Genotypic differences in flag leaf area and their contribution to grain yield in wheat

Summary Flag leaf areas of the wheat variety Chinese Spring, six chromosome substitution lines of the variety Hope into Chinese Spring and their hybrids were measured by the planimeter method. Data on tiller number at ear emergence and ear number and grain yield at harvest were also obtained. Considerable variation existed in each of the characters investigated. The inheritance of flag leaf area showed some evidence of over dominance and non-allelic interaction while ear number was mainly under additive genetic control with partial dominance. Highly significant associations were found between flag leaf area, ear number and grain yield per plant. The importance of flag leaf area in yield determination was discussed in the light of the results obtained. It was concluded that despite the correlation between flag leaf area and grain yield, the major components of yield and grain yield itself, still offer the best guide for selection.