Inheritance of field resistance to sorghum charcoal rot and selection for multiple disease resistance

Abstract

Six segregating and nonsegregating generations of three R x S and two S x S crosses were studied for charcoal rot resistance under epiphytotic conditions. CSV-5 (148/168) was comparatively the most resistant parent. The F1 showed partial dominance of resistance. The resistance appears to be a polygenic threshold character governed by duplicate epistasis with low heritability (38%). The F3 progenies transgress the parental limits. In absence of absolute resistance for charcoal rot, selection 2 S.D. below population mean (S.I. = 1%) results in selecting resistant transgressive segregates. Charcoal rot, SDM and leaf rust inherit independently. It is possible to combine these characters through simultaneous selection by choosing rust resistant plants from the segregating F3 progenies possessing <1% SDM and <10% charcoal rot susceptibility