A Dominant Gene for Male Sterility in Wheat

A dominant gene inducing male sterility in wheat is described. It is located on the short arm of chromosme 4D with a recombination percentage of 31.16 with the centromere. The potential use of this allele in breeding and cytogenetic studies in both tetraploid and hexaploid with is discussed.     

Utilization of Intervarietal Chromosome Substitutions in Breeding Winter Wheat

Using monosomic lines of wheat cultivars ‘Palur’ and ‘Compal’ as recipient parents as well as disomic substitution lines of chromosomes 5A and 5D of the wheat cv. ‘Atlas 66’, F₃-populations and BC₁′- to BC₃′-populations with limited and free recombination of the 20 and 21 parental chromosomes, respectively, were realized and tested in field trials in comparison to the corresponding recipient cvs. ‘Palur’ and ‘Compal’. F₃- and BC'-populations with the homozygous chromosomes 5A and 5D of the wheat cv. ‘Atlas 66’ expressed higher and more stable grain protein values than the comparable populations with free recombination of the same chromosomes. The grain protein content of populations with limited recombination was significantly increased compared with the recipient cultivars. Some advantages of using intervarietal substitutions in wheat breeding are discussed.     

小麦TaLon1基因克隆与分析

在酵母和人类中,依赖于ATP的Lon蛋白酶起着降解线粒体内非正常蛋白质和维持线粒体DNA的稳定等重要作用。本研究应用RT-PCR和RACE技术,克隆了小麦Lon蛋白酶家族的一个基因,命名为TaLon1。TaLon1和籼稻Lon1、玉米Lon1的相似性分别为94%和92%。表达分析表明,TaLon1在小麦根、叶和花药中均表现组成型表达,表明该基因在小麦的生长发育过程中很重要,起着类似管家基因的作用。在菜豆上已经间接证明Lon蛋白酶与细胞质雄性不育有一定的相关性。但在本研究中, TaLon1的表达在小麦K型细胞质雄性不育系和其他正常的品系之间没有差别。与大肠杆菌和酵母中的lon基因不同,TaLon1不能被90 min的42℃热激所诱导。另外250 mmol/L NaCl处理后,该基因的表达量下降。     

Chromosome Irregularities in Wheat and Triticale Plants Regenerated from Leaf Base Callus

Basal leaf sections of Triticum aestivum L., cv. ‘Chinese Spring’, and XTriticosecale Wittmack cv.‘Welsh’were cultured on Kao's medium with 2 mg/l of 2,4-D. Callus was induced on the leaf sections at frequencies of 64 and 63 %, respectively, and plant-lets regenerated at 18 and 31 %, respectively. Compared to the controls, the regenerated plants showed higher frequencies of univalent chromosomes at meiosis and low frequencies of trivalents, and quadrivalents; indicating that the callus phase had induced low frequencies of chromosome irregularity.     

小麦TaPHYA基因亚家族的克隆及表达分析

光敏色素是一类与作物农艺性状密切相关的基因家族。本研究克隆了中国春小麦光敏色素TaPHYA1、TaPHYA2和TaPHYA3基因完整的编码序列,并对它们进行了生物信息学以及转录分析。在NCBI数据库中对其推测的氨基酸序列进行BLAST分析,发现TaPHYA1和TaPHYA3氨基酸序列中包含光敏色素基因完整的功能结构域。系统进化树分析表明,小麦TaPHYA1、TaPHYA2和TaPHYA3之间进化关系相近,且与单子叶植物玉米、水稻的PHYA聚为一个亚类。另外,TaPHYA的表达丰度具有组织特异性,在茎、叶、穗中表达量分别是根中的1.35、0.34和0.87倍;而在同光质条件下,其表达丰度也具有光质特异性,TaPHYA的总表达量在黑暗和远红光条件下最高,在蓝光条件下次之,而红光和白光条件下最低。该结果为深入研究小麦光敏色素A基因亚家族的功能奠定了基础。     

Development of dominant nuclear male-sterile lines with a blue seed marker in durum and common wheat

