Landscape genomic approach to detect selection signatures in locally adapted Brazilian swine genetic groups

Samples of 191 animals from 18 different Brazilian locally adapted swine genetic groups were genotyped using Illumina Porcine SNP60 BeadChip in order to identify selection signatures related to the monthly variation of Brazilian environmental variables. Using BayeScan software, 71 SNP markers were identified as F_ST outliers and 60 genotypes (58 markers) were found by Samβada software in 371 logistic models correlated with 112 environmental variables. Five markers were identified in both methods, with a Kappa value of 0.073 (95% CI: 0.011–0.134). The frequency of these markers indicated a clear north–south country division that reflects Brazilian environmental differences in temperature, solar radiation, and precipitation. Global spatial territory correlation for environmental variables corroborates this finding (average Moran's I = 0.89, range from 0.55 to 0.97). The distribution of alleles over the territory was not strongly correlated with the breed/genetic groups. These results are congruent with previous mtDNA studies and should be used to direct germplasm collection for the National gene bank.     

The Politics of Multiplication in a Failed Soviet Irrigation Project,Or, How Sasyk Has Been Kept from the Sea

Between 1976 and 1980, a Soviet agro-industrial project turned the Sasyk estuary in southern Ukraine into a freshwater irrigation reservoir. While the project failed to produce irrigable water, it had many negative environmental consequences. Despite two decades of activism, this water body persists in its freshwater state. To understand how this situation persists, resources need to be conceived as materialities emergent in and distributed across assemblages of human and nonhuman elements rather than pre-existing substances. This move helps reveal a politics of multiplication that has enabled officials to sustain the resource potential of Danube–Dnister Irrigation System waters. As recognition of Sasyk as polluted and valueless increased, officials mobilized linkages that consolidated Sasyk as a fish reservoir, and its main canal as irrigable and drinking water, thereby stymieing activists' restoration campaign.     

Land Cover Switching in Autumn by Female Mallards in Ohio

Autumn waterfowl habitat management often focuses on providing high energy food resources to attract and concentrate waterfowl for harvest. Similarly, many waterfowl conservation plans assume food resources are the primary, controllable limiting factor influencing waterfowl distribution during migration; however, hunting-related disturbance also influences waterfowl distribution in autumn. We investigated factors influencing mallard (Anas platyrhynchos) movements in an intensively hunted and food-rich landscape in Ohio, USA, during autumn of 2015 and 2016. We used locations from female mallards equipped with global positioning system (GPS) back-pack-transmitters to determine the probability of mallards switching land cover types based on seasonal and daily patterns of hunting disturbance and to determine the distances mallards moved between cover types that offer refuge and those that offer food resources as evidence for or against food resource depletion during the hunting season. Mallards switched cover types to exploit food-rich but intensively hunted locations nocturnally and cover type switching during times subject to disturbance increased significantly from the early segment to the late segment of hunting season. Distances mallards moved between refuge cover types and food-rich cover types did not change over the duration of the study. Hunting disturbance is a key variable influencing autumn movements and distribution of mallards, and mallards in a food-rich and intensively hunted landscape likely employ nocturnal foraging as a strategy to survive autumn migration. Nocturnal foraging behavior has consequences for waterfowl managers tasked with providing quality waterfowl hunting opportunities because ducks that forage only at night are largely unavailable to hunters. © 2020 The Wildlife Society.     

家蚕地方品种遗传多样性及其分子系统学研究

为检测家蚕(Bombyx mori)地方品种间的遗传差异,分析其遗传多样性和系统分化模式,为家蚕的品种鉴定和杂交育种亲本选择提供分子依据,本文对72个家蚕地方品种的淀粉酶基因(Bmamy2)片段进行测序,采用DNA序列分析技术探究了家蚕地方品种在核苷酸序列水平上的遗传差异及其系统分化特征.结果显示,家蚕地方品种在Bmamy2基因变异丰富,碱基突变率为5.6-8.2％,单倍型多样度为0.8294,核苷酸多样度为0.0236±0.00122,表明Bmamy2是一个具有丰富序列多样性的标记基因,能够较好地区分家蚕地方品种间的遗传多样性.系统发育分析、分子方差分析和Network分析等多种分析方法均检测到家蚕地方品种不按地理系统或生态类型聚类,各聚类种群均由来自不同地理系统或生态类型的品种构成,而来自同一地理系统或生态类型的品种则分别归属于不同的聚类种群.推测在家蚕的进化过程中并没有形成按地理系统或生态类型归类的分化格局,家蚕可能具有多种化性混合驯化起源的遗传背景和系统分化特征.     

Stable isotope analysis of larval mosquito diets in agricultural wetlands in the coastal plain of Georgia,U.S.A.

