Genetic diversity and historic introgression in German Angler and Red Dual Purpose cattle and possibilities to reverse introgression

Recovering native uniqueness has major importance for breeds with historic introgression. The aim of the study was to estimate population genetic parameters for two local red cattle breeds from Northern Germany and to study possibilities to reverse introgression. Genealogical information consisted of 90,783 individuals for German Angler and 187,255 individuals for Red Dual-Purpose cattle breed, with additional information on sex, born, breed, status, and conventional breeding values. It is concluded that the native genetic contribution could be included as an additional trait in the total merit index in order to recover a part of the native genetic background. Native contributions should be estimated in the long term from marker data in order to account for Mendelian sampling. The maintenance of a sufficient genetic diversity of native alleles can be achieved by an advanced OCS with appropriate constraints.     

红三叶遗传图谱构建及抗白粉病基因QTL定位

本研究以感(岷山红三叶)、抗(澳大利亚红三叶品种♀Sensation×Renegade♂杂交新品系“甘农PR1”)白粉病红三叶材料为父母本杂交并种植成苗经人工接菌后筛选出抗、感白粉病的F₁群体为作图群体,利用AFLP标记构建红三叶高密度遗传图谱,并利用区间作图法对抗白粉病QTL进行了定位分析,可以为红三叶抗白粉病基因克隆和转基因等分子辅助育种奠定基础。结果表明,149个AFLP标记构建得到的遗传图谱包含7个连锁群(LG1,LG2,LG3,LG4,LG5,LG6和LG7),遗传图谱的总距离为640.5 cM。其中,LG1连锁群的遗传距离(140.6 cM)和标记间平均距离(9.4 cM)均最大;LG4连锁群的遗传距离(55.2 cM)和标记间平均距离(1.8 cM)最小。应用区间作图法对红三叶抗白粉病基因进行QTL分析定位,共检测到5个抗白粉病相关QTL位点(qrp-1,qrp-2,qrp-3,qrp-4和qrp-5),其中qrp-1、qrp-2、qrp-3和qrp-4位于LG4连锁群上,qrp-5位于LG5连锁群上。5个QTL位点对抗白粉病的贡献率为29%~90%,qrp-1对红三叶白粉病抗性的贡献率最大(90%),为主效QTL。     

AtSOS基因在紫花苜蓿中的表达及其耐盐性研究

本研究采用基因工程技术改良紫花苜蓿耐盐性,通过种植转基因耐盐紫花苜蓿达到改良土壤的目的。以紫花苜蓿子叶节为外植体,通过农杆菌介导法将来源于拟南芥的AtSOS1-AtSOS2-AtSOS3多基因表达载体导入阿尔冈金紫花苜蓿中,经PCR检测、抗除草剂筛选和RT-PCR鉴定,获得了能稳定表达的转基因株系。以转基因的紫花苜蓿和野生型紫花苜蓿为材料进行盐处理,每个处理重复3次,测定其生理生化指标、株高、Na⁺和K⁺含量、细胞膜透性、叶绿素含量。结果显示,在不同盐浓度处理下,所有植株的株高均有所增长,但在100和200 mmol·L^-1的NaCl处理下,转基因植株的长势显著高于野生型植株;随着处理时间的增加,所有植株的叶绿素含量均呈先上升后下降的趋势,且野生型植株叶绿素含量均低于转基因植株;在100和200 mmol·L^-1的NaCl处理下,转基因植株的细胞膜透性、超氧化物歧化酶活性和脯氨酸含量的增加量均小于野生型植株,而过氧化物酶、过氧化氢酶活性和可溶性糖含量的增加量均大于野生型;各植株中丙二醛含量均下降,且野生型植株下降的更为明显;盐处理后,转基因植株根系中Na⁺的积累比野生型植株少,而K⁺的吸收多于野生型植株。转AtSOS基因的紫花苜蓿通过发挥AtSOS途径的作用,促进了植物体将细胞内的Na⁺外排,从而减轻盐胁迫对植物体的伤害,提高了转基因植株的耐盐性。     

羊草叶绿体非编码区多态性标记筛选及群体遗传多样性

为筛选多态性丰富的羊草叶绿体非编码区片段,本研究以9个不同地理位置的羊草居群为材料,通过对12个叶绿体非编码区DNA片段测序及其序列间变异分析试图从中找出有遗传差异的叶绿体DNA(cpDNA)片段,并利用有多态性的cpDNA片段进行遗传多样性分析。结果表明,序列ndhF-rpl32、trnL-trnF、trnC-ycf6、aptI-aptH具有比较丰富的变异,可作为下一步研究野生羊草群体遗传学和谱系地理学较为理想的分子标记。在37个羊草个体4条非编码区片段的合并序列中,共检测到15种单倍型,单倍型多态性(Hd)为0.928,核苷酸多态性(Pi)为0.00101;遗传分化指数(Fst)为0.58884,基因流(Nm)为0.17,基因流较小;中性检验Tajima’s D(-1.08542)和Fu’s Fs(-5.301)均为负值,且差异不显著(P>0.10),推测羊草遵循中性进化理论,可能经历过种群扩张;AMOVA结果显示,65%的分子变异出现在居群间,35%出现在居群内;Mantel检验得到,遗传距离与地理距离具有显著相关性(r=0.449,P<0.05);居群分化值Nst 0.386(0.1865)大于Gst 0.234(0.1506),差异显著(P<0.05),表明羊草居群存在分子谱系地理结构。通过系统发育树分析得到,羊草15个单倍型分为两大分支,H2和H10聚为一支,它们与别的居群个体亲缘关系较远,其余单倍型聚为另一支;单倍型网络图显示,H2和H12、H10和H12亲缘关系较远,与系统发育树分析结果基本一致。本研究为羊草的种质资源保护、谱系地理学研究等工作奠定了基础。     

Innovative layer genetics to handle global challenges in egg production

1. In commercial layer breeding, extensive gene pools are tested and selected for market requirements which must be anticipated at least 5 years ahead. Field results confirm a continuous positive genetic trend in egg output and better feed efficiency which can be converted into land savings.