In order to develop genie male‐sterile lines with a blue seed marker, male‐sterile plants, controlled by a dominant nuclear gene Ms2, were used as female parents against a 4E disomic addition line ‘Xiaoyan Lanli’(2n= 44, AABBDD+4EII) as the male parent to produce monosomic addition lines with blue seed. Male‐sterile plants from the monosomic addition lines were pollinated with durum wheat for several generations and in 1989 a male‐sterile line with the blue grain gene and the male‐sterile gene Ms2 on the same additional chromosome was detected and named line 89‐2343. Using this line, the blue seed marker was successfully added to a short male‐sterile line containing Ms2 and Rht10. The segregation ratios of male sterility and seed colour as well as the chromosome figurations of different plants indicated that the blue grain genes, Ms2 and Rht10 were located on the same additional chromosome. Cytological analysis showed that the blue marker male‐sterile lines in durum wheat and common wheat were monosomic with an additional chromosome 4E. The inheritance ratio for blue seed male‐sterile plants and white seed male‐fertile plants was 19.7% and 80.3%, respectively, in common wheat. The potential for using blue marker sterile lines in population improvement and hybrid production is discussed.     

Nitrogen Accumulation and Translocation for Winter Wheat under Different Irrigation Regimes

The translocation of pre‐anthesis nitrogen to the grain is an important source for winter wheat. The relation between the nitrogen translocation and irrigation regime was studied in the field under a rain‐proof trough shelter. Nitrogen (N) translocation amount, N translocation efficiency decreased with a decline in irrigation amount or by excessive irrigation. Compared with different organs, the leaf and stem had higher N translocation amounts, and contributions to grain for both cultivars – Jinan 17 and Lumai 21, indicating that stem also is a major N source for grain development. The contribution of pre‐anthesis total above ground N to grain N ranged from 57 to 76 %, indicating the importance of pre‐anthesis storage of N for achieving high grain N concentrations. Grain nitrogen and yield (kg ha^?1) were positively and significantly correlated with the N translocation amounts and contributions, respectively, suggesting that the sink strength may be involved in the translocation of N from a vegetative organ to the grain. N harvest index (NHI) was significantly correlated with N translocation efficiency, suggesting that the latter is a prerequisite for increasing grain N and improving grain quality. The experiment showed that N translocation status is enhanced by better irrigation practices, but limited by severely deficient or excessive irrigation.     

Phosphorus Accumulation and Translocation in Wheat as Affected by Cultivar and Nitrogen Fertilization

To improve nutrient management strategies in wheat more information is needed about the interaction effects among nutrients in their uptake and redistribution in the plants, in relation to different genotypes. Therefore, two bread ( T. aestivum L.) and two durum ( T. durum Desf.) winter wheat cultivars were grown in the field for 2 years (1986, 1987) in a silty-clay soil under different nitrogen (N) levels, in Northern Greece. Nitrogen at a rate of 150 kg ha⁻¹ was applied before planting or 100 kg ha⁻¹ before planting and then 50 kg ha⁻¹ at early boot stage. Cultivar differences in phosphorus (p) concentration were observed only in vegetative parts but not in the grain. Maximum p accumulation was observed either at anthesis or at maturity. During grain filling dry matter and p accumulation in the grain followed almost the same pattern. Phosphorus translocation efficiency of the cultivars at the 2 years ranged from 70.7 to 84.3 % and the amount of p in the grain derived from translocation 52 to 100 %. Phosphorus translocation efficiency was weakly correlated with p content in grain only in 1986, while phosphorus harvest index (PHI) was positively correlated with harvest indst (HI) both years (r = 0.82** in 1986 and 0.75** in 1987). Nitrogen application mainly affected p accumulation of the cultivars via its effect on biomass production. The split N application promoted slightly the p uptake in 1987 and this resulted in the reduction of both the contribution of the translocated p to the grain and the efficiency of p utilization for total biomass. Results indicated that p accumulation and translocation and the efficiency of p utilization in wheat were mainly determined by the genotype in relation to environmental condition of growth.     

Improved Techniques for Haploid Production in Wheat using Chromosome Elimination

Wheat × maize and wheat × pearl millet crosses have proved efficient for haploid production using various genotypes of wheat; 22 and 27 % of florets produced embryos. In favourable conditions 6—9 haploid plants per spike were produced. The following simplifications or improvements in technique are recommended: 1. Only a single treatment with an aqueous solution of dicamba or 2,4-D (50–100 ppm) for embryo stimulation in vivo; 2. Application by spraying or dipping the spikes; 3. Application time two to four days after pollination; 4. Embryo rescue 15 to 18 days after pollination; 5. Crosses without emasculation are possible if pollination occurs 1–2 days before anthesis. More than 450 haploids and some doubled haploid (DH) lines (after colchicine treatment in vitro) were produced using these methods. No hybrid plants, chromosome additions or substitutions were found.     

