Yield and Nutritional Quality of Oat (Avena sativa) Genotypes under Vertisols Conditions in the Central Highlands of Ethiopia

Shortage of feed is a critical problem for livestock production in Ethiopia. However, the selection of oat genotypes that perform better under vertisol conditions is very important to mitigate the feed shortage problem in the central highlands of Ethiopia. So, the study was designed to evaluate the agro-morphological and nutritional performance of fifteen oat genotypes under vertisol conditions during the main cropping seasons of 2015 and 2016 at Kuyu and Ginchi sub-stations of Holetta Agricultural Research Center. Randomized complete block design replicated three times was used for evaluating the genotypes. The genotypes were sown with the recommended seeding rate of 100 kg ha-1 using an inter-row spacing of 20 cm. Diammonium phosphate (DAP) fertilizer at the rate of 100 kg ha-1 was uniformly applied at sowing for all genotypes at both locations and years. Data were collected on plant height, dry matter yield, leaf to stem ratio, straw yield, seed yield, thousand seed weight, harvest index, and nutritive values. All measured data were subjected to analysis of variance using procedures of SAS general linear model. The genotypes responded differently (P<0.001) for plant height, leaf to stem ratio, straw yield, seed yield, thousand seed weight, and harvest index. All measured agro-morphological traits of oat genotypes were significantly influenced by genotype by location by year interaction. In both cropping seasons, the genotypes produced relatively better dry matter yield at Kuyu than Ginchi indicating the performance of genotypes was highly hampered by heavy vertisol characteristics of Ginchi location. In the over years and locations combined analysis, genotypes 1600, 1740, 2596, 79983, 1493, and 1742 produced more than 15 t ha-1 dry matter yield at the soft dough stage. Oat genotypes that had relatively higher plant height and better dry matter yield showed higher straw yield when compared with small plant height and lower dry matter-producing genotypes. The mean seed yield performance of oat genotypes in the combined analysis was 2250 kg ha-1 and the highest seed yield was recorded for genotype 2806 followed by 79983, 2291, 8251, and 1742. Moreover, the chemical and in-vitro dry matter digestibility analysis of oat genotypes was done and genotype 1486 produced the highest crude protein and in-vitro dry matter digestibility contents while the lowest was recorded from genotype SAIA. The highest crude protein yield was recorded for oat genotype 2291 followed by 2596, 2806, 1506, and 1742 and oat genotypes that produced the highest crude protein yield also gave the highest digestible yield. Generally, better dry matter yield, crude protein yield, digestible yield, and seed yield performances were recorded from genotypes 2291, 2596, 2806, 1506, 1742, 8251, and 79983. Therefore, these oat genotypes were recommended for vertisol conditions of the study areas and similar agro-ecologies.