Optimal regimes of selection for grain yield and harvest index in spring wheat

Summary Alternative strategies of multi-site testing of advanced lines in the northern wheat belt of New South Wales have been evaluated, using genetic parameters for large plot grain yield and hill plot harvest index estimated from dryland and irrigated trials at regional sites during 1975–1981. The average pairwise genetic correlation of large plot grain yields recorded at different sites within years was 0.45±.03, with a mean repeatability within trials of 0.56±.05. Harvest index measured in 20-grain hill plots in 1978 showe genetic correlations of 0.98±.08 with plot yield at the same site, and 0.39±0.06 with plot yield assessed at other sites in the same year.The genetic correlation between harvest index in hill plots and total biological yield in large plots at the same site was 0.84±.13, the relationship showing no evidence of curvilinearity. Selection for harvest index in hill plots is therefore expected to lead to an increase in biological yield as well as grain yield in the breeding populations studied. Quantitative genetic theory suggests that the response to selection for grain yield can be increased by approximately 40% with an initial screening using hill plot harvest index at three sites instead of one, and reallocation of resources in the first stage of large plot yield assessment to include 6–8 sites, rather than dryland and irrigated trials at a single location.     

仁用杏园坡地径流利用技术研究

提出了适宜仁用杏生长、结实的整地规格,并对其蓄水效果进行了分析。研究认为沟间距5m-6m,其蓄水效果最佳,对提高仁用杏产量及促进根系生长最有效。     

Interactions between Widely Spaced Young Poplars (Populus spp.) and Introduced Pasture Mixtures

Silvopastoral systems involving poplars are widespread in rural landscapes in a number of regions of New Zealand. The effect of widely spaced trees of Populus nigra × P. maximowiczii, aged 8–11 years, on the growth and botanical composition of understorey pasture mixes was determined over 3 years at a southern North Island hill country site. Pasture mixes comprised existing pasture, and two introduced test swards comprising new grass (Agrostis capillaris, Dactylis glomerata, Lolium perenne) and legume (Lotus uliginosus, Trifolium repens) cultivars. Pasture accumulation beneath trees (6.6 t DM ha⁻¹ year⁻¹) was 23% less than open (unshaded, no trees) pasture (8.6 t DM ha⁻¹ year⁻¹) and differences in accumulation occurred between tree aspects (North and South sides of trees) when trees were foliated. In early spring, North plots produced 11–14% more herbage than South plots whereas in late summer, South plots produced up to 44% more herbage than North plots. Yield of both test swards (6.4 and 8.0 t DM ha⁻¹ year⁻¹) was not significantly different from that of the existing sward (7.4 t DM ha⁻¹ year⁻¹) but productivity varied between swards in spring and summer. One test sward included Lotus uliginosus cv. Grasslands Maku, and the sward produced 30% more DM than the other swards in mid-summer. Dactylis glomerata cv. Grasslands Wana comprised 37% of the DM of swards in which it was sown and was the most successful cultivar, followed by Grasslands Maku. Both cultivars are recommended for silvopastoral systems where pasture is lightly grazed.     

旱坡地幼龄枣树综合丰产栽培技术

就黄土丘陵区旱坡地枣园幼树的丰产栽培技术，从几个方面进行了理论探讨和试验总结，包括：隔坡集蓄径流水平沟的规格设计与施工、根蘖苗的定植、栽植密度的选择、花期管理、整形修剪、肥水管理、病虫害防治和园地管理。     

旱作山地果园栽培技术研究

本文根据河北省太行山山地果园的特点,结合多年研究结果,论述了旱作山地果园的主要栽培技术。认为高标准、高质量整地是建园的关键;拦蓄径流、覆盖地膜、雨季深施有机肥等,是蓄水保水的重要措施;采用矮小树形,是旱作山地果园丰产的基础。     

三门峡城郊黄土丘陵沟壑生态治理规划

本文对生态建设规划进行了有益的探讨,设计理论以近自然林业理论为主结合生态学、景观生态学的要求,追求符合演替理论;并在考虑生态与经济的最佳结合,发挥林业、农业、水利、城建等方面的协同作用,项目的动态分析和工程管理等方面进行努力。以期更加符合生态恢复的客观规律。     

The indigenous hill-farming system of Khasia tribes in moulvibazar district of Bangladesh: Status and impacts

Rapid economic growth of the Khasia people has resulted from a most successful betel leaf farming system practiced within the fringe of reserved forests, where government policies have facilitated effective use of the local people as a labour force for production, protection and conservation of biodiversity of the surrounding forests. Khasia tribes have traditionally grown betel leaf plants on naturally occurring trees. Deforestation is a serious problem in Bangladesh, whereas the Khasia people living within forests are protecting trees for their livelihood, including selling betel leaf, collecting fuelwood and consuming and selling fruits from support trees. It is a profitable yet sustainable forest production system, maintaining soil fertility, stable production and optimal family size, and has created employment opportunities for the people living within and outside the forests. It has enhanced the supply of socially required betel leaf to the local markets, contributed to price stability, and generated some export revenue. However, the revenue of growers has been reduced by plant diseases and the capture of resource rent by middlemen. Economic benefits could be further increased through government initiatives to improve management and the marketing system. This paper is based on a presentation at the International Conference on Economics of Sustainable Forest Management, University of Toronto, Canada, May 20–22, 2004.     

花岗片麻岩低山丘陵区林草立体种植结构研究

针对太行山花岗片麻岩低山丘陵区水土流失严重，生态环境恶化的现状，通过对草木樨，紫花芷蓿，挲相旺与刺槐的不同搭配与种植方式的研究，发现刺槐与草木樨混种结构，尽管在造林初期林木的存活率及年生长量稍低，但在造林后４ａ的累计经济效益最高，可大大缩短造林成本的回收期，为一良好的林草立体种植结构。     

黄龙岗城市森林公园规划设计

根据黄龙岗森林公园所在区域的立地条件和开原市的总体规划,利用生态学原理之边缘效应,从项目概况、规划性质和目标、规划的依据和原则、总体规划和经济技术指标5个方面对其进行规划设计。通过规划设计不仅使该公园成为开原市人们休闲、度假、旅游观光和生态保护、培育的场所,还使其成为向外界展现开原市自然生态和地方文化底蕴的窗口。     

城市面山精准化造林绿化作业设计探讨

恢复城市面山生态景观，造林绿化作业设计是前提和基础．文章重点阐述了城市面山造林绿化作业设计中引入精准化设计的必要性以及常规造林与精准化造林绿化作业设计的区别．总结了精准化造林绿化作业设计中的市场调查、造林绿化方法的选择、现地调查设计等应重点关注的问题，并藉此提出制定切合本地的地方标准、提高造林经费、建立信息库等推行精准化造林绿化作业设计的建议．