Variation between and within lentil landraces from Yemen Arab Republic

Summary The variation in 31 landraces of lentil collected from Yemen Arab Republic was partitioned to estimate the variation between populations and the variation between families within populations by studying a total of 568 progenies of randomly selected plants. There was significant variation between populations and between families within populations in seedling pigmentation, time to flower, time to maturity and plant height, but the predominant source of variation was between populations. This variation was unrelated to altitude of collection. The landraces were equally variable across characters. The implications of this analysis of variation on lentil breeding and germplasm collection are discussed.     

高粱新选不育系A2F4A,A1356A配合力分析

用不完全双列杂交方法,对新选不育系Ｆ４Ａ,３５６Ａ及目前生产上常用的３个不育系９个恢复系进行了配合力及遗传效应的分析,株高,穗长,穗茎粗,开花期,穗重,穗粒重,穗粒数和千粒重等８个性状的分析结果表明,所有亲本各性状配合力方差均达到极显著水准,在全部被研究性状的遗传控制中,加性基因效应占主导地位,５个不育系中,Ａ２Ｆ４Ａ在全部８个性状上的一般配合力效应值最高,恢复系８６４３变在株高,穗重,穗粒重和开     

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.     

瘠薄胁迫对高粱主要农艺性状的影响及品种耐瘠性评价

高粱对单个养分的利用存在遗传差异和互作现象,开展全肥性的耐瘠薄分析对高粱育种与种质资源评价有指导意义。利用55个高粱品种在瘠薄和正常土壤条件下开展2年田间试验,调查生育期、株高和穗柄长等15个性状,建立耐瘠性评价方法,对高粱进行分级筛选和评价。结果表明,在瘠薄胁迫下高粱生育期延长,穗柄长和穗柄伸出长度增长,倒2叶面积降低,23个品种株高增高,32个品种株高降低,其余10个性状均降低。产量相关性状以及穗柄长和穗柄伸出长对瘠薄胁迫敏感。株高、穗柄长、穗柄伸出长、茎粗和生育期与耐瘠性呈负相关。土壤瘠薄胁迫对高粱多个性状有影响且存在差异。在瘠薄胁迫下高粱的株高主要受穗柄长和穗柄伸出长度的影响。产量和鲜生物量是耐瘠评价的首选指标,千粒重和倒2叶面积是耐瘠评价的次级指标。本研究共筛选出晋杂31号等12个耐瘠品种。     

Early generation genetic variation and heritability of yield and related traits among tef populations

The extent of genetic variation and heritability of a trait are among the major determinants of selection gains in plant breeding programs. The aim of this study was to determine the magnitude of genetic variation and inheritance of grain yield, and component traits of newly developed tef populations under moisture-stressed and non-stressed conditions for drought tolerance breeding. Seventeen crosses along with the parents were evaluated in the F2 generation under moisture-stressed and non-stressed conditions in northern Ethiopia during 2015 and 2016. There were marked genotypic and phenotypic variation among the crosses in the F2 generation for plant height, panicle length, peduncle length, number of productive tillers per plant, main shoot panicle seed weight, biomass yield, and grain yield under both test conditions, important for successful selection and genetic advancement. The families of DZ-Cr-387 x 207832 and DZ-Cr-387 x 222076 were high grain yielders with early maturity under both test conditions.     

