EFFECTS OF SEED RATES AND HERBICIDES ON PRODUCTIVITY OF DURUM WHEAT (TRITICUM TURGIDUM L.VAR DURUM) AT BISHOFTU, CENTRAL HIGHLANDS OF ETHIOPIA

Abstract

Wheat is one of the most important food security crops which is cultivated from small to large scale farms in Ethiopia. However, its productivity has been limited due to various abiotic and biotic factors including weeds. Therefore, the study was conducted to evaluate the effect of seed rates and herbicides application on weed, growth, quality, yield component, and yield of durum wheat and to asses the economic feasibility of seed rates and herbicide application at debre zeit Agricultural research center, central highlands of Ethiopia, during the 2023 main cropping season. Treatments consisted factorial arrangements of four levels of seed rates (100,125, 150 and 200 kg ha-1 ) and two types of herbicides (2,4D L ha-1 , Pallas 45 OD 0.5L ha-1 ), and their combination, 2,4D 0.5L ha-1 + Pallas 45 OD 0.0.25L ha-1 laid out in randomized complete block design with three replications. The results showed that, the total of identified 13 weed species were recorded (76.03% broad and 26.93% grass weeds). The results also revealed that significant effects of seed rate by herbicide combination for most traits studied. The minimum weed densities (10.67 m -2 ) after application , was recorded from the combination of 150 seed rate with Pallas 45 OD while the maximum weed densities (31.33 m -2 ) after application was recorded at 100 kg ha-1 seed rate with Pallas 45 OD. The highest spike length (4.97cm),spikelet per spike (24.94), kernel per spike (55.69), biological yield (8.76t ha-1 ), thousand grain weight (44.53 g), and grain yield (4.37 t ha-1 ) were recorded from the combination of 150 kg ha-1 seed rate with Pallas 45 OD while, the lowest values were obtained from the control plot. However, the highest number of productive tillers (336.67 m -2 ),and harvest index (52.71%) were recorded from the combination of 150 kg ha 1 seed rate with Pallas 45 OD + 2,4D while the lowest values (110.00 m -2 and 39.20%),were observed from the control plot respectively.. Similarly, the highest hectoliter weight (66.96 Kg hl 1 ) and protein content (11.68%) were recorded from the combination of 100 kg ha-1 seed rate with Pallas 45 OD, while the lowest values (63.59 Kg hl-1 and 10.27%), were observed from the control plot respectively. Grain yield had strong positive correlations with each of the yield components, however it was negatively correlated with weed density. The partial budget analysis revealed that the highest net benefit of (221,990 ETB ha 1) with acceptable MRR of (954%) was achieved from the treatment combination of 150 kg ha-1 seed rate with Pallas 45 OD. Therefore, it can be concluded that treatment combination of 150 kg ha-1 seed rate with Pallas 45 OD proved to be superior in grain yield as well as economically profitable and recommended for use. However, this study was done for one season at a single location, the experiment has to be repeated over a year and location to reconfirm in different agro ecology and seasons to reach a conclusive recommendation.