Reactions of differential rice genotypes to African rice gall midge in West Africa

Considerable diversity was observed in the reactions of 20 rice genotypes to African rice gall midge (AfRGM) at five locations in four countries in West Africa. Of 14 Oryza sativa lines studied, TOS14519 had the lowest mean plant damage; TOG7106 had the lowest mean damage among five O. glaberrima lines in the trials. The only O. sativa 2 O. glaberrima progeny in the study, WAB450-I-B-P-181-22-1- HB, showed mean damage comparable with the resistant check NHTA 8. The levels of resistance shown by the glaberrimas were better than those of the sativas. Eight genotypes could be described as possessing both stable and acceptable levels of resistance to the pest. TOG7106 and TOS14519 were rated highly stable and highly resistant. The high genotype 2 environment interaction in the reactions of the rice lines to AfRGM could not be attributed to agroclimatic or crop management factors, leaving us to suggest the possible existence of different biotypes of AfRGM in West Africa.