Status of resistance to Chilo partellus (Lepidoptera: Pyralidae) in South African grain sorghum hybrids

Abstract

The level of resistance to Chilo partellus was evaluated in 49 commercially available grain sorghum hybrids using artificial infestation in each of two field trials. The assessment of leaf feeding damage on a scale of one to nine indicated levels ranging from susceptibility to intermediate resistance. Hybrid performance in relation to reduction in peduncle length was inconsistent for all seasons. Pronounced differences in yield loss were observed between hybrids within each trial (9–67%) as well as in yields of the same hybrids for all seasons. This was ascribed to tolerance to damage and the ability of the plant to compensate for damage by means of tiller formation. Hybrids CRN 7690, CRN 7692 and PAN 8501 exhibited the greatest tolerance to borer damage, and consequently suffered comparatively low yield losses. This study provides a basis for the evaluation of future progress in grain sorghum resistance breeding.