USING STOMATAL APERTURE-RELATED TRAITS TO SELECT FOR HIGH YIELD POTENTIAL IN BREAD WHEAT

摘要

More efficient wheat breeding methods are needed to meet demand for wheat from expectedpopulation growth in developing countries. This paper reports results from recent studiesconducted at CIMMYT aimed at assessing the use of stomatal aperture-related traits (SATs)as indirect selection criteria for high yield-potential in bread wheat. Two classes of SATswere assessed: the instantaneous trait leaf porosity (FOR), which is a close surrogate forstomatal conductance, and the integrative traits DELTA~(13) C of leaf and grain and delta~(18) O of grain. For 3 out of the 4 populations of breeding lines tested in 2001-02, the results indicated strong prospects for using SATs in screening for high yield potential. Grain DELTA~(13)C, leaf DELTA~(13)C and FOR each showed promise, with moderate to high heritability, moderate to strong genetic correlations with yield, and yield gains from retrospective selection of about 40-50g m~(-2)at trial mean yields of 520g m~(-2). Grain delta~(18)O showed less promise. Heritability of thistrait was moderately high, but grain delta~(18)O was not strongly correlated with yield and retrospective gains from selection were small. For one population, none of the SATs showedany convincing association with yield. The reasons for this need further investigation asSATs are evaluated over additional seasons.