基于表型性状的陆地棉种质资源遗传多样性分析

通过田间性状观测、室内考种分析及纤维品质检测,对来自我国各棉区及国外各类型的429份陆地棉优异种质进行连续2年2点15个表型性状的鉴定及综合评价。结果表明:15个表型性状中始节高、单株铃数和果枝始节位的变异系数最大;各性状的平均遗传多样性指数较高为2.02;主成分分析确立了3类影响因子,表明陆地棉品种选育应集中在纤维品质优良(尤其纤维长度和比强度要高)、高衣分和株铃数多的品种;聚类分析将所有材料分为10个类群,其中第Ⅰ类群占供试材料总数的76.9%,各类群间性状差异明显,聚类结果与材料的地理来源之间没有直接的关系。     

我国现存亚洲棉的表型多样性分析

对我国棉花中期库保存的200份不同地理来源的亚洲棉代表性样本进行了表型遗传多样性分析,结果表明,亚洲棉表型多样性丰富,种质间表型性状差异显著或极显著.19个表型性状的Shannon-Wiener多样性指数在0.34 ～2.15间,其大小依次为:衣分＞株高＞生育期＞铃重＞果枝始节=子指＞叶枝数＞短绒色＞黄萎病抗性＞茎色＞...     

陆地棉优良种质综合评价

1997-1999年在江苏南京、河南安阳两个生态点对"八五"初选的55份棉花优良种质进行综合评价,鉴定生育期、铃重、衣分、产量、纤维品质、抗病性等农艺、经济性状.结果表明,各性状品种间差异显著;评价出某一性状优异或综合性状优良、遗传稳定的种质16份提供利用.     

彩色棉种质资源农艺性状和纤维品质鉴定与分析

基于农艺性状和纤维品质对61份彩色棉种质材料进行鉴定分析,结果表明：材料间衣分、2．5％跨长、马克隆值呈极显著差异,整齐度、伸长率、比强度和单株铃数存在显著差异,株高、果枝数、单铃重差异不显著;供试材料纤维品质较差,除中国农业科学院棉花研究所选育的棕125、棕絮1号等材料外,大部分种质系2．5％跨长、比强度等指标不能满足纺织工业的需求,但仍有31份种质系单一性状较优,如棕2—63（IAA）、棕3-944等。采用类平均法对供试材料进行聚类分析,61份材料聚为7个类群,供试材料表现型性状相似较低,尤其部分基础彩色棉遗传材料与其他材料相似性极低,单独构成一类,如皱缩红鸡角叶棕絮、hunan绿等。综合分析表明,供试材料农艺性状和纤维品质较差,遗传多样性较丰富。     

134份国外陆地棉种质主要农艺性状与纤维品质性状的遗传多样性分析

为拓宽本地棉花种质基因库,筛选适于作杂交亲本的种质资源,以134份国外棉花种质为试验材料,研究了其主要品质与农艺性状的变异情况、遗传多样性指数、品质性状间的相关性,并以主要农艺与品质性状为指标,对134份种质进行了聚类分析和主成分分析。结果表明,纤维品质性状中整齐度指数的遗传多样性指数(5.16)最高,马克隆值的变异系数(11.96%)最大,农艺性状中霜前衣分的遗传多样性指数(5.42)最高,不孕籽率的变异系数(49.18%)最大,参试种质的遗传多样性丰富;整齐度指数与上半部平均长度、断裂比强度均呈极显著正相关,断裂比强度与上半部平均长度间也呈极显著正相关;10个农艺性状和5个品质性状的主成分分析结果表明,前6个主成分的累计贡献率达75.277%;Ward法聚类将134份参试种质按品质性状分为5类,其中第Ⅱ类群的35份种质棉纤维品质性状表现最好,按农艺性状分为3类,其中第Ⅰ类群的58份种质产量最高。通过综合35份纤维品质优异的种质与58份农艺性状优异的种质筛选出美1870、美1884、FM1830等14份品质与产量俱佳的优异种质。     

