Microscopic examination and AFLP molecular markers were employed to determine the incidence and related markers of 2n pollen (unreduced pollen) in Populus tomentosa Carr. The parallel and tripolar spindle at metaphase...Microscopic examination and AFLP molecular markers were employed to determine the incidence and related markers of 2n pollen (unreduced pollen) in Populus tomentosa Carr. The parallel and tripolar spindle at metaphase Ⅱ and the absence of cytokinesis at telophase Ⅱ led to the formation of 2n pollen. A group of 298 clones came from their indigenous areas was investigated for the production of 2n pollen based on the pollen size differences, within a clone and between n and 2n pollen. Pollen grains of 224 clones were collected, six of them only produced normal pollen, and the rest produced 2n pollen at different frequencies (0.6% -21.9%). Clones producing six normal and 22 2n pollen were selected for AFLP analysis. Following an initial screening with 55 primer combinations, the E50-M38 (CAT/ACT) primer was identified, which generated a PCR fragment (246 bp) from the normal clones, but not from the 2n pollen producers. In addition, the E31-M50 (AAA/CAT) amplified DNA fragment (204 bp) that was present in 2n pollen producers, and absent in normal clones. Two polymorphic bands were found and they were distinguished between normal and 2n pollen clones. They are very useful as AFLP markers for molecular-assisted selection in triploid breeding of 2n gametes in P.tomentosa.展开更多
Wood basic densityies of about 100 Populus tomentosa Carr. clones grown in 4 clone testing plantations located in Hebei, Henan, Shandong and Gansu were tested and its inheritance and variation among clones and sites w...Wood basic densityies of about 100 Populus tomentosa Carr. clones grown in 4 clone testing plantations located in Hebei, Henan, Shandong and Gansu were tested and its inheritance and variation among clones and sites were studied. The results showed that the average wood basic density of the studied clones was 0 4363?g/cm 3 and there was significant difference in wood basic density between clones and sites. The high value of clonal repeatability(0 82～0 91)of wood basic density indicated that the character was under strong genetic control. Correlation analysis showed general significantly negative correlation between growth traits(including diameter at breast height, height, and volume) and wood basic density, although the correlation coefficients varied in a certain degree from one site to another. Studies on wood properties and relationships between tree growth and wood quality are of importance in such fields as wood properties breeding and combined improvement of both growth and wood quality.展开更多
文摘Microscopic examination and AFLP molecular markers were employed to determine the incidence and related markers of 2n pollen (unreduced pollen) in Populus tomentosa Carr. The parallel and tripolar spindle at metaphase Ⅱ and the absence of cytokinesis at telophase Ⅱ led to the formation of 2n pollen. A group of 298 clones came from their indigenous areas was investigated for the production of 2n pollen based on the pollen size differences, within a clone and between n and 2n pollen. Pollen grains of 224 clones were collected, six of them only produced normal pollen, and the rest produced 2n pollen at different frequencies (0.6% -21.9%). Clones producing six normal and 22 2n pollen were selected for AFLP analysis. Following an initial screening with 55 primer combinations, the E50-M38 (CAT/ACT) primer was identified, which generated a PCR fragment (246 bp) from the normal clones, but not from the 2n pollen producers. In addition, the E31-M50 (AAA/CAT) amplified DNA fragment (204 bp) that was present in 2n pollen producers, and absent in normal clones. Two polymorphic bands were found and they were distinguished between normal and 2n pollen clones. They are very useful as AFLP markers for molecular-assisted selection in triploid breeding of 2n gametes in P.tomentosa.
文摘Wood basic densityies of about 100 Populus tomentosa Carr. clones grown in 4 clone testing plantations located in Hebei, Henan, Shandong and Gansu were tested and its inheritance and variation among clones and sites were studied. The results showed that the average wood basic density of the studied clones was 0 4363?g/cm 3 and there was significant difference in wood basic density between clones and sites. The high value of clonal repeatability(0 82～0 91)of wood basic density indicated that the character was under strong genetic control. Correlation analysis showed general significantly negative correlation between growth traits(including diameter at breast height, height, and volume) and wood basic density, although the correlation coefficients varied in a certain degree from one site to another. Studies on wood properties and relationships between tree growth and wood quality are of importance in such fields as wood properties breeding and combined improvement of both growth and wood quality.
