Response of dual-purpose sorghum (Sorghum bicolour L.) varieties to anthracnose disease, growth and yield performances under dry land crop-livestock farming systems of southern Ethiopia

Abstract

Integration of food crop production with feed supply in quantity and quality by considering some important foliar diseases could be an ideal approach in the crop-livestock farming system of tropical agriculture. Evaluating the responses of dual-purpose sorghum varieties to anthracnose diseases, growth and yield performances under the dry land farming system was undertaken in Arguba and Chamomile research substation during the 2018 and 2019 major production seasons. Five sorghum varieties (Chelenko, A-2267_2 and NTJ_2, Dishkara, Konoda) and one local check (Rara) were arranged factorial in a randomized complete block design with four replications. The assessment was done on plant height, leaf number, leaf width, leaf length, tiller number, dry biomass and grain yields, as well as on anthracnose disease infection. Variety Chelenko exhibited the tallest main crop plant height while Dishkara was the tallest at ratoon crop harvesting. Rara had a higher tiller number among the varieties. Chelenko had a higher dry biomass yield at the main crop while Dishkara at ratoon harvesting. The total dry biomass yield recorded by Dishkara, Chelenko A-2267_2, Rara, NTJ_2 and Konoda varieties was 45.3, 33.3, 31.8, 29.8 21.7 and 18.5 t/ha, respectively. Dry biomass yield was strongly and positively correlated with plant height. The varieties A-2267_2 and NTJ_2 recorded Anthracnose incidence of 98.90 and 100%, respectively while the severity was about 43.67 and 40.36% in the same order.  Similarly, the area under disease progress curves for A-2267_2 and NTJ_2 varieties were 860 and 1085.27%-days, respectively. Dishkara and Chelenko varieties produced 45.3 t/ha and 33.3 t/ha dry biomass yields, which were 33.6% and 9.6%, respectively, higher (P<0.05) compared to the overall mean dry biomass yield (30.1 t/ha). On the other hand, the Konoda variety produced about 62.7% (18.5 t/ha) less dry biomass yield than the overall mean dry biomass yield. Although the anthracnose infection was highest in the varieties Konoda and NTJ_2, they produced significantly (P<0.001) higher grain yield (3.89 t/ha) than others. Under anthracnose pressure, Chelenko and Dishkara varieties are suggested for dry biomass yield while NTJ_2 for grain yield production in the study area and areas with similar agro-ecologies. Further research on the performance of the varieties under irrigation conditions and the inclusion of their feed quality is also recommended.