Observations on different mildew sources used in apple breeding at Ahrensburg

Fifty-six populations of common bean (Phaseolus vulgaris L.) were grown in Pontevedra (Northwestern Spain) in four different environments in order to study their genetic diversity in 18 agronomical traits. All characters showed significant differences among populations, and most of them had significant genotype-environment interactions. Broad-sense heritability for this pool of characters ranged from 0.87 (seed length) to 0.12 (seed yield). Sixteen populations which deserve special attention because of their breeding value for earliness, yield, pod and seed size have been identified.     

利用SSR标记分析野生小豆及其近缘野生植物的遗传多样性

利用28对SSR引物对96份野生小豆资源、小豆近缘野生植物及栽培小豆品种进行遗传多样性分析,共检测到255个等位变异,平均每对SSR引物9.10个,多态信息含量的变异范围从0.374到0.865,平均为0.722。野生小豆材料和近缘植物Vigna minima遗传变异丰富。来自不同地域的野生小豆材料具有大量特异等位变异,基于非加权成组配对算术平均法的聚类分析可将不同地理来源的野生小豆单独分群,且与主坐标分析的结果相一致。4份栽培小豆材料与日本野生小豆遗传距离较近,表明目前国内小豆育种中较多使用了含有日本血缘的小豆材料,以及国内野生小豆资源的搜集和利用工作落后于日本。本研究对国内野生小豆资源的搜集和保存具有指导意义,并可以为这些资源的评价、利用和优异基因的发掘提供参考。     

Phaseolin Diversity in the Tepary Bean, Phaseolus acutifolius A. Gray

The tepary bean (Phaseolus acutifolius A. Gray) is grown mainly in and regions of Mexico and the southwestern U.S. as a subsistence crop by small farmers. It is also a store of genetic variability for traits such as disease and pest resistance and stress tolerance to improve the common bean (P. vulgaris L.). To determine geographic patterns of variation and the influence of domestication on genetic variability, the genetic diversity of phaseolin, the major seed storage protein, was characterized among 55 wild and 8 cultivated teparies using polyacrylamide gel electrophoresis. Fifteen electrophoretic phaseolin patterns were identified among wild forms, whereas only one pattern was exhibited by cultivars. This result suggests a single domestication in this species leading to a strong reduction in diversity. An additional finding is the divergence m phaseolin types between populations east and west of the Sierra Madre Occidental mountains.     

Genetic diversity of Argentinean common bean and its evolution during domestication

Wild populations of common bean pertainingto the Andean gene pool are distributedfrom southern Peru to northern Argentina.The objectives of this study were todetermine the genetic structure of Andeanlandraces from northern Argentina, as oneof the potential domestication sites of theAndean domesticated gene pool, and toestablish a correspondence between Andeanprimitive landraces and wild populationsthat might have served as the source ofdomesticated bean. Forty-four landraces and21 wild populations representing thediversity of common bean in northernArgentina were included in this study. Results indicated that Andean gene pool inArgentina has a large genetic base on thebasis of morphological and adaptivevariability and biochemical analysis. Theexistence of introgressed populations withsympatric wild forms was evidenced.     

滇重楼不同居群的表型多样性研究

为揭示滇重楼不同居群的表型多样性,为滇重楼种质资源的保护利用提供科学的理论依据。观测20个居群滇重楼15个性状的表型性状, 采用变异系数、方差分析、主成分分析和聚类分析进行分析。滇重楼各表型性状变异丰富,变异系数在14.3%~46.2%之间,表型分化系数为52.13%,居群间和居群内变异相当。滇重楼显示出较高的多样(2.4415),20个不同居群的平均多样性指数为2.2255~2.5363。主成分分析显示茎高、叶柄长、叶片长、宽、花瓣长,花萼长,花茎高是引起滇重楼不同居群间表型差异较大的因素。聚类分析表明,滇重楼20个居群可以分为3大类。滇重楼表型多样性较高,对其资源的保护和利用具有重要意义。     

