| In this study, according to the principle of heterosis, test-strains of four cultivation strains W1, L205, Q6,271 and 2 wild strains SHL12, SHL44 were selected to form four pairs of complementary crossing combination, hybridized by the technique of Mon-Mon crossing and Di-Mon crossing breeding. Then according to the speed of Mycelial growth and laccase activity,87 hybrids were Selected from them. The method of grey correlation degree analysis was applicated to comprehensively analysis the 8 main agronomic characters of test-strains, which were pileus diameter, pileus thinkness, stipe length, stipe diameter, average fresh weight of a single fruitbody, average fresh yield of fruit body per bag, average numbers of fruitbody per bag and fruiting period. Six more excellent strains (XZ-3, XZ-8, XZ-40, XZ-74, XZ-81, XZ-87) selected from 44 normal fruiting of hybrid strains were further studied in the middle test.IRAP marker was applied to analyze the genetic diversity of 39 hybrid strains from the W1×SHL12 cross combination.12 pairs of IRAP primers were selected and a total of 128 fragments were attained, among which 127 fragments (rate of 99.2%) were polymorphic. Based on amplification map, software NTSYS2.10e was used to calculate the genetic similarity and analyze cluster results between the tested strains. The results show that, all the tested strains were clusted into 2 groups at 0.69 similarity level. the strains of all Mon-Mon crossings except XZ-27, XZ-28 were put into the first group, and all Di-Mon crossings except XZ-5, XZ-23 into the second group. XZ-10 and XZ-11 had few but big fruitbody, so they could be put into one group at 0.88 similarity level. XZ-3 and XZ-8 had big fruitbody, higher yield than their parents, clusted into one group with XZ-2 at 0.77 similarity level. XZ-19, XZ-20, XZ-27 had few and small fruitbody, cultivation bags of which were apt to spit out yellow water, classified into one group at 0.83 similarity level. XZ-5, XZ-23 have no fruitbody, classified into one group at 0.83 similarity level. XZ-7, XZ-17 covered with mycelium in bags completely, which had no tumor and no turn color, were clusted into one group at 0.86 similarity level. The results of IRAP analysis could well reflect the genetic diversity of the Lentinula edodes, and could guid for initial screening excellen hybrid strains of L. edodes strains, which could further improve the efficiency of hybrid breeding.We chosed 6 dicaryotic parents (W1, L205, Q6,271, SHL12, SHL44) and 55 monocaryotic parents (16 monocaryons of W1,7 monocaryons of L205,3 monocaryons of Q6,10 monocaryons of L271,9 monocaryons of SHL12,10 monocaryons of SHL44) as tested strains to analyze their genetic similarity by DNA Fingerprint with TRAP, ISSR, SSR, RAPD, SRAP.28 pairs of primers were selected to amplify the hybrid strains, and a total of 912 fragments were attained from the pair of W1×SHL12, among which 850 fragments were polymorphic, with the rate of 93.2%; 924 fragments from the pair of L205×SHL12, among which 877 fragments were polymorphic, with the rate of 94.9%; 863 fragments from the pair of L205×SHL44, among which 806 fragments were polymorphic, with the rate of 93.4%; 780 fragments from the pair of Q6×L271, among which 700 fragments were polymorphic, with the rate of 89.7%; According to amplification results, amplification products supported the genetic relationship among strains. However, genetic distance and the value of the main agronomic traits and sort results of grey relation degree were not significantly correlated. The method using molecular markers to estimate correlation of genetic distance and traits of hybrids exists many uncertainties, the results of which not only are affected by the genetic background, but also by environmental factors to some extent. |
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