Studies On Heterosis Among Different Wheat Varieties Or Lines In Different Ecological Regions

23 characters of photosynthetic characters of flag leaves in heading date and some important agricultural characters were studied with 48 hybrids from 4 ecotypic regions and their parents in heterosis, the correlations between all characters of F₁ and the corresponding average values of parents, the correlations between all characters of F₁ and the corresponding values of high parent, multi-regression among grain yield per plant and corresponding influencing factors. The results showed that,â…  Heterosis in 4 ecotypic regions' cultivars or lines existed extensively for all 48 hybrids. And expression extents of heterosis of different characters are not uniform in combinations of different ecotypic regions.â…¡ Hybrids of both high yield and first class of comprehensive characters are obtained by proper selection of cultivars or lines in different ectypic regions. In this study, We can select hybrids of high yield, resist-lodge and right canopy architecture from combinations of cultivars or lines in ecotypic regions of Huanghui and the North. However, it is more difficult to attain combination with strong heterosis in ecotypic areas of mid-backward position of the Yangtse River and the North.â…¢ Except for fertile spikelets per head, photosynthetic efficiency of flag leaf, transpiration velocity, stomatal conductivity, grain yield per plant, biomass per plant and number of grains per plant, the correlations between other characters and the corresponding average values of parents reach significant or highly significant degree. In addition to so I speak of, adding to number of grain per head, harvest index, grains per spike and ratio of grains weight and stems weight, the correlations between all the other characters and the corresponding values of high-parents reach significant or highly significant degree.â…£ Multi-regressions among grain yield per plant and corresponding influencing factors reflect more truthfully extents of influences of different characters on grain yield per plant and eliminate interaction of different characters.V All 5 factors of flag leaves' photosynthetic efficiency express positive mid-parent heterosis in combinations of cultivars or lines in ecotypic regions of Huanghui and mid-backward position of the Yangtse River, areas of mid-backward position of the Yangtse River, areas of the South-West and areas of the South-West and the North. And they express positive contrastive heterosis in hybrids of cultivars or lines in ecotypic regions of Huanghui and mid-backward position of the Yangtse River, areas of Huanghui and the South-West, areas of mid-backward position of the Yangtse River, areas of mid-backward position of the Yangtse River and the North, areas of mid-backward position of the Yangtse River and the South-West and areas of the South-west.