多穗轴节类小麦性状关系探讨

研究多穗轴节类小麦资源的穗轴节数与小穗数间及它们与其它穗部性状和抽穗间的关系是评价多穗轴节类利用价值,确定利用方式和策略的重要基础。本文通过对部分多穗轴节类和普通穗类基因型及多穗轴节×普通穗类杂种Ｆ１性状间简单相关和多元相关分析发现：１．多穗轴节类所具有的不利性状是可以克服的,只是不同性状改良难易程度不同。因而在多穗轴节小麦育种中应进一步创造、引入变异类型,丰富遗传资源,使之更接近早熟高产多穗轴节育种目标。２．各穗部性状在（ＭＲＮ×ＣＳ）Ｆ１中有利和不利关系共同存在。以现有多穗轴节类为亲本利用杂种优势,需要综合考虑性状间的关系和特定的生态环境要求。３．本试验采用的多穗轴节类基因型的多穗轴节性状和小穗数性状可能存在不同的遗传基础,两者与其它穗部性状和生育期间的关系也有所不同,推测其差异可能是由于穗轴节和结实小穗的发育差异造成的。在这些多穗轴节类基因型的基础上进行多穗轴节小麦育种应注意区别穗轴节数和结实小穗数,在穗轴节数多的基础上进一步对结实小穗数进行选择。     

小麦穗轴节发育及其与穗部性状的遗传关系

对包括多穗轴节在内的 2 3个基因型穗轴节发育特征及其与穗部性状的关系进行了相关分析与典型分析 ,结果表明 :①初始穗轴节数和后生穗轴节数增加均可能导致穗轴节数增加 ,初始穗轴节数的增加主要源于分化期延长 ,而后生穗轴节数的增加主要是由于分化速率提高 ;②影响穗部性状的主要发育特征是后生穗轴节数、初始穗轴节数、初始穗轴节分化速率和初始穗轴节分化期 ,而穗轴节的发育特征对千粒重并无必然不利作用 ,但对小穗结实率有不利影响 ,要获得小穗数多且结实率高的基因型需要引入新的遗传变异资源。     

小麦穗抽节发育及其与穗部性状的遗传关系

对包括多穗轴节在内的23个基因型穗轴节育特征及其与穗部性状的关系进行了相关分析与典型分析，结果表明：（1）初始穗轴节数和后生穗轴节数增加均可导致穗轴节数增加，初始穗轴节数的增加主要源于分化期延长，而后小穗轴节数的增加主要是由于分化速度提高；（2）影响穗部性状的主要发育特征是后生穗轴节数、初始穗轴节数、初始穗轴节分化速率和初始穗轴节分化期，而穗轴节的发育特征对千粒重并无必须不利作用，但对小穗结实率有不利影响，要获得小穗数多且结实率高的基因型需要引入新的遗传变异资源。     

多小穗小麦10A幼穗发育的遗传研究

将多小穗小麦１０－Ａ与普通小穗小麦绵阳１１和矮孟牛，及其杂种Ｆ１的幼穗分化特点作了系统比较分析，结果表明：１０－Ａ具有小穗分持续期长和小穗分化率速率高等两个显著特性，其中，小穗分化持续期长的特殊未在杂种Ｆ１中表达，而小穗分化速率高的特性不仅能在杂种Ｆ１代中表达，且出现较强的杂种优势。     

小麦品种抗赤霉病穗轴病理解剖的研究

研究了不同抗赤霉病类型品种的病理解剖学，发现抗病品种穗轴维管束数量比感病品种的多；穗轴节上部的节间组织排列较下部节间组织致密；菌丝体只存在于穗维管束的导管内，并且抗病品种内的菌丝体数量比感病品种数量少、且发育不良；感病品种穗轴组织的坏死速率为抗病品种的７倍。     

普通小麦遗传改良的潜在价值

详尽探讨了普通小麦遗传改良的潜在价值,认为普通小麦遗传改良的研究方向应该是通过物种间远缘杂交和染色体组多倍化创造新物种,促进麦类植物的物种升级,由此挖掘其更大的产量潜力,同时提出了普通小麦遗传改良的技术思路。     

节节麦与普通小麦杂交后代的遗传多样性分析

运用SSR标记的方法,对节节麦SQ-214与普通小麦杂交后代的BC1F2群体的64份材料和高代系群体的147份材料在D基因组上的68个SSR位点的遗传多样性进行了分析.结果表明:68对SSR引物在杂交后代的两个群体等位变异位点较多,BC1F2群体共检测到67个位点有变异,等位变异数为212个,主要集中在3D染色体上.高代系中58个位点有变异,等位变异数为184个,等位变异位点多集中在2D上.BC1F2和高代系群体在D基因组的7条染色体上遗传多样性的表现不一致,BC1F2在7条染色体上的遗传多样性显著高于高代系,等位变异分布较高代系均衡.BC1F2材料间的遗传多样性高于高代系.由此可知,节节麦与普通小麦杂交衍生后代具有较高的遗传多样性,可用于进一步改良小麦;同一衍生亲本的衍生后代具有较大的遗传分化,尤其是在随机群体;经过选择后的群体遗传多样性会明显的降低.     