滇西北野生牡丹天然居群的表型多样性

为揭示滇西北天然牡丹居群的表型变异程度和变异规律,利用12 个形态指标对18 个滇西北牡丹(Paeonia delavayi)的天然居群进行表型多样性研究。结果表明：滇西北牡丹表型性状在居群间存在广泛的变异,12 个性状居群间的变异系数为16.65%~107.78%,种群间的平均变异系数为38.44%。在研究的18 个居群中,宁蒗拉伯乡居群的变异最小,变异系数为25.02%;其次是玉龙县大平坝居群,变异系数为26.68%;以丽鸣线路旁居群的变异为最大,变异系数为50.86%。滇西北牡丹变型性状在居群间和居群内存在着丰富的表型多样性,12 个表型性状的平均表型分化系数为98.51%,居群间的变异(48.87%)大于居群内的变异(0.59%),表明居群间的变异是表型变异的主要来源。滇西北牡丹表型性状与地理因子的典型相关分析表明,坡度能正向依次解释单荚荚长(y11)、果柄长(y8)、叶柄长(y4)和单荚总数(y10),负向依次解释单荚荚宽(y12)、荚果数(y9)和株高(y1);聚类分析结果说明滇西北牡丹居群间表型性状变异是不连续的。     

Isozyme variation in a number of populations of Theobroma cacao L. obtained through various sampling regimes

Summary Isozyme polymorphism in four enzyme systems was used to estimate the genetic diversity in nine populations of Theobroma cacao L. The distribution of allelic variation observed in this study was inconsistent with the currently held view that the Upper Amazon region of Peru is the centre of cacao genetic diversity. All the populations analysed from this area of Peru were genetically similar, and contained a low level of isozyme polymorphism. It is argued that this is a result of genuine low diversity in the region rather than a sampling artifact. If a centre of diversity of wild cacao truly exists, this work indicates that it lies further north in Ecuador and Colombia.Although they are morphologically highly variable, Trinitario cacao populations derived from cultivation are currently accorded low priority for conservation. This phenotypic variation was observed to be reflected in high levels of isozyme polymorphism. It is suggested that the present strategy for the conservation of cacao germplasm, which accords priority to the Upper Amazon region of Peru while neglecting the Carribbean should be reconsidered.     

中国板栗北方种群表型变异频率研究

研究了中国板栗北方产区5个地理种群种子及叶片特征的表型分化、表型性状值(数量性状)的频率分布及表型频率多样性。结果表明,板栗种群间的方差分量占总变异的10.97%,种群内的占41.57%,7个性状种群间的表型分化系数变幅在11.85%~28.34%。板栗7个性状种群间的表型分化系数平均为24.26%,表明种群内变异是板栗表型变异的主要来源,种群内品种间的多样性大于种群间的多样性。板栗7个性状频率分布基本符合正态分布,但偏度和削度各自不同,众数的位置及所在组的频率也存在一定差异。表型多样度、Shannon信息指数均可用于表型多样性的评价。     

Phenotypic and genotypic analysis of a commercial cultivar and wild populations of Anemone coronaria

Seven wild populations of Anemonecoronaria were assessed for 11 phenotypic traits, most of them having economic value for the flower industry. The wild populations were sampled to represent the diversity in habitats, climates, rock and soil types, terrains, and elevations in Israel. AFLP analysis was carried out on 12 individuals from each of six out of the seven wild populations and for six individuals from the commercial cultivar ‘Mona-Lisa’. It was found that the Dorot population, which is located in the area bordering the semi-arid zone at the very end of the species distribution, exhibits extreme and different phenotypes with relatively low variability compared withthe other wild populations. The other six wild populations, that grow in more favorable geographic and climatic conditions exhibit phenotypes with larger plants, larger numbers of flowers and less dissected leaves. These populations were less uniform than that of Dorot. Genetic characterization by AFLP markers revealed a total of 165 bands. The wild populations exhibit wide variation within-population, with about 80% polymorphic bands and average gene diversity between pairs of about 30%. The Dorot population has the lowest genetic variation and the Megido population the highest. Thus, the phenotypic variation reflects the genetic variation. The cultivar ‘Mona-Lisa’, as expected, has much lower genetic variation. The Dorot population and the ‘Mona-Lisa’ cultivar were found to have the largest genetic distances from the other wild populations, and the highest genetic variation between themselves. Phenetic analysis yielded a dendrogram describing the genetic relatedness of these populations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Genetic characterization and gene flow in different geographical-distance neighbouring natural populations of wild soybean (Glycinesoja Sieb. & Zucc.) and implications for protection from GM soybeans

