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1.
Understanding the genetic relationships among breeding lines is fundamental in crop improvement programs. The objectives of this study were to apply selected polymorphic single sequence repeat (SSR) DNA markers and cluster medium to late maturing tropical elite maize inbred lines for effective hybrid breeding. Twenty elite inbred lines were genotyped with 20 SSR markers. The analysis detected a total of 108 alleles. The unweighted pair group method with arithmetic mean allocated the inbred lines into five clusters consistent with the known pedigrees. The tested inbred lines that were adapted to mid-altitude, sub-humid agro-ecologies were classified in different clusters, except for a few discrepancies. The greatest genetic distance was identified between the clusters of lines CML-202 and Gibe-1-91-1-1-1-1. The analysis determined the genetic grouping present in the source population, which will assist in effective utilization of the lines in tropical hybrid maize breeding programs to exploit heterosis.  相似文献   

2.
J. C. Ascenso 《Euphytica》1966,15(2):268-277
The methods and techniques of oil palm selection and breeding are discussed in relation to the problems of the oil palm industry in Portuguese Guinea.A general survey of the oil palm populations, both cultivated and natural palm groves, was carried out in order to determine existing varieties, their distribution, range of variability, disease incidence and palm oil quality.Yield was established as the major aim in the breeding programme. Short-stem habit and adaptability to different sets of conditions are also considered.Both a long-term and a short-term project are undertaken simultaneously.The long-term programme includes selection of Deli female parents, pollen and seed introductions from pisifera and tenera palms selected in San Thome and single crosses among selected parents. Emphasis is laid on the Deli × pisifera cross to increase oil content, though Deli × tenera and Deli × Deli seed are also produced.The short-term programme involves multiple crosses. A number of mass-selected Deli palms is pollinated using pollen from pisifere or tenera palms selected in San Thome. As a result of the short-term programme over 450,000 hybrid seeds were produced up to the end of 1964.Abbreviations INEAC Institut National pour l'Étude Agronomique du Congo Belge - IRHO Institut de Recherches pour les Huiles et Oléagineux - MEAU Missão de Estudos Agronómicos do Ultramar - WAIFOR West African Institute for Oil Palm Research  相似文献   

3.
A total of 251 Dura cross Pisifera (DxP) hybrid palms from six populations descending from six parental African Pisifera origins and involving 12 progenies were analyzed with 19 selected Simple Sequence Repeats (SSR) markers. A total of 110 alleles were produced, ranging from three to eight per SSR, with a mean of 5.8 alleles per SSR locus. Of these, 68.5% were considered shared alleles by more than one population and the remaining 31.5% were population specific alleles. They generated between six and 21 haplotypes in all populations, and depending on the SSR marker, between one and 10 haplotypes within populations. Various parameters for analyzing genetic variability, differentiation and genetic structure were computed using GenAlEx, Structure and Darwin software. The obtained results confirmed microsatellites as a robust, feasible and trustful method for obtaining DNA fingerprints, tracing the source of oil palm samples. With respect to the authenticity of materials or for solving legitimacy issues, accession belonging to each population by SSR markers could be distinguished, but additional SSR should be screened for improving this process.  相似文献   

