Breeding Of Thermotolerant Strains Of Stropharia Rugosoannulata

As one of the major edible fungi species,Stropharia rugosoannulata,is widely sought after and cultivated in recent years because of its delicious taste,rich nutrition,easy to cultivate,and obvious economic and environmental benefits.The cultivation area continues to expand.S.rugosoannulata is a medium-low temperature species.Its open-air cultivation in east China is mainly in spring and autumn.The fruiting time is mainly in the winter and spring,and the yield and quality are poor under high-temperature environment in summer.Therefore the supply is insufficient.In order to solve the problem of poor quality in high temperature,this study started with the high-temperature acclimation of mycelia,and initially screened and obtained high temperature acclimated strains,and then selected and bred heat resistant strains of S.rugosoannulata,through the method of protoplasmic.Finally,the quality and stability of the selected strains were verified in different environments,and high-yield and high-quality thermotolerant strains were selected to provide appropriate varieties for cultivation of S.rugosoannulata in summer in east China.The main results are as follows:1.Genetic relationship analysis of the tested strains: Genetic diversity and geneticrelationship of 23 primary strains were analyzed by SRAP molecular marker technique.The results show that the genetic diversity among the tested strains is abundant.The strains TA and JN were synonymous strains.The strain JN was removed and 22 strains were selected as the test strains for the breeding of heat-resistant strains.2.Domestication of thermotolerant strains: High-temperature cycling cultures were used for high-temperature acclimation of the tested strains.The cycles were set as(26℃,16h;30℃,8h),(26℃,16h;34℃,8h),(26℃,16h;38℃,8h),(26℃,18h;42℃,6h),each domestication cycle was 16 d,and the strains incubated at a constant temperature of 26℃ were used as comparisons.After stability verification,four thermotolerant strains was selected.3.S.rugosoannulata protoplasmic breeding:1)The effects of enzyme concentration,enzymolysis temperature,enzymolysis time and mycelial age on the preparation of high temperature resistant protoplasts were investigated.The results showed that the highest yield of protoplasts can be obtained by using 1.5% Lywallzyme,digesting for 3h at the condition of 32℃.2)Three heat-tolerant strains were selected and bred through protoplast regeneration,the heterogeneity of the acclimated strains was eliminated,and the heat-resistant strains were purified.3)Three strains resistant to high temperature mutation were selected by protoplast UV mutagenesis.4)Protoplast fusion method was used to fuse high temperature resistant strains and high-yield strains,and three high temperature and high yield fusion strains were directional selected.4.Verification of thermotolerant strains of S.rugosoannulata: Combined with antagonistic test,subculture,SRAP relationship analysis and fruiting test of 15 thermotolerant strains,3 strains of thermotolerant strains were screened out.The results showed that the breeding strains performed better than the comparison.Among them,the highest yield was the high-temperature regeneration strain S20,the earliest strain was the thermotolerant strain D2,and the highest proportion of the first-class mushroom was the fusion strain R10.