陆地棉优良种质综合评价

1997--1999年在江苏南京、河南安阳两个生态点对“八五”初选的55份棉花优良种质进行综合评价,鉴定生育期、铃重、衣分、产量、纤维品质、抗病性等农艺、经济性状。结果表明,各性状品种间差异显;评价出某一性状优异或综合性状优良、遗传稳定的种质16份提供利用。     

我国陆地棉基础种质遗传多样性的SSR分子标记分析

利用398对BNL、JESPR、TMB等SSR引物,对不同亲本来源、不同选育时期、不同种植生态区的43份陆地棉基础种质进行了遗传多样性的SSR分子标记分析。扩增产物用8％的非变性聚丙烯酰胺凝胶检测,银染观察并照相。遗传多样性带型分析按位点多态信息量（PIC）,Shannon-weaver多样性指数（H^＋）等方法,利用NTSYSpc2．1软件计算品种间的遗传相似系数（Jaccard系数）,并用类平均法（UPGMA）进行聚类。结果表明所选择多态性引物分布在棉花基因组的第3、4、5、8、9、10、16、18、20、23号等染色体上,36对多态性引物在基础种质中扩增等位基因130个,其中多态性等位基因占80％,每个引物扩增等位基因2～8个,平均3．6个,PIC为0．278～0．865,平均0．62,基因型多样性（H^＋）为0．451～2．039,平均1．102,基础种质问SSR遗传相似系数平均为0．610,变幅为0．409～0．865,这说明所选基础种质基因组水平的多样性较丰富,变化范围大、代表性强。按品种不同选育时期来讲,第一、二、三期基础种质的SSR分子标记平均遗传相似系数分别是0．587、0．630、0．630,说明现代基础种质比早期基础种质在基因组水平的差异呈下降的趋势,可能是由于育种者偏重于使用优质高产性状的亲本品种,致使我国棉花的育种基础逐渐变窄。不同棉区基础种质SSR标记性状差异大,北部特早熟棉区基础种质间的SSR标记的多样性大于黄河、长江棉区,主要原因是长江、黄河棉区的育种过分强调高产、优质品种选育,品种间的差异变小;基础种质中的国内品种SSR相似系数（0．624）比引进品种（0.85）高,说明国内品种在遗传多样性上目前还没有超越国外品种。总之,我国棉花现代基础种质比早期基础种质的遗传多样性呈下降的趋势,黄河、长江主产棉区基础种质的遗传多样性还没有超过国外基础种质,品种间的遗传背景较为狭窄,还必须采用多种途径丰富我国棉花种质资源的遗传多样性。     

火龙果种质资源果实特性的遗传多样性分析

为筛选火龙果(Hylocereus undatus)优良种质资源,对22份种质资源果实的表型性状、农艺性状、品质性状进行遗传多样性分析。结果表明,火龙果种质资源果实的表型性状、农艺性状和品质性状具有丰富的遗传多样性和较高的变异性,表型性状的多样性指数(H′)为0～1.04,品质性状为0.40～2.01;农艺性状的变异系数(CV)为0.06～0.38,品质性状为0.01～0.62。聚类分析表明,在遗传距离为15时,火龙果22份种质资源可分为5类,说明不同资源间亲缘关系较远。这为发掘火龙果的育种潜力,筛选优异基因资源,改良种质奠定了基础。     