2. Animal welfare and cage-free housing dominate future needs of the market. Nesting behaviour and minimal tendency to develop feather-pecking or cannibalism without beak treatment are key trait complexes. Stronger shells for longer production cycles without moulting have to be combined with better bones.

3. No single big gene effect can be expected to control the multifactorial problem of feather-pecking. Adjusting the shape of the beak, with a heritability of .10–.25, can contribute to reducing the risk of severe cannibalism.

4. For better skeletal integrity, the assessment of bone quality in pedigree birds housed in enriched cages is done by keel bone palpation or ultrasound measurement of the humerus. Both traits show similar heritabilities in the range of .15–.30 and can be included in a balanced selection approach for performance, quality and welfare traits.

5. The combination of performance testing and genome-wide DNA marker analysis is a promising tool to generate more progress for a balanced performance and behaviour profile.     

Effect of sweet potato vines on performance parameters and some carcass characteristics of rabbits

Conventional feedstuffs in Brazil are expensive, which has led to the search for less conventional cheaper and locally available feedstuffs. Thus, this study was carried out to determine the dietary effect of dry sweet potato vines (SPV) on the performance and some carcass characteristics of rabbits. A total of twenty‐seven weaned White New Zealand rabbits (14 male and 13 female) 35 days old with an average initial weight of 755 g were allocated into three treatments. Nine rabbits were assigned to each treatment in a completely randomized design. Three diets were formulated to similar protein and energy levels: 0SPV – diet without inclusion of dry sweet potato vines; 10SPV – diet with 10% alfalfa hay replaced by dry sweet potato vines; and 15SPV – diet with 15% of alfalfa hay replaced by dry sweet potato vines. The experiment lasted for 49 days during which data for feed intake and body weight were recorded. The daily feed intake ranged from 73.17 to 78.02 g; daily weight gain from 22.32 to 23.17 g; feed conversion ratio (FCR) from 3.16 to 3.49 and final live weight ranged from 1839.44 to 1880.55 g. None of the evaluated performance parameters as well as carcass weight, heart weight and percentages of fat and protein in meat were significantly affected by any of the tested dietary treatments. However, the liver weight was statistically lower in animals fed the diets containing 10% of SPV, mainly due to lower glucose content. Glycogen within the tissue, did not differ significantly among treatments. It was therefore concluded that up to 15% of SPV can successfully be included in the diet of rabbits as a cheaper replacement for alfalfa hay without adversely affecting performance.     

Single step genomic evaluation for female fertility in Nordic Red dairy cattle

Joint Nordic (Denmark, Finland, Sweden) genetic evaluation of female fertility is currently based on the multiple trait multilactation animal model (BLUP). Here, single step genomic model (ssGBLUP) was applied for the Nordic Red dairy cattle fertility evaluation. The 11 traits comprised of nonreturn rate and days from first to last insemination in heifers and first three parities, and days from calving to first insemination in the first three parities. Traits had low heritabilities (0.015–0.04), but moderately high genetic correlations between the parities (0.60–0.88). Phenotypic data included 4,226,715 animals with records and pedigree 5,445,392 animals. Unknown parents were assigned into 332 phantom parent groups (PPG). In mixed model equations animals were associated with PPG effects through the pedigree or both the pedigree and genomic information. Genotype information of 46,914 SNPs was available for 33,969 animals in the pedigree. When PPG used pedigree information only, BLUP converged after 2,420 iterations whereas the ssGBLUP evaluation needed over ten thousand iterations. When the PPG effects were solved accounting both the pedigree and the genomic information, the ssGBLUP model converged after 2,406 iterations. Also, with the latter model breeding values by ssGBLUP and BLUP became more consistent and genetic trends followed each other well. Models were validated using forward prediction of the young bulls. Reliabilities and variance inflation of predicted genomic breeding values (values for parent averages in brackets) for the 11 traits ranged 0.22–0.31 (0.10–0.27) and 0.81–0.95 (0.83–1.06), respectively. The ssGBLUP model gave always higher validation reliabilities than BLUP, but largest increases were for the cow fertility traits.     

广州石门国家森林公园野生观赏植物资源调查

通过野外调查和查阅文献资料,得出石门国家森林公园共有野生观赏植物122科267属377种,其中蕨类植物19科23属28种,裸子植物4科5属7种,被子植物99科239属342种。分析了石门国家森林公园野生观赏植物资源的基本特征和用途,并探讨其保护和开发利用。     

广州市绿道体育资源开发与利用*

运用了文献资料法、实地考察法、专家访谈法、问卷调查法、数理统计法等研究方法，根据我市不同绿道建设的特点对其进行分层和归类，选取了具有代表性的区域绿道体育资源作为研究对象。现有的体育设施有自行车驿站、健身路径、简易球场等，开展的体育运动项目有远足、越野赛、自行车等。拟通过开发场地、交通、文化、参与人群等来整合绿道体育资源，提升绿道价值。     

印江自治县洋溪镇森林资源特点及林业发展规划

洋溪镇山区脱贫致富的最大优势在于山,提出林业发展措施：（1）采取有效的技术措施把现有的近3335hm2茶园基地管理好,并适度发展鲜果类经济林;（2）加强幼龄林的抚育和林分的封山育林工作;（3）进行山区林业综合开发,大力发展以马尾松、杉木为辅的用材林造林和低产林分改造,以优质烤烟为主产业化建设;（4）利用区位优势,发展森林旅游业。