小麦白斑突变体I30的特征特性及遗传分析

类病斑突变体是研究植物程序性死亡和抗病性的理想材料。为了丰富小麦斑点突变体的研究,对叠氮化钠诱变小麦品种陕农33产生的稳定遗传的白斑突变体I30进行了特征特性研究和遗传分析。结果表明,突变体I30从三叶期开始表现白色块斑和长条纹。锥虫蓝染色和DAB染色显示,I30斑点处出现细胞死亡和H_2O_2积累现象。透射电子显微镜观察表明,I30的叶绿体形状发生改变,数目减少,基粒垛叠高度无序,部分甚至降解。农艺性状调查结果表明,I30的株高、单株有效穗数、穗粒数、穗长和结实率与野生型间无显著差异,但千粒重、穗粒重、单株产量、旗叶长度和宽度显著低于野生型。遗传分析表明,I30由1对隐性核基因控制。利用BSA+660K基因芯片技术,将该基因定位于小麦6D染色体上,位于SSR分子标记Xcfd190和6DS-5之间,遗传距离分别为6.4cM和9.1cM。     

Analysis of residuals for stability assessment of rice genotypes

The analysis of residuals computes general adaptabilities (GAs) and specific adaptabilities (SAs) of genotypes similar to combining ability analysis. The residual analysis is simple and robust being based on the first-degree statistics, and is assumption-free. A unique statistic of ratio of variances (VR) of residuals for individual genotypes allows comparing their stability. The residuals analysis of genotype × environment (GE) interactions was performed for grain yield (t ha^?1) of 25 rice (Oryza sativa L.) genotypes, including two developed by marker-assisted selection for root traits quantitative trait loci (QTL), tested across 16 sites. Results were compared with the linear regression analysis for (i) full set of 16 sites showing adequacy of linear model and (ii) subset of nine-poor sites showing inadequacy of linear model. There was agreement between the two analyses for situation (i) but not for situation (ii) when the regression analysis fails because of nonlinearity but the residual analysis retains its validity.     

Quantitative trait loci responsible for the difference in γ-oryzanol content in brown rice between japonica-type and indica-type rice cultivars

γ-Oryzanol is a main oleophilic component in rice bran oil and has been well recognized as a good dietary supplement for human health, as well as having uses in industrial materials. japonica-type rice cultivars generally showed significantly higher contents of total γ-oryzanol in brown rice compared with indica-type cultivars, although within-group variation was significant. The objective of this study was to explore quantitative trait loci (QTLs) responsible for the difference in the γ-oryzanol content between japonica-type and indica-type rice cultivars, using recombinant inbred lines (RILs), backcross inbred lines (BILs), and corresponding chromosome segment substitution lines (CSSLs) derived from crosses between japonica-type and indica-type. Results from RILs and BILs showed that eight QTLs were detected with R² from .09 to .16. Nine candidate regions for QTL were also suggested from corresponding CSSLs. These QTLs from RILs and BILs and the candidate regions from CSSLs were not overlapped, although one QTLs was mapped near the boundaries of the respective candidate region. At four QTLs and three candidate regions, alleles or segments from japonica-type caused higher contents than those from indica-type. On the other hand, at the other four QTLs and six candidate regions, alleles or segments from indica-type caused higher contents than those from japonica-type, which is a reverse result to the parental differences. This result strongly suggested that alleles with increasing effects on γ-oryzanol content could be accumulated not only from japonica-type but also from indica-type, leading to a potential for increase in γ-oryzanol content in future breeding programs.     

Molecular mapping of soybean seed tocopherols in the cross ‘OAC Bayfield’ × ‘OAC Shire’

Soybean (Glycine max [L.] Merr.) is cultivated primarily for its protein and oil in the seed. In addition, soybean seeds contain nutraceutical compounds such as tocopherols (vitamin E), which are powerful antioxidants with health benefits. The objective of this study was to identify molecular markers linked to quantitative trait loci (QTL) that affect accumulation of soybean seed tocopherols. A recombinant inbred line (RIL) population derived from the cross ‘OAC Bayfield’ × ‘OAC Shire’ was grown in three locations over 2 years. A total of 151 SSR markers were polymorphic of which a one‐way analysis of variance identified 42 markers whereas composite interval mapping identified 26 markers linked to tocopherol QTL across 17 chromosomes. Individual QTL explained from 7% to 42% of the total phenotypic variation. Significant two‐locus epistatic interactions were identified for a total of 122 combinations in 2009 and 152 in 2010. The multiple‐locus models explained 18.4–72.2% of the total phenotypic variation. The reported QTL may be used in marker‐assisted selection (MAS) to develop high tocopherol soybean cultivars.     