转基因抗虫棉农艺性状和纤维品质的遗传多样性

本研究以国内育成和国外引进的52份转基因抗虫棉品种(系)为材料,在河北农业大学棉花育种圃种植,调查农艺性状、测定纤维品质,基于农艺性状和纤维品质分析供试品种(系)的遗传多样性.结果表明:在9个农艺性状中,烂铃数的变异系数最大,其次为产量、有效铃数和第一果枝节位高度,变异系数最小的是衣分和果枝数.转基因抗虫棉品种纤维长度基本能够满足纺织工业需求,2.5%跨长主要集中在28～30mm;纤维比强度平均值为27.1cN/tex,变幅为23.0～31.6cN/tex;马克隆值的平均值为4.8,变幅为4.0～5.6.成对品种的欧氏距离变化在1.53～13.31之间,平均值为4.79,单一品种欧氏距离的平均值分布在3.62～10.51之间,表明不同品种之间具有一定的差异.采用离差平方和法对欧氏距离进行聚类,可以将供试品种明显地划分为2类,一类为中熟品种,另一类为早熟品种.     

大麦表型多样性分析及优异饲草种质资源筛选

为探究中国库存大麦种质资源的表型多样性及其变异规律,同时挑选高生物产量的大麦遗传资源发展饲草大麦,本研究以来源于全国不同地区的102份库存高秆大麦种质为材料,通过Shannon-Weaver多样性指数、相关分析、聚类分析、主成分分析等方法对15个表型性状进行综合评价。结果表明:15个性状中拔节期底部叶片黄化、倒伏性、灌浆期底部叶片黄化、千粒重变异较大,粒宽、株高变异较小,表型多样性指数范围为0.729～0.957,皮裸性、千粒重、籽粒周长、灌浆期株高等性状的遗传多样性较高。不同来源种质间表型多样性比较结果表明,冬大麦生态区表型多样性(0.721)高于西南及青藏高原裸大麦生态区(0.706)。相关分析、主成分分析、聚类分析均表明,皮裸性是影响大麦种质表型差异的重要影响因素,而倒伏、拔节期和灌浆期底部叶片黄化等饲草相关性状相对独立。聚类分析将102份种质分为4类,相同来源地的种质聚在一起。本研究结果表明中国库存大麦种质资源具有丰富的表型多样性,从中筛选的高秆、大叶、抗倒伏等优异性状的大麦资源,为后续培育青饲、青贮专用型大麦品种提供了资源保障。     

陆地棉主要产量相关性状的SSR标记关联分析

高产优质育种是我国棉花育种的主要目标。寻找与目标性状关联的分子标记,可克服常规育种的盲目性,提高分子标记辅助选择育种的准确性。本研究对118份陆地棉种质资源的衣分、单铃重、单株铃数及子指等4个产量相关性状进行2年2点的表型鉴定,并利用覆盖全基因组的、有多态性的214对SSR标记进行标记与性状的关联分析。结果表明:118份材料的4个产量相关性状表型变异丰富,平均变异系数的变幅在6.1%~19.1%之间,且在各环境中表现较为稳定;基因型分析表明,214对标记共检测到460个等位变异,基因多样性指数平均为0.5151,PIC值平均为0.4587,表明该批标记具有较多的等位变异数和较高的基因多样性;群体结构分析表明该批材料可分为4个亚群,且各类群中材料与地理来源无对应关系;关联分析结果显示,在显著条件下(-log10P1.3,P0.05),共有39个标记位点能够在2个及2个以上的环境中同时检测到,其中有4个标记位点同时与2个以上性状相关联,进一步比较发现,有7个位点与前人研究结果一致,其余32个位点为新发现的位点。研究结果可为陆地棉产量性状遗传改良的分子标记辅助选择提供理论依据。     

Mapping quantitative trait loci for lint yield and fiber quality across environments in a Gossypium hirsutum × Gossypium barbadense backcross inbred line population

