Genetic variation and inheritance in a 9 × 9 diallel in silver birch (Betula pendula)

A complete diallel cross was made among nine Betula pendula trees growing in a natural population and a trial was planted on agricultural soil at one site. This exceptional trial has provided estimates of genetic parameters that can only be estimated in complete diallels. Traits measured were height and diameter during a period of 37 years, and assessments were made of bud burst, leaf abscission and rust infection at the early ages. All traits showed genetic variation and the variance components of general combining ability (GCA) effects were dominating, with heritability estimates of 0.16 and 0.23 for height and diameter at age six years. The best-growing families could be identified at that age. At age 37 years, when the trial had been thinned twice, the offspring from the highest and lowest ranked parent for growth contributed with 19% and 6% of the total volume of the stand, respectively. The GCA effects were also highly significant for the assessment traits, but with an interaction with year for bud burst. High values of estimates of genetic correlations proved that bud burst, leaf abscission and rust infection are interrelated, and also to some extent with growth traits. Families with an early bud burst were tallest, were less affected by the rust fungus and kept their leaves later in the autumn.     

林地变更调查系统的研建

林地变更调查是目前林业主管部门的主要工作之一,本文以重庆市为例,介绍了林地变更调查系统的设计思路与主要功能,同时结合工作需求,重点研究了数据质检、查询统计、小班编辑、成果输出等模块关键功能的实现,为今后林地变更调查系统的建立提供参考依据。     

鄱阳湖滨不同植被类型沙地土壤有效持水能力研究

鄱阳湖滨沙地是我国南方典型的沙地。研究采用经过筛选的土壤转换函数（PTFs）比较分析了鄱阳湖滨沙地4种主要植被类型（刺槐、湿地松、蔓荆子和自然荒草地植被）土壤的有效持水量,旨在为南方湖滨沙地生态植被恢复提供土壤水分评价方法参考,也为更好地评价不同植被类型的沙地生态恢复模式效应提供依据。结果表明:通过统计检验,Rawls模型的ME和RMSE值分别为0.005 8,0.001 0,显示其较Saxton模型、Batjes模型、Minasny模型具有更好的预测准确度,更适合于鄱阳湖滨沙地土壤水分特征估算分析;经过测定表明,不同植被类型土壤田间持水量依次为湿地松 > 蔓荆子 > 刺槐 > 荒草地;Rawls模型计算结果表明:不同植被类型土壤凋萎系数依次为刺槐 > 湿地松 > 蔓荆子 > 荒草地,不同植被类型土壤有效持水量依次为湿地松 > 蔓荆子 > 刺槐 > 荒草地。     

渭河流域气象干旱向农业干旱的传播研究

为探究渭河流域不同子流域和土地利用类型的气象、农业干旱传播规律,基于研究区1980—2014年的气象数据,使用标准化降水指数和标准化土壤湿度指数分别表征气象干旱和农业干旱,采用皮尔逊相关系数和de Martonne干燥度指数,评估气象和农业干旱的传播时间和响应关系,并通过游程理论提取气象干旱与农业干旱历时、烈度,同时利用 Copula 函数度量气象干旱到农业干旱的传播阈值和农业干旱风险特征。结果表明:1)渭河干流和泾河流域气象干旱向农业干旱的传播时间为3个月,北洛河流域的干旱传播时间为2个月;2)水热条件变化对干旱传播有一定影响,这种影响沿干燥度梯度呈分段变化;3)不同子流域和土地利用类型的抗旱性不同,其中各子流域的草地及泾河、北洛河流域的林地干旱传播阈值较小,易发农业干旱;4)各分区气象干旱传播到农业干旱后历时延长、烈度增大,泾河、北洛河流域耕地的扩大作用最强。本研究可为评估不同干旱类型之间的响应关系,构建流域干旱预警系统提供新思路。     

基于VAR模型下农业产业结构调整对农民增收的影响

以1983-2007年<江西统计年鉴>的农业总产值和农民纯收入为统计分析数据,运用计量经济的向量自回归(VAR)方法,从种植业、林业、牧业、渔业等几方面分析了宜春市农业各产业产值间对农民纯收入的影响.结果表明:宜春市农业总产值不是形成农民收入增长的关键因素.从长期来看,牧业产值对农民纯收入的影响因素最大,为32.36%;其次是渔业产值,为31.65%;第三是种植业产值为20.54%.另外,林业产值对农民纯收入的影响为9.67%.即牧业的发展对农民增收的贡献最大,其次是渔业、种植业.说明,牧业是宜春市未来农业产业结构调整的重点.     

Environmental and Genotypic Effects on Pod Characteristics Related to Common Bean Quality

A collection of 121 common bean (Phaseolus vulgaris L.) landraces from Spain and Portugal (Iberian Peninsula) was evaluated in six environments (three locations and 2 years). Significant differences among landraces were found for period of flowering, pod maturity and pod morphology (weight, length, width/thickness and curvature). Wide variation among landraces was revealed by the range of variation observed. Environmental effects were not significant although year × location and landrace × year × location interactions were significant for all traits studied except for pod curvature. Poor consistent expression across the different environments for most of the traits studied was expressed by the low values of constancy (C) with the exception of width/thickness indicating that pod shape (round or flat) was expressed regularly across different environments. Principal component analysis enhanced differences among environments affecting the performance of the bean landraces evaluated. Analysis by environment showed that 51 landraces were adapted to specific environments and only four of them had broad geographical adaptability with similar performance under different conditions. These results could be a starting point for selection of new inbred lines adapted to distinct environments with potential for the improvement of current snap bean cultivars.     

随机区组试验CASIO fx－4500P分析程序

利用ＣＡＳＩＯｆＸ－４５００Ｐ计算器进行随机区组试验设计的统计分析表明，该程序对有或无次级样本的随机区组试验均适用，并同时进行多重比较，操作简单。     

陆地棉果枝发育的遗传分析

采用非条件和条件数量遗传分析方法，研究了不同时期果枝的发育遗传规律。非条件遗传方差分析表明，陆地棉果枝的发育动态主要受加性效应控制，并且表达效果逐渐加强。显性效应在果枝发育的前期、后期几乎不表达，中期有一定的表达，且超过加性效应。条件遗传方差分析表明，加性效应在前期就达到1％的显著，中前期几乎不表达，到后期加性效应又逐渐加强；而显性效应在510d时段不表达，在1015d时段显性效应开始表现且逐渐增大，至30125天表达量最高，除首、尾发育阶段，其它各发育阶段主要受显性效应控制。因此，根据陆地棉果枝的发育遗传规律，选择在中、后期进行将会获得较好的效果。     

Genetic correlations among and between wool, growth and reproduction traits in Merino sheep

Summary Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, and 50 000 records for reproduction and growth traits with over 2700 sires and 25 000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 ± 0.02). YWT was positively correlated with CFW (0.23 ± 0.04), FD (0.17 ± 0.04) and LWEJ (0.58 ± 0.06), while LW/EJ was negatively correlated with CFW (−0.26 ± 0.05) and positively correlated with FD (0.06 ± 0.04) and LS (0.68 ± 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits.