利用Ln位点进行分子设计提高大豆单荚粒数

分子设计育种是将分子遗传学与传统育种相结合,并培育成具有优良性状的新品种的重要方法之一,尽管该方法很大程度上能够缩短育种进程,但在实际育种过程中却应用较少。在大豆的育种过程中,提高产量是主要的育种目标之一,其中,每荚粒数是决定大豆单株产量的关键性状之一。在大豆中,每荚粒数与叶片形状呈正相关,由一对等位基因Ln/ln控制,宽叶的大豆品种一般为Ln,窄叶的大豆品种一般为突变型ln,且ln伴随着更多的四粒荚。尽管Ln对于大豆单产的提高,具有潜在的重要作用,但将该位点应用于分子设计育种中,报道较少。本研究通过分析483份来自不同纬度大豆品种的Ln基因型发现,高纬度地区大豆品种一般为ln,而低纬度地区大豆品种一般为Ln。通过调查来自不同纬度的8个大豆品种的叶型和一粒荚至四粒荚个数发现,低纬度大豆品种均为圆叶品种,且几乎没有四粒荚。为将ln应用于低纬度地区大豆育种中,成功开发了Ln的分子标记,并通过连续回交的方法,将ln代换到圆叶型品种Willams 82和华夏3号中,获得了四粒荚较多的大豆新材料。本研究利用大豆分子设计育种的手段,提高了大豆单株产量,为加快大豆高产育种进程提供了重要的理论及实践基...     

Mapping and use of QTLs controlling pod dehiscence in soybean

While the cultivated soybean, Glycine max (L.) Merr., is more recalcitrant to pod dehiscence (shattering-resistant) than wild soybean, Glycine soja Sieb. & Zucc., there is also significant genetic variation in shattering resistance among cultivated soybean cultivars. To reveal the genetic basis and develop DNA markers for pod dehiscence, several research groups have conducted quantitative trait locus (QTL) analysis using segregated populations derived from crosses between G. max accessions or between a G. max and G. soja accession. In the populations of G. max, a major QTL was repeatedly identified near SSR marker Sat_366 on linkage group J (chromosome 16). Minor QTLs were also detected in several studies, although less commonality was found for the magnitudes of effect and location. In G. max × G. soja populations, only QTLs with a relatively small effect were detected. The major QTL found in G. max was further fine-mapped, leading to the development of specific markers for the shattering resistance allele at this locus. The markers were used in a breeding program, resulting in the production of near-isogenic lines with shattering resistance and genetic backgrounds of Japanese elite cultivars. The markers and lines developed will hopefully contribute to the rapid production of a variety of shattering-resistant soybean cultivars.     

Breaking Strength of Pedicel and Grain Shattering Habit in Two Species of Buckwheat (Fagopyrum spp.)

Abstract

The grain shattering habit was examined in nine common buckwheat cultivars/strains (Fagopyrum esculentum Moench.) and four tartary buckwheat strains (F. tataricum Gaertner). As indices of grain shattering habit, the breaking bending strength and breaking tensile strength of the pedicel and the pedicel diameter were measured. Thin longitudinal pedicel sections were also observed. The breaking strength showed significant differences among cultivars, but the stage of seed maturity influenced the grain shattering habit. The two breaking strengths were larger in common buckwheat than in tartary buckwheat, and these differences may be explained by the pedicel diameter. The abscission layer was not observed in the pedicel tissue of the buckwheat cultivars.     

Characteristics of Flowering and Pod Set in Wild and Cultivated Types of Soybean

Abstract

Characteristics of flowering and pod set were compared between wild and cultivated types of soybean grown in pots (1/5000 a) in a vinyl house. The wild type had 10-fold more nodes than the cultivated type. The flowering habit of the wild type was similar to that of the indeterminate type. The wild type developed 10-fold more flowers than the cultivated type, but set relatively few pods. During the process of domestication from wild to cultivated type, i) the pole climbing characteristic disappeared and development of branches and racemes with compound leaves was repressed, resulting in a decreased number of nodes, ii) flower production decreased and the rate of pod set increased markedly, and iii) the number of pods decreased, but seed size became bigger.     

大豆结荚期密植田光温效应的初步研究

以揭示巴彦大豆密植增产的机理为目的 ,依据结荚期大豆田光温湿等小气候要素的田间实测观测资料 ,对比分析了密植田与对照田大豆冠层下光强、活动面温度与湿度的分布特征与变化特点 ,并从农业气象角度对其变化特点与规律产生的原因予以解释。结果表明 :结荚期出植大豆田冠层下光强普遍低于对照田 ;活动面温度昼间高于对照田 ,夜间低于对照田 ;株间相对湿度低于对照田。     

紫檀属树种实生苗培育技术的研究

对早期引种并已正常开花结实的印度紫檀、檀香紫檀、马拉巴紫檀和古巴紫檀的实生苗培育技术进行了研究 ,结果表明 :去翅荚果袋装贮于室内可达 1年以上而不影响发芽率 ;用 6 0℃或 80℃温水浸泡荚果2 4h可明显提高马拉巴紫檀、古巴紫檀荚果的发芽率 ,分别由 1 1 .0 %和 6 .0 %提高到 31 .7%和 4 8.0 % ;但这种方法不利于印度紫檀、檀香紫檀荚果的萌发 ,其发芽率反而下降 ;30～ 35℃气温有利于荚果发芽和苗木生长 ;高 30cm以上的健壮苗木可以短时间忍耐 0℃低温 ,4个树种苗期耐低温能力依次为檀香紫檀 >印度紫檀 >马拉巴紫檀 >古巴紫檀。研究结果为紫檀属树种在我国的扩大栽培提供了技术储备     

Inheritance of pigmentation and pod shape in winged bean

Summary The inheritance of five qualitative character differences in winged bean was studied in two crosses. All five character pairs were based on a single gene difference with complete dominance of purple over green stem colour, purple over green calyx colour, purple over green pod wing colour, purple specks over green pod and rectangular over flat pod shape. Linkage was observed between stem and calyx colour and also pod wing colour and pod specks.     

