Inheritance of resistance to the panicle-feeding bug Eurystylus oldi and the sorghum midge Stenodiplosis sorghicola in sorghum

摘要

A study of the inheritance of sorghum resistance to head-bug Eurystylus oldi and midge Stenodiplosis sorghicola has been conducted from an F1-based complete diallel involving four parental lines (namely head-bug resistant Malisor 84-7 & 87W810, and susceptible S 34 & ICSV 197). The trial was conducted at Samanko, Mali, under both natural and artificial head-bug infestation, in one date of sowing (DOS) in 1995 and two DOS in 1996. Headbug visual damage scores (under both types of infestation) were indicated and analyzed in all these trials. Head-bug numbers under artificial infestation on the two DOS of 1996, and midge damage score under natural infestation on the second DOS of 1996 were recorded. All four parents confirmed their expected level of resistance to head-bugs, while ICSV 197 confirmed its resistance to midge. Diallel analyses showed that general combining ability (GCA) and thus additive gene effects were very important in the inheritance of resistance to both pests. Specific combining ability and maternal effects were generally of minor importance. Mean performance of the parents and their GCA effects were linked, which suggests high heritability. Head-bug resistant parents, Malisor 84-7 & 87W810, with high per se resistance and negative GCA should therefore be used in breeding for resistance to this pest, while for a similar reason, ICSV 197 should be used in breeding for midge resistance. Results concerning independance between resistance to head-bugs and to midge, are also discussed.