Striga hermonthica is a major constraint to increased maize production and productivity in the savannas of West and Central Africa OVCA. The IITA-WECAMAN Maize Program has developed two extra-early source populations and several extra-early varieties, synthetics and inbred lines with resistance/tolerance to drought and/or S. hermonthica, eleven extra-early maturing varieties were evaluated at Ferkessedougou, Abuia and Mokwa in 2002 and at Mokwa and Abuja in 2004 under artificial Striga infestation and Striga- free conditions. In another trial conducted at Mokwa and Abuja in 2004, 36 extra-early maturing inbred lines were evaluated under Striga infestation and Striga-free conditions. Significant differences occurred among the varieties for grain yield under both infested and Striga-free conditions. Several promising Striga resistant extra-early maturing varieties (2000Syn EE W, 99 Syn EE-W and Sine TZEE-W STil were identified based on grain yield, Striga damage ratings and Striga emergence counts. Cluster analysis of the extra-early inbred lines, based on the similarity of quantitative characters, produced four and six major clusters under Striga infested and Striga -free conditions, respectively. The extra-early inbred lines assigned to each cluster under Striga infestation were different from those of the corresponding clusters of the Striga-free conditions. Superior specific hybrid combinations could be obtained by crossing inbred lines of different clusters rather than matings within clusters and by selecting parents with high grain yield and low Striga damage symptoms. Several promising extra-early maturing inbred lines were identified as sources of Striga resistance for the development of synthetic varieties and population.Striga hermonthica est une contrainte maieure i l'augmentation de laproduction et de la productivite du mais dans les savanes d'AfriqLrede l'ouest et du Centre (AOC). Deux populations sources de maturitdpr6coce et deux autres de maturit6 extra-pr6coce, des synthetiques et des lignees dotdes de resistance/tolerance i la sEcheresse eVoua S. hennonthico ont 6t6 developp6es par le programme mais llTA-WECAMAN. Onze vari€tds de maTs extra-pr6coces ont 6t€ chacune6valu6e i Ferkessedougou, Abuja et i Mokwa en 2002 et i Mokwa et Abuja en 2004 sous infestation artificielle de Su^igo et sous condition denon-infestation de Strigo. Dans deux autres essais conduits a Mol<wa eta Abuia en 2004, 36 lignees extra-pr€coces ont 6te chacune 6valu6essous infestation artificielle de Sfrgc et sous conditions de non-infestationde Sn-iga. Des diff€rences significatives ont 6t6 obtenues entre lesvari6t€s pour le rendement grain sous les deux conditions d'infestationartificielle de Strigo et de non-infestation de Strigo. Plusieurs vari6t6s prometteuses r6sistantes d Striga, extra-pr6coces (2000 Syn EE-W, 99Syn EE-W et Sine TZEE-W STR ont et€ identifiees sur la base durendement grain, des 6valuations des dommages dus i Sfrlgo et dunombre de plants de Striga 6mergds. L'analyse multivari€e des lign€esextra-pr€coces sur la base des similarit6s des caractdres quantitatifs,a produit quatre groupes maieurs sous les conditions d'infestationartificielle et six groupes maieurs sous les conditions de non-infestationde Striga. Cependant, les lign6es extra-pr6coces attribu6es d chaquegroupe sous infestation de Striga, dtaient differentes de celles desconditions de non-infestation de Striga. Des combinaisons d'hybridesspecifiques de qualit6 sup6rieur pourraient 6tre obtenus en croisantdes lign€es de groupes diff6rerrts au lieu de croiser des individus dum€me groupe et en selectionnant des parents avec un haut rendementgrain et peu de dommage de Strigo. Plusieurs lignees prometteusesextra-prdcoces ont et€ iderrtifiees comme sources de r6sistance d Striga et pourraient 6tre utilis6es pour le d€veloppement de populations etde vari€t6s synthetique.

Maize; Plant Diseases; Plant Health; Plant Breeding

Breeding; Maize

Africa; West Africa

Nigeria