Diversity of Growth Habits and Their Association with VRN Allele of 81 American Wheat Lines

Eighty-one wheat accessions including 50 southern regional performance nursery （SRPN） lines and 31 northern regional performance nursery （NRPN） lines from the United States were tested to evaluate the growth habit by chilling treatments and to estimate the VRN allele variation with 19 pairs of published VRN primers. Two spring wheat accessions and 44 semi-spring wheat accessions were confirmed based on their chilling days＇ requirement and polymorphism was found at VRN loci. The Vrn-A1 allele had the highest frequency in the RPN accessions and VA1-CAPs markers identified growth habit of RPN lines. No polymorphism was found at the VRN3 loci and some polymorphism at the region of promoter and the first intron of VRN1 was not always consistent to growth habit in the wheat RPN accessions. The existence of variation in VRN alleles suggested that singly using the dominant Vrn allele is possible to extend the diversity of wheat accessions and improve their adaption to different environments in autumn-sowing region. This information will be useful for the cultivars exploitation and wheat breeding program.     

互助白牦牛红细胞钾浓度多态性的研究

采用火焰光度计法对７０头互助白牦牛的红细胞钾浓度多态性进行研究。结果表明：①被检白牦牛有高血钾和低血钾两种表型，以高血钾型为优势表型（８５．７１％）；②Ｋ＾ｈ和Ｋ＾Ｌ等位基因频率分别为０．９２５８和０．０７４２；③白牦牛红细胞钾浓度基因座的有效等位基因数、基因杂合度和基因均质度指数分别为１．１５９３，０．１３７４和０．７５２。     

黄麻(corchorus olitorius L.)花青素的性状遗传及其表现的影响因素

1986～1988年对长果黄麻(Corchorus olitorius L.)花青素的性状遗传及其表现作了研究。结果表明,长果黄麻花青素遗传受一对等位基因控制。花青素的合成需要光照条件,但合成的速度和含量则决定于糖浓度。光照强弱和供氮水平对花青素含量的影响,是通过对糖浓度的影响而起作用。合成花青素的细胞可能与合成叶绿素有关。花青素在体内可以转移。     

Selection based on progeny testing induces rapid changes in myostatin allele frequencies - a case study in sheep

In this study we show that selection based on progeny testing is able to induce a rapid change in allele frequency, even when a fairly broad and balanced breeding goal is applied. The myostatin 3'-UTR mutation (c.*1232G>A) previously found to affect muscularity in Texel sheep is also present in the Norwegian White Sheep population. By genotyping the rams used for artificial insemination (born in1977-2006), a rapid increase in the c.*1232G>A allele frequency was observed, from 0.31 in 1990 to 0.82 in 2006. The major increase was observed after BLUP-based breeding values and the EUROP classification system for carcass quality was implemented in 1991 and 1996, respectively. The MSTN frameshift mutation c.960delG, recently identified in this population, did not show a similar increase in allele frequency during the same period, in spite that it has a strong desirable effect on meat and fat traits. The results also illustrate that unwanted side effects can rapidly be introduced into a population using an efficient breeding scheme. A system for monitoring changes in phenotypic traits additional to those under selection is therefore recommended to identify possible side effects at an early stage.     

四十八份青花菜品种SSR指纹图谱构建

为筛选一套适用于青花菜品种DNA指纹鉴定的核心简单重复序列标记(simple sequence repeat,SSR)引物,给青花菜品种的特异性、真实性、准确性鉴定提供依据,以12份性状差异较大的青花菜品种为材料,结合聚丙烯酰胺凝胶电泳与荧光毛细管电泳检测技术,从945对芸薹属SSR引物中筛选出20对引物作为青花菜品种的核心SSR引物。利用该套核心SSR引物在48份青花菜主要栽培品种中共扩增出等位基因位点79个,平均每对引物扩增得到等位基因与基因型数量为3.95、5.55个;引物多态性信息含量(PIC)介于0.302~0.750,平均为0.547;20对核心SSR引物的杂合度介于0.350 0~0.784 9,均值为0.608 2。用该套核心SSR引物构建的48份青花菜品种的指纹图谱,每一条指纹都具有唯一性,可表征一个品种,该指纹图谱为青花菜品种鉴定与资源保护提供了科学依据。     

Effect of allele frequencies,effect sizes and number of markers on prediction of quantitative traits in chickens

The objective was to assess goodness of fit and predictive ability of subsets of single nucleotide polymorphism (SNP) markers constructed based on minor allele frequency (MAF), effect sizes and varying marker density. Target traits were body weight (BW), ultrasound measurement of breast muscle (BM) and hen house egg production (HHP) in broiler chickens. We used a 600 K Affymetrix platform with 1352 birds genotyped. The prediction method was genomic best linear unbiased prediction (GBLUP) with 354 564 single nucleotide polymorphisms (SNPs) used to derive a genomic relationship matrix ( G ). Predictive ability was assessed as the correlation between predicted genomic values and corrected phenotypes from a threefold cross‐validation. Predictive ability was 0.27 ± 0.002 for BW, 0.33 ± 0.001 for BM and 0.20 ± 0.002 for HHP. For the three traits studied, predictive ability decreased when SNPs with a higher MAF were used to construct G . Selection of the 20% SNPs with the largest absolute effect sizes induced a predictive ability equal to that from fitting all markers together. When density of markers increased from 5 K to 20 K, predictive ability enhanced slightly. These results provide evidence that designing a low‐density chip using low‐frequency markers with large effect sizes may be useful for commercial usage.     