Isolation, identification and characterization of disomic and translocated barley chromosome addition lines of common wheat

Two disomic barley chromosome addition lines and five translocated chromosome addition lines of common wheat cultivar Shinchunaga were isolated. They were derived from a hybrid plant between Shinchunaga and cultivated barley Nyugoruden (New Golden) by backcrossing with wheat and self pollination. Barley chromosomes added to chromosome arms involved in the translocated chromosomes were identified by C-banding method and by crossing these lines with Chinese Spring/Betzes addition lines. Two disomic addition lines were identified to have chromosome 6 and 7 of barley, respectively. Two of the five translocated chromosome addition lines were clarified to have same chromosome constitution, 42 wheat chromosomes and a pair of translocated chromosomes constituted with a long arm of chromosome 5B of wheat and a short arm of chromosome 7 of barley. The other three lines could not be identified due to chromosome rearrangement. Performances of these seven lines on agronomic characters were examined. Addition of barley chromosome 7 induced early heading, and chromosome 6 showed lated heading. Almost all of the lines except that of chromosome 6 showed short culm length and all showed reduced number of tillers, spikelets and grains per ear, and low seed fertility. These lines would be useful for genetic analyses in wheat and barley and for induction of useful genes of barley into wheat. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic Analysis of Chromosome 2D of Wheat

The Yugoslavian varieties ‘Novosadska Rana 1’ and ‘Sava’ are shown by monosomic comparisons to carry weak height promoters on chromosome 2D characteristic of the ‘Akakomugi’ gene for reduced height, Rht8. Reciprocal monosomic crosses between ‘Bersee’ and ‘Sava’ demonstrate ‘Sava’ chromosome 2D reduces height by about 16 cms, accelerates ear emergence by about 9 days and increases yield through increased grain number and grain size. Recombinant lines developed for chromosome 2D suggest that this chromosome in Mediterranean wheats carries three genes, Rht8, Ppd1 and Yr16, important to their adaptation. Rht8 and Ppd1, a gene for day length insensitivity together reduce height. Ppd1 and, to a minor degree, either yr16, the susceptible allele of a gene for adult plant resistance to yellow rust or a closely linked gene, accelerate time to flowering and thereby avoid desiccating Yugoslavian summer conditions. The same genes reduce spikelets numbers but this is offset by increased floret fertility producing an overall increase in the number of grains per ear. Ppd1 also by avoiding desiccating conditions increases gram size and together with either yr16 or the closely linked fertility gene increases ear and plant yields.     

Confirmation of a 1A/1R Wheat-Rye Chromosome Translocation in the Wheat Variety 'Amigo'

Differential chromosome staining by using the Giemsa C- banding technique and test crosses have revealed rye chroma tin in the hexaploid wheat variety ‘Amigo’ which resulted from wheat crosses with the octoploid triticale ‘Gaucho’. The results demonstrated a pair of translocated wheat chromosomes involving the short arm of rye chromosome 1R and the long arm of the homoeologous wheat chromosome 1A (1Aq/1Rp translocation). The localization of the translocation breakpoint is supposed 10 be within the centromeric region.     

The Effect of Chromosome 1B/1R Translocation on the Yield Potential of Certain Spring Wheats (Triticum aestivum L.)

Nearly 50 percent of the 1988 advanced breeding lines of the CIMMYT bread wheat breeding program possess the 1B/1R homozygous translocation. Hence, a trial was conducted to estimate the effect of 1B/1R chromosome translocation on the yield potential of some of our high-yielding spring wheats, where non-limiting levels of fertility, moisture, preventive pest and disease programs were used. In conclusing the 1B/1R lines seemed to have increased their above-ground biomass yield, number of spikes per meter², 1000-grain weight and test weight. They also exhibited a slight advantage over the 1B homozygous lines on grain yield. The observed difference, however, was non-significant, as was the plant height difference observed among the two groups. Varietal comparisons indicated that the 1B/1R group headed later than the 1B group.     

Effects of Wheat Chromosome 1D Telosomes on Hybrid Seed Development in Wheat × Rye Crosses

Pollination of ‘Chinese Spring,’ monosome 1D plants with rye results in failure of hybrid seed development in a proportion of the F₁ seeds corresponding to the transmission rate of the nullisomic 1D egg cells. Development and viability of these hybrid seeds closely resemble that normally observed in T. aurum× rye crosses. Using ‘Chinese Spring’ chromosome ID telosomic plants in crosses with rye, it was possible to illustrate that the observed effect was associated with the long arm of this chromosome.     

