Identification And Tissue Culture Of Interspecies Hybrid Between Betula Luminifera And Betula Nigra

Both Betula luminifera and B.nigra are deciduous trees of Betulacea.B.luminifera is not onlya fast-growing species,but also a high-quality timber tree.However,B.nigra havea strong resistance to moisture,hot and dry,infertility.It is of great practical significance to create new varieties with high quality,fast-growing and high-resistant traits by introducing the excellent resistance gene of B.nigra into B.luminifera.In this paper,the early generation of B.luminifera andB.nigra hybrids were used as materials,their authenticity of hybrids was identified by SSR,and their morphological and photosynthetic characteristics were analyzed.Further more,the tissue culture techniques were developed.The main results are as follows:1.In the identification of molecular markers,the primers were screened by parental B.luminifera andB.nigra.The results showed that 12 pairs of primers such as BL?515?,BL?555?and BL?563?could amplify 1-2 specific bands in the B.nigra,that can be used for the authenticity of hybrid offspring identification.The results of the identification of hybrid progeny showed that all 29 offspring plantshad specific bands of the male parent,which confirmed the real hybrids between the B.luminifera andB.nigra interspecific.2.In terms of morphological characteristics and photosynthetic characteristics,interspecific hybrids are different from B.luminifera andB.nigra.Interspecific hybrids are sprouting earlier than B.nigra,but later than B.luminifera.There were significant differences in the unit area,leaf length,leaf width,petiole length,leaf area,leaf color between hybrids and their parents,and the value was between B.luminifera andB.nigra.Light saturation point of hybridis 1292.0?mol/?m²·s?,below B.luminifera andB.nigra.B.luminifera andB.nigra.Light compensation point of hybrid is46.3?mol/?m²·s?,higher than both parenrs.Photosynthesis-CO₂ response measurement display the maximum net photosynthetic rate of B.luminifera?B.nigra andhybrids respectively is 21.46?14.78?11.4?mol CO₂/?m²·s?under CO₂ saturation point.3.Choosing the tender stems of interspecific hybrids during the vigorous growth period as explants,and then washing with 75% alcohol for 3-4 times,soaking with 0.1% HgCl₂ for 10 minutes.The sterility rate was up to 85.5% after inoculation,and the survival rate was up to 80.3%.The aseptic rate of explants can reach more than 80%.The suitable rooting medium of hybrid explants culture was MS +0.5mg/LIBA,which obtained after experiments;In the study of leaf differentiation,the optimum culture medium was MS + 0.05 mg/L NAA+0.4mg/L TDZ?The above results not only confirm that no obvious reproductive disorders between B.luminifera andB.nigra.but also lay the foundation for the creation of fine hybrids and their rapid development.