Screening Of Low Calcium Tolerance Peanut Germplasm Resources

Southern China is rich in acid and calcium-deficient soil,and peanut is one of the main economic crops and oil crops in this region.In order to select the germplasm resources which are full pods and suitable for growth in acidic soil with low level of calcium,the field experiment was conducted on acid low-calcium soil to study the effects of calcium application and non-calcium application on the main agronomic traits of 105 peanut resources from all over the country.Relevant statistics and analysis were carried out with the average of peanut plant traits,agronomic traits,yield indicators and low calcium tolerance coefficient.Using correlation analysis and principal component analysis to screen the identification index of peanut in low calcium tolerance.Using comprehensive evaluation method and cluster analysis to evaluate low calcium tolerance.The peanut germplasm resources of low calcium tolerance soil were selected and their basic characteristics were clarified The main results show that:(1)Through the analysis of 24 agronomic traits in 105 peanut germplasm resources,it was found that compared with calcium application,non-application of calcium fertilizer has reduced peanut seedling rate,chlorophyll content(SPAD value),main stem height,side branch length.,pod yield,the number of fruit per plant,the number of total fruit per plant,kernel yield rate,pod fullness degrees,rate of full fruit,full fruit weight,full kernel weight and the quality of peanut kernel,but the rate of empty fruit was improved,Other traits were less affected by low calcium.The difference between peanut yield and empty fruit rate reached a significant level under the two treatments.(2)There are abundant variations in the low calcium tolerance coefficient of different germplasm resources in acidic low-calcium soil.The coefficient of variation(CV)reached 2.315%-79.103%,and the CV of empty fruit rate and number of capsules per plant is more than 65%.The total number of branches,main stem height,lateral branch length,number of full fruit per plant,total fruit per plant,single plant yield,oil ratio were all greater than 10%,and other traits were smaller.(3)Comprehensive analysis of yield and 23 agronomic traits,the low calcium-tolerance coefficient of yield and 23 agronomic characters,the coefficient of low calcium-tolerance in yield and 23 agronomic traits showed that the yield and the low calcium tolerance coefficient of the yield in low-calcium acidic soil were significantly or significant positively correlated with the number of full fruit per plant,the total number of fruits per plant,and the total number of branches.This results indicated that the peanut varieties with high yield under low-calcium conditions were characterized by more total branches,especially more fruiting branches.The number of fruits is more.the number of hollow fruits is less,the number of full fruits is large,and the yield is higher.By using stepwise regression and path analysis the key agronomic traits affected the yield of peanuts were comprehensively determined to be the number of full fruit per plant and the number of fruit per kilogram.(4)Principal component analysis was used to convert the low calcium tolerance coefficient of 24 individual indicators into 8 relatively independent comprehensive indicators(CI1~CI8),which were peanut high yielding factor,peanut grain oil content,peanut plant type factor and peanut photosynthetic factors.The factors mentioned above can be used to evaluate the peanut germplasm more accurately,the yield and the percentage of full fruit is the largest proportion in the main component contribution rate and the feature vector,which can represent the response of different peanut varieties to low calcium.(5)According to the cluster analysis,105 peanut germplasm resources were divided into 5 groups: 2 varieties with extremely resistant to low-calcium(Jinxin black purple red,F5023).these kind of varieties have higher relative yield and higher coefficient of low-calcium tolerance;1 variety with strong resistance to low-calcium(Xiangheixiaoguo),the relative yield of this varieties is relatively high,and the coefficient of low-calcium tolerancet is low;19 moderately low-calcium resistant varieties(F5041,eucalyptus red 2,sweet-scented osmanthus 32,etc.),the relative yield of these varieties were medium,and the low-calcium tolerance coefficient were high;82 sensitive varieties(Kai Nong 172,Nongda 511,Xianghua 2008,etc.),these varieties have relatively lower yield,moderate low-calcium tolerance coefficient;1 variety with high sensitivity(Xianghua 819),and the relative yield of this variety is low and unstable.These varieties can further used to low calcium tolerance breeding and production.