Study On Genetic Diversity Of Botany Characters In Melon Varieties From Northern China

This thesis studied On45morphological characters, sugar composition andpericarp structure through107melon material (planted mostly in northern China,89missing,107partially data missing), to investigate the genetic diversity of the melonmorphology, grading and evaluation of fruit quantitative traits, core Collection of fruit,the features of sugar components, and the correlation between structure and storage ofmelons, drawing the following conclusions by summary and analysis:1. Average genetic diversity index of14quality traits about106material is0.982,peel background is the largest（1.956）, fruit acidity is smallest（0.162）; the averagecoefficient of variation about14quantitative traits of stems and leaves is21.2%,trichomes is the largest（56.5%）, leaf index is smallest(6.1%); the averagecoefficient of variation about15quantitative traits of fruit is30.4%,fruit weight is thelargest（68.4%）,seed shape index is smallest（9.1%）.2.15fruit quantitative traits about106material were graded and evaluated, allcharacters were divided into1-5,1was the lowest,5was the highest,3was themiddle-class, frequency distribution of the most advanced of all traits were greaterthan30%,2was the most advanced in8traits,3was the most advanced in3traits,4was the most advanced in4traits, frequency distribution of the most advanced of4traits (fruit quality, the number of single melon seed, fruit umbilical size, fruit shapeindex) were more than50%, each class was selected three reference varieties andaccordingly evaluated, the aims were to improve the evaluation of quantitative traitsand know the current situation of cultivars in northern China；27fruit Characters (15quantitative traits and12quality Traits) of105material carried on cluster analysis, thethin-skinned and thick-skinned melons were separated in the genetic distance39.1,the material was divided into six groups in the genetic distance21.1; the material wasdivided into21groups based on cluster analysis, to extract the core species with thegreatest genetic distance method, a random method and the minimum genetic distancemethod in each of the groups, the results showed that the random method was betterthan he minimum genetic distance method and the greatest genetic distance methodwas the best, the standard deviation of all15quantitative traits from the greatestgenetic distance method was greater than the original sample, retention rate of allvariation margin was more than75%,core species from the greatest genetic distancemethod can represent the diversity of the original sample about fruit traits.3．Glucose、fructose、reducing sugar、sucrose and total soluble sugar from106material were measured and carried on the correlation and principal componentanalysis, the results showed that the coefficient of variation about glucose was thelargest(82.5%), sucrose content was the highest（mean52.1mg/g）, total soluble sugar and sweetness had strong correlation（r=0.919）, sweetness had large positivecorrelation with sucrose and fructose, sucrose content was the most important factoraffecting the total soluble sugar and fruit sweetness.4. Peel microscopic structure of20different storage material was observed,storage and transportation of the material were divided into four categories: resistantstorage type、middle resistant storage type、intolerance storage type、extremelyintolerant storage type; epidermal thickness、cuticle thickness and full cell gap、exocarp cell layers and small cell and tightly packed had positive correlation withstorage and transportation of melon fruit, the storage of thick melon was better thanthin melon, the storage of thick and no textured melon was better, the storage ofmelon fruit was the result of the combined effects of peel the layers structure.