小麦DH群体氨基酸含量的遗传变异及相关性分析

为了给小麦营养品质改良提供依据,以花培3号/豫麦57构建的小麦DH群体的168个株系为材料,利用该群体两年的表型数据,对小麦籽粒所含17种氨基酸、必需氨基酸、非必需氨基酸及氨基酸总量的遗传变异及其之间的相关性进行了分析。结果表明,小麦籽粒氨基酸含量组成不平衡,谷氨酸在籽粒总氨基酸中所占比例最高,达25.81%;亮氨酸和脯氨酸次之;赖氨酸和组氨酸在籽粒总氨基酸中所占比例最低,仅2.27%和2.10%。所有氨基酸含量在两个年份中的变异系数均较大（大于7%）,半胱氨酸含量在两个环境中的平均变异系数最大,为23.16%;天冬氨酸含量的平均变异系数最小,为7.62%。除赖氨酸和半胱氨酸含量在两个年份中均不存在相关性外,其余氨基酸含量之间显著或极显著正相关,多数氨基酸含量在两个年份中均存在极显著的正相关;同时两年数据略有差异,说明小麦籽粒氨基酸含量受气候条件影响。     

11个瓠瓜品种主要农艺性状的相关与通径分析

对11个瓠瓜品种的14个农艺性状进行相关与通径分析。结果表明，小区前期产量与雌花开花期、子房柱宽为极显著相关，相关系数依次为-0.83、0.73；小区产量与单瓜重、小区采瓜数、小区前期产量为显著相关，相关系数依次为0.76、0.85、0.65；通径与回归分析的结果表明，子房柱形指数对前期产量形成的贡献最大，直接作用系数为1.401 5，单瓜重对产量形成的贡献最大，直接作用系数为0.789 0。因此，在瓠瓜早熟性育种实践中，应注重选择雌花期早、子房粗短、瓜形比较短的类型；在丰产性育种实践中，应着重选择单瓜重、结瓜数多的类型。     

Genetic evaluation for latent variables derived from factor analysis in broilers

ABSTRACT

1. The aim of this study was to investigate the associations between several carcass, performance and meat quality traits in broilers through factor analysis and use the latent variables (i.e. factors) as pseudo-phenotypes in genetic evaluations.

2. Factors were extracted using the principal components method and varimax rotation algorithm. Genetic parameters were estimated via Bayesian inference under a multiple-trait animal model.

3. All factors taken together explained 71% of the original variance of the data. The first factor, denominated as ‘weight’, was associated with carcass and body weight traits; and the second factor, defined as ‘tenderness’, represented traits related to water-holding capacity and shear force. The third factor, ‘colour’, was associated with traits related to meat colour, whereas the fourth, referenced as ‘viscera’, was related to heart, liver and abdominal fat.

4. The four biological factors presented moderate to high heritability (ranging from 0.35 to 0.75), which may confer genetic gains in this population.

5. In conclusion, it seems possible to reduce the number of traits in the genetic evaluation of broilers using latent variables derived from factor analysis.     

江口萝卜猪UCP2基因多态性与基因表达量及肉品质的相关性研究

为研究UCP2基因与猪肉品质性状之间的关系,本研究测定10～12月龄144头江口萝卜猪11项肉品质指标,并提取基因组DNA构建DNA池扩增UCP2基因全部外显子序列,测序后筛选SNPs位点,单个样本DNA扩增后测序验证并分型,分析不同基因型个体肉品质差异。检测不同基因型个体背最长肌中UCP2基因表达量,研究UCP2基因表达量与肉品质的相关性。结果表明:共发现3个SNPs位点,分别为UCP2-T5728G、UCP2-T5774G、UCP2-C5878T;群体遗传参数分析发现等位基因频率差异均较大,多态信息含量均为中度多态,UCP2-C5878T位点显著偏离Hardy-Weinberg平衡;UCP2-T5728G和UCP2-T5774G位点为完全连锁不平衡;UCP2-T5728G和UCP2-T5774G位点野生型的大理石纹评分显著高于杂合型,UCP2-C5878T位点杂合型和野生型的剪切力显著高于突变型;UCP2-T5728G和UCP2-T5774G位点杂合型的UCP2基因表达量极显著高于野生型和突变型,UCP2-C5878T位点杂合型和野生型的表达量极显著高于突变型;UCP2基因在背最长肌中的表达量与剪切力呈极显著正相关,与大理石纹和肌内脂肪含量呈极显著负相关。上述结果说明,江口萝卜猪背最长肌中UCP2基因的表达量越高则肌内脂肪含量越低,肉品质越差,UCP2-T5728G和UCP2-T5774G位点杂合型为基因高表达型,肌内脂肪沉积效率降低,对肉品质有不利影响,UCP2-C5878T位点突变型基因表达量极显著降低,肌内脂肪沉积效率升高,有利于肉品质性改善。本研究证明UCP2基因可以作为辅助江口萝卜猪选种选育的候选基因,筛选到的3个SNPs位点均可能是影响猪肉品质性状的重要SNPs位点。     

