Recent advances in CIMMYT's highland maize program - Mexico, DF (Mexico) CIMMYT : 2003 - p. 206-207 - Printed
Many farmers in developing countries do not replace their seed annually with newly purchased commercial seed. Instead they rely on recyded seed saved from their own harvest or obtained from other farmers. Smale and Phiri (1998) recommended that maize breeders working for areas where farmers commonly recyde seed should consider inbreeding depression as a criteria in their hybrid releases. Highland maize is grown on about 6 million hectares worldwide with almost 3 million hectares in Mexico (Beck 2001). In Mexican highland areas, only about 10% of the area is planted with improved hybrid cultivars. It is a common practice for farmers in these areas to recyde their seed. Average maize yields in the Mexican highlands are about 2.5 t/ha. Yields are constrained by various factors including drought, low soil fertility, hail, and lack of availability of improved seed at accessible prices. The objective of this trial was to evaluate the inbreeding depression in various highland hybrid types by comparing the F1 to the F2 and F3 generations under both low soil nitrogen and non-stressed conditions.