Mapping and validation of the quantitative trait loci for leaf stay‐green‐associated parameters in maize

Functional stay‐green is generally regarded as a desirable trait of varieties in major crops including maize. In this study, we used an F_3:4 recombinant inbred line population with 165 lines from a cross between a stay‐green inbred line (Zheng58) and a model inbred line (B73) using 211 polymorphic simple sequence repeat markers to map quantitative trait loci for three stay‐green‐associated parameters, chlorophyll content, photosystem II photochemical efficiency and stay‐green area, at maturity stage, detected a total of 23 quantitative trait loci (QTL) on nine chromosomes. Single QTL explained 3.7–13.5% of the phenotypic variance. Additionally, we validated some important stay‐green QTL using a heterogeneous inbred family approach and found that the stay‐green‐associated parameters were significantly correlated with the plant yield. This study may contribute to a better insight into the regulatory mechanism behind leaf stay‐green in maize and a novel development of elite maize varieties with delayed leaf senescence through molecular marker‐assisted selection.     

Genomewide association study reveals novel quantitative trait loci associated with resistance towards Septoria tritici blotch in North European winter wheat

Fungal diseases are a major constraint for wheat production. Effective disease resistance is essential for ensuring a high production quality and yield. One of the most severe fungal diseases of wheat is Septoria tritici blotch (STB), which influences wheat production across the world. In this study, genomewide association mapping was used to identify new chromosomal regions on the wheat genome conferring effective resistance towards STB. A winter wheat population of 164 North European varieties and breeding lines was genotyped with 15K single nucleotide polymorphism (SNP) wheat array. The varieties were evaluated for STB in field trials at three locations in Denmark and across 3 years. The association analysis revealed four quantitative trait loci, on chromosomes 1B, 2A, 5D and 7A, highly associated with STB resistance. By comparing varieties containing several quantitative trait loci (QTL) with varieties containing none of the found QTL, a significant difference was found in the mean disease score. This indicates that an effective resistance can be obtained by pyramiding several QTL.     

普通菜豆籽粒大小与形状的QTL定位

普通菜豆是世界上最重要的食用豆类作物之一,其籽粒大小和形状与产量及外观品质密切相关。本研究以来自安第斯基因库的大粒品种龙270709和来自中美基因库的小粒品种F5910配置杂交组合,获得的F2分离群体分别在哈尔滨大田与北京昌平温室种植,对百粒重、粒长、粒宽、粒厚、长宽比和长厚比6个籽粒性状进行了相关性分析和QTL定位。相关性分析表明,百粒重与粒长、粒宽、粒厚、长宽比、长厚比5个衡量籽粒大小和形状的性状均显著正相关。利用基于完备区间作图方法的Ici Mapping 4.1进行QTL定位,哈尔滨环境下定位到38个与百粒重、粒长、粒宽、粒厚、长宽比、长厚比相关的QTL,表型贡献率介于2.39%~17.37%之间,分布在除第1染色体外的其余10条染色体上;北京昌平环境下定位到21个上述性状的QTL,表型贡献率介于5.92%~22.53%之间,分布在第1、第3、第6、第7、第8、第9和第11染色体上。其中,百粒重QTLSW7与SW7’,SW6.1与SW6’,粒长QTLSL6.1与SL6.1’,粒厚QTLSH11与SH11’在2个环境下的标记区间重叠或者重合,SW7、SW6.1、SL6.1、SW6’和SL6.1’的表型贡献率在10%以上。     

马铃薯品种遗传多样性分析

为解析一套(559份)从世界各国收集的马铃薯种质资源的遗传多样性,用16个表型性状和36个SSR标记进行了聚类和多样性参数分析。对454份表型数据完整材料的UPGMA聚类分析表明,在欧氏距离14.66处被聚成2个类群(A_1和A),其中A_1在欧氏距离12.74处被分为A_(11)和A_(12)亚群;454份材料在欧氏距离11.73处被划成9个类群,包括4个小类(A、B、C和H)和5个大类(D、E、F、G和I),其中类群I所包括的材料占总数的57.5%,该结果较好地揭示了马铃薯种质材料之间的形态差异,区分生态类型不同和遗传差异明显的亲本。36个SSR标记在559份材料中共检测出134个多态性位点,每对引物检测1~7个等位变异,平均3.72个,引物多态性信息量(PIC)为0.1545~0.7743,平均为0.5783,说明品种间有丰富的遗传多样性。NJ系统进化树分析表明,559份材料可分为3个大群。类群I为一个混合群,各地区品种均有分布,包括133份马铃薯材料,占总数的23.8%;类群II中欧洲、北美及中国东北和西北地区的材料所占比重较大,数量为187,占33.5%;类群III中北美、南美以及中国东北和西南地区马铃薯材料所占比重较大,包含239份材料,占42.8%。表型性状聚类与SSR分子标记聚类结果相似,均与地理位置有很大相关性,应结合共同用于评价马铃薯品种遗传多样性。     