Genetic structure of landrace populations of the New World grain amaranths

Summary Grain amaranth populations from their centers of origin in the New World had shown a pattern of allozyme variation that suggested most landraces to be highly homozygous mixtures of genotypes. To compare this pattern of variation with the variation for morphological traits, 15 selfed families from each of six populations were grown in a replicated field experiment. Four pigmentation traits known to be smiply inherited were scored along 18 other morphological traits. Populations varied for the amount of polymorphism for marker loci, and exhibited little heterozygosity. Analysis of variance for the quantitative traits showed significant interpopulation differences for each of the observed characters. Populations differed for the number of metric traits showing significant between-family differences for just one of the metric traits whereas another had between-family differences for all ten. These results suggested high levels of homozygosity within these landraces; thus, variation for quantitative traits conformed well with the allozyme variation patterns.Stepwise multiple regression of all characters on yield as the dependent variable was used to compare the relative contributions of specific characters to yield within individual populations. Plant height, days to flowering, and leaf length were included in the regression equations for 6, 5, and 5, of the populations, respectively. Days to floweing was negatively correlated with yield, while plant height and leaf length were positively correlated. These correlations suggest the potential for developing early flowering, high yielding cultivars having short stature, selected by breaking its correlation with yield. Several breeding strategies based on these findings on genetic resources are discussed briefly.     

不同来源高粱品系农艺性状及品质性状遗传多样性分析

选用来自中国、美国、印度的61份高粱品系作为试验材料,采用随机区组设计,成熟期对高粱的9个性状进行统计分析和聚类分析。研究表明,不同品系间性状表现具有丰富多样性,其中生育期和淀粉的变异程度最低,株高、穗长、单宁的变异程度较大,穗粒重、千粒重、粗蛋白、脂肪的变异程度较为明显。株高、穗粒重与穗长呈显著正相关,千粒重与穗粒重呈极显著正相关,单宁、粗蛋白与脂肪呈极显著正相关,单宁、粗蛋白、脂肪与总淀粉呈极显著负相关。聚类分析结果显示,61份高粱品系可划分为三个类群,各类群都表现出独特的地域性特征。供试高粱品系的农艺性状和品质性状均有着巨大的改良潜力,为进一步改良高粱品种和亲本选育提供科学依据。     

Variation and association of morphological and biochemical characters in grass pea (Lathyrus sativus L.)

Fifty grass pea land race populations of Ethiopia that were selected based on administrative regions and different altitude classes were used in this study to determine variability in morphological characters, Oxalyl Diamino Propanoic acid(ODAP) – a causative agent of lathyrism, and protein contents and their associations. Highly significant differences were observed among the populations for most of the morphological characters. Populations collected from Gondar region and the higher altitude group (>2550 m) showed the highest mean and coefficient of variation indicating the presence of high genetic diversity in this region and altitude group. ODAP analysis from single plants showed significant variation both within a population and between populations. Four individual plants with low ODAP contents ranging from 0.149% to 0.182% (range within safe level) were identified in populations collected from different regions, indicating the diversity and variation of this trait with in one population and between regions. These low ODAP lines are considered important for further breeding. The association of ODAP with grain yield, biomass, plant height and seed size was negative, suggesting that the selection of tall and late maturing varieties with large seed size and high grain yield potential will enable the development of varieties with low ODAP content. This revised version was published online in August 2006 with corrections to the Cover Date.     

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.     

Genetic analysis of the response to day length in rice

Summary Inheritance of time-to-flowering, plant height, tiller number, spikelet number and flag leaf area was studied under day lengths of 10 and 14 hours in a diallel cross of six rice varieties. Early flowering was dominant to late in both environments but the varieties flowering early in one environment were late flowering in the other. Analysis of F₁ and F₂ data from the cross of Heenati-310 x IR-8 suggested a digenic control of early flowering in short days with complementary interaction. It is considered that while relatively few genes control time-to-flowering in rice a previous proposal that separate genes for time-to-flowering and photoperiod sensitivity exist is unnecessary on present evidence. Whereas culm length, tiller number and flag leaf area were increased by longer days, the number of spikelets per panicle was reduced. The length of the panicle was little affected by changing environment, and throughout certain characters and varieties, such as tiller number in I-geo-tze, were more stable than others. Varietal crosses of Heenati-310 x IR-8 and Tainan x MI-273(m) appeared to give high yield potential.     

