In an attempt to form a pair of heterotic drought tolerant populations adapted to the Sudan Savanna of Cameroon, seven varieties introduced from drought-prone areas of West Africa and from ClMMYT were crossed in a partial diallel during the 1991 second growing season. In Evaluations of 31 F1s obtained at four Sudan Savanna environments in 1992, Tuxpeño Sequia x BDP-SR, MAKA-SR x FBC6 and MAKA-SR x Tuxpeño Sequia demonstrated 16%, 13% and 12% high parent heterosis, respectively, and 5.1 t/ha average yield. Among the 10 top F1s, MAKA-SR and Tuxpeño Sequia were involved as parents in four and three crosses, respectively. This suggests that they are good combiners, and the observed heterosis indicates that they belong to opposing heterotic pools. During the 1993 season, six drought tolerant varieties and three drought tolerant inbreds introduced from IITA, in addition to MAKA- SR, Tuxpeño Sequia, Pool 16 DT and P2 Kollo from Niger, were reciprocally crossed in an incomplete diallel. The resulting crosses were evaluated in three drought-prone sites. Results showed that the general combining ability (GCA) of parents varied with their utilization as male or female. Used as female, MAKA-SR, KU 141 4, Tuxpeño Sequia, DR-SR-W3 and DR SYNT exhibited positive GCA. Used as male MAKA-SR, Tuxpeño Sequia, DR-SR-YI, 1787 and Pool 16 DT showed positive GCAs. Early-to intermediate-maturity varieties exhibiting better floral synchronization, good standability at 65,000 plants/ha, and good yield potential were recombined and advanced to F2 in 1994.

English

9802|AGRIS 9702

Jose Juan Caballero

CIMMYT Publications Collection