利用杂交技术选育六妹羊肚菌适应高温的优良菌株OA

Morchella spp.are highly susceptible to abnormally high temperatures during the fruiting stage,which leads to severe yield reduction.Therefor,breeding excellent strains with strong high-temperature adaptability is an urgent requirement for industrial development of Morchella.To accelerate the breeding process of thermotolerant Morchella sextelata varieties,this study used strains M4 and M6 as parents to generate a hybrid population via monospore hybridization.The mycelial growth rates,colony phenotypes,key antioxidant enzyme activities,non-enzymatic antioxidant substance contents,and agronomic traits of field cultivation under high-temperature stress were systematically evaluated.The results indicated that through preliminary high-temperature screening on PDA plates at 20,25,and 30 ℃,six hybrid strains(H1,H27,H30,H33,H38,and H42)with significantly better high-temperature adaptability than their parents were obtained.At 25 ℃ and 30 ℃,the mycelial growth rates of the six hybrid strains were all higher than those of the parents,and a highly significant positive correlation(P＜0.01)was observed between the mycelial growth rates in cultivation substrate and those on PDA plates.Under high-temperature stress at 30 ℃,the activities of superoxide dismutase(SOD)and glutathione peroxidase(GPX)in the six hybrid strains generally increased,among which strains H27 and H42 exhibited outstanding comprehensive performance.Field cultivation experiments demonstrated that the number of primordia differentiation,heat-damage resistance,and yields of the six hybrid strains all surpassed those of the parents strains.Except for strain H1,the fresh weight per mushroom of the other five hybrid strains was all significantly higher than that of the parents.Strain H27 displayed the optimal comprehensive traits,achieving a fruiting body yield of 2.58 kg/m2.This study successfully bred multiple novel M.sextelata strains with strong high-temperature adaptability and established a rapid screening method based on mycelial growth performance for thermotolerant strains.This method can effectively predict the high-temperature adaptability of strains in the field and shorten the breeding cycle,thereby providing an essential theoretical basis and technical support for the breeding of thermotolerant Morchella strains.