高粱育种资源耐瘠性鉴定及评价

通过对高粱育种资源进行全生育期瘠薄胁迫,探讨瘠薄胁迫对高粱主要农艺性状及产量的影响,明确不同高粱资源的耐瘠性,为高粱耐瘠材料鉴选和选育提供支持。试验在2016-2018年4月至10月进行,采用随机区组设计,设置正常和瘠薄胁迫处理,运用耐瘠系数和隶属函数相结合的方法对56份高粱材料的耐瘠性进行综合评价。结果显示,与正常处理相比,瘠薄胁迫下高粱材料生育期延长,株高变大,茎粗、穗长、穗宽、穗粒重和千粒重下降。供试高粱材料各农艺性状瘠薄与对照处理的变异系数为0.10~0.46,其中穗粒重变异最大。56份高粱材料平均隶属函数值为0.23~0.79,鉴定筛选出耐瘠材料BTx378、BSX44和A2早BTx623-5B等。     

贵州省不同年代糯高粱品种（系）农艺性状演变分析

以贵州省不同年代酿酒用糯高粱品种（系）为研究对象,采用随机区组试验设计,对其农艺性状、产量构成以及抗性差异进行分析,结果表明：随着年代更替,贵州省酿酒用糯高粱单产逐步提高。新品种（红缨子、黔高8号）较老品系（黑壳糯、红壳糯）平均单产增幅25%以上;穗粒数、穗粒重增加显著,增幅分别为51.7%、62.7%;主穗一、二级枝梗数增加幅度分别为19.8%、62.7%;株高降低24.9%,茎粗增加9.5%;节间数增加0.9个,节间长缩短13.3cm;单株叶面积和叶面积指数增加显著;倒伏率、发病率下降显著,成穗率明显提升。各指标相关性分析显示,产量与穗粒数、穗粒重,穗粒数与主穗一、二级枝梗数呈极显著正相关;产量与株高、倒伏率极显著负相关,与茎粗正相关,相关系数分别为-0.981、-0.970和0.928,株高、茎粗与倒伏率相关显著,相关系数分别为0.964和-0.910;产量与叶面积指数正相关,与发病率显著负相关。总的结果表明,主穗一、二级枝梗数的增加提高了糯高粱的穗粒数,植株株高的降低、茎粗的增加促进了抗倒性的提升,抗病性的提升保证了后期叶片光合作用的持续进行,最终提高了糯高粱产量。     

Geographic distribution of variation in quantitative traits in a world lentil collection

Summary In a world lentil collection the distribution of variation amongst accessions from 13 major lentil-producing countries was examined on the basis of nine quantitative morphological characters by discriminant analysis and canonical analysis. Stepwise discriminant analysis revealed major differences between accessions from different countries. Three major regional groups were apparent: 1) a levantine group (Egypt, Jordan, Lebanon and Syria, 2) a more northern group composed of Greece, Iran, Turkey, and USSR, and 3) accessions from India and Ethiopia with strikingly similar quantitative morphological characters. Misclassifications of individuals within groups were frequent. Characters useful in discriminating between accessions from different countries were in descending order of importance: time to maturity, lowest pod height and 100-seed weight. The regional grouping indicates the importance of local adaptation through clusters of associated characters with phenological adaptation to the ecological environment as the major evolutionary force in the species.     

Making an Indian traditional rice variety Mahsuri, bacterial blight resistant using marker-assisted selection