普通小麦Genomic-SSR和EST-SSR分子标记遗传差异

[目的]探讨国内外的24份普通小麦品种间的遗传差异。[方法]以改进的酚-氯仿法提取国内外24份普通小麦品种基因组DNA,采用Genomic-SSR和EST-SSR标记技术分析24份小麦品种的遗传多样性,并对2种评价方法进行分析比较。[结果]采用37对Genomic-SSR引物对24份小麦基因型的38个位点进行扩增,24个位点共扩增出152个多态性片段,每个位点上平均片段数为5.85。采用67对EST-SSR引物对24个小麦基因型的78个位点进行扩增,37个位点共扩增出120个多态性片段,每个位点平均片段数为3.24.24份小麦品种的综合遗传距离为0.1541～0.7820,平均为0.4231。[结论]EST-SSR标记能更准确地反映出不同小麦基因型之间遗传差异和亲缘关系。     

四川小麦主栽品种酯酶同工酶遗传差异分析

对四川近５０ 年来年推广面积６－６７ 万ｈｍ２（１００ 万亩） 以上的４０ 个主栽小麦品种进行了酯酶同工酶聚丙烯酰胺凝胶电泳分析。结果表明,１６ 条酯酶同工酶酶带中有７ 条酶带呈现多态性,其余９ 条酶带在所有供试品种中无差异,为四川栽培小麦品种的基本带。４０ 个小麦品种具有７ 种酯酶酶谱,其中３２ 个品种具有完全相同的酶谱,该酶谱为四川主栽小麦品种的优势酶谱。另外,８ 个品种具有６ 种酶谱类型,表明这些品种在同工酶水平上的分子特异性,可以作为这些品种鉴定的同工酶指纹。     

小麦与白黑麦、卵穗山羊草正反杂交的可交配性分析

小麦与白黑麦、卵穗山羊草正反杂交的可交配性分析＊叶兴国徐惠君李志武杜丽璞赵乐莲（中国农业科学院作物育种栽培研究所，北京１０００８１）ＣｒｏｓｓａｂｉｌｉｔｙＡｎａｌｙｓｉｓｏｆＲｅｃｉｐｒｏｃａｌＨｙｂｒｉｄｉｚａｔｉｏｎｓＢｅｔｗｅｅｎＣｏｍｍｏｎ...     

Detection of Allelic Variation in Chinese Wheat (Triticum aestivum L.) Germplasm with Drought Tolerance Using SSR Markers

Allelic variation in two domestic wheat landraces, Pingyaobaimai and Mazhamai, two cornerstone breeding materials and their derived cultivars with drought tolerance was detected by SSR (simple sequence repeat) markers. The clustering of 25 accessions showed that the similarity between Pingyaobaimai and Yanda1817, the latter was developed from the former, was 0.71, the highest one of all accessions, but the similarities were very low between these two accessions and other accessions including their derived cultivars. A similar situation was revealed between Mazhamai and its derived cultivars. Pingyaobaimai and its three derived cultivars shared three alleles at loci Xgwm526, Xgwm538 and Xgwm126 on chromosome arms 2BL, 4BL and 5AL, respectively. There were six shared alleles in Mazhamai and its derived cultivars, in order of Xgwm157,Xgwm126, Xgwm212, Xgwm626, Xgwm471 and Xgwm44 on chromosome arms 2DL, 5AL, 5DL, 6BL, 7AS and 7DC, respectively. Only one shared allele was detected between the pedigrees of Pingyaobaimai and Mazhamai. The difference of shared alleles in two cornerstone breeding materials and their derived cultivars revealed the diversity in Chinese wheat germplasm with drought tolerance and the complication in genetic basis of drought tolerance in wheat.     

Genetic Diversity of Recurrent Selection Populations with Ms2 Gene Assessed by Gliadins in Common Wheat （Triticum aestivum L.）

The male-sterile lines with Ms2 gene were highly evaluated in recurrent selection in wheat （Triticum aestivum L.）. Three populations C6 （population after six cycles of selection）, C7 （population after seven cycles of selection）, and C8 （population after eight cycles of selection） were constructed through recurrent selection with 12 parental materials （P）. Acid polyacrymide gel electrophoresis （A-PAGE） analysis was used to identify gliadin patterns and evaluate the genetic diversity in 12 parents and three populations. A total of 63 bands were identified, of which 17 polymorphic bands and 7 unique bands were present in populations and seven polymorphic bands and four unique bands were present in parents. The number of polymorphic and unique bands decreased gradually from C6 to C8, especially for to- and y-gliadins. The genetic distances in C6, C7, and C8 were calculated. The distributions of genetic distance were different in three recurrent selection populations. From C6 to C8, the genetic distance was 0.2687, 0.2652 and 0.1987, respectively. Statistically significant differences were detected between C7 and C8 with the T value of 37.9718. The result of cluster analysis based on genetic similarity matrix of three populations fitted well to those of principle coordinates analysis （PCoA）. Compared with 12 parents, almost all individuals of three populations are new genotypes. Most of the individuals from C6 and C7 could be divided into two groups, while most individuals of C8 were in one cluster. In conclusion, the results indicated that the genetic diversity was decreased severely according to the information revealed by A-PAGE, although some variations could be created in the recurrent selection. It was necessary to introduce diverse germplasm based on the genetic database of recurrent population to maintain and improve the breeding efficiency in the further program.     