Identification of stable quantitative trait loci (QTLs) across different environments and mapping populations is a prerequisite for marker-assisted selection (MAS) for cotton yield and fiber quality. To construct a genetic linkage map and to identify QTLs for fiber quality and yield traits, a backcross inbred line (BIL) population of 146 lines was developed from a cross between Upland cotton (Gossypium hirsutum) and Egyptian cotton (Gossypium barbadense) through two generations of backcrossing using Upland cotton as the recurrent parent followed by four generations of self pollination. The BIL population together with its two parents was tested in five environments representing three major cotton production regions in China. The genetic map spanned a total genetic distance of 2,895 cM and contained 392 polymorphic SSR loci with an average genetic distance of 7.4 cM per marker. A total of 67 QTLs including 28 for fiber quality and 39 for yield and its components were detected on 23 chromosomes, each of which explained 6.65–25.27 % of the phenotypic variation. Twenty-nine QTLs were located on the At subgenome originated from a cultivated diploid cotton, while 38 were on the Dt subgenome from an ancestor that does not produce spinnable fibers. Of the eight common QTLs (12 %) detected in more than two environments, two were for fiber quality traits including one for fiber strength and one for uniformity, and six for yield and its components including three for lint yield, one for seedcotton yield, one for lint percentage and one for boll weight. QTL clusters for the same traits or different traits were also identified. This research represents one of the first reports using a permanent advanced backcross inbred population of an interspecific hybrid population to identify QTLs for fiber quality and yield traits in cotton across diverse environments. It provides useful information for transferring desirable genes from G. barbadense to G. hirsutum using MAS.     

Genetic relationships and discrimination of ten influential Upland cotton varieties using RAPD markers

Influential Upland cotton ( Gossypium hirsutum L.) varieties are those that have the higher genetic contributions to modern Upland cultivars than other germplasms. Our previous research has shown significant differences in general combining ability (GCA) effects for yield, yield components, and fiber properties among ten influential cotton varieties. In this study, we used random amplified polymorphic DNA (RAPD) data to evaluate DNA variation of these ten varieties. Of 86 random decamer primers screened for their capability of amplifying DNA via the polymerase chain reaction (PCR), 63 generated a total of 312 DNA fragments. Forty two bands were polymorphic, which showed a low percentage (13.5%) of DNA variation among these influential varieties. Genetic similarities among the ten varieties based on RAPD data were from 92.7% to 97.6%. All of the varieties were individually identified by variety specific markers in genetic fingerprinting. One primer, UBC-149, amplified a 1,430-bp DNA fragment that was absent in five varieties and present in the other five varieties. This RAPD marker had significant negative relationships with GCA-effect estimates for seed cotton yield, lint yield, number of bolls per plant and micronaire, and significant positive relationships with GCA effects for boll size and seed index. This finding, for the first time, identifies a DNA fragment in cotton that is a potential DNA marker linked to a yield gene(s) or a yield-related gene(s).     

Association Mapping for Epistasis and Environmental Interaction of Yield Traits in 323 Cotton Cultivars under 9 Different Environments

Improving yield is a major objective for cotton breeding schemes, and lint yield and its three component traits (boll number, boll weight and lint percentage) are complex traits controlled by multiple genes and various environments. Association mapping was performed to detect markers associated with these four traits using 651 simple sequence repeats (SSRs). A mixed linear model including epistasis and environmental interaction was used to screen the loci associated with these four yield traits by 323 accessions of Gossypium hirsutum L. evaluated in nine different environments. 251 significant loci were detected to be associated with lint yield and its three components, including 69 loci with individual effects and all involved in epistasis interactions. These significant loci explain ∼ 62.05% of the phenotypic variance (ranging from 49.06% ∼ 72.29% for these four traits). It was indicated by high contribution of environmental interaction to the phenotypic variance for lint yield and boll numbers, that genetic effects of SSR loci were susceptible to environment factors. Shared loci were also observed among these four traits, which may be used for simultaneous improvement in cotton breeding for yield traits. Furthermore, consistent and elite loci were screened with −Log₁₀ (P-value) >8.0 based on predicted effects of loci detected in different environments. There was one locus and 6 pairs of epistasis for lint yield, 4 loci and 10 epistasis for boll number, 15 loci and 2 epistasis for boll weight, and 2 loci and 5 epistasis for lint percentage, respectively. These results provided insights into the genetic basis of lint yield and its components and may be useful for marker-assisted breeding to improve cotton production.     