燕麦耐盐性的生理生化指标网络分析

为探讨盐胁迫下燕麦幼苗耐盐性与生理生化指标之间的关系,采用沙培法对6个栽培燕麦品种进行盐胁迫处理（0、1、2、4、6、8g/kg NaCl）,在播种7、14、21d时测定各处理下幼苗的生长指标和生理生化指标,并用单因素方差、相关性网络、隶属函数等方法进行数据分析。结果表明,耐盐指标间存在显著正相关关系,过氧化物酶活性、叶绿素含量与耐盐指标间存在显著正相关,丙二醛、可溶性糖、脯氨酸含量与耐盐指标间存在显著负相关;种子千粒重与耐盐指标、过氧化物酶及叶绿素含量之间存在显著负相关关系。     

基于主成分与聚类分析的辣椒主要农艺性状评价

为了筛选出适宜石家庄地区早春塑料大棚栽培的辣椒品种,对来自不同地区的14个辣椒品种的11个农艺性状进行了相关性分析、主成分分析和聚类分析。结果表明:单果质量与果形、商品果纵径呈极显著负相关,与商品果横径呈极显著正相关;单产与熟性呈极显著负相关;商品果纵径与商品果横径、商品果肉厚、辣味呈极显著负相关,与果形呈极显著正相关,与青熟果色呈显著负相关;商品果横径与商品果肉厚、辣味呈极显著正相关,与果形呈极显著负相关,与青熟果色呈显著正相关;商品果肉厚与果形呈极显著负相关,与辣味呈极显著正相关;果形与青熟果色呈显著负相关;熟性与光泽呈显著负相关。经主成分分析,前3个主成分的特征值均大于1,累计方差贡献率达84.865%,能综合辣椒农艺性状的的大部分信息。经聚类分析,在类间距离为10时,14个品种分为五大类。第Ⅰ类为灯笼形黄果,表皮光泽;第Ⅱ类为方灯笼形甜椒;第Ⅲ类为大果型辣椒,单果质量较大;第Ⅳ类为薄果肉的牛角椒,口感好,病毒病抗性强;第Ⅴ类为长果形的薄果肉长羊角椒。经相关性分析、主成分分析和聚类分析3项综合分析,确定‘峰冠’单果质量较大,但病毒病抗性较差,建议在石家庄地区早春种植;‘尊虎六号’‘改良大果虎皮椒’为薄果肉的牛角椒,口感好,病毒病抗性强,产量也较高,适宜在石家庄地区种植;其余品种产量较低、病毒病抗性较差及辣度较大(石家庄地区不喜欢太辣的品种),因此均不适宜在石家庄地区种植。     

马铃薯块茎膨大特性及其与单薯鲜重之间的相关性

为定量分析马铃薯块茎膨大特性及其与单薯鲜重之间的相关性,于2018-2019年马铃薯生长季开展不同种植管理模式的田间试验,通过分析马铃薯单薯鲜重和块茎膨大速率等随结薯天数的变化规律,以及块茎膨大参数与单薯鲜重之间的内在关系,明确了马铃薯块茎膨大特性及其与单薯鲜重的相关性。结果表明：各处理马铃薯单薯鲜重随结薯天数呈“S”型曲线变化趋势,在结薯35d后,水肥一体化（TI）处理的单薯鲜重显著高于常规水肥（TC）处理;各处理马铃薯块茎膨大速率随结薯天数呈“单峰”曲线的变化趋势,块茎膨大速率达到最大值成熟期时,TI处理的块茎膨大速率高于TC处理,但差异不显著;马铃薯块茎膨大主要参数均与最终单薯鲜重呈正相关,但均未达到显著相关水平,快增期膨大速率R₂和缓增期膨大速率R₃均与平均膨大速率R间达到极显著正相关,说明TI处理可以保障水肥的精准供应,特别是在马铃薯生长后期可以有效防止植株早衰,提高块茎膨大快增期和缓增期膨大速率,促进马铃薯块茎膨大和干物质积累,而TC处理在马铃薯生长后期容易出现肥料供应不足的情况,抑制了马铃薯块茎膨大。此外,马铃薯块茎平均膨大速率和最大膨大速率主要受块茎快增期和缓增期膨大速率的影响。     

