Transgene stability of transgenic hybrid of Populus〔(Populus tomentosa ×P. bolleanaP. tomentosa〕 and its effect on soil microorganisms ESTIMATION OF THE GENETIC HETEROZYGOSITY OF POPULUS TOMENTOSA AND ITS HYBRID P.TOMENTOSA×P. BOLLEANA USING AFLP TECHNIQUE POLYPLOID INDUCTION OF Populus HYBRID THROUGH ZYGOTIC CHROMOSOME DOUBLING WITH HIGH-TEMPERATURE TREATMENT QTL Analysis of Leaf Morphology and Spring Bud Flush in (Populus tomentosa×P. bolleanaP. tomentosa