Protoplast fusion to obtain high-yield strains from interspecific hybridization between black cultivated species and yellow uncultured species of <italic>Morchella</italic>

<bold>Objective</bold> At present，the main issues that restricting the development of <italic>Morchella</italic> industry in Jiangxi Province are low yield，difficulty in replicating high yields，and limited availability of high-quality strains，and the key to addressing these challenges lies in the improvement of strains.The purpose of this study is to breed a new strain of <italic>Morchella</italic> with high yield，which is suitable for local cultivation in Jiangxi. <bold>Method</bold> According to the theory of interaction between heredity and environment，targeted selection was made of the wild yellow <italic>Morchella</italic> strain JFRL01-161 collected locally in Jiangxi，along with the commercially cultivated <italic>Morchella importuna</italic> strain JFRL01-107 and <italic>Morchella sextelata</italic> strain JFRL01-217 from Yingtan region of Jiangxi Province，which were used as original strains，and protoplasts were prepared by dissolving the cell wall with a complex enzyme composed of 20 g/L lywallzyme and 10 g/L snail enzyme，and then two kinds of inactivated protoplasts were obtained by high temperature and ultraviolet double inactivation.The obtained fusants were tested by antagonism，cultivar ratio and Inter-Simple Sequence Repeat to determine the provenance relationship. <bold>Result</bold> Sixteen fusion strains were obtained by protoplast fusion，namely A11，A37，A39，B7，B12，B17，B18，B25，B26，B29，C1，C2，C5，C6，C11 and C12.Among them，strains A11，A37，A39 and B18 successfully fruited and produced yields，the yield of the fusion strain A11 reached 351.90 g/m²，which was significantly higher than that of the parent JFRL01-107（264.51 g/m²）.The annual repeated cultivation verification test confirmed that the yield of A11 could reach 527.8 g/m²，and that of the parent JFRL01-107 was 262.4 g/m².The phylogenetic tree（UPGMA）of unweighted arithmetic mean clustering system showed that A11 was in different branches from its parents JFRL01-161（similarity coefficient 0.24）and JFRL01-107（similarity coefficient level 0.696），which proved that A11 was a new strain different from its parents. <bold>Conclusion</bold> The yield of fused strain A11 was significantly higher than that of its parents.Repeated cultivation experiments confirmed that its germplasm was stable，and ISSR confirmed that it was different from its parents.Therefore，fused strain A11 can be used as a new strain of high-yield <italic>Morchella</italic> adapted to local cultivation in Jiangxi.