Evaluation of amplified fragment length polymorphism markers in tef, Eragrostis tef (Zucc.) Trotter, and related species

Tef is an important cereal crop in Ethiopia. This study was conducted to investigate (1) genetic diversity within and among three Eragrostis species (E. tef, E. pilosa and E. curvula), and (2) the relationship between E. tef, E. pilosa and E. curvula. A total of 529 AFLP markers were obtained, out of which 58% (368) were polymorphic, using 10 primer, combinations. The three species were separated distinctly using amplified fragment length polymorphism (AFLP), However, diversity revealed at the morphological trait level was not commensurate with that observed for AFLP. This was due to the small number of morphological traits available and their interaction with the environment. Within tef, ‘Rubicunda’ and DZ‐01‐1093 were found to be distantly related to the rest of the tef accessions. The diversity within species was such that E. pilosa was the most diverse followed by E. curvula and E. tef. Moreover, E. pilosa was more closely related to E. tef than E. curvula. Therefore, further study is needed of E. pilosa accessions and of ‘Rubicunda’ and DZ‐01‐1093 in a crossing programme to generate a population for selection and/or genetic mapping. A total of 19 cultivars or accessions had one or more unique fragments using one or more AFLP primers, indicating the potential of the technology in fingerprinting tef in a breeding or seed multiplication programme.     

Heritability and genetic advance in recombinant inbred lines of tef (Eragrostis tef)

Recombinant inbred lines (RILs) of the tef cross Kaye Murri × Fesho were evaluated for nine quantitative traits at three locations in the central highlands of Ethiopia during the 1998/99 main season in order to estimate the genetic coefficient of variation (GCV), heritability and genetic advance expected from selection. Highly significant differences were obtained among the RILs for all traits studied. Grain yield, panicle weight and yield per panicle showed a relatively high GCV (12–16%). A comparatively high heritability was obtained from days to heading (31%) followed by panicle length (25%) and grain yield (23%). Moderate amounts of heritability values were obtained for panicle weight and yield per panicle. High genetic advance as percent of the mean were obtained from grain yield (16%), yield per panicle (12%) and panicle weight (10%) at5% selection intensity, which indicated the possibility of improving these traits. Several RILs were identified that have exceeded the better yielding parent at all locations. Grain yield showed a strong positive association (r = 0.26–0.70) with shoot biomass, lodging index, panicle length, plant height, panicle weight and yield per panicle. Overall, the present results showed a) the availability of genetic variance for some useful traits in the RILs for exploitation through selection, b) the existence of significant genotype × location interaction that indicated the need to test inbred populations in more environments, and c)the availability of superior inbred lines for further breeding work. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetics of grain yield and other agronomic characters in t'ef (Eragrostis tef Zucc. Trotter). I. Generation means and variances analysis

Quantitative genetics of grain yield and other agronomic characters of t'ef (Eragrostis tef) were studied using the F₁, F₂, BC₁, and BC₂ of the cross Fesho × Kay Murri. The study was carried out to estimate gene effects controlling the inheritance of grain yield and related agronomic characters. Significant additive [d] and dominance × dominance [l] interaction effects were detected for grain yield. The variations of yield per panicle and panicle weight were explained in terms of [d], dominance [h], and additive × additive [i] interactions. Non-allelic gene interactions were also detected for kernel weight, harvest index, tiller number, plant height, days to heading and days to maturity. The simple additive-dominance model explained the variation for panicle length, culm diameter and plant weight, allowing unbiased estimates of additive (D) and dominance (H) variance components. Large dominance variances (H) were estimated for grain yield, yield per panicle, and panicle weight. The additive variances for plant height, panicle length, days to heading and days to maturity were higher than the respective dominance variances. High narrow-sense heritability (h²) values (> 0.50) were estimated for plant height, panicle length, days to heading and days to maturity. The lowest h² (0.09) was obtained for kernel weight for which there was little variability. Since grain yield and several important agronomic characters of t'ef are influenced by non-allelic gene interaction, it is advisable to delay selection for yield to later generations with increased homozygosity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetics of grain yield and other agronomic characters in t'ef (Eragrostis tef Zucc Trotter). II. The triple test cross