不同日龄乌蒙凤鸡体尺与屠宰性能相关性与主成分分析

为研究乌蒙凤鸡的生长发育和生产性能,实验选择210、240、270、300日龄乌蒙凤鸡各60只(公母各半)进行体尺与屠宰测定,同时对其体尺与屠宰性能进行相关性与主成分分析。结果表明:不同日龄公鸡的龙骨长、胸宽、胸深和骨盆宽存在极显著差异,不同日龄母鸡的胸宽、胸深和骨盆宽存在极显著差异。心脏重在210日龄与300日龄乌蒙凤鸡母鸡中差异显著,胸肌重在240日龄与270日龄乌蒙凤鸡公鸡中差异极显著。210、240、270、300日龄乌蒙凤鸡公母鸡的体斜长与活体重、屠体重、半净膛重、全净膛重、胸肌重呈极显著正相关。从主成分的特征根和贡献率来看,主成分Ⅰ主要反映乌蒙凤鸡的屠体性能,视为屠体因子,主成分Ⅱ主要反映体躯发育状况,视为体躯因子,以210、240、270、300日龄阶段的乌蒙凤鸡作为肉用鸡,能保证较好的肉用性能,而体斜长、龙骨长可作为重要参考指标。乌蒙凤鸡的体尺和大部分屠宰性状有显著相关关系,由此可见相关性和主成分分析指标对乌蒙凤鸡的选种选育具有重要意义。     

不同水分条件下小麦持绿表型性状评价及其与产量相关性研究

找出适宜在多个环境条件下评价小麦持绿性状的表型指标,为快速筛选小麦持绿品系,加速抗旱、高光效育种进程提供数据支撑。以包含306个家系的RIL群体（旱选10号×鲁麦14）为材料,分析了不同水分条件下灌浆不同时期旗叶叶绿素SPAD值、功能绿叶面积持续期（GLAD）以及衰老参数变化特征,并对其与产量性状的相关性进行了研究。结果表明：RIL群体SPAD值、GLAD在整个灌浆期的变化动态复杂,衰老相关参数无法反映其动态变化过程。2种水分条件下,在灌浆后期（花后20、25和30d）SPAD值与粒宽、粒厚、千粒重以及单株产量呈显著或极显著正相关。在灌溉条件下花后10、13、16、19和22d的GLAD与单株产量呈极显著正相关;而在干旱胁迫条件下GLAD与单株产量相关性则未达到显著水平。不同环境条件下,旗叶SPAD值在灌浆后期（花后20、25和30d）相比于GLAD和衰老特征参数与产量性状具有更好的相关性,且测定相对简单,更适宜于持绿品系的快速筛选。     

Weed pressure level and the correlation between weed competitiveness and rice yield without weed competition: An analysis of empirical data

Improving rice (Oryza spp.) competitiveness against weeds would provide a low-cost and safe tool for an integrated weed management strategy. This paper addresses the underlying causes of tradeoff between yield without weed competition and weed competitiveness. Rice yield or weed biomass under weedy conditions are used as indicators of weed competitiveness. For this analysis, a common database was compiled from the results of 45 concurrent field trials comparing the performance of four to 64 genotypes in weed-free and weedy conditions in Asia, West Africa, North America and Latin America. Cyperus spp., Echinochloa spp. and Eleusine indica were the most frequent dominant weed species, being found in 9, 20 and 7 trials, respectively. Mean relative yield reduction [(yield under weed-free conditions − yield under weedy conditions)/yield under weed-free conditions] across genotypes tested for each trial was defined as weed pressure level. Mean yield without weed competition across genotypes ranged from 1.8 to 11.6 t ha⁻¹ with mean relative yield reduction from almost 0 to 91%. Correlations for rice yield between weed-free and weedy conditions were generally positive, and significant in 27 trials. The correlations were related to weed pressure level and dominant weed species, but not to ecosystem (upland or lowland) or yield level under weed-free conditions. Relative yield reduction had a more pronounced effect than dominant weed species. Correlation decreased as weed pressure level increased, and became negative when relative yield reduction exceeded 80%, suggesting that different morpho-physiological mechanisms are responsible for high yields under weed-free conditions or severe weed competition. Correlations between rice yield under weed-free conditions and weed biomass varied, giving 17 and 19 for positive and negative ones, respectively. These correlations were related neither to weed pressure level, ecosystem and yield level under weed-free conditions, nor to dominant weed species. These results indicate that correlations between rice yields under weed-free and weedy conditions can be strongly affected by weed pressure level, and, unless severe weed competition occurs, there appears to be no tradeoff between them. Association of morpho-physiological mechanisms with weed competitiveness under conditions differing in weed pressure levels and dominant weed species deserves further investigation.