To design appropriate strategies for ex situ and in situ conservation of wild soybean and safeguard the biosafety of the wild soybean gene pool when genetically modified soybeans are grown, it is important to understand its genetic characteristics, and to quantify gene flow and kinship within and between neighboring populations. We analyzed 9 pairs of neighboring populations of wild soybeans using 20 pairs of nuclear SSR markers. Results showed that Chinese wild soybean natural populations had outcrossing rates of 0–3.5% and that most populations contained many kinship families. The kinship families could be attributed to the accumulation of outcrossed offspring within populations during the history of population colonization. Wild soybean is very sensitive to environmental selection, which results in genetic differentiation of populations, and the emergence of specific alleles. We used an index τ to explain why genetic differences would exist between the pairwise populations; the interpopulation genetic differentiation chiefly consisted in the differences of allele frequencies over the genome. We found long-distance dispersal (1.5 km) of wild soybean seeds in a land ecosystem. There was close correlation between genetic and geographical distance among natural populations of Chinese wild soybean. Within a distance of 50 km, there was greater gene flow when the distance between populations was shorter. These findings have implications for ex situ and in situ conservation in an ecogeographical region, and also for protection of the gene pool from contamination by GM soybeans in wild soybean species.     

Segregation for performance in recombinant inbred populations resulting from inter-gene pool crosses of common bean ( Phaseolus vulgaris L.)

The germplasm of cultivated common bean exhibits a lower level of genetic diversity within each geographical gene pools (Mesoamerican and Andean) compared to that of the respective wild ancestors. Crosses between these two gene pools potentially provide a source of additional genetic diversity but their progenies have been characterized by phenotypic abnormalities and reduced productivity. In order to gain additional insights into this problem, we examined the segregation for performance in two recombinant inbred populations (RIPs) resulting from Mesoamerican × Andean crosses in three contrasting environments and two years. The two RIPs – ‘California Dark Red Kidney’ (of Andean origin) × ‘Yolano’ (Mesoamerican), n = 150, and A55 (Mesoamerican) × G122 (Andean), n = 67 – were grown in replicated field tests to assess the agronomic performance of each recombinant inbred line. Both populations exhibited, on average, greater days to maturity (DTM), lower biomass growth rate (above-ground dry weight/DTM), lower economic growth rate (seed yield/DTM), and lesser harvest index. In contrast with the conclusions of earlier experiments, there was no evidence from the field trials for a genetic association (due to linkage or pleiotropy) between seed weight and economic growth rate, but there may be a genetic association between seed weight and life cycle length. We compare the results of these studies with earlier experiments on inter-gene pool recombinant populations of common beans and relate our observations of diminished performance to models of speciation mechanisms. This revised version was published online in July 2006 with corrections to the Cover Date.     

油松天然群体种实性状表型多样性分析

在油松天然林分布区共抽取了10个群体,分别测量了8个种实性状。方差分析表明:油松种实性状在群体间和群体内存在广泛的变异,8个性状在群体间和群体内差异均达极显著水平。表型分化系数即群体间的变异为51.86%,大于群体内变异(48.14%),是油松表型遗传变异的主要部分。球果长、球果径、球果形状指数、种子长、种子宽、种子厚、种子形状指数和千粒重的变异系数分别为:12.87%、12.43%、11.19%、13.97%、16.92%、18.8%、11.53%和32.50%。利用群体间欧氏距离进行UPGMA表型性状的聚类分析,可将油松10个天然群体划分为5类。相关分析表明,油松球果长和果径相关紧密,种长、种宽和千粒重两两相关显著。种形指数与纬度、海拔和生态梯度值(EGA)呈显著负相关,与年均温、年降水量和生长期呈显著正相关。     

