Assessment of partial resistance to powdery mildew in Chinese wheat varieties

Field trials in two cropping seasons and two locations in central China were conducted on 60 Chinese autumn‐sown wheat varieties to assess their partial resistance to powdery mildew. Mean levels of disease severity ranged from close to 0 to more than 90%. The method of inoculation and the location in which trials were conducted affected the relative performance of the varieties, but these effects were much smaller than the main effect of variety. The area under the disease progress curve was highly correlated with final disease severity, but both were poorly correlated with apparent infection rate. Disease severity was regressed against frequencies of virulence in the Blumeria graminis (syn. Erysiphe graminis) f sp. tritici populations in the trial plots. A vertical distance (D) from the mean mildew severity to the fitted line was calculated for each variety and was used to quantify partial resistance. Five of the 60 varieties, ‘Hx8541’, ‘E28547’, ‘Chuan1066’, ‘Zhe88pin6’ and ‘Lin5064’, consistently expressed relatively low levels of disease despite high frequencies of virulence in the pathogen and had consistently high D‐values. They may therefore have good levels of partial resistance.     

Crossability percentages of bread wheat landraces from Sichuan Province,China with rye

Summary The crossabilities of 177 landraces of wheat (Triticum aestivum L.) from Sichuan Basin and its adjacent mountain ranges with rye (Secale cereale L.) have been tested. 16 landraces possess a higher crossability than Chinese Spring, 34 landraces have a similar and 127 landraces have a lower crossability than Chinese Spring or are non-crossable with rye. Most landraces with high crossability occur in Qinling Mountain and Dabashan Mountain Ranges in north of Sichuan and the valleys of Minjiang River, Fujiang River and Jialinjiang River in Sichuan Basin.     

Cytogenetical studies in wheat. XVIII. Gene Yr24 for resistance to stripe rust

A new gene, Yr24, for resistance to stripe rust was transferred from a durum accession to common wheat via an amphiploid (synthetic wheat) with Aegilops tauschii. Yr24 was located in chromosome 1B by monosomic analysis. Its genetic linkage of 4 cM with Yr15 indicated its localization to the short arm.     

CIMMYT小麦种质农艺及品质性状分析

为给黄淮南片冬麦区小麦育种提供种质信息,将1 328份CIMMYT国际面包小麦观察圃(IBWSN)的种质于2011-2015年度种植于黄淮南片冬麦区的新乡,调查了42^nd ～46^th国际面包小麦观察圃种质的主要农艺性状和抗病性,分析了45^th国际面包小麦观察圃种质的品质表现及优质亚基基因状况。结果表明,CIMMYT国际面包小麦观察圃种质均表现为春性,综合农艺性状差;株高不低于80 cm,大多数（84.6%）在90～110 cm之间;千粒重高于45.0 g和50.0 g的比例分别为28.4%和10.0%。CIMMYT国际面包小麦观察圃种质的花期与黄淮南片冬麦区品种一致,多数小麦种质白粉病发生比较轻。45^th国际面包小麦观察圃种质的湿面筋含量为23.6%～41.6%,其中,13.2%的小麦种质湿面筋含量大于35.0%,40.8%的小麦种质湿面筋指数不低于80.0%;49.7%的小麦种质携带Dx5+Dy10基因,3.0%的小麦种质携带Bx7^OE 基因;有 10个小麦种质含有优质5+10亚基及7超量表达亚基,可作为优质亲本改良黄淮南片冬麦区高产品种。     

Genetic and Association Mapping Study of English Grain Aphid Resistance and Tolerance in Bread Wheat Germplasm

English grain aphid （EGA） is a destructive insect pest of wheat. To identify the loci associated with EGA resistance and tolerance, 70 bread wheat accessions mainly from central Asia were evaluated for EGA resistance and tolerance traits at two locations, and genotyped with 51 SSR markers. Totally, three accessions showed high or moderate levels resistance and 17 genotypes displayed highly or moderately tolerate to EGA. Genetic diversity of these lines was investigated also. After 97 SSR loci which evenly covered all wheat chromosomes were scanned for association, four SSR loci were significantly associated with EGA resistance and four with EGA tolerance. After association analysis was conducted with dynamic aphid densities, we found four loci Xgwm192b, Xgwm391, Xbarc98, and Xgwm613b were detected continuously at different growing stages of wheat. In addition, the loci of EGA resistance/tolerance and Russian wheat aphid resistance were compared. The results generated in this study would be helpful for utilization of the EGA resistance/tolerance germplasm, and for development of mapping populations in EGA resistance breeding programs.     