A Monosomic Analysis of Russian Wheat Aphid Resistance in the Common Wheat PI 294994

Chromosome 7D of PI 294994 was indicated as carrying a single dominant gene for resistance to the Russian wheat aphid. The symbol Dn5 is proposed to designate the gene.     

SSR and SCAR markers linked to the fertility-restoring gene for a D2-type cytoplasmic male-sterile line in wheat

‘Yi 4060’ is an elite restorer line of a non‐photoperiod‐sensitive D²‐type cytoplasmic male‐sterile (CMS) line of wheat. Random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were employed to map one major fertility‐restoring gene (D²Rf₁) in ‘Yi 4060′. The sterile and fertile DNA pools were established from individuals in BC₆, based on bulked segregant analysis. One RAPD marker E09, linked to D²Rf₁, was converted to a SCAR marker and designated as E09‐SCAR₈₆₅. The genetic distance between E09‐SCAR₈₆₅ and D²Rf₁ is 9.5 cM. Two SSR markers, Xgwm11 and Xgwm18, were also linked to a D²Rf₁ and co‐segregated with E09‐SCAR₈₆₅. The three molecular markers are useful in marker‐assisted breeding of the elite restorer lines for D² ‐type CMS lines in wheat.     

Characterization of Triticum aestivum/Psathyrostachys juncea derivatives by genomic in situ hybridization

Using the genomic in situ hybridization (GISH) technique, one translocation line, seven translocation-addition lines, five translocation plus translocation addition lines and two ditelosomic addition lines were identified in backcross progenies of Triticum aestivum L. -Psathyrostachys juncea (Fisch.) Nevski intergeneric hybrids. No complete P. juncea chromosomes were detected in the 25 lines studied. The results suggest that intact P. juncea chromosomes may be difficult to isolate in a wheat background. This revised version was published online in July 2006 with corrections to the Cover Date.     

小麦品质性状分子标记多重PCR体系的建立

小麦高分子量谷蛋白亚基组成、1B/1R易位、籽粒硬度、直链淀粉含量和穗发芽抗性等性状与加工品质密切相关，建立相关性状的多重PCR体系在小麦品质分子育种中具有重要意义。本研究利用现有品质性状基因的分子标记，建立了适合不同品质类型品种评价和分子聚合育种的3个多重PCR体系，并用已知基因的品种（系）进行验证。多重PCR体系Ⅰ包括ω-secalin（1B/1R）、Vp1B3和Pinb-D1b基因的分子标记检测，可用于一般的品质检测；体系Ⅱ包括ω-secalin、Ax2*、Bx17和Dx5 基因的检测，可望用于强筋小麦品种的选育；体系Ⅲ包括Wx-A1、Wx-B1和Wx-D1位点的检测，可用于淀粉品质或糯小麦的选育。每个体系内的引物之间不存在相互抑制作用和错配，检测品种（系）的结果可靠、重复性好，成本低。3个多重PCR体系用于小麦品质育种的亲本评价和杂交后代优质基因的聚合，将会提高优质专用小麦品种评价和选育的效率。     

普通小麦辉县红-荆州黑麦异染色体系的选育及其梭条花叶病抗性鉴定

为发掘和利用荆州黑麦所携抗梭条花叶病基因，综合利用分子细胞遗传学与分子标记技术结合多年抗性鉴定，从高感梭条花叶病小麦地方品种辉县红与荆州黑麦杂交后代（F₇~F₉）中选育出二体异附加系5个(分别添加1R、2R、R3、5R和R7)、5RS端二体异附加系1个和多重异附加代换系2个（染色体组成分别为20’’+2R(2D)’’+4R’’和19’’+1R（1B）’’+2R（2B）’’+4R’’）。鉴定表明，双二倍体荆辉1号高抗梭条花叶病，表明黑麦抗性基因可在小麦背景中稳定表达，2R、R7二体异附加系及2个含2R的多重异附加代换系均表现高抗，推测2R和R7上可能携带抗病基因。这些材料是研究荆州黑麦抗性基因遗传及小麦抗病育种的新种质。     

小麦粒重基因定位研究

本文以低粒重的多小穗品种"10阿"为被测材料,"中国春" 和"阿勃"两套单体系列为测验系,对粒重性状进行了基因定位研究.结果表明,被测材料"10阿"粒重低受5A、1B、2B、2D和7D等染色体上的隐性基因所控制。从其减小效应的程度来看,1B和2B染色体上的基因表现为强效。5A、6B、2D和7D染色体上的基因表现为弱效。