Mahsuri a popular traditional variety and the first rain-fed mega variety of the Indian sub- continent. It is highly susceptible to bacterial leaf blight caused by Xanthomonas oryzae pv.oryzae. Nine best performing families of Mahsuri pyramid containing four bacterial blight resistance genes (Xa4, xa5, xa13 and Xa21) were evaluated for agronomic, yield and its related characters viz. days to 50% flowering, plant height, number of tillers, panicle length, filled grains per panicle, grain weight, and yield under natural and disease pressure conditions for three consecutive wet seasons. In addition these pyramids were also evaluated for three different spacings to find out the optimum spacing under disease free and disease pressure conditions. Results revealed that under disease free conditions there was no significant difference between the pyramids and the parent for the characters evaluated in each spacing. However characters plant height, number of tillers, panicle length, filled grains per panicle, yield per plant and yield per sq. m. showed significant variation between the different spacings across seasons. Under heavy disease pressure the parent exhibited highly susceptible reaction whereas the pyramid families were highly resistant. A wider spacing had less yield loss when compared to dense planting under BB infestation in case of parent. There was no such yield loss in the pyramid families. When yield per sq. m. was taken into consideration the 20 × 20 cm spacing showed the highest yield when compared to the other two spacings since number of plants were more. The pyramids insulated the yield loss against bacterial leaf blight and are a gain to the farmers to help overcome the heavy yield losses due to this disease. These pyramids have the potential to replace the parent and can be used directly. In addition they can be used as donors for bacterial blight resistance in any breeding program.     

Agro-morphological characterization of ovary culture-derived plants of rice (Oryza sativa L.)

Plants derived from unpollinated ovary culture of ten rice genotypes showed significant variability in agro-morphological characteristics. The ovary-derived plant (H1) populations were completely haploid, doubled haploid or haploid-doubled haploid mixture. Haploids had very drastic reduction in plant height, panicle length, grain length, breadth and number and spikelet fertility (0.0%–2.1%). Doubled haploids from the hybrid of UPRI 95–121 × UPRI 95–165 were normal with fertility ranging between 69.6% and 97.7%. A genetic segregation in ratio of 1:1 was observed for five pigmentation characters in the H1 population derived from hybrid UPRI 95–122 × UPRI 95–165. Plant height showed the largest coefficient of variability (28.5%) followed by the number of spikelets per panicle (24.2%), number of grains per panicle (22.0%), percent seed set (9.2%) and panicle length (9.0%). The range of variation in the H1 population from fully fertile hybrid PMS 2A (CMS) × IR 31802 (restorer) was similar to its corresponding F2 population for plant height, spikelet fertility and number of grains/panicle. A single clone of plants from the cultivar BG 1321 exhibited complete male sterility but normal female fertility when pollinated with other varieties. Ovary-derived plants from the CMS lines PMS 2A and IR 58025A showed stable male sterility and those from thermosensitive genetic male sterile line UPRI 95–140 showed thermosensitive genetic male sterility. These lines have potential in the hybrid breeding program and are being currently exploited. This revised version was published online in July 2006 with corrections to the Cover Date.     

贵州不同地区高粱种质资源表型多样性与聚类分析

对贵州地区220份高粱种质资源进行了多样性和聚类分析。结果表明：籽粒包被度、壳色和粒色分布较分散,穗形、穗柄状态和穗型频率分布较集中,侧散（伞）类型居多;生育期、有效分蘖数、节间数、株高、茎粗、穗长、穗柄长、穗粒重和千粒重均存在较大变异,变异系数为8.36%~37.46%,各性状多样性指数均较大,平均为2.00;从区域来看,黔东南地区种质变异系数和多样性指数均最高,分别为28.56%和1.52;相关分析结果显示,部分数值型性状间存在显著的相关性;聚类分析将220份高粱种质分为3个类群,类群Ⅰ包含211份种质,表现为侧散（伞）穗、生育期短、分蘖力强、穗长和穗粒重小等特点,可作为中早熟侧散型高粱育种的基础材料;类群Ⅱ包含8份种质,主要表现为周散（伞）穗、穗柄直等特点,可用作帚用高粱材料的改良亲本;类群Ⅲ仅含1份种质,主要表现为棒形紧穗、生育期长、分蘖力弱、节间数多、植株高大粗壮、主穗短、穗柄长和穗粒重大等特点,可作为能源用高粱种质创新。     

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.     

