Study On The Fast-growing Varieties Of Ulmus Pumila Excellent Clones

Ulmus pumila White elm is an important timber tree species in northern China, In recent years, the pest elm leaf beetle blue harm pumila, how to select germplasm collection and breeding superior strains of insect research resources to promote the application of native trees to meet community needs pumila high-grade timber need to be solved on the current production problems, This paper selects Ulmus pumila excellent fast-growing varieties:CK、65212、225、anti Su、34、50、61、43、55and72 (hybrids),10 pumila 6-year-old elite hybrid clones seedling leaves for the study,through cross breeding, test source, breeding, clonal comparison experiment, physiological indexes of drought resistance in clones, greenhouse artificial hybridization, leaf tissue structure. The main results are as follows:1. Pumila blade structure and insect resistance:pumila leaf structure there are differences between varieties, and morphological characteristics of different leaf structure is different, indicating pumila in the joint action of genes and the environment, an ecological polymorphism phenomena. Elm leaf beetle blue blade is directly feeding site, its life activity will elm leaf beetle blue certain extent. This study showed that the number of lines in the selected 10 indicators blade structure and Comprehensive spawning index, the density of the surface of leaf epidermis, mesophyll cells under the skin thickness and the tightness of the main factors affecting species of insect resistance. The organizational structure of plant leaves are divided into upper epidermis, palisade tissue, spongy tissue under the skin cells of four parts; the density and pore size of crop varieties resistant to a certain relevance. Generally density, small pores, is not conducive to neat feeding pest damage; the No. 10 blade stomata distribution system rarely, and under more stomata, stomatal density per square millimeter large changes in 405-758um between. Each species pore shapes, substantially oval, round, square and rectangular. Wherein the pore surface area is relatively small,55,43,50 and the larger anti-Su. Each tree leaf thickness change is bigger, the thickest blade is 251.83 μm, the thinnest ck tree of 29.4 μm.The bigger the blade thickness is not easy to be pests feeding. Plant leaves of insect resistance ability was strengthened. Blade to obtain convenient, observation of relatively simple structure, can through leaves at seedling stage, which looked at these indicators preliminary judgment of the insect resistance to get up early, can greatly save the time of insect-resistant varieties breeding and cultivation.2. Shape and each strain grown insect research pumila:the establishment of germplasm banks Ulmus, pumila stored in the repository of three types of natural populations 1114 months, genotype 112, of which two superior clones; elm 19 a species, two hybrids, and Ulmus species except one. Study pumila growth and insect Variation Patterns of Ulmus each species grow, dry and insect resistance were studied to determine the trunk straight tall piles planted with white × 2, Langya elm, red Ye Mingling Yu, Chun Yu, red elm; species highly resistant elm hairy chest firefly beetle has Taihang elm, European large-leaved elm, piles of elm, red elm, bolt branch Chun elm, Ulmus davidiana No.1, davidii, lobed leaf elm; high resistance there are species of beetles Chun Yu, Yu Taihang, hair elm, gray elm; determining a green elm species suitable for urban gardens:Taihang Yu, Yu-chun, dry elm, Langya elm. Clarify the variation law Ulmus crossbreeding with a male half-female differences with the present and the male parent, that is insect-resistant hybrid male and female different variation, the offspring of insect resistance occurs due to different parental increases and vice versa. Identified Chun Yu, Mao Yu, Taihang Yu, Su anti No.1,65212 of insect resistance, growth GCA size and sequence, highly resistant elm hairy chest firefly beetle Su anti No.1,65212 is higher genetic ability, breaking the old theory that people recognized plant trees insect pest resistance can not be stably inherited. Insect resistance is determined to get strong and fast-growing hybrids. Both anti-elm leaf beetle firefly chest hair fork combination of fast-growing hair have 8045 x elm (Ulmus pumila × gray) × Chun Yu,65216 × 65212,8015 × anti-Su No.1,65212 × anti-Su No.1. Both anti beetles fork fast-growing combinations are 65216 × Taihang elm,8015 × Chun Yu.60 were selected from insect-resistant plant hybrid combinations.