Yield and yield components of wheat (Triticum aestivum L.) and their interrelationships as influenced by nitrogen and seed rate in the Sudan

Abstract

SUMMARYField experiments were conducted for three seasons, 1971–2, 1972–3 and 1973–4 to study the effects of nitrogen fertilizer and seed rate and their interactions on grain yield and its components and attributes of growth of two wheat varieties, Giza 155 and Mexipak. The semi-dwarf Mexipak was found to be more responsive to nitrogen application than the taller Giza 155 in a number of aspects, namely, grain yield per unit area of land, the number and weight of grains per ear, the dry weight per ear and dry weight of ears/m2. The numbers of spikelets and grains per ear of both varieties decreased linearly with an increase in seed rate. The 1000-grain weight was not affected in both varieties by either seed rate or N fertilizer.Variety × nitrogen, variety × seed rate and nitrogen × seed rate interactions were significant; the variety × nitrogen × seed rate interactions were not significant. Mexipak was found to have a definite optimum seed rate of 192 kg/ha at an optimum N level of 129kgN/ha for maximum grain yield. Giza 155 was less responsive to changes in seed rate and therefore its optimum seed rate was not as definite as that for Mexipak. Evidence presented here suggests that wheat varieties of different growth habits grown in the Sudan should receive differential treatments when the policies of setting optimum seed rates and nitrogen fertilizer rates are considered.Grain yield of both varieties was positively correlated with total dry weight of shoot at heading.