Study On Grain-to-leaf Area Ratio And Its Relative Traits Of High-yielding Wheat Cultivars With Different Spike Types

The grain-leaf area ratio and its relating traits were measured among 12 high-yielding wheat cultivars broadly planted in Henan Province,in the continues two planting seasons (both 2006.10-2007.6 and 2007.10-2008.6) in the field of Jiyuan Agricultural Sciences,The main results were as following:1.There were significant difference in the grain-leaf ratio among four cultivars for multi-spike wheat cultivars,four mid-spike wheat cultivars and four big-spike wheat cultivars under different planting densities.However,the grain-leaf area ratio of different types of high-yielding wheat cultivars under the high seeding density was significantly higher than the low seeding density.Correlation analysis showed that the grain-leaf area ratio under the high seeding density had a positive effect on the grain-leaf ratio under the low seeding density.2.Grain number per spike/ flag leaf area(GNPS/FLA),spike grain weight / flag leaf area(SGW/FLA) and spike grain weight / flag and 2nd top leaf areas were positively correlated to grain yields,but the positive effects were significantly higher than the third,and correlation of grain number per spike/ flag and 2nd top leaf areas and grain yield greatly changed among different planting seasons.These results indicated that GNPS/FLA and SGW/FLA could be more effective selecting factors in the wheat.breeding.3.Increasing the 2nd top leaf base angle could be helpful to the grain-leaf area ratios,however, increasing the flag leaf width,the flag leaf area,the 2nd top leaf length,the 2nd top leaf width,the 2nd top leaf area and plant height could not be helpful to the grain-leaf area ratios.4.Heritabilities and genetic coefficients of grain-leaf area ratios among different types of high-yielding cultivars were different in different planting years and different planting densities.The heritabilities of grain-leaf area ratios were at middle-low level and there were some variance of its genetic coefficients.5.The yields of the mid-spike cultivars were the hightest and those of multi-spike cultivars were higher than big-spike cultivars in two continurous plangting seasons and different planting density.The grain-leaf area ratios of all wheat cultivars were different from their own yields,but almost all of the grain-leaf area ratios had a positive effect on grain yields.Accordingly,the mid-spike cultivars could be the preferred type in present high-yielding wheat breeding under the ecological conditions of Henan Province.