Field Evaluation of Sorghum Accessions and Improved Varieties for Resistance to Major Diseases under Natural Infection Conditions

Abstract

Sorghum is an important food and fodder crop in Eritrea, where production is constrained by several biotic and abiotic factors, including plant diseases. This study evaluated 23 sorghum accessions and three improved varieties for resistance to naturally occurring diseases under field conditions at Hamelmalo Agricultural College, Keren, using three replications. Genotypes were planted by the single-line method, and disease incidence and severity were assessed at the adult plant stage. Disease severity was rated on a 0–9 scale. Anthracnose, leaf blight, sooty stripe, target leaf spot, zonate leaf spot, and bacterial streak were recorded during the growing season. Disease occurrence and severity differed among the evaluated genotypes. Anthracnose was the most prevalent disease, occurring in 76.92% of entries, followed by leaf blight at 61.54%. Sooty stripe occurred in 23.08% of entries, zonate leaf spot in 11.54%, and target spot and bacterial streak each in 7.69%. Although target spot was less prevalent, relatively high severity was recorded in affected accessions. Anthracnose showed the highest overall severity, particularly in EG795, whereas zonate leaf spot and bacterial streak generally showed low incidence and severity. The variation observed among accessions and improved varieties indicates differential responses to natural disease pressure and identifies materials that warrant further evaluation as potential sources of disease resistance for sorghum improvement under Eritrean conditions.