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【Objective】The present paper aimed to establish the evaluation method of heat resistance of leek resources, select heat-resistant leek varieties, and solve the problem of shortage of heat-resistant leek varieties in Guangxi.【Method】Taking three kinds of local germplasm resources of leek（marked as A, B, C, D, E, F, G, H and I, respectively） of Guangxi large leaf leek, wide leaf leek and thin leaf leek collected from the general survey of germplasm resources by Ministry of Agricultural and Rural Affairs（2015-2020） as test materials, the changes of the maximum growth length of leek leaves, the newly increased aboveground biomass and the contents of chlorophyll, proline and malondialdehyde after 7 days of high temperature stress at 38 ℃ were measured. Combined with field natural high temperature stress（field group） actual heat resistance performance, the heat resistance of different types of leek was comprehensively evaluated by multivariate statistical analysis（variance analysis, principal component analysis, membership function method and cluster analysis） methods.【Result】Under high temperature stress of 38 ℃,the maximum leaf growth length and the newly increased biomass of 9 leek germplasms of the three types in Guangxi were extremely significantly decreased compared with their proper temperature control（CK）（P＜0.01）.The largest decline was the type of large-leaved leek, and the smallest decline was the type of fine-leaved leek. Chlorophyll content decreased to different degrees, of which the largest decline was the type of leek with large leaves, and the smallest decline was the type of leek with thin leaves. The content of MDA increased to different degrees, of which the largest increase was the type of leek with large leaves, and the smallest increase was the type of leek with thin leaves. Pro content increased to different degrees, of which, the largest increase was the type of leek with thin leaves, and the smallest increase was the type of leek with large leaves. The comprehensive evaluation results showed that the heat tolerance of the three kinds of local leek germplasm resources of leek in Guangxi was ranked as follows: leek with thin leaves＞leek with broad leaves＞leek with large leaves. Germplasm G（No.2016451159） and Germplasm I（No.2016453604） had the strongest heat tolerance among the nine leek germplasms, and Germplasm C（No.SC20191200） had the weakest heat tolerance.【Conclusion】The maximum growth length of leaves, new aboveground biomass and the content of chlorophyll, Pro and MDA contents were used as the evaluation indicators of heat tolerance of leek germplasm resources, the heat tolerance of three kinds of leek germplasm resources in Guangxi can be ranked as follows: Leek with thin leaves＞ leek with broad leaves＞leek with large leaves by variance analysis, principal component analysis, membership function and cluster analysis. Germplasm G and germplasm I were determined to be more heat-resistant, while germplasm C was the least heat-resistant. [ABSTRACT FROM AUTHOR]

【Objective】The present paper aimed to compare overall characteristics of Sterculia nobilis Smith strains plantation in southwest Guangxi and provide a reference basis for qualified S. nobilis Smith strains screening and species cultivation.【Method】Comprehensively compare and investigate the flowering and fruiting habits,agronomic traits,stress resistance,and economic traits of six excellent strains of S. nobilis Smith planted in southwest Guangxi(NY2,LH2,SK14,SJ30,BJ32,and BJ33),and evaluate other traits,including yield and fruit quality,of the six strains by DTOPSIS.【Result】There were some differences in flowering and fruit habits,agronomic traits,stress resistance and fruit traits among different lines. Among them,SK14(14.86 kg) and BJ33 strains(14.50 kg) showed the highest yield per plant,without significant difference(P>0.05,the same as below),which were significantly higher than the other four strains(P<0.05,the same as below).No significant differences were found in yield per plant among the four strains. The single fruit weight of SK14(65.3 g) was the heaviest,extremely significantly heavier than that of NY2,LH2 and BJ32 strains(P<0.01,the same as below),and significantly heavier than that of SK14 and SJ30 strains. BJ32 had the highest seed production rate(58.6 %),which was extremely significantly higher than NY2,SK14 and SJ30 strains,and significantly higher than BJ33 strain. The single seed weight of SK14 was only 5.90 g,which was extremely significantly lower compared with the other five strains. The differences among the five strains were not significant. NY2 had the lowest pod boring rate(5.2 %),extremely significantly lower than SK14 strain,and significantly lower than LH2,BJ32 and BJ33. The starch content of SK14 was the highest(65.899 %),which was very significantly higher than that of NY2,LH2,SJ30 and BJ32 strains. The soluble sugar content of BJ32 was the highest(27.496 %),extremely significantly higher than that of NY2,LH2 and BJ33 strains,and significantly higher than that of SK14 and SJ30 strains. The soluble protein content of SJ30 was the highest(11.808 mg/gFW),which was very significantly higher than that of BJ33. No significant differences were found in soluble protein content among SJ30,NY2,LH2,SK14 and BJ33. DTOPSIS evaluation demonstrated that BJ33 had the highest score,C_i was 0.8336,and the optimal comprehensive characters.【Conclusion】BJ33 has strong tree vigor, high yield, filled fruit, big seed, high seed production rate, good quality and taste. It has the optimal comprehensive evaluation and can be developed as good S. nobilis Smith variety. SK 14, BJ 32 and NY2 has fine performance on single trait, and can be used as genetic resources in variety improvement. [ABSTRACT FROM AUTHOR]