Genetic diversity of feral alfalfa (<Emphasis Type="Italic">Medicago</Emphasis> <Emphasis Type="Italic">sativa</Emphasis> L.) populations occurring in Manitoba,Canada and comparison with alfalfa cultivars: an analysis using SSR markers and phenotypic traits

Feral populations of cultivated crops may act as reservoirs for novel traits and aid in trait movement across the landscape. Knowledge on the genetic diversity of feral populations may provide new insights into their origin and evolution and may help in the design of efficient novel trait confinement protocols. In this study, the genetic diversity of 12 feral alfalfa (Medicago sativa) populations originating from southern Manitoba (Canada) and 10 alfalfa cultivars and a M. falcata germplasm were investigated using eight SSR markers (i.e., microsatellites) and 14 phenotypic traits. We found that the genetic diversity observed in feral populations was similar to the diversity detected among the 10 cultivars. Analysis of molecular variance revealed that there was great genetic variation within (99.8%) rather than between different feral populations. Cluster analysis (unweighted pair-group method using arithmetic average) revealed no differentiation between feral populations and cultivars for neutral loci. High levels of population differentiation for phenotypic traits (and not for neutral markers) suggest the occurrence of heterogeneous selection for adaptive traits. The phenotypic traits we studied did not distinctly separate feral populations from cultivars but there was evidence of natural selection in feral populations for traits including winter survivability, rhizome production, and prostrate growth habit. Our results suggest that feral alfalfa populations need to be considered in the risk assessment of alfalfa containing novel genetically modified (GM) traits. Further, feral alfalfa populations may be regarded as a source of new germplasm for plant improvement.     

Genetic diversity in Lima bean (Phaseolus lunatus L.) as revealed by RAPD markers

The genetic variability of 46 accessions of the Lima bean (P. lunatus L.) including 16 wild forms and 30 landraces belonging to the three cultigroups Big lima, Sieva, Potato, and their intermediates, was evaluated using RAPD (Random amplified polymorphic DNA) markers. Twelve oligonucleotide primers produced 172 RAPD markers which allowed the differentiation of two main groups: the mesoamerican and the andean groups. This was confirmed by an AMOVA analysis which indicated that 37.7% of the variation was found between these two groups. For each botanical form (wild and cultivated), the molecular markers showed that small-seeded types (i.e. Sieva and Potato types and their related wild forms) had a wide distribution (from Mexico to Argentina) while the large-seeded types (Big lima type and its related wild forms) were circumscribed to the narrow west-coastal region from Ecuador to Bolivia. The results are in favour of an independent domestication process within the two groups, as the differentiation between mesoamerican and andean accessions was found to occur in both wild forms and landraces. Within each of the two main groups, wild forms and landraces were also found to be genetically differentiated and higher genetic diversity was observed among landraces than among wild forms. Within the mesoamerican landraces, low but significant differentiation between the Sieva and Potato cultigroups was observed. Some suggestions and hypotheses are discussed about evolution of the two small-seeded types. This revised version was published online in July 2006 with corrections to the Cover Date.     

用于中国小豆种质资源遗传多样性分析SSR分子标记筛选及应用

以375份小豆核心种质为试验材料, 利用从小豆及其近缘种SSR引物中筛选出的13对引物进行遗传多样性分析。检测结果显示, 小豆种质资源具有丰富的遗传多样性, 共检测到133个等位变异, 每对SSR引物检测到等位变异4~19个, 平均10.23个, 国内各省多态信息含量(PIC)平均为0.561, 多态位点比例(P)平均为93.523%。聚类结果表明, 小豆资源遗传关系与生态分区间有明显的联系, 且东北地区资源与中南部资源遗传关系较近。湖北、安徽、陕西3省资源的PIC较高, 且基本位于主坐标三维图的中心区域, 推断湖北、安徽、陕西是中国栽培小豆的起源地或多样性中心。该结果有助于更好地对小豆种质资源进行收集、保护和利用。     

Pollen-style compatibility relations in natural populations of the wild diploid potato species Solanum spegazzinii Bitt.