Diversity among germplasm lines of the Ethiopian cereal tef [ Eragrostis tef (Zucc.) Trotter]

Three hundred twenty germplasm lines of the major Ethiopian cereal, tef, [ Eragrostis tef (Zucc.) Trotter], were evaluated for 20 morphological, phenological and agronomic characters in two-replicated randomized complete blocks at Debre Zeit and Melkassa Agricultural Research Centers in Ethiopia during the 1995 main season. The objectives were to assess the diversity of the lines, and to estimate the broad sense heritability (H) and genetic advance (GA) of the various characters. The mean squares of genotypes were highly significant (p ≤ 0.001) for all the traits. The phenotypic and genotypic coefficients of variation ranged in that order from about 6–40% and 3–23% for days to maturity and grain yield/plant, and days to maturity and number of spikelets/main shoot panicle, respectively. The cluster analysis grouped the genotypes into 14 major complexes consisting of one to 183 lines. Of the 19 principal components involved in explaining the entire variation among the genotypes the first five which had eigenvalues of more than one explained about 73.8%. The first principal component which accounted for about 34% of the total variance was due chiefly to plant height, culm and panicle length, diameters of the two basal culm internodes, main shoot panicle mass and grain yield, number of main shoot panicle branches and spikelets, and days to panicle emergence and maturity. Estimates of H varied from about 22% for length of the lowest main shoot stem internode to 74% for number of main shoot panicle branches. Values of GA (expected from selection of the superior 5% of the lines and expressed relative to the means) ranged from about 3% for days to maturity to 36% for number of spikelets/main shoot panicle. Overall, the study indicated the existence of trait diversity in tef germplasm and this can be exploited in the genetic improvement of the crop through hybridization and selection. This revised version was published online in July 2006 with corrections to the Cover Date.     

24份甜高粱主要农艺性状与生物产量综合分析

为了探究甜高粱主要农艺性状与生物产量的关系,筛选出综合表现优良的甜高粱材料,进而为今后甜高粱育种提供理论依据。以24份甜高粱杂交组合为试材,对其主要农艺性状及生物产量进行灰色关联度分析、相关性分析、通径分析以及主成分分析。结果表明：主穗长度和穗粒数的变异系数较大;灰色关联度结果表明糖锤度与生物产量关联度最大。相关分析表明株高与茎秆长度,主穗长度与千粒重达到极显著正相关;通径分析结果表明主穗长度、茎秆长度、千粒重、榨汁率、糖锤度本身的直接效应对甜高粱的生物产量有正向作用。主成分分析得出株高、茎秆长度、穗粒数、糖锤度、榨汁率、主穗长度、生物产量这7个性状相对品种的综合表现影响更大。因此,在选育甜高粱杂交种时,要注重对糖锤度、茎粗、茎秆长度的选择,同时兼顾对株高、穗粒数、主穗长度、榨汁率、千粒重的选择。     

Structure and variation of subterranean clover populations from Sicily,Italy

Summary A collection of subterranean clover lines singled out from populations of the species Trifolium brachycalycinum and T. subterraneum collected in Sicily, Italy, was examined at two localities for flowering time and at one locality for oestrogen content and seed yield. The structure and variation of the populations of the two species were compared. The relationship between flowering time of the populations and some environmental features of their collection sites was examined to assess whether the maturity requirements of the two species were similar and to frame selection models focused on developing varieties of appropriate maturity. Populations of T. subterraneum were, on average, more complex than those of T. brachycalycinum, being characterized by higher number of lines per population and greater intra-population variation for flowering time, oestrogen content and seed yield. Furthermore, populations of T. subterraneum were, on average, about 15 days earlier than sympatric populations of T. brachycalycinum. Both the greater variation and the relative earliness of T. subterraneum occurred irrespective of the environments of origin of the populations. Inferences are drawn on the adaptive advantages that such features confer to T. subterraneum. Mean flowering time of the populations increased on increasing annual rainfall and altitude of the collection sites. However, the changes in maturity appeared almost exclusively related to variations in rainfall in T. subterraneum, while in T. brachycalycinum the effect of altitude was greater and that of rainfall less marked than in the former species.