小麦叶绿素缺失突变体Mt135的叶绿体基因差异表达分析

小麦叶绿素缺失突变体Mt135自交后代稳定表现绿株、条纹株和白化株3种类型, 其中条纹株白色组织和白化株的叶绿体数目和结构发生突变, 完全失去光合能力。为研究该突变体叶绿体基因表达与光合作用的关系, 采用实时荧光定量PCR技术, 分析了白化株和条纹株的叶绿体基因表达。在白化株中共检测到40个差异表达基因, 涉及4类功能(编码光反应相关蛋白、编码叶绿体内能量代谢相关酶、核糖体合成和tRNA合成), 包括18个上调表达和22个下调表达基因;在条纹株中共检测到13个上调表达基因, 其表达变化趋势与在白化株中一致。白化株的差异表达基因中, 编码光系统II、I结构蛋白的psb、psa及ycf等基因家族的基因表达量显著下调;多个编码核糖体蛋白大、小亚基的基因表达量改变, 尤其是核糖体蛋白小亚基编码基因rps14和23S rRNA的编码基因23S rDNA表达量显著下调。推测Mt135突变性状与参与光反应相关蛋白的编码基因、叶绿体内能量代谢相关酶的编码基因、核糖体合成相关基因以及tRNA合成相关基因表达量的改变密切相关。     

爱玉子与薜荔比较分析研究

爱玉子与薜荔为同属不同种的藤本植物,两者虽有相似之处,但也存在许多较大的区别。通过收集有关资料和研究,着重介绍爱玉子与薜荔在形态特征、隐花果特性、天然分布以及商品品质等方面的不同之处,以供有关学者和拟引种爱玉子的投资者参考。     

Genetic analysis of resistance to spot blotch disease in wheat (Triticum aestivum L.) in Zambia

Understanding the genetics of resistance to spot blotch disease, caused by Bipolaris sorokiniana (Sacc.) Shoem, is important to design an appropriate breeding strategy to improve the trait. The objective of this study was to determine the gene action and mode of inheritance of resistance to spot blotch in wheat. Eight genotypes with varying resistance to the disease were crossed in a full diallel mating design. Parents and their progenies were evaluated for spot blotch resistance. Data were analyzed using Hayman’s diallel analysis. The results suggested the importance of additive gene effects in controlling the resistance to spot blotch in the materials under study. No epistasis, maternal, or reciprocal effects were detected. Resistance to spot blotch exhibited partial dominance. Therefore, exercising selection for resistance in the early segregating generation should be an effective approach because of the predominance of additive gene effects. The Wr/Vr graph showed that the parents 30SAWSN5 (P3) and Coucal (P4) possessed more dominant genes, which makes them particularly suitable for inclusion in breeding for resistance to spot blotch.     

槟榔叶片总蛋白质提取及双向电泳条件初探

采用3种提取植物组织蛋白的方法(TCA/丙酮沉淀法、E-TCA法、酚法)提取槟榔叶片总蛋白,在蛋白产量,一维和二维电泳图谱等方面对3种方法的提取效果进行比较.结果表明,TCA/丙酮沉淀法效果较好,是槟榔叶片总蛋白提取的可选方法,同时优化了双向电泳的条件和上样量.     

Inheritance of slow rusting to stem rust in wheat

Summary The inheritance of the slow rusting character was studied on F₅ progenies from seven spring wheat cultivars (Triticum aestivum) crossed in all possible combinations without reciprocals. The cultivars and their progenies were evaluated for slow rusting in 1974 and 1975 in epidemics of Puccinia graminis f. sp. tritici, races 15 and 151, and traces of other races. Slow rusting varied significantly among the parents and among the F₅ progeny of each cross. Transgressive segregation occurred in each cross, i.e. some progeny rusted more slowly than the parents and some faster. In crosses with both Idaed 59 and Kenya 58 the progeny distributions were skewed towards slow rust development but the distributions in the other crosses were normal. The genetic control of slow rusting was predominantly additive, and narrow sense heritability was approximately 80 percent. The number of segregating genes having an effect on slow rusting was estimated to be 2 to 12 pairs depending on the cross. Correlation between slow rusting and maturity was usually negative but in most crosses the relationship was small.Contribution No. 9624 from the Agricultural Experiment Station, University of Minnesota, St. Paul, Minnesota 55108.