Study on the connection between Harvest Index and Yield

[Objective] The study aimed to confirm the function of harvest index in the cultivar breeding of wheat. [Method] Especial-early, mid-early and mid-late mature wheat were selected and 3 planting densities of low, middle and high were set up to study the relationship between harvest index and yield of wheat cultivars with different maturing dates. [Result] Under middle density, the plant height and ear length had positive correlation with population yield and negative correlation with individual yield, and the area, length and width of the second leaf above and flag leaf length were in favor of population yield. Under high density, the ear length had positive correlation with both population and individual yields and negative correlation with plant height, flag leaf area and the area of the second leaf above. Under middle and high densities, both filling velocity and duration had positive correlation with population yield. Harvest index had positive correlation with grains yield. Plant height, ear length, leaf area, grain weight per ear, filling velocity, plant height component index, fruiting spikelet number and ratio of grain to leaf etc had close correlation with harvest index and population yield. The biomass differences per plant of different cultivars were different under different competing environments. [Conclusion] Harvest index and biomass should be used as selection indices in the breeding of wheat cultivars with high yield.