Solanum spegazzinii Bitt., a wild diploid potato species endemic to Argentina, possesses resistance to adverse biotic and abiotic agents. Northwestern Argentinean populations grouped according to their morphological variability (G1 = localities East of the Calchaquí Valley, G2 = Calchaquí Valley and G3 = locality Belén) presented problems in seed set following controlled crosses. Thus, to evaluate if the morphological variability previously reported was sustained on a genetic basis, three introductions per group and five plants per introduction were used in controlled crosses (genotypic combinations). These were classified according to the number of seeds produced per fruit. Pollen-style compatibility relations were studied in those crosses that did not set seeds or that produced less than 30 seeds each. Within groups, G1 produced seeds normally, whereas hybridization barriers were found in 71.4% and 50.0% of the combinations within G2 and G3, respectively; on the other hand, from 46.7% to 73.3% of the combinations among groups exhibited similar barriers. Variability in the expression of the sites of pollen tube inhibition in the style was observed both within and among groups. Speculations are made on the possible hybrid origin of the populations. This revised version was published online in July 2006 with corrections to the Cover Date.     

广西野生稻资源原生境保存探讨

农业野生植物资源原生境保存是国际植物遗传资源界推崇的一种保存方式,开展野生稻资源原生境保存,能为野生稻资源利用提供丰富的优异种质与特异基因;为稻种基础理论研究提供更广泛的遗传多样性,具有十分重大的意义。本文认真探讨广西野生稻资源原生境保存方式,保存检测技术方法及保护制度运行机制等问题,并提出广西野生稻资源原生境保存的合理化建议。     

紫荆群体表型性状多样性研究

以紫荆全分布区的7个天然群体为研究试材,另取2个栽培群体为对照,对当年生枝的叶片、荚果、种子等14个表型性状进行比较分析,讨论群体间和群体内的表型多样性。结果表明,紫荆种内表型性状在群体间和群体内存在着极其丰富的变异。群体平均表型分化系数(VST)为32.30%,群体内的变异贡献大于群体间的。紫荆表型性状与生态因子相关分析表明,其种内群体表型变异呈梯度规律性,随着海拔的升高,叶片和种子逐渐变大;随着经纬度的增加,荚果形状从窄条形向宽条形变异,种子形状从近圆形向椭圆形变异。利用主成分分析对8个群体进行了排序、归类(其中P6群体性状值缺失比较多,故未进行排序),分析表明8个群体大致可以划为天然和栽培两类,天然群体又可分为两亚类。天然紫荆与栽培紫荆在表型上已经产生了分化。     

Molecular evaluation of genetic variability in wild populations of mulberry (Morus serrata Roxb.)

Sixteen populations of the wild mulberry, Morus serrata Roxb., were analysed for their genetic diversity with the aim of using them in introgressive breeding programmes with cultivated relatives. Five genets from each population were collected from different natural populations of M. serrata present in Uttaranchal and Himachal Pradesh in India, and diversity of morpho‐anatomical traits and inter‐simple sequence repeat (ISSR) markers were studied. Significant amounts of genetic diversity were observed among these populations for morpho‐anatomical as well as DNA markers. The 17 ISSR primers generated a total of 95 DNA markers, 51 of which were polymorphic, revealing 67% polymorphism among the populations. The pair‐wise genetic distance, estimated from these DNA markers varied from 0.091 between Urgam‐3 and Kathpuria to 0.258 between Dakrakao‐1 and Dunda with an average genetic distance of 0.165. Clustering analysis grouped these 16 populations into three broad groups. The grouping showed a moderate correlation with the geographical distances. Based on the morphological traits and molecular genetic variability, plants of Urgam‐1, Bhowali farm, Nainitikar, Dunda or Korwa‐2 can be selected for breeding and conservation programmes.