| Germplasm resources are an important prerequisite for the selection and breeding of new varieties,and abundant germplasm resources are the material basis for cultivating high-quality and high-yield crops.Potato germplasm resources have rich genetic diversity in quality,stress resistance and agronomic traits.For a long time,there has been little research on farm potato germplasm resources.Collecting and sorting farm potato germplasm resources and conducting comprehensive evaluations are also conducive to the improvement of potato varieties.In this experiment,40 farm potato germplasm resources were collected and analyzed from three aspects: the correlation between agronomic characters and yield,the determination of tuber nutritional quality and plant drought resistance,so as to provide theoretical basis for the selection and comprehensive evaluation of farm potato germplasm resources.The results of the study are as follows:1.The grey relational analysis showed that the grey relational degrees between the agronomic traits and yield of the 40 farm potato germplasm resources from large to small were as follows: Number of tubers per plant(0.810)>emergence rate(0.744)>plant height(0.740)>ratio of tuber length to width(0.730)>stem diameter(0.726)>branch number(0.724)>commodity tuber rate(0.721),the greater the degree of association,the stronger the relationship.The order of variation coefficient of each agronomic trait from large to small is: number of tubers per plant>number of branches>commodity tuber rate>ratio of tuber length to width>stem diameter>plant height>emergence rate.Correlation analysis showed that potato yield had a very significant positive correlation with plant height(P<0.01),number of tubers per plant and seedling emergence rate,and had a significant positive correlation with stem diameter and number of branches(P<0.05).The membership function analysis showed that the top five materials of agronomic characters were old undead potato in Langao county,white potato in Chenggu county,light yellow rose 1 in Yangling district,redeyed potato in Zhenba county and Changjiang potato in Ningqiang county.2.The contents of soluble protein,vitamin C,reducing sugar,starch and dry matter in 40 farm potato germplasm resources were determined and analyzed,and the membership function method and principal component analysis were used for comprehensive evaluation.The nutritional qualities of potatoes from different farms are quite different.The coefficient of variation is between 12.76% and 47.23%.The minimum variation coefficient of dry matter content is 12.76,and the maximum variation coefficient of reducing sugar content is47.23%.Among the 40 potato materials tested,31 have a reducing sugar content of less than0.33%,which is suitable for potato chips processing,and 37 have a starch content of more than 16%,which is suitable for starch processing.After the extraction of principal components,membership function analysis was carried out on reducing sugar content,vitamin C content and starch content,and the 40 germplasm resources were divided into 3 categories according to the average membership function value(X).X>0.5 is the best nutritional quality,and there are 6 servings with the best nutritional quality,which are the red-skinned old potato from Huazhou,the 175 potato from Nanzheng County,the rice-white potato from Ziyang County,and the white potato from Xixiang County.County farmer white potato,Fengxian yellow heart potato;0.5>X>0.3 is better nutritional quality,with 28 servings;X<0.3 is poor nutritional quality,with 6 servings.3.40 farm potato germplasm resources were subjected to natural drought treatment under potted conditions,and the drought resistance of the shoot was analyzed,and the indicators after 15 days of drought were compared.The results showed that the plant height and stem diameter of potato plants under drought stress decreased compared with the control,the net photosynthetic rate,stomatal conductance and transpiration rate were also lower than those of the control,and the SPAD value was higher than that of the control.By calculating the drought resistance coefficient of each single index,the direct identification method of drought resistance coefficient and the comprehensive evaluation method of drought resistance were used to evaluate the drought resistance of potato materials under different conditions,including plant height,stem diameter,SPAD value,net photosynthetic rate,stomatal conductance,transpiration rate and water use efficiency.The results showed that the comprehensive drought resistance coefficients(CDC)of old immortal potato in Langao County,Jiwo potato in Fengxian county,Dahongpao potato in Danfeng county,Malian red potato in Longxian county and Fengxian white potato in Fengxian county were1.07,0.88,0.85,0.79 respectively,and the comprehensive evaluation values of drought resistance(D)were 0.82,0.69,0.62,0.60,0.58,0.58,respectively.Consistent with the results of direct identification of drought resistance coefficient evaluation method,it belongs to the same category in cluster analysis,accounting for 15% of the total materials,and belongs to high drought resistance materials.4.Through the membership function analysis method,the agronomic character index,nutritional quality index and drought resistance index were comprehensively evaluated,and the comprehensive membership function value and ranking of 40 farm potato germplasm resources were obtained,among which the old immortal potato in Langao County ranked first,and the comprehensive performance was the best. |
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