选用郑单958(ZD958)和先玉335(XY335)为试验材料,在砂培和大田条件下设置3、5、7和9 cm 4个播种深度,并在大田条件下以不同播种深度混播作为对照(CK),研究播种深度对夏玉米幼苗性状和根系特性的影响.结果表明:随着播种深度的增加,夏玉...选用郑单958(ZD958)和先玉335(XY335)为试验材料,在砂培和大田条件下设置3、5、7和9 cm 4个播种深度,并在大田条件下以不同播种深度混播作为对照(CK),研究播种深度对夏玉米幼苗性状和根系特性的影响.结果表明:随着播种深度的增加,夏玉米的出苗率下降,出苗时间延长.ZD958和XY335播深9 cm的出苗率较3 cm的分别降低9.4%和11.8%,出苗时间较3 cm的均延长1.5 d.随着播种深度的增加,幼苗长度及幼苗整齐度显著降低,中胚轴长度显著增加,胚芽鞘长度差异不显著;初生胚根长度逐渐减小,次生胚根总长度逐渐增加,总根长度差异不显著;幼苗与中胚轴的总干质量增加,总根干质量差异不显著.随播种深度的增加,种子萌发时幼苗各部位可溶性糖含量增加,营养物质消耗量增加,幼苗根系生长速度增加,根系活力降低,总节根数及节根层数增加.播深增加后出苗率及幼苗活力的降低导致收获穗数的显著降低,最终影响产量形成.此外,播深一致有利于群体整齐度的提高和群体性状的改善,从而提高产量.展开更多
The seedling stage test on 55 open-pollinated families of plus trees of Betula luminifera H. Winkl. from Shaowu, Nanping and Wuping in Fujian Province was carried out in State-owned Forest Farm of Weimin, Shaowu. The ...The seedling stage test on 55 open-pollinated families of plus trees of Betula luminifera H. Winkl. from Shaowu, Nanping and Wuping in Fujian Province was carried out in State-owned Forest Farm of Weimin, Shaowu. The genetic variations of Betula luminifera were studied, based on the investigation of 1-year-old seedling traits from different families. The results showed that there were abundant variations within the Betula luminifera and very significant differences among families in seedling height, diameter and lateral branch. The variations were mainly controlled by genetic factors. According to this analysis, 11 excellent families were tentatively selected, the average genetic gain of height and diameter were 18.72% and 10.44% respectively. The selection effect was very striking. The Shaowu region was probably a superior genetic resource area of Betula luminifera .展开更多
Utilization of heterosis has greatly contributed to rice productivity in China and many Asian countries. Superior hybrids usually show heterosis at two stages: canopy development at vegetative stage and panicle devel...Utilization of heterosis has greatly contributed to rice productivity in China and many Asian countries. Superior hybrids usually show heterosis at two stages: canopy development at vegetative stage and panicle development at reproductive stage resulting in heterosis in yield. Although the genetic basis of heterosis in rice has been extensively investigated, all the previous studies focused on yield traits at maturity stage. In this study, we analyzed the genetic basis of heterosis at seedling stage making use of an "immortalized F2" population composed of 105 hybrids produced by intercrossing recombinant inbred lines (RILs) from a cross between Zhenshan 97 and Minghui 63, the parents of Shanyou 63, which is an elite hybrid widely grown in China. Eight seedling traits, seedling height, tiller number, leaf number, root number, maximum root length, root dry weight, shoot dry weight and total dry weight, were investigated using hydroponic culture. We analyzed single-locus and digenic genetic effects at the whole genome level using an ultrahigh-density SNP bin map obtained by population re-sequencing. The analysis revealed large numbers of heterotic effects for seedling traits including dominance, over- dominance and digenic dominance (epistasis) in both positive and negative directions. Overdominance effects were prevalent for all the traits, and digenic dominance effects also accounted for a large portion of the genetic effects. The results suggested that cumulative small advantages of the single-locus effects and two-locus interactions, most of which could not be detected statistically, could explain the genetic basis of seedling heterosis of the F1 hybrid.展开更多
文摘The seedling stage test on 55 open-pollinated families of plus trees of Betula luminifera H. Winkl. from Shaowu, Nanping and Wuping in Fujian Province was carried out in State-owned Forest Farm of Weimin, Shaowu. The genetic variations of Betula luminifera were studied, based on the investigation of 1-year-old seedling traits from different families. The results showed that there were abundant variations within the Betula luminifera and very significant differences among families in seedling height, diameter and lateral branch. The variations were mainly controlled by genetic factors. According to this analysis, 11 excellent families were tentatively selected, the average genetic gain of height and diameter were 18.72% and 10.44% respectively. The selection effect was very striking. The Shaowu region was probably a superior genetic resource area of Betula luminifera .
基金supported by grants from the National Natural Science Foundation of China(No.31330039)National 863 Project(No.2014AA10A604)the Bill&Melinda Gates Foundation(No.OPP51587)
文摘Utilization of heterosis has greatly contributed to rice productivity in China and many Asian countries. Superior hybrids usually show heterosis at two stages: canopy development at vegetative stage and panicle development at reproductive stage resulting in heterosis in yield. Although the genetic basis of heterosis in rice has been extensively investigated, all the previous studies focused on yield traits at maturity stage. In this study, we analyzed the genetic basis of heterosis at seedling stage making use of an "immortalized F2" population composed of 105 hybrids produced by intercrossing recombinant inbred lines (RILs) from a cross between Zhenshan 97 and Minghui 63, the parents of Shanyou 63, which is an elite hybrid widely grown in China. Eight seedling traits, seedling height, tiller number, leaf number, root number, maximum root length, root dry weight, shoot dry weight and total dry weight, were investigated using hydroponic culture. We analyzed single-locus and digenic genetic effects at the whole genome level using an ultrahigh-density SNP bin map obtained by population re-sequencing. The analysis revealed large numbers of heterotic effects for seedling traits including dominance, over- dominance and digenic dominance (epistasis) in both positive and negative directions. Overdominance effects were prevalent for all the traits, and digenic dominance effects also accounted for a large portion of the genetic effects. The results suggested that cumulative small advantages of the single-locus effects and two-locus interactions, most of which could not be detected statistically, could explain the genetic basis of seedling heterosis of the F1 hybrid.