Previous studies have used C and N isotope ratios to investigate the use of different food resources such as plant and animal detritus by container‐breeding mosquitoes. This study is the first to report on the potential food resources assimilated by larval mosquitoes in agricultural and reference wetlands. Larval mosquitoes (Diptera: Culcidae) were sampled, along with their potential food resources, from agricultural and reference wetland habitats throughout a seasonal hydroperiod. IsoSource mixing model results indicated that food resources had greater δ¹⁵N isotope values in agricultural wetlands compared with cypress‐gum swamps. In February, Aedes vexans (Meigen) and Culex territans Walker larvae fed primarily on lower quality food resources (coarse particulate organic matter and sediment) based on C:N. In contrast, higher quality food resources (fine particulate organic matter) were utilized by Anopheles spp. throughout the study and by Psorophora columbiae (Dyer and Knab) in May. This research contributes to a more comprehensive understanding of the food resources available and assimilated by larval mosquitoes in agricultural wetlands.     

Genotype x environment interactions in a core collection of French perennial ryegrass populations

A representative sample (core collection) of natural populations of perennial ryegrass (Lolium perenne L.) from France was evaluated for agronomic traits at seven locations. This sample exhibits a high level of genotype-environment interaction for most traits. The interactions for summer-growth (a key-factor of adaptation in most French regions) were studied by means of regression using climatic factors of the evaluation sites and the sites of population origin as covariates. This method succeeded in explaining most of the interaction term and also part of the main effects. It appears that populations from either warm or dry sites generally have a positive interaction when evaluated in a site with similar characteristics, as expected as a consequence of natural selection. A population component of regression on environmental covariates, however, was significant and could be exploited through breeding to improve adaptation of perennial ryegrass to either drier or warmer regions.     

气候变化背景下中国农业气候资源变化Ⅶ.青藏高原干旱半干旱区农业气候资源变化特征

基于青藏高原干旱半干旱区1961-2007年55个气象站点地面观测资料,利用五日滑动平均法及GIS软件的IDW模块进行栅格处理,对比分析了研究区1961-1980年（时段Ⅰ）和1981-2007年（时段Ⅱ）各气候要素的时空变化特征及其气候倾向率.结果表明：1961-2007年,研究区喜凉作物生长季内日照时数的变化不明显,喜温作物生长季内日照时数呈增加趋势,但空间分布的变化较小;与时段Ⅰ相比,时段Ⅱ喜温作物生长季内积温值≥1500 ℃·d的地区面积扩大33.9%;降水量的空间分布总体表现为由东南低地向西北内陆逐渐递减,研究期间青藏高原东南部喜凉作物生长季内降水量均达到800 mm,其他地区喜凉作物生长季内降水量的气候倾向率有正有负,变幅相对较小,与时段Ⅰ相比,时段Ⅱ喜温作物生长季内降水量≥400 mm的分布面积扩大了40%;参考作物蒸散量（ET₀）总体略有增加,其空间分布格局与日照时数和积温的分布相似,时段Ⅱ较时段Ⅰ喜温作物生长季内ET₀≥400 mm的分布面积扩大了35.7%.研究期间,青藏高原作物生长季内的热量与降水资源有一定幅度增加,这对农牧业生产非常有利,但ET₀的增大表明潜在蒸发增大,需进一步加强研究气候变化对该区域农牧业生产带来的可能影响.     

福建省永春县木本药用植物资源调查

永春县地处中亚热带和南亚热带的过渡区域,自然条件优越,木本药用植物资源丰富。通过野外实地考察、标本采集、资料查阅整理及标本鉴定,初步查明,永春县境内有木本药用植物45科90属129种(含变种)。对其药用部位和功用作了简要介绍,对本地药用植物资源的保护和开发利用提出建议。     

水仙属植物遗传学及生物学特性研究进展(综述)

水仙属为世界重要的观赏花卉大属,品种更新及品质改良是产业发展的核心。本文简述了水仙属种质资源现状,归纳了有关生物学特性、矮化栽培、遗传多样性、离体培养与扩繁、基因克隆与转基因等方面的研究进展,并针对目前存在问题及发展方向提出若干建议。     

新疆具抗菌活性的植物资源

对分属于新疆41科88种高等植物的抗菌活性进行了归纳。这些抗菌植物主要分布在菊科、唇形科、豆科、百合科、蓼科和伞形科。对人体和植物病原菌抗性较强的有土木香(Inula helenium)、苍耳(Xanthium sibiricum)、蓖麻(Ricinus communis)、荆芥(Schizonepeta tenuifolia)、石榴(Punica granatum)、孜然芹(Cuminum cyminum),以及蒿属(Artemisia spp．)、槐属(Sophora spp．)和酸模属(Rumex spp．)植物。新疆植物的抗菌活性成分和结构阐明还需要进行深入的研究。