Investigation of some yield and fibre quality characteristics of interspecific hybrid (Gossypium hirsutum L. x G. barbadense L.) cotton varieties

Interspecific hybrid cottons (Gossypium hirsutum L. x G. barbadense L.) have great both yield and quality potential. This study was conducted to determine potential yields and quality characteristics of hybrid cotton varieties in southeastern Anatolia region of Turkey. The experiment was set out a completely randomized block design with four replications during 2003 and 2004 at University of Dicle, Faculty of Agriculture Experimental Field. Seven interspecific hybrid cotton varieties (48-08, Sevilla, Europe, Ica, Etna, 14-08 and Acalpi) which were obtained from Israel, and commonly grown varieties in this region, non-hybrid cotton varieties, GW Teks and DP-Opal were used as the materials of the study. Difference among the cultivars was significant for all traits except sympodial branch. Maximum number of boll and lint yield was 20.18 n plant(-1) and 1685.8 kg ha(-1) from interspecific hybrid cotton Ica, while interspecific hybrid cotton Europe recorded the lowest number of boll and lint yield. Interspecific hybrid cotton varieties showed higher value for fibre length, fibre fineness and fibre strength than non-hybrid cotton varieties. The longest fibres were obtained from Acalpi and Etna (34.08 and 33.88 mm), while non-hybrid varieties, DP-Opal and GW-Teks, had the lowest fibre length, 28.50 and 30.03 mm, respectively. The finest fibres obtained from Ica and 48-08 (3.42 and 3.45 mic.), the strongest fibres from Etna and Acalpi (40.07 and 40.23 g tex(-1)), and most elongation fibres from Acalpi (8.00%) and Sevilla (7.45%). Lint yield correlated positive and significant with fiber length.     

转基因抗虫棉的产量、品质及抗虫性比较研究

对36个转基因抗虫棉品种(品系)进行试验,比较了它们的产量、抗棉铃虫和红铃虫特性以及纤维品质之间的差异,并进行综合评价。在不打药的情况下,筛选出252等13份皮棉产量比鄂抗9号显著提高、抗棉铃虫和红铃虫的种质材料,其纤维品质综合性状表现一般。     

The role of propagule pressure in the invasion success of bluegill sunfish, Lepomis macrochirus, in Japan

The bluegill sunfish, Lepomis macrochirus, is a widespread exotic species in Japan that is considered to have originated from 15 fish introduced from Guttenberg, Iowa, in 1960. Here, the genetic and phenotypic traits of Japanese populations were examined, together with 11 native populations of the USA using 10 microsatellite markers and six meristic traits. Phylogenetic analysis reconfirmed a single origin of Japanese populations, among which populations established in the 1960s were genetically close to Guttenberg population, keeping high genetic diversity comparable to the ancestral population. In contrast, genetic diversity of later-established populations significantly declined with genetic divergence from the ancestral population. Among the 1960s established populations, that from Lake Biwa showed a significant isolation-by-distance pattern with surrounding populations in which genetic bottlenecks increased with geographical distance from Lake Biwa. Although phenotypic divergence among populations was recognized in both neutral and adaptive traits, P(ST)-F(ST) comparisons showed that it is independent of neutral genetic divergence. Divergent selection was suggested in some populations from reservoirs with unstable habitats, while stabilizing selection was dominant. Accordingly, many Japanese populations of L. macrochirus appear to have derived from Lake Biwa population, expanding their distribution with population bottlenecks. Despite low propagule pressure, the invasion success of L. macrochirus is probably because of its drastic population growth in Lake Biwa shortly after its introduction, together with artificial transplantations. It not only enabled the avoidance of a loss in genetic diversity but also formed a major gene pool that supported local adaptation with high phenotypic plasticity.