F1代法检测棉铃虫种群对Bt棉的抗性等位基因频率变化

 在具有室内高抗Bt棉棉铃虫品系的前提下,F₁代法是检测棉铃虫对Bt棉抗性等位基因频率的最简捷、快速的生物测定方法。2010－2012年采用F₁代法检测了河北省邱县棉铃虫田间种群对Bt棉的抗性等位基因频率变化。结果表明,2010－2012年采集的122、141及124头田间雄虫中,分别有32、22及43头携带抗性基因,抗性等位基因频率分别为0.131(95%置信限CI:0.101～0.162)、0.078(95% CI:0.034～0.122)及0.199(95% CI:0.124～0.274)。2012年采用带毒饲料法测定河北邱县等4个地区Bt棉田间棉铃虫对Cry1Ac的抗性。结果表明,河北邱县棉铃虫种群的抗性最高(抗性倍数RR为19.2倍）,明显高于湖北荆州、湖北枣阳和安徽萧县种群的抗性（RR为4.9～9.3倍)。该地区长期大面积种植转单价Bt棉导致田间棉铃虫抗性进化,需要尽快采取有效的抗性治理措施。     

两种SNP分型方法的比较及其在柚品种鉴定中的应用

 用两种常用的SNP分型方法,等位基因特异性PCR法（Allele-specific PCR,AS-PCR）和高分辨率熔解曲线分析（High resolution melting analysis,HRMA）,对16个柚栽培品种和8个柚杂种后代材料进行了7个SNP位点的分型研究。结果表明这两种方法所得的分型结果相同,都将24个样本分成了22种基因型。值得一提的是,样本‘八朔’与‘红八朔’,‘红甘夏’与‘川野夏橙’之间在所测位点无差别,表明其应当是同一来源的无性系变异。‘早熟真龙柚’和‘中熟真龙柚’的分型结果表明它们的基因型不同,看来并非是起源同一基因型的不同芽变品种,也不存在亲子关系。可见,AS-PCR和HRMA均适用于柚类品种的区分和鉴定。AS-PCR法是一种准确、低成本的SNP分型方法,适合普通实验室使用,惟对PCR反应体系要求严格。HRMA分型法具有准确、快速、简便、分析量大的特点,但需要专门的设备,试剂成本也高。     

Characterization and PCR-based detection of benzimidazole-resistant isolates of Monilinia laxa in California

Monilinia laxa is a pathogen of brown rot of stone fruit and almond in California, causing blossom blights and fruit rots. In this study, low-level resistance to the benzimidazole fungicides benomyl and thiophanate-methyl was detected in field isolates of M laxa collected from stone fruits and almonds in California. Low-resistant (LR) isolates grew in potato dextrose agar (PDA) plates amended with benomyl and thiophanate-methyl at 1 and 5 microg ml(-1), respectively, but not in plates amended with benomyl at 5 microg ml(-1) or thiophanate-methyl at 50 microg ml(-1). The benzimidazole LR isolates were characterized by temperature sensitivity and the DNA sequence of the beta-tubulin gene. The LR isolates showed high-temperature sensitivity, being sensitive to 1 microg ml(-1) of benomyl at 28 degrees C but resistant at 8-24 degrees C. Analysis of the DNA sequence of the beta-tubulin gene showed that the LR isolates had a point mutation at the amino-acid position 240, causing substitution of leucine by phenylalanine. Based on the point mutation, a pair of allele-specific PCR primers was developed for rapid detection of LR isolates of M laxa. In addition, a pair of PCR primers specific to M laxa was developed on the basis of the differences in the DNA sequence of the intron 6 of beta-tubulin gene from M laxa, M fructicola and other fungal species. The primer pair amplified the expected 376-bp DNA fragment from all M laxa isolates tested, but not from 14 other fungal species isolated from stone fruit and almond crops. The restriction endonuclease BsmA I recognized the sequence GTCTCC in the PCR products from sensitive (S) isolates only, but not the GTTTCC sequence in the PCR products from LR isolates. The endonuclease digested the 376-bp PCR products from S isolates to produce two bands (111 and 265 bp) on agarose gels. Thus, both allele-specific PCR and the PCR-restriction fragment length polymorphism (PCR-RFLP) methods could be useful for rapidly detecting benzimidazole-resistant isolates of M laxa from stone fruit and almond crops in California.