Inheritance of Resistance of Three Sorghum Lines to Pathotypes of Colletotrichum sublineola , Causal Agent of Anthracnose

摘要

bBackground and Objective:/b Anthracnose incited by Colletotrichum sublineola is the most important foliar disease of sorghum worldwide. The hyper-variable nature of the pathogen requires continual evaluations of sorghum germplasm to identify sources with different resistance genes. Thus, this research was undertaken to determine the inheritance of two Sudanese lines PI570726 and PI569979 to pathotype 30 and BT×378 (Redlan) to pathotypes 30 (P30) and 35 (P35) of the anthracnose pathogen. bMaterials and Methods:/b Crosses between these three sorghum lines and a susceptible parent PI609251 were performed and the resulting Fsub2/sub populations were evaluated in greenhouse. Seeds were planted in 1-gallon cans and 30 d post planting, plants were inoculated with the anthracnose pathotypes. Individual plants from each cross were scored based on a scale of 1-5, where 1 = No symptoms or chlorotic flecks on leaves; 2 = Hypersensitive reaction; 3, 4 and 5= Infected leaf lesions with acervuli formation. bResults:/b Chi-square test for the Fsub2 /subpopulations of BT×378×PI609251 against P30 and P35, segregated in the expected Mendelian ratio 3 (resistant): 1(susceptible) fashion, indicating that resistance in BT×378 to P30 and P35 of C . sublineola obtained from the USA is governed by a single dominant gene. Segregation analysis for the PI569979×PI609251 and PI570726×PI609251 Fsub2 /subpopulations revealed 1:3 ratio of resistance to susceptible, indicating that resistance in PI569979 and PI570726 to P30 was conditioned by a recessive trait. bConclusion:/b Resistance in the sorghum line BT×378 was shown to be dominant and will therefore be more desirable for use in breeding for anthracnose resistance, especially in sorghum hybrid production.