4.
In the present study a population consisting of 247 F2 individuals from the cross between Basmati 370, a superior quality basmati variety and ASD16, a non-basmati high-yielding variety was analyzed for their segregation pattern of grain length (GL), grain breadth (GB), cooked grain length (CGL), cooked grain breadth (CGB), and gelatinization temperature (GT). Except GT, all other traits showed normal distribution indicating the polygenic control over the traits. The correlation analysis between traits indicated that GT had positive significant association with GL (0.125), and CGL (0.243). To identify main effect QTL (MQTL) for the above grain quality traits, both the parents were surveyed with 86 primer pairs of simple sequence repeats (SSR). The parental survey revealed 63.95% polymorphism between parents. In order to detect the MQTL associated with grain quality traits, a strategy of combining the DNA pooling from selected segregants and genotyping was adopted. The number of individuals forming the bulk influenced the identification of putative marker(s) for each of the traits. The association of putative markers identified based on DNA pooling from selected segregants was established by Single Marker Analysis (SMA). The results of SMA revealed that SSR markers, RM225 on chromosome #6 and RM247 on chromosome #12 showed significant association with GB and CGB respectively. It is established that molecular marker analysis involving DNA pooling of phenotypic extremes and selective genotyping helps to detect MQTL for complex traits involving early segregating generations. The molecular marker analysis involving the DNA pooling of phenotypic extremes could be a useful strategy to detect the genetic loci with major effects of other complex grain quality traits in rice.  相似文献   

5.
新疆早熟棉品种SSR指纹图谱构建与品种鉴别   总被引：11，自引：5，他引：6  
以新疆自1978年以来审定命名的42个早熟棉品种为材料,利用SSR分子标记对新疆早熟棉品种进行研究。从2300对SSR引物中筛选出了52对具有稳定多态性的引物,每对引物可检测到3～24个多态性片段,共检测到506个,平均9.7个,片段大小介于100～2000bp之间。对所得到的52个SSR指纹图谱进行组合和综合分析,用其中2对就可将所有供试品种区分开来。同时,分别对42个早熟棉品种进行指纹分析,获得各个品种的特异性指纹,可为今后棉花种子真伪快速鉴别奠定基础。  相似文献   

6.
油棕是热带地区重要的木本油料作物之一。由于是多年生植物,传统的常规杂交育种方法周期长,随着组培技术和分子生物学技术在油棕育种中的应用,已成为油棕遗传改良研究的重要辅助手段。本文从油棕育种的研究现状及未来发展等进行综述。  相似文献   

7.
Variation in metabolite composition and content is often observed in citrus, however, it is poorly understood to what extent this variation has a genetic basis. C. aurantium genotypes originating from Tunisia were evaluated to detect genomic (SSR markers) and chemotypic polymorphisms and to discover possible associations between them. A total of fifteen highly polymorphic SSR markers were selected to screen the genetic variability of the most widespread sour orange genotypes. Targeted secondary metabolite profiling analysis generated twenty-one compounds differentially accumulated in the leaves of sour orange genotypes. PCA analysis revealed that genomic and chemotypic data generated similar pattern of clustering, highlighting the intra-specific variability in C. aurantium species. Both data were integrated, leading to the identification of associated SSR alleles with secondary metabolites. Based on results, a relatively high correlation (r = 0.381; p < 0.0001) between chemotypic patterns and genetic markers was identified. Associations between traits of interest for phenolic compounds and genetic markers were tested using statistical methods including three linear model approaches. These results consolidate the presence of a chemical fingerprint that may be suitable for assessing identity and quality of a particular genotype which will be very useful for citrus breeding programs.  相似文献   

8.
利用SRAP与SSR标记分析不同类型甜菜的遗传多样性   总被引：19，自引：1，他引：18  
为选育优质甜菜新品种, 指导种质资源引进和利用, 为进行分子标记辅助选择育种提供科学依据, 采用SRAP和SSR两种分子标记方法相结合, 对甜菜单胚雄性不育系及保持系等49份材料进行遗传多样性分析。利用4个表型差异显著的甜菜品系对SRAP的64对引物组合及SSR的11对引物组合进行扩增, 分别筛选出有效引物组合11对和9对。SRAP的11对引物组合共产生199条扩增带, 其中有86条多态性带, 多态性带的比率平均为43.7%。SSR的9对引物共产生35条扩增带, 多态性比率为100%。全部材料的平均遗传距离为0.3860, 平均遗传相似系数为0.6795, 大约30%的材料遗传距离或遗传相似系数具显著或极显著差异。遗传相似系数平均值比较, 多胚四倍体品系0.7264＞单胚杂交组合0.7243＞国外品种0.7060＞多胚二倍体品系0.6908＞单胚品系0.6837。在遗传距离0.20处, 将49个甜菜材料划分为A、B、C、D 4个类群, D类群又分为4个亚类, 较好地显示了甜菜材料丰富的遗传多样性。表明不同甜菜品种具有相当高的异质性, 国外与国内材料的遗传基础存在一定差异, 但生产应用的甜菜品种间存在亲缘关系较近、遗传基础较窄的倾向。  相似文献   

