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11.
Takaaki Fujimoto Kazuhito Kita Kazuko Uchiyama Makoto Kuromaru Hisashi Akutsu Kazuyuki Oda 《Journal of Forest Research》2006,11(3):157-163
Age trends in variance components and heritability of overall wood density, earlywood and latewood density, and latewood proportion
were investigated in 29-year-old trees of 19 full-sib families of hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F1. The age–age correlation and optimum selection age for these traits were also estimated and genetic and phenotypic correlations
between wood density and radial growth rate were calculated for each growth ring. Intraring wood density data were obtained
using X-ray densitometry. The coefficient of additive genetic variance was stable over all ages, whereas the coefficient of
environmental variances gradually decreased with increasing age, resulting in increases in heritability estimates with age
for overall density. The latewood proportion had the highest heritability estimates at all ages, ranging from 0.44 to 0.66.
Overall density and its various components at 28 years of age showed strong genetic correlations with their respective traits
at all younger ages. Optimum selection ages for the wood density traits ranged from 8 to 14 years, at which point maximum
gain efficiencies per year were obtained. There were negative correlations between wood density and radial growth rate at
early ages, although these relationships tended to be weaker with increasing age. These results suggest that selection at
a young age is effective for wood density, but particular care must be taken in selecting trees with an improved radial growth
rate because rapid growth will result in a low-density wood product, especially in the early growth period. 相似文献
12.
杂种致死是一种生殖隔离类型,致死材料的鉴定及遗传分析不仅有助于了解杂种致死的遗传机制,还可以为致死基因的定位和克隆奠定基础。利用已知携带杂种致死基因的甘蓝自交系09-211、09-222、10-260和其他自交系配制的杂交组合为试材,鉴定携带致死基因的新材料,并对甘蓝杂种致死性状进行了遗传分析。结果表明:11-204和11-176是2个新的甘蓝致死材料;11-176与09-222及10-260具有遗传等效性,而11-204与09-211具有遗传等效性;甘蓝杂种致死性状是由2个显性基因互补控制的,其中1个致死基因来自09-211或11-204,另1个致死基因来自09-222或10-260或11-176,其遗传模式符合Dobzhansky-Muller(DM)模式。 相似文献
13.
A Review of Fine Root Dynamics in Populus Plantations 总被引:1,自引:0,他引:1
Production of native and hybridized varieties of Populus has received considerable interest in temperate regions as an alternative to agricultural crops and an additional wood source,
while acting as a potential carbon (C) sink to offset emissions of fossil fuel-based greenhouse gases. Research of root system
dynamics in Populus species is expanding, however, our understanding of the nature and role of fine roots (FR) is incomplete. The study objective,
therefore, was to review the literature regarding FR production, mortality and longevity in Populus, and evaluate the magnitude and significance of the FR fraction to C sequestration. FRs, conventionally defined as less than
2 mm in diameter and responsible for water and nutrient uptake, are an essential component of the tree. Populus FRs are relatively short-lived, with reported lifespans ranging from 30 to 300 days, depending on root diameter, tree species
and age, and soil environmental factors. Standing FR biomass fluctuates throughout the growing season. Fine root production
generally peaks in mid-summer, and ranges between 1.0 and 5.0 mg ha−1 yr−1, while FR mortality has less seasonal amplitude. Production and mortality dynamics in Populus are highly plastic in response to soil environmental conditions, and although opposing conclusions have been proposed, research
suggests soil moisture and nitrogen to be most important. Results from the literature indicate annual FR turnover to the soil
C pool may be small (0.2–1.6 mg C ha−1 yr−1), but substantial in maintaining or enhancing C levels in natural and managed stands of Populus. 相似文献
14.
15.
以5年生36个杂种落叶松家系为材料,测定其树高、胸径生长性状,估算变异系数、遗传力和遗传增益,筛选出优良家系。结果表明:各家系的树高、胸径存在较丰富变异,树高变异系数小于胸径,树高、胸径极显著相关(P<0.01),家系间树高、胸径差异均达极显著差异水平(P<0.01)。以10%的入选率,初选出家系1317、1324、1318、和1327为优良家系,树高平均增益为15.98%,胸径平均增益为29.46%。 相似文献
16.
17.
三香优410在建瓯种植,表现出丰产性好、抗性较强、米质优良等特性,栽培上要注意选好秧田、培育壮秧、合理密植、科学施肥、做好水管、病虫防治。 相似文献
18.
19.
In an effort to increase the accessibility and functionality of shallow green roof systems, the ability of warm-season grasses to provide acceptable growth needs to be further investigated. In the current study, which was conducted during 2011 and 2012, three warm-season grasses (hybrid bermudagrass, Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy ‘MiniVerde’; seashore paspalum, Paspalum vaginatum Swartz ‘Platinum TE’ and zoysiagrass, Zoysia japonica Steud. ‘Zenith’) were established in outdoor lysimeters. The lysimeters were equipped with all necessary green roof layers placed below a coarse-textured substrate that comprised pumice, thermally treated attapulgite clay, peat, compost and zeolite. Half of the lysimeters had a substrate depth of 15 cm, while the other half had a substrate depth of 7.5 cm. Irrigation was applied at crop evapotranspiration (ETc). Measurements included determination of substrate moisture content, green turf cover (GTC) and leaf stomatal resistance. Significant differences were observed in the values of GTC among the three turfgrass species and the two substrate depths. Zoysiagrass exhibited the best adaptation at the lower depths of shallow green roof systems. At 15 cm substrate depth, zoysiagrass managed to sustain green coverage for the two study periods. In addition, it was the only turfgrass species that managed to perform well at the substrate depth of 7.5 cm. Seashore paspalum exhibited limited green cover at both substrate depths, while hybrid bermudagrass could provide acceptable green coverage only at 15 cm substrate depth. 相似文献
20.
东方百合高效离体再生体系的建立 总被引:2,自引:0,他引:2
采用东方百合鳞片叶切块为初始外植体,以从初始外植体上分化的丛生芽切段为次级外植体的两步外植体法,成功建立了东方百合的离体再生体系。研究了不同的2,4-D浓度及次级外植体的不同部位对愈伤组织诱导效果的影响,并确定了G418选择的临界浓度。结果表明:不同部位的次级外植体中,以短缩茎切片出愈率高、出愈快、愈伤组织致密;以MS附加2.0 mg/L 2,4-D和0.1 mg/L BA的培养基最适于东方百合愈伤组织的诱导;G418选择的临界浓度为50 mg/L。一个中等大小已脱春化的鳞茎通过愈伤组织再分化植株一代就能扩繁出27 000株左右的新植株,从鳞片叶开始至开花需9个月。 相似文献