Studies On Preselected Indices Of Dwarf Rootstock And Molecular Markers Relevanted With Dwarf Character In Pear

Dwarf dense planting has been become a trend and indication for fruit tree products in the world. Selection of variety and rootstock of dwarfish and cold resistance in pear, not only can boost industry of pear tree, but also can adapt cultivation condition for producing in north region. In this study, With Shanli (Pyrus ussuriensis Maxim),S2×Shanli (vigorous), S2×Shanli (dwarfing), S2, super-dwarfing germplasm as the materials, the dwarfing traits of each germplasm were identified by indices including leaf stomata density, branch-cortex ratio, leaf thickness, palisade tissue thickness, palsade-spongy ratio and vessel density.There was a Significant difference in leaf thickness, palisade tissue thickness and palisade-spongy ratio branch-cortex ratio of different growth potential with five pear germplasms, With the weakening of growth potential, the index value was increased. Branch bark rate, leaf thickness, palisade tissue thickness and palisade ratio with growth potential has significant negative correlation,the related coefficient was-0.9166,-0.9959,-0.9968,-0.9703.There was a Significant difference in stomata density and vessel density, With the weakening of growth potential, the index value was decreased and has significant Positive correlation, the related coefficient was 0.9979,0.9927. So stomata density, branch-cortex ratio, leaf thickness, palisade tissue thickness, palisade-spongy ratio and vessel density can be used as indices of identification for pear growth potential in early period.Segregation patterns in S2X Shanli F1 progeny by using SRAP marker were divided into three types:The markers accorded with Mendelian segregation were 44,occupied 36.1%; Deviated from Mendelian segregation markers were 10, the ratio was 8.2%; Abnomoral segregation markers were one, the proportion was 0.82%. It can be yielded 2.0 available mapping markers by each primer bewteen Medelian sergregation and deviated from Medelian segregation (54 bands) which accorded with 1:1 or 3:1 pattern, can be used to construct parents and F1 progeny genetic linkage map.There were 11 linkage groups in this map of S2X Shanli using SRAP marker, including 25 Mendelian markers and 2 distorted markers, it covered 286.4 cM, and the average distance was 10.61cM.One SRAP marker (E6m4-1300bp) was acquired which may be linked with dwarf character by utilizing 154 primers, which was located in eleventh linkage map after JoinMap@3.0 analysis.