Determination of the heterotic groups of maize inbred lines and the inheritance of their resistance to the maize weevil

Maize weevil ( Sitophilus zeamais Motschulsky) is a major maize ( Zea mays L) storage insect pest in the tropics. Fifty-two inbred lines developed for weevil resistance were crossed to two testers, A and B, to determine their heterotic groups and inheritance of resistance to maize weevil. For 10 testcrosses selected for performance by tester, the correspondent testcrosses onto the opposite tester and all the parents involved in those crosses, were included in the combining study. Of 52 inbred lines, 7 had significantly positive general combining ability (GCA) for yield, with a maximum GCA effect of 1.24t.ha-1. Based on the specific combining ability (SCA) effect, 23 inbred lines were assigned to heterotic Group A, 24 to Group B, and 5 to both A and B. The combining ability test for weevil resistance revealed that only one inbred, WL118-9, was classified as moderately resistant with a susceptibility index (SI=5.4), two lines were moderately susceptible; and the remaining inbreds were susceptible to highly susceptible to the maize weevil. Additive and non-additive gene action were important for yield, but for weevil resistance, additive gene action was more important. Weevil resistance exists and is moderately heritable.Le charan\ue7on du ma\uefs ( Sitophilus zeamais Motschulsky) est un plus grand ravageur du ma\uefs ( Zea mays L) dans les tropiques. Cinquante-deux lign\ue9es d\ue9velopp\ue9es pour la r\ue9sistance au charan\ue7on du ma\uefs \ue9taient crois\ue9es aux testeurs A et B afin de d\ue9terminer leurs groupes h\ue9t\ue9rotiques ainsi que la transmission de la r\ue9sistance au charan\ue7on du ma\uefs. Pour dix lign\ue9es s\ue9lectionn\ue9es pour test de performance par le testeur, les croisements correspondants au testeur oppos\ue9 ainsi que tous les parents impliqu\ue9s dans le croisement \ue9taient inclus dans l\u2019 \ue9tude d\u2019aptitude. Parmi les 52 lign\ue9es, 7 avaient significativement montr\ue9 une positive Aptitude G\ue9n\ue9rale \ue0 la combinaison (GCA) pour le rendement, avec un effet maximum GCA de 1.24 t ha-1. Bas\ue9 sur l\u2019 Aptitude Sp\ue9cifique \ue0 la Combinaison (SCA), 23 lign\ue9es ont \ue9t\ue9 attribu\ue9es au groupe h\ue9t\ue9rotique A, 24 au groupe B et 5 aux deux groupes h\ue9t\ue9rotiques A et B. Le test d\u2019aptitude \ue0 la r\ue9sistance au charan\ue7on a r\ue9v\ue9l\ue9e q\u2019une seule lign\ue9e, WL118-9 \ue9tait classifi\ue9e comme mod\ue9r\ue9ment r\ue9sistante avec un index de susceptibilit\ue9 de 5.4, deux lign\ue9es \ue9taient mod\ue9r\ue9ment susceptibles tandis que les lign\ue9es restantes \ue9taient soit susceptibles ou hautement susceptibles au charan\ue7on du ma\uefs. L\u2019action additive et non additive des g\ue8nes \ue9taient tr\ue8s importante. Les g\ue8nes de r\ue9sistance au charan\ue7on du ma\uefs existent et sont mod\ue9r\ue9ment transmissibles \ue0 la descendance