Isoenzyme differences between the wild diploid and tetraploid wheats

Variability of acid phosphatase (ACP), esterase (EST), and superoxide dismutase (SOD) isoenzymes among 660 accessions of wild diploid wheats Triticum boeoticum (475) and T. urartu (185) and among 35 accessions of wild tetraploid wheats T. araraticum (21) and T. dicoccoides (14) was studied with the use of polyacrylamide gel electrophoresis. The wild diploids are differentiated by the electrophoretic variants of ACP-B, ACP-C, EST-A, EST-B, EST-C, EST-D, and SOD-B. Triticum urartu matches the A genome of wild tetraploid wheats T. araraticum and T. dicoccoides by allozymes of ACP-B, ACP-C and SOD-B, but differs distinctly by the monomorphic allozyme EST-A66. Triticum boeoticum fits the A genome of polyploid wheats by allozymes of EST-A and EST-B, but differs in allozymes of ACP-B and SOD-B. Thus, none of the two contemporary diploid wheats corresponds exactly to the A genome of wild tetraploid wheats by all diagnostic isoenzymes. Triticum boeoticum and T. arararicum share EST-C46 and EST-D71, whereas T. urartu and T. dicoccoides are fixed for silent EST-C0 and share EST-D73, suggesting independent origin of the two tetraploid wheats with a contribution from ancestral forms of both diploids.     

小麦属G组染色体编码的高分子量谷蛋白亚基多态性

用SDS－PAGE和PCR扩增方法对提莫菲维小麦和阿拉拉特小麦G组染色体编码的高分子量谷蛋白亚基（HMW－GS）的多态性进行了研究。无论从蛋白质水平还是从DNA水平来看，G组染色体编码的HMW－GS都存在遗传多样性，15个供试材料表现出8种表型，并与普通小麦和硬粒小麦的HMW－GS不同，为了研究G组染色体编码的HMW－GS与小麦品质的关系；利用普通小麦的Glu-1Y位点中部重复结构区的保守序列设计的2个特异性引物对G组染色体进行PCR扩增可以鉴别Glu-1G位点的等位基因变异，且与SDS－PAGE的结果一致。     

阿拉拉特小麦高分子量谷蛋白新基因1Gy的克隆及序列分析

利用y-型高分子量谷蛋白亚基的特异引物,对阿拉拉特小麦(PI427305)的基因组DNA进行PCR扩增,得到大小为2.2 kb的目的条带,将该条带回收纯化并克隆到pMD18-T载体中,经梯度亚克隆测序拼接,得到编码区的全序列为2 202 bp(GenBank登录号:HM131806),共编码732个氨基酸。它与1Gy7*序列的同源性高达99%,而且氨基酸序列结构与大多数y-型亚基相同,推断该基因为1Gy。1Gy的分子量比1Gy7*稍小,迁移率比1Gy7*慢。与小麦属其他基因组编码的y-型亚基相比,其在靠近C端的重复区多了一个半胱氨酸残基。利用在线PSIPRED对其二级结构预测结果显示,其重复区主要是无规则卷曲结构。这些结构都可能使得1Gy对小麦加工品质产生正面影响。     

阿拉拉特小麦高分子量谷蛋白亚基遗传多样性分析

为了给普通小麦的品质改良提供基础材料,利用SDS-PAGE技术对264份阿拉拉特小麦高分子谷蛋白亚基遗传变异进行了分析。结果表明:有5种Ax、5种Ay、4种Gx和3种Gy亚基类型,并形成20种亚基组合类型,其分布频率最高的是Ax1+Ay(A),Gx(A)和Ax1,Gx(A),分别占18.94%和18.18%。在264份材料中,有158份材料(59.85%)中检测到Ay亚基表达,249份材料(94.32%)中检测Gx亚基表达,而Gy亚基仅在部分材料中(20.08%)表达。由此可见,阿拉拉特小麦Glu-A1位点的遗传多样性高于Glu-G1。     

Genetic distance between Triticum timopheevi Zhuk., T. aramticum Jakubz. and T. aestivum L.

The genetic distances between two cultivated wheat (Triticum aestivum L.) varieties (Martonvásári 9, Martonvásári 15), a Martonvásári 9 line possessing the crossability gene krl, and 21 accessions of T. timopheevi Zhuk. and T. araraticum Jakubz. were estimated, based on agro-morphological, physiological and biochemical analysis of data. Cluster analysis based on Mahalanobis' D² values was applied. All 21 accessions of T. timopheevi and T. araraticum could be classified into eight clusters. Clusters I and II consisted of all the T. timopheevi, while T. araraticum was located in six clusters. Discriminant analysis was applied to test significant differences between cluster pairs. The genetic distance (GD) based on the electrophoretic data of gliadins indicated two types of electrophoregrams in T. timopheevvi, distinguished as groups A and B. T. araraticum accessions were variable as regards the spectra. Mean, minimum and maximum GD were estimated within and between different wheat groups based on acid polyacrylamide gel electrophoresis.     

New durum wheat with Hessian fly resistance from Triticum araraticum and T. carthlicum in Morocco

Hessian fly is an important pest of wheat on the North American continent and the temperate Mediterranean drylands. Yield losses caused by this insect in Morocco are the heaviest in the Mediterranean region and are estimated to be 36% on average. Genetic resistance to Mediterranean Hessian fly biotypes has not been found in durum wheat, although large numbers of durum accessions were screened. Genes for resistance were found in common wheat; some of which are transferable to durum. However, there is a need to broaden the genetic base for resistance in durum wheat. The objective of this work was to introgress resistance from selected Triticum araraticum and T. carthlicum accessions using multiple backcross methodology. The experimental recipient durum wheat included numerous adapted and high‐yielding lines. Testing for Hessian fly resistance under controlled conditions and field yield data showed that this programme yields Hessian fly‐resistant durum lines with good yields and adaptation.