1 for ‘BARI Gom 28’ in the first and second year when seeded at 140kg ha─1. For the same seed rate, the GY of ‘BARI Gom 24’ increased by 5.3 to 9.6% and that of ‘BARI Gom 28’ increased from2.8 to 5% over the two years. Therefore, a seeding rate of 140 kg seed ha─1 is recommended for ‘BARI Gom 24’ and ‘BARIGom 28’, while the current recommended rate (120 kg ha─1) should be continued for the other three varieties when grown underirrigation on the Old Himalayan Piedmont Plain of Bangladesh.