四川主栽小麦品种RAPD标记遗传差异研究

采用随机扩增多态性ＤＮＡ（ＲＡＰＤ） 标记,对四川近５０ 年来年推广面积６－６７ 万ｈｍ２（１００万亩）以上的４０ 个小麦主栽品种遗传差异进行了初步探讨。结果表明,５５ 个随机引物中,有３２个引物（ 占５８－２％ ） 扩增产物具有多态性。３２ 个引物共扩增出１８５ 条带,其中９３ 条带（ 占５０％ ）具有多态性,每个引物可扩增出１ ～１１ 条多态性带,平均２－９ 条。４０ 个品种ＲＡＰＤ 标记遗传距离（ＧＤ） 变异为０－０１９ ～０－４７５ ,平均ＧＤ 值为０－２２１。聚类分析表明,在ＧＤ 值０－２３ 水平上,４０ 个品种可聚为５ 类。一些随机引物对有些品种能进行特异性扩增。引物ＯＰＮ１４ 对小麦１ＢＳ 扩增能产生特异性ＤＮＡ 片段,能完全鉴定出４０ 个供试品种中的９ 个１ＢＬ／１ＲＳ小麦－ 黑麦易位系品种。据此认为,ＲＡＰＤ标记可以作为小麦品种鉴定的指纹图谱。     

小麦戊聚糖研究进展

戊聚糖是小麦籽粒中非淀粉多糖的主要成分.戊聚糖在小麦籽粒中的含量较低,但它对小麦的营养品质和加工品质都有重要的影响.本文综述了近年来国内外关于小麦戊聚糖的最新研究进展,包括小麦品种间戊聚糖含量的变异、戊聚糖的影响因素和遗传特性、戊聚糖与农艺性状关系及戊聚糖对小麦品质的影响等,旨在为中国小麦品质改良提供依据.     

小麦遗传背景对糯性品质的影响

测试了5个遗传背景不同的糯小麦品系和1个非糯小麦品种的直链淀粉含量和RVA参数。糯小麦品系的直链淀粉含量大幅度地低于非糯小麦,糊化温度及高峰粘度、低谷粘度、最终粘度、崩解值、反弹值、峰值时间也显著低于非糯小麦,糯与非糯小麦品系问直链淀粉含量和各RVA参数存在正相关的趋势。糯小麦品系间直链淀粉含量与RVA参数也存在显著性差异,不同糯小麦品系表现出独特的糊化特性,但直链淀粉含量与各RVA参数间没有相关关系。结果表明,小麦的糯性除了受3对独立遗传的隐性基因支配外,糯小麦品系间的直链淀粉含量和糊化特性还受遗传背景的影响。     

小麦GAPDH 基因克隆及序列分析

采用Trizol法提取高质量小麦总RNA,并运用RT-PCR方法克隆了小麦GAPDH（甘油醛三磷酸脱氢酶）基因的部分序列（EU022331）,长度为604bp,核苷酸序列比对结果表明,该序列与大麦（M36650）、玉米（AY109397）、番茄（BT012693）GAPDH核苷酸序列的同源性分别为95%、86%和84%。GAPDH基因的克隆为在禾谷类作物研究的应用提供了一个较好的对照基因。     

Cloning of TaCYP707A1 Gene that Encodes ABA 8'-Hydroxylase in Common Wheat (Triticum aestivum L.)

The plant hormone abscisic acid (ABA) regulates many important physiological and developmental processes in plants.The objective of this study was to clone the ABA 8'-hydroxylase gene in common wheat. In the present study, we used the cDNA sequence of barley HvCYP707A1 gene (GenBank accession no. AB239299) as a probe for BLAST search against the common wheat (Triticum aestivum L.) EST database in GenBank. All wheat ESTs sharing high similarity with the reference gene were subjected to contig assembly. Primers were designed based on the constructed contigs to clone the wheat CYP707A1 gene, designated as TaCYP707AI. The genomic DNA sequence of TaCYP707A1 gene comprised five exons and four introns, with a size of 2 225 bp. The corresponding cDNA sequence of TaCYP707A1 was 1 737 bp,containing an open reading frame (ORF) of 1 431 bp, a 42-bp 5'-untranslated region (UTR) and a 264-bp 3'UTR, with 94.9% of identical sequences to HvCYP707A1 gene (AB239299). The neighbor joining tree indicated that the deduced amino acid sequences of TaCYP707A1 gene was highly similar to those of barley and rice. The TaCYP707A1 gene was located on chromosome 6BL using a set of Chinese Spring nullisomic-tetrasomic lines and ditelosomic line 6BS. These results will be of high importance in understanding of molecular mechanism of ABA catabolism.