玉米新品种正大305的选育研究     

樊荣峰  刘涛  朱晓峰  郭雪恒  刘晓 《玉米科学》2007,15(Z1):046-047

正大305是以自选系CTL101为母本,自选系CTL102为父本杂交选育的玉米单交种。在各级试验中表现为高产、稳产、多抗,两年区试比对照农大108、郑单958平均增产9.4%,2006年1月通过辽宁省农作物品种审定委员会审定。适宜在辽宁省郑单958种植的地区种植,适宜密度42 000～45 000株/hm2。  相似文献   

贵州省主要自育杂交水稻超高产潜力研究   总被引：1，自引：0，他引：1  

唐相群  王怀昕  张元琴  王炜  杨秀伟  令狐昌英  余常水 《安徽农业科学》2009,(2):540-541

[目的]为提高水稻的单产水平提供理论依据。[方法]以水稻品种黔优88、益农1号和黔南优2058、Ⅱ优838（对照）为供试材料，研究了不同品种的高产特性。[结果]黔优88、益农1号和黔南优2058的产量分别为12990．0、12823．5和12460．5kg／hm^2，分别比对照Ⅱ优838增产20．0％、18．5％和15．1％。与对照Ⅱ优838相比，黔优88、益农1号和黔南优2058的有效穗增加15．1％、24．5％和3．5％；千粒重分别高2．7％、4．2％和11．4％；总颖花数分别增加10．5％、11．7％和8．3％，生物产量分别高187．0、98．0和220．0g/m^2。黔优88和益农1号库容量分别比Ⅱ优838大13．4％和16．4％。上述3个品种的干物质生产优势表现在中期和后期。[结论]黔优88、益农1号和黔南优2058的平均产量达到12757．5kg／hm^2。  相似文献   

优质早籼三系不育系贺50A选育     

唐海燕  杨孚初  宋武  姜守全  黎小平  严钦泉 《作物研究》2007,21(1):9-10

贺50A是以金23A为母本，中9B／161—5B／金23B的F4代单株为父本，经多代择优回交与选择育成的早籼型三系不育系。该不育系具有不育性稳定，株叶形态好，生育期适中，开花习性好，柱头外露率和异交结实率高，米质较优，配合力强等特点。介绍了贺50A的繁殖制种技术要点。  相似文献   

三倍体毛白杨引种试验初报   总被引：2，自引：0，他引：2  

欧阳永俊  刘军华  肖水清 《江西林业科技》2004,(1):10-11,13

三倍体毛白杨具有生长迅速、抗逆性强、材质优良等特性，在北方广为种植，是当前最有开发价值的10大杨树新品种之一。首次在江西开展引种栽培试验，当年平均苗高3．5m，平均地径3．2cm，病虫危害少，苗期生长基本正常。初步显示，三倍体毛白杨在江西也能引种栽培。  相似文献   

毛白杨异源三倍体B301等无性系选育的研究   总被引：49，自引：3，他引：49  

《林业科学》1995,(6)

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转基因741杨高效配套育苗体系建立     

杨敏生  梁海永  王进茂  朱淑新  马玉湖 《河北林果研究》2005,20(1):1-6

针对转基因741杨硬枝扦插难生根的特性，将组织培养及多种扦插繁殖技术有机结合在一起，建立了转基因741杨综合配套育苗体系，提出了适合无性繁殖的“遮阴间歇喷雾扦插”和“移棚不移苗扦插繁殖”育苗方法。转基因741杨组培快繁中，初始启动培养基为MS 6-BA1．0mg／L NAA0．1ms／L，嫩茎增殖培养基为MS 6-BA0．3～1．0mg／L IBA0～0．3mg／L，茎尖生根培养基为1／2MS 0．3IBA 1．5％蔗糖。不同月份嫩枝扦插培养的苗木中，5月份扦插的嫩枝生长较快，但苗木间分化程度较高；8月份扦插的嫩枝生长相对较慢，但苗木的分化程度低，生长整齐。不同月份苗木移栽后，生长节律相同，经过1a生长，不同月份间苗木生长差异不明显，5月份扦插的苗木生长略优于其他月份扦插的苗木。  相似文献   

Effects of nitrogen and phosphorus fertilization on the growth and nutrition of hybrid poplars on Vancouver Island     

K. R. Brown  R. van den Driessche 《New Forests》2005,29(1):89-104

The effects of nitrogen (N) and phosphorus (P) rates, P source, and method of P application were tested on growth and nutrition of four clones of hybrid poplar (Populus trichocarpa Torr. & Gray×P. deltoides Bartr. ex Marsh or P. trichocarpa×P. maximowiczii A. Henry) in a plantation on Vancouver Island. Treatments were applied shortly after planting. Nitrogen (0, 500kgNha^–1) was supplied as ammonium sulfate (AS); half of the AS was added at the start of the second growing season. Phosphorus (0, 100, 200kgPha^–1) was supplied as triple super phosphate (TSP), rock phosphate (RP), or diammonium phosphate (DAP) and banded or broadcast. Over four growing seasons, stem volumes increased with AS and P additions. The effects of AS and P each were greatest when the other was also added. Volume was greater when P was applied at 100kgha^–1 than in the P control and did not significantly increase further at 200kgPha^–1. Phosphorus additions were more effective when added as TSP or DAP than when added as RP, but only in P100 and when banded. Banding increased volume when P was applied at 200kgha^–1, but increases were significant only for DAP fertilized trees. Roto-tilling associated with the banding treatment also increased volume when AS and P were not added. Rankings of clones with respect to stem volume varied with N supply and changed over time.  相似文献   

Deformation analysis of timber-framed panel dome structure I: simulation of a dome model connected by elastic springs     

Ying Gao  Masamitsu Ohta 《Journal of Wood Science》2007,53(2):100-107

This study develops an analytical method that enables the simulation of the deformation of timber-framed plywood panel dome structures, of which strength is largely governed by the rigidity of joints. A hybrid truss structure model was employed to analyze this structure. In this model, we aimed to incorporate the mechanical properties of bolted and nailed joints, which were employed to build the structures, although the present investigation focused on the deformation characteristics of a dome in which the panel elements were connected mutually by elastic springs. The results of the theoretical analysis are compared with those obtained by experiments. The simulated results were found to be in good agreement with the results of the experiments under similar loading conditions.  相似文献   

Age trends in the genetic parameters of wood density and the relationship with growth rates in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1     

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   

A Review of Fine Root Dynamics in Populus Plantations   总被引：1，自引：0，他引：1  

R. M. A. Block  K. C. J. Van Rees  J. D. Knight 《Agroforestry Systems》2006,67(1):73-84

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