Breeding for increased grain protein and micronutrient content in wheat: Ten years of the GPC-B1 gene

To provide food and nutrition security for a growing world population, continued improvements in the yield and nutritional quality of agricultural crops will be required. Wheat is an important source of calories, protein and micronutrients and is thus a priority to breed for improvements in these traits. The GRAIN PROTEIN CONTENT-B1 (GPC-B1) gene is a positive regulator of nutrient translocation which increases protein, iron and zinc concentration in the wheat grain. In the ten years since it was cloned, the impacts of GPC-B1 allelic variation on quality and yield traits have been extensively analyzed in diverse genetic backgrounds in field studies spanning forty environments and seven countries. In this review, we compile data from twenty-five studies to summarize the impact of GPC-B1 allelic variation on fifty different traits. Taken together, the results demonstrate that the functional copy of the GPC-B1 gene is associated with consistent positive effects on grain protein, Fe and Zn content with only marginally negative impacts on yield. We conclude that the GPC-B1 gene has the potential to increase nutritional and end use quality in a wide range of modern cultivars and environments and discuss the possibilities for its application in wheat breeding.     

桃若干重要特异性状的遗传趋向分析

为了明确桃树菊花花形、窄叶形、白化与黄化叶色及盘龙形与垂枝形树形等6个性状的遗传特性,以‘粉菊花桃’ב红根甘肃桃1号’、‘红花重瓣垂枝桃’(简称‘红垂枝’)ב粉菊花桃’、‘S9’ב粉菊花桃’、‘粉菊花桃’ב瑞光2号’、‘红珊瑚’×(‘粉菊花桃’ב瑞光2号’)为组合配制F_1和F_2代,研究菊花花形、叶片白化及垂枝树形的遗传特性;以‘98-4-32’ב金蜜狭叶桃’、‘99-7-14’ב金蜜狭叶桃’及‘99-7-15’ב金蜜狭叶桃’为组合配制F_1和F_2代,研究窄叶形遗传趋向;以‘北京2-7’ב白花山碧桃’为组合配制F_1和F_2代,研究叶片黄化遗传特点;以‘红垂枝’ב帚形山桃’及‘96-7-56’ב帚形山桃’为组合配制F_1和F_2代,研究盘龙形树形的遗传。结果表明:在蔷薇花形与菊花花形组合中,"蔷薇形/菊花形"表现出2对等位基因(Ch/ch及Ch_2/ch_2)控制的遗传特性,且蔷薇形对菊花形为显性;在铃形花形与菊花花形组合中,F_1代蔷薇形表现为二者的中间类型。在‘98-4-32’ב金蜜狭叶桃’及‘99-7-14’ב金蜜狭叶桃’组合中,"宽叶/窄叶"表现出2对等位基因(Nl/nl及Nl_2/nl_2)控制的遗传特性,且宽叶对窄叶为显性;在‘99-7-15’ב金蜜狭叶桃’组合中,"宽叶/窄叶"表现出1对等位基因控制的遗传特性。叶片"正常/白化"表现出1对等位基因(Wl/wl)控制的遗传特性,且正常对白化为显性,白化基因可能来自‘粉菊花桃’;叶片"正常/黄化"表现出2对等位基因(Yl/yl及Yl_2/yl_2)控制的遗传特性,其中1对为显性时对另一对具有抑制作用,黄化基因可能来自‘白花山碧桃’。直立树形同时表现为盘龙形与垂枝形及盘龙形与开张形的中间类型;"开张形/垂枝形"表现出1对等位基因(We/we)控制的遗传特性,且开张对垂枝为显性。结论:菊花花形由2对隐性基因(chchch_2ch_2)控制;窄叶形可能由2对隐性基因(nlnlnl_2nl_2)控制;叶片白化由1对隐性基因(wlwl)控制;叶片黄化可能由2对等位基因(Yl_yl_2yl_2或Yl_2_ylyl)控制;仅盘龙形与直立形由1对等位基因(Br_2/br_2)控制,其中盘龙形基因型为br_2br_2;垂枝形由1对隐性基因(wewe)控制。