The normal and selfed families of the triple test cross were employed to detect gene action in t'ef for grain yield and other useful agronomic characters in the breeding programme. Cultivars Kay Murri and Fesho were used as L₁ and L₂ testers, respectively. Eight randomly selected cultivars and two released varieties (DZ-01-354 and DZ-01-196) were crossed with the testers L₁, L₂ and L₃ (the F₁ of L₁ × L₂). In the case of the selfed families, 14 cultivars and two released varieties were used for crossing with the testers. The normal families were grown on an Inceptisol developed from volcanic ash whilst the selfed families were grown on a pellic Vertisol at the Debre Zeit Agricultural Research Centre, Ethiopia. The rainfall during the experimental season was 463 mm. Epistasis was detected for grain yield, yield per panicle, panicle weight, plant weight, harvest index, tiller number, panicle length, culm diameter, days to heading and days to maturity in the normal families of the triple test cross (TTC) of t'ef. Similarly the characters grain yield, yield per panicle, panicle weight, plant height, panicle length, days to heading and days to maturity showed epistasis in the selfed families of the TTC. Epistatic interaction was not important for shoot biomass and for harvest index (for the transformed data) in this family. Therefore, both the normal and selfed families of the TTC were in agreement with regard to detecting epistasis for grain yield, yield per panicle, panicle weight, panicle length, days to heading and days to maturity. Significant additive (D) and dominance (H) components were estimated for the characters in both families, although the magnitudes might have been inflated due to epistasis. The dominance component for panicle length was unimportant in both families of the TTC and as a result the additive components were not biased. In general, the additive, dominance and epistatic components were important in t'ef. Since the crop is self-fertilized only the additive and additive × additive terms are important to develop pure breeding varieties. Therefore, selection for superior segregants should start in advanced generations as homozygosity increases. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diversity for osmotic adjustment and root depth in TEF [Eragrostis tef (Zucc) Trotter]

Osmotic adjustment (OA) and deep roots were shown to be important drought resistance mechanism in many crop plants. In this study, geno types systematically selected from an Ethiopian endemic tef [Eragrostis tef (Zucc) Trotter] germplasm pool were evaluated for osmotic adjustment and root depth in greenhouse in several experiments. The association of these traits with other plant characters was also studied. Osmotic adjustment was investigated in two experiments. Experiment 1 was conducted using nine genotypes for two seasons (spring and fall 1996), and experiment 2 was undertaken in the spring of 1997 with 45 genotypes. In experiment 1, there were significant genotype effects on OA. Though there was also significant genotype by season interaction for OA, some of the extreme lines gave consistently high (Ada and DZ-01-99) and low (DZ-01-354 and Trotteriana) OA values across seasons. There was a significant variation among genotypes for OA in experiment 2. Osmotic adjustment was not associated with the altitude of the region of origin of the particular tef genotype. In both experiments, OA was significantly correlated across tef genotypes with delayed wilting and the maintenance of higher relative water content (RWC) under conditions of soil moisture stress. Three experiments were conducted to evaluate the phenotypic diversity for root depth. In all experiments tef genotypes differed significantly for root depth as measured at flowering time. The late maturing genotypes tended to have greater root depth as compared to early maturing genotypes. Root depth was not associated with the altitude of the region of origin of the tested genotypes. There was no association between root depth and OA across genotypes. This revised version was published online in August 2006 with corrections to the Cover Date.     

25份贵州镇宁野生茶树种质资源的表型及生化组分多样性分析

为了挖掘特异茶树种质资源,以贵州镇宁新发现的25株野生茶树资源为材料,对26个表型性状和12个主要生化组分运用统计分析、遗传多样性分析和聚类分析等方法进行研究,进而对这25份资源进行综合评价。 结果表明这25份种质的表型性状和生化组分变异类型丰富,其中26个表型性状的平均变异系数29.26%,平均多样性指数0.87;12个生化组分性状的平均变异系数25.21%,平均多样性指数2.78;25份种质资源的酚氨比在6.12~20.09之间。聚类分析将其分为三个类群,其中类群一全部为小乔木,类群二、三全为灌木;类群三中资源的生化组分含量最为丰富。从中初步筛选出了3份生化组分丰富的潜在优异种质资源,为后续资源保护、开发和育种应用提供依据。     

Phosphorus Response Studies on Some Varieties of Durum Wheat (Triticum durum Desf.) and Tef (Eragrostis tef (Zucc.) Trotter) Grown in Sand Culture

The response of four varieties each of durum wheat (DZ-04-118, DZ-320, DZ-918 and TOB-2) and tef (DZ-01-354, DZ-01-787, DZ-01-1445, and DZ-Cr-37) to P application levels was examined in a sand culture study conducted in a glasshouse for 4 weeks. Results showed that plant height, shoot and root dry weights, and plant P uptake were increased by increasing levels of P application from 0 to 5 (tef) and 0 to 10 mg P 100 g⁻¹ (wheat). Varietal differences were also observed in all parameters, except in shoot dry weight of the four durum wheat varieties. In general, all modern varieties of the two crops showed better growth and P uptake than the corresponding traditional varieties. The short period study proved that variations generally existed in the P responses of durum wheat and tef varieties which may be confirmed by long-term study up to maturity. Inclusion of more populations in similar studies may help to identify P efficient genotypes.     

