| Heterosis breeding can improve the yield of watermelon, fruit quality and enhance the resistance, ect. Understanding of heterosis mechanism and prediction methods can also improve the accuracy and excellent breeding combination screening efficiency. Accelerating the breeding process helps save manpower, material and financial resources. Therefore, heterosis prediction and application of genetics and crop breeding is an important subject in the field. But on watermelon heterosis prediction and application research is rare, this topic in Watermelon Seedling Physiological and biochemical indexes of agronomic traits and heterosis, correlation and combining ability analysis foundation, on watermelon phenotypic traits and Heterosis and physiological indices and the correlation between Heterosis of two aspects of the study, for the Heterosis in Watermelon Breeding Application and provide a scientific basis. The results are as follows:Firstly, the author chose3in the production of large area promotion and application of watermelon hybrids and6parent strains as the experimental material. Utilization of hybrids and their parental agronomic traits correlation analysis between differences, the results show:(1) Three varieties and their parents in the leaf area, leaf material area and total leaf area showed more than11%ultra rate advantage. So leaf area, leaf material area and total leaf area can make as breeding" hybrid" early reference index.(2) The heterosis rate of each item in plant dry weight all showed more than21percent, far beyond its fresh weight in heterosis rate. So it can be chosen as breeding parent selection of a reference index.(3)Three hybrid varieties of plant stem high super advantage all showed7percent above, especially (e*f) high amounts to15.32percent, have reached a significant level; plant height in the super advantage becomes more apparent, ultra advantage rate all be in17percent above, have reached a significant level. The stem height and plant height can be chosen as parents selection is one of the important indexes.(4) The difference between interval number and its parent variety female is not obvious. Super dominant value rate is very small and the advantage is not clear, therefore cannot be used as an early heterosis index.(5) Hybrids yield has super advantages. From sowing to harvest for longer periods of time (a*b) and (c*d) the early yield were lower than the late output, description of the first female flower position of the varieties of high, mature late, higher total yield;(e*f) the first female flower a low, blossom time is early, early high yield, but total output is relatively low.Secondly, through to the10watermelon F1and its parent seedling of7physiological and biochemical indices were determined, analysis. The results show that:the chlorophyll a/chlorophyll b and paternal correlates significantly; water soluble protein content was positively correlated with female parent. The remaining indicators correlated with its parents is not significant negative correlation.Based on the hybrid field yield and physiological and biochemical index in seedling stage of contrast, seedling chlorophyll content, chlorophyll a/b ratio and Water Soluble Chlorophyll Pr content and fruit weight were significantly related to chlorophyll, chlorophyll a/b ratio and the average yield per mu had extremely significant correlation. This shows that with the content of total chlorophyll, chlorophyll a/b ratio and Water Soluble Chlorophyll Pr content and Seedling Physiological and biochemical indexes can be used as predictors of Watermelon Hybrid Yield Heterosis index.Thirdly, using the above experimental results to guide watermelon breeding parents selection. Combined with screening, breeding of new watermelon hybrid and through traditional breeding method, the results obtained are accorded with the breeding objectives. It showed that illustrated by seedling physiological and biochemical determination to predict heterosis in watermelon is feasible and effective. |
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