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Comprehensive Evaluation Of Heat Tolerance Of Bitter Gourd And The Breeding Of Hybrid Combination With Heat Tolerance

Posted on:2021-05-26Degree:MasterType:Thesis
Country:ChinaCandidate:Z S ChenFull Text:PDF
GTID:2393330614955670Subject:Agriculture
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High temperature in summer is an important environmental factor that affects the growth and development of bitter gourd.High temperature stress arrests the growth and development of bitter gourd,reduce disease resistance,increase malformed melon,shorten the growth period,and seriously affect the yield and quality.In this study,20 bitter gourd inbred lines were used to evaluate the heat tolerance,and the heat tolerance indexes were selected to establish a reliable mathematical model for evaluating the heat tolerance,software of segregation analysis of quantitative traits in plants was conducted for inheritance analysis of heat tolerance,the comparative test of bitter gourd hybrid combination was carried out in order to select the heat-resistant bitter gourd hybrid.The research aim to provide a theoretical basis for the identification and evaluation of heat tolerance,the genetic mechanism of heat tolerance and the breeding of new varieties of bitter gourd.The main research results are as follows:1.Comprehensive evaluation and screening of identification indexes of heat tolerance of bitter gourd in seedling stageThe 13 physiological-biochemical and photosynthetic characterist ics indexes of POD,SOD,CAT,Chl,MDA,REC,Pro,O2·-,H2O2,Pn,F0,Fv/Fm,ΦPSⅡwere determined under high temperature stress,comprehensi ve evaluation of 20 bitter gourd inbred lines were evaluated by the principal components,subordinate function,hierarchical cluster analy sis and regression analysis.The mathematical model for bitter gourd heat tolerance was established.The results showed that the 13 physi ological-biochemical and photosynthetic characteristics indexes were transformed into 4 independent comprehensive indexes with 87.258%cumulative contribution ratio.The 20 bitter gourd inbred lines were classified into 4 types according to their heat tolerance:strong heat tolerance,medium heat tolerance and weak heat tolerance,stro ng heat tolerance types of bitter gourd inbred lines including T9,T10,T13,T14 and T17.The optimal regression equation for heat tole rance evaluation of bitter gourd was established by stepwise regressi on analysis:D=-0.650+0.143SOD+0.352Chl+0.088MDA-0.149REC+0.102H2O2+0.846Fv/Fm.The average estimation accuracy of regression e quation was 96.92%,and 6 identification indexes which were SOD,C hl,MDA,REC,H2O2and Fv/Fmfor heat tolerance of bitter gourd were selected.2.Genetic analysis of heat tolerance in bitter gourd at seeding stageSix generations(P1、P2、F1、F2、B1、B2)were produced by hybridization and backcross between heat tolerance bitter gourd inbred line‘0974’and heat sensitive bitter gourd inbred line‘1590’,software of segregation analysis of quantitative traits in plants was conducted for inheritance analysis of heat tolerance.The results showed that the inheritance of heat tolerance in bitter gourd at seeding stage was controlled by two pairs of major genes which showed additive-dominance-epistasis effect(B-1model),Estimates of genetic parameters of 1st and 2nd order parameter showed that the additive effects of the two major genes of heat tolerance were-0.8468 and-0.5033,and the dominance effects of the two major genes were 0.0992 and-0.4517,the epistatic effect is dominated by dominant-dominant interaction effect.the heritability of the major gene in B1、B2、F2was high which was 65.71%,61.2%and 71.58%,respectively.The separation material should be selected in early generation,and the environmental consistency should be strictly controlled in the selection process to reduce the impact of environment.3.Comparative of heat-resistant bitter gourd hybrid combinationsThe growth period,main agronomic characters,yield characters and disease resistance was investigated in 50 bitter gourd hybrid combinations,the result showed that K38 and K48 had the longest harvesting period,and the growth and branching ability of K7,K30,K38,K39,K43,K48 and K50 were strong.The yield of K38,K48 and K40were the top three,which equivalent yield per 667m2were 3297.9 kg,3112.8 kg and 3011.3 kg,respectively,the yield increased by 28.15%,20.96%and 17.01%respectively compared with CK.The resistance of 10combinations to downy mildew was disease resistance,through comprehensive evaluation,four heat-resistant hybrid combinations(K7,K38,K39,K48)with strong growth,disease resistance,long harvest time,high yield and good commercial quality were selected.
Keywords/Search Tags:Bitter gourd, Heat tolerance, Comprehensive evaluation, genetic analysis
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