Evaluation of experimental varieties from recurrent selection for Striga resistance in two extra-early maize populations in the savannas of West and Central Africa
International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria; c/o L.W. Lambourn (UK) Limited, Carolyn House, 26 Dingwall Road, Croydon, CR9 3EE, United Kingdom; Obafemi Awolowo University, Ile-Ife, Nigeria
A breeding programme for resistance to Striga hermonthica in maize (Zea mays) was initiated in Côte d'Ivoire in 1994. Two extra-early populations, white (TZEE-W Pop STR) and yellow (TZEE-Y Pop STR), were formed from diallel crosses of the best adapted extra-early maturing maize germplasm in the West and Central African subregion. In an effort to improve the populations for Striga resistance, TZEE-W Pop was crossed to inbred 1368 STR (Tzi 3 STR), and TZEE-Y Pop to 9450 STR (Tzi 25 STR). The resulting F1 populations were carried through two backcross (BC) generations. S1 lines were developed from the BC2 and subjected to two cycles of random mating to generate TZEE-W Pop STR C0 and TZEE-Y Pop STR C0. These two populations were subjected to three cycles of S1 recurrent selection under artificial Striga infestation and several experimental varieties were extracted from the different cycles of the selection programme. The original populations (C0), improved populations, and experimental varieties were evaluated in two experiments under Striga-infested and Striga-free conditions. The primary objective was to determine the effectiveness of S1 recurrent selection in developing Striga-resistant extra-early maize varieties. Results of the performance tests showed that the populations were good sources of Striga-resistant varieties with high-yield potential under both Striga-infested and Striga-free conditions. The results have also confirmed the effectiveness of inbreeding, selection and hybridization, as well as the backcross breeding methods, as tools for the development of extra-early populations, synthetic varieties and inbred lines. © 2007 Cambridge University Press.
Striga; Striga hermonthica; Zea mays