木薯种质资源遗传多态性SSR分子标记的研究

为了研究广西壮族自治区亚热带作物研究所从泰国、菲律宾、缅甸、印度尼西亚等国引进的25份木薯种质资源及海南省和广西壮族自治区亚热带作物研究所等选育的65份木薯品种(系)的遗传多样性,应用12对SSR引物对80个木薯种质进行PCR扩增,获得119个扩增带形,扩增产物的片段大小范围在100~300 bp之间,每对引物检测等位基因4~16个,平均为10个。根据品系间的遗传相似系数,利用UPGMA法进行聚类分析,以遗传相似系数0.46为阈值,将80个木薯品系分为两类。聚类分析结果表明,引进的国外资源和所选育的种质资源丰富了中国木薯种质库,拓宽了中国木薯遗传育种的物质基础,为进一步进行木薯新品种的选育和种质资源的收集及管理提供了遗传依据。     

不同来源棉花种质资源遗传多样性的ISSR分析

 采取ISSR分子标记对48份棉花种质资源的遗传多样性进行分析,从60条ISSR引物中筛选出11条引物,这11条引物共扩增出92个条带,平均每条引物扩增出8.36个条带;其中多态性带77个条带,多态率达83.70％。UPGMA聚类分析显示,48份材料的相似性系数（GS）变化范围在0.27～0.93之间。聚类将48个种质资源划分为 4个大类(GS=0.55),湛江野生棉、廉江野生棉与其它品种在遗传上有很大差别,属于较原始类型,归为一类;长绒棉与陆地棉品种存在明显的遗传差异也单独归为一类;其它不同省份的陆地棉品种在遗传上有较高的相似性,归为其它类型。分析结果表明,ISSR具有丰富遗传多样性和稳定性, 是一种较好的遗传分子标记,适宜于棉花品种遗传多样性分析     

南疆陆地棉种质资源表型性状遗传多样性分析

通过田间调查、室内考种及纤维品质检测,对南疆90份陆地棉种质资源16个表型性状进行鉴定及评价分析,为南疆陆地棉亲本选配和新品种选育提供参考。结果表明:16个表型性状中叶枝数(36.24%)、中部果枝长度(22.63%)、单株铃数(17.64%)变异系数较大,节位数(6.07%)、上半部均长(4.63%)、伸长率(2.59%)变异系数较小;各性状的遗传多样性指数平均值为2.01;相关分析结果表明,陆地棉品质性状与产量性状表现为负相关;主成分分析结果表明,前5个主成分累计贡献率达到71.69%,培育陆地棉优良品种应选择纤维品质优良、结铃数多、株型紧凑、单铃重适中、衣分较高的品种;聚类分析将90份种质分为4个类群,各类群性状差异较大,可为棉花新品种培育提供不同特性的种质材料。     

Expected Response to Selection in Synthetic Populations of Perennial Ryegrass

Confidence intervals for heritability and expected genetic advance of seven agronomic traits in two populations of perennial ryegrass have been computed in two ways (a = bootstrap method; b = parametric method) for five different combinations of selection. Two conclusions can be drawn from our results:

• — Superiority of individual selection over family or every combination of selection.
• — Usefulness of methods based on resampling to estimate confidence intervals for genetic parameters without particular statistical hypotheses.

     

海南、云南油棕种质材料遗传多样性的ISSR分析

为进一步开发利用海南和云南油棕种质资源,从DNA分子水平上对海南和云南油棕种质资源进行遗传多样性研究.应用ISSR技术对海南和云南的63份油棕种质材料进行遗传多样性分析,用23个引物共扩增得到201条扩增条带,其中有多态性的条带为155条,多态性条带占总扩增条带的77.1%.聚类分析的结果将不同地方采集的种质明显的分为8类,采自不同地方的种质材料能明显的根据种质来源相对集中在一起,油棕种质材料可按采集地进行分类.     

中国油棕种质材料的遗传多样性研究

为开发利用中国油棕种质资源,从DNA分子水平上对海南和云南油棕种质资源进行遗传多样性研究。应用ISSR技术对海南和云南的85份油棕种质材料进行遗传多样性分析,用23个引物对所有85个新引进油棕种质及原有油棕种质材料进行ISSR扩增,23个引物共扩增出201条带,其中多态性条带占78.6%。聚类分析的结果显示,采自海南、云南的新选育油棕种质及原有的油棕种质材料基本上能按不同的采集地点或不同的来源途径而分别聚类在一起。     

122份国外普通菜豆资源聚类分析和主成分分析

对122份国外普通菜豆资源的熟性、生育日数、生长习性、出土子叶色、叶形、花旗瓣色、花翼瓣色、株高、株型、主茎节数、单株分枝数、结荚习性、单株荚数、每果节荚数、荚色、荚形、荚面、荚长、荚宽、单荚粒数、粒形、种皮光泽、种皮斑纹、粒色、百粒重、单株产量、小区产量15个质量性状和12个数量性状进行聚类分析和主成分分析.结果表明...