Effect of Nitrogen Fertilizer Rates on Yield and Yield Related Traits of Durum Wheat (Triticum turgidum L.) Varieties

Low productivity and poor quality of the durum wheat compels Ethiopian pasta industries to import the required raw material; Thus, proper type and amount of nitrogen fertilizer application is the major factor that affects yield and quality components of durum wheat. Hence, field experiment was carried out on farmers’ training center field to determine the effect of nitrogen fertilizerrates in combination with durum wheat varieties on growth, yield and quality components of durum wheat. Factorial combinations of three durum varieties (Mangudo, Ude and Utuba) with six levels of nitrogen (0, 23, 46, 69, 92 and115 kgha-1) were laid out in a randomized complete block design in three replications. The analysis of variance indicated that the interaction effect of nitrogen fertilizer and variety significantly (p< 0.05) influenced 90% days to maturity and spike length. The highest days to 90% maturity (128 days) was recorded from Utuba variety at 115kg N ha-1 application. The longest spike length was recorded from Ude variety at 92 kg N ha- 1 application. However, seed per spike, plant height, productive tiller, grain yield and grain protein content were significantly (p<0.01) influenced by the main effect of nitrogen rates. The highest plant height (85.82cm), productive tiller (7.56), grain yield (4862 kg ha-1), and grain protein content (15.88%) were recorded at the highest N rate (92 kg N ha-1) applied; but, a maximum seed per spike (51.89) was obtained at the rate of 69 N kg ha-1 applied. The analysis of variance also showed that the difference of varieties significantly (p<0.01) influenced the plant height, thousand kernel weight, grain yield, and protein content with highest result obtained from Ude except highest protein content obtained from Utuba. The economic analysis revealed that for a treatment to be considered worthwhile to farmers, application of 92 kg N ha-1to all varieties gave better yields as compared to other N treatments. However, Ude variety is a promising variety for better productivity with profitable economic benefit to the crop at 92 kg N ha-1 application in the study area. However, since the study was done once in single place it is recommended to replicate it spatially and seasonally to have a concrete recommendation on the wheat varieties and nitrogen rates.