Inheritance and molecular mapping of anthracnose resistance genes present in sorghum line SC112-14

Abstract

Anthracnose (Colletotrichum sublineolum) is one of the most destructive diseases of sorghum [Sorghum bicolor (L.) Moench], affecting all aerial tissues of the plant. The most effective strategy for its control is the incorporation of resistance genes. The anthracnose resistance response present in the sorghum line SC112-14 (Cs-SC112) was therefore studied against pathotypes from Puerto Rico, Texas, Arkansas, and Georgia using F2 progenies and recombinant inbred lines. The results show that a series of nearest single loci at the distal region of chromosome 5 control the resistance responses against pathotypes from Puerto Rico, Texas, and Arkansas. Resistance loci against pathotypes from Texas and Puerto Rico are tightly linked and flanked by simple sequence repeat (SSR) markers Ch5-55.0 and Ch5-56.1, while the resistance locus against pathotypes from Arkansas is 9.5 cM below SSR marker Ch5-56.1. The resistance locus against pathotypes from Georgia is not located in the distal region of chromosome 5, and its location could not be determined. Comparative analysis confirmed that the region associated with these three loci is not associated with the anthracnose resistance locus Cg1, which was previously mapped in the distal region of the same chromosome. The dominant mode of action against pathotypes from Puerto Rico suggests that these resistances sources can be beneficial for sorghum hybrid production. The durability of anthracnose resistance in sorghum depends on the adequate use of multiple resistance sources. Thus, the knowledge and genetic markers developed herein provide tools to initiate the pyramiding of multiple anthracnose resistance loci through marker-assisted selection.