Inheritance of pod cross-section in beans (Phaseolus vulgaris L.)

Summary OSU 5062, a green bean line with a tendency for pods to become creasebacked (wider than deep) in cross-section, was crossed to near-round-podded cultivars Oregon 83 and Slenderette, oval-podded Bountiful, and flat-podded Roma, to further clarify the inheritance of pod cross-section. Differences among generations in pod cross-section index (PCS), calculated as pod width/depth, were small in the near-round x creaseback crosses (1.07 and 1.01 for Oregon 83 and Slenderette versus 1.20 for OSU 5062). Bountiful (0.63) and Roma (0.50) differed to a greater extent from 5062. Generation means of individual plant PCS of the F₁ and F₂ were almost identical, were almost exactly intermediate between parents, and strongly supported additive inheritance. Backcross data generally supported additive inheritance, but in some cases indicated degrees of dominance of higher PCS. A generation means analysis indicated additive gene action, but deviations from an additive-dominance model were significant in each cross.     

Water Stress-induced Injury to Reproductive Phase in Chickpea: Evaluation of Stress Sensitivity in Wild and Cultivated Species in Relation to Abscisic Acid and Polyamines

Chickpea (Cicer arietinum L.) is more sensitive to water stress during its reproductive growth and consequently experiences substantial yield loss. Wild species being relatively tolerant to abiotic stresses offer a potential gene source for incorporation of drought tolerance in cultivated species. In the present study, the differential stress sensitivity of wild (Cicer reticulatum Ladiz.) and cultivated species (C. arietinum) was evaluated by subjecting the plants of both the species to water stress for 14 days during the reproductive phase and examined for stress injury, endogenous status of polyamines (PA) and abscisic acid (ABA). Comparatively, the cultivated species experienced higher stress injury (assessed as electrolyte leakage, 2,3,5‐triphenyl tetrazolium chloride reduction ability, chlorophyll loss) as well as decreased leaf water potential (Ψ_w; ?2.48 MPa) than the wild species (?1.98 MPa). The stressed plants of cultivated species lost more number of flowers (62 %) and pods (65 %) when compared with the unstressed ones while those of wild species showed 30 % and 44 % loss, respectively. The number of infertile pods was significantly more in stressed plants of cultivated species than in those of wild species. The endogenous status of PA revealed that putrescine (PUT), spermidine (SPD) and spermine (SPM) levels accumulated to a higher extent in the cultivated species relative to the wild species until the eighth day of stress, and thereafter, the wild species had significantly higher levels of PA. In contrast, ABA levels increased to a higher extent in the wild species until the eighth day of stress and declined subsequently to a greater degree than the cultivated species. The injury to reproductive growth appeared to accentuate with reduction in leaf Ψ_w that was coupled with depletion of PA in both the species, especially in the cultivated one. Exogenous application of 10 mm PUT partially alleviated the damage to reproductive growth by increasing the leaf water status and chlorophyll content while decreasing the ABA content, which resulted in improvement of retention of flowers and pods, particularly in the cultivated species.     

Evaluation and utilisation of cacao (Theobroma cacao L.) germplasm at the International Cocoa Genebank, Trinidad

The aim of this study was to identify promising genotypes in the International Cocoa Gene bank, Trinidad (ICG,T) for use in cacao breeding. Subsets of the germ plasm collection were evaluated for bean number, bean weight, pod index (581 genotypes) and resistance to Phytophthora pod rot(500 genotypes). Among three groups of cacao assessed (For astero, Refractario and Trinitario), Trinitario had the highest percentage of genotypes (36.9%) with large bean weight (> 1.2 g), while For astero possessed the highest proportion of genotypes (22.6%) with a large number of beans (> 45). The ICS population had the highest percentage (44.1%) of genotypes with heavy beans, and IMC the highest percentage of genotypes with large bean number (68.6%). A low, but significant negative correlation (r = –0.19, p≤ 0.001) between bean number and bean weight suggests that an increase in bean number may repress an increase in bean weight and vice versa. However, inten genotypes good values of bean weight and number were combined demonstrating that selection for both large bean number and bean weight is possible. The highest percentage (28.1%) of genotypes with low pod index (< 20.1) was observed in the Trinitario group (mainly ICS). The Forastero group had the highest percentage of Phytophthora resistant accessions(18.0%). The PA population had the highest proportion of resistant (24.0%) and moderately resistant (38.0%)genotypes. Sixty-five and 99 genotypes were categorised with large bean weight and high bean number, respectively, and 60 genotypes were found with a low pod index. Seventy-eight genotypes were identified with resistance to Phytophthora podrot. A significant relationship was observed between resistance to Phytophthora pod rot (measured as the frequency of localised lesions) and bean number (r = –0.45, p ≤ 0.001)showing that the two traits may complement each other. The combination of low to intermediate pod index with moderate to high resistance to Phytophthora podrot was found in 87 genotypes, 12 of which were also reported to have resistance to witches’ broom disease. These genotypes are of high potential value in cacao breeding and their inclusion in working and corecollections would be justified. This revised version was published online in July 2006 with corrections to the Cover Date.