Performance of Spring Wheat (Triticum aestivumL.) Varietiesunder Water Regimes and Nitrogen Rates

Abstract

The high cost of supplying water and nitrogen is reducing the planted hectarage and restricting the production of spring wheat among wheat growers in Zambia. A field experiment was carried to determine the performance of twelve common spring wheat varieties when subjected to water regimes and nitrogen application rates at Nanga Irrigation Research Station in Mazabuka in 2011 winter season. The experiment was performed as a Split-split in a Randomised Complete Block Design with three replications. Water regimes (100%, 75% and 50% crop water requirements (CWR)) were considered as the main factor, nitrogen rates (80, 160 and 240 Kg N ha-1) as sub-factor and variety (Nduna, Shine, Sekuru, Sahai I, Loerie II, Pungwa, Choza, UNZA I, UNZA II, Mampolyo, Nseba and Coucal) as sub-sub factor. Grain yield, spike length, above ground biomass, plant height, thousand kernel weight,harvest index, spikelets per spike and number of grains per spike were measured. Results: Mampolyo, Nduna and Pungwa significantly (p < 0.05) produced the same and highest grain yield of 6,473, 6,494 and 6,395 kg ha-1, respectively at 100% CWR and lowest nitrogen rate. At 50% CWR and optimum nitrogen rate, Loerie II (5,351kg ha-1) and Sahai I (6,086kg ha-1) significantly (p < 0.05) produced the same and highest yields. At 75% CWR and 160 kg N ha-1, Mampolyo (5,703kg ha-1) and Sekuru (5,325kg ha-1) significantly (p < 0.05) produced the same and the highest yields and 75% CWR and 80 kg N ha-1,Nseba (5,667kg ha-1), Shine (5,224kg ha-1) and Choza (5,559kg ha-1) significantly (p < 0.05)produced the same and highest grain yields. The optimum and low level of either water on nitrogen or vice versa and 80 kg N ha-1 with 75% CWR offers wide options for spring wheat variety choice for wheat production. Conclusion: It was concluded that farmers could select some varieties with high grain yields based on the input combination suiting their capacity and increase on planted hectarage and ultimately wheat production.