9.
以远杂9102×中花5号杂交后代衍生的重组近交系F8代家系为材料，在含油量测试的基础上，选用10份低油材料(平均含油量52.91%)、12份高油材料(平均含油量58.85%)以及亲本进行SSR引物筛选，通过631对SSR引物扩增，筛选出来源于7对引物的13个有显著差异的片段可以有效区分低油材料和高油材料。以这7对差异引物在F8 RIL群体中扩增，对20份低油家系材料(含油量<55%)和45份高油家系材料(含油量>56%)进行统计分析，获得1个与花生含油量相关的分子标记2A5-250/240，其中，标记2A5-250为低油材料(含油量<55%)所拥有，相符率为95.0%，标记2A5-240为高油材料(含油量>56%)所拥有，相符率为88.9%。用SSR标记2A5-250/240检测11份高油(平均含油量为55.93%)栽培种花生和11份低油(平均含油量为48.41%)栽培种花生，结果表明，标记2A5-240与高油栽培种花生的符合率为63.6%，2A5-250与低油栽培种花生的符合率为90.9%。在19份高油(平均含油量为58.60%)野生花生中，10份野生花生能检测到标记2A5-240。综合分析RIL群体和自然群体的研究结果表明，标记2A5-250/240可用于花生含油量分子标记辅助选择。  相似文献   

10.
The traditional process of obtaining maize hybrids involves the generation of inbred lines through successive generations of selfing and subsequent testcrosses in order to identify the best combining ability by allelic complementation. A fast alternative to obtain inbred lines is to induce the formation of haploids followed by chromosome doubling. However, even with the aid of haploid-inducing genetic sources, this strategy has not been widely used in maize breeding programs, partly due to difficulties inherent to haploid generation and identification. In order to evaluate the possibility of using dihaploids to generate homozygous maize tropical lines, we used the androgenetic haploid inducer line W23 as a female parent in crosses with the tropical single-cross hybrid BRS1010. Within the progeny of these crosses, 462 seeds were phenotypically selected as putative haploids by the purple-colored endosperm and colorless embryo conditioned by the R1-nj gene. Among these, only four individuals were confirmed as being haploids using SSR markers, chromosome counting and flow cytometry, showing that the phenotypic marker was not efficient in detecting haploids in the tropical maize genotype used. All four haploids as well as some diploid plants presented reduced size, corroborating the difficulties for haploid identification by phenotypic evaluation. Genetic diversity analysis revealed by SSR markers divided the haploids in two groups represented by flint and dent maize inbred lines, which could be helpful in identifying complementary dihaploid lines. The present article demonstrates that a combination of haploid production and SSR fingerprinting is a feasible strategy for maize hybrid development in tropical germplasm.  相似文献   

11.
大豆品种豫豆25抗疫霉根腐病基因的鉴定   总被引：6，自引：1，他引：5  
大豆疫霉根腐病是大豆破坏性病害之一。防治该病的最有效方法是利用抗病品种。迄今,已在大豆基因组的9个座位鉴定了15个抗大豆疫霉根腐病基因,但是只有少数基因如Rps1c、Rps1k抗性在我国是有效的。因此,必需发掘新的抗疫霉根腐病基因,以满足抗病育种的需求。豫豆25具有对大豆疫霉菌的广谱抗性,是目前筛选出的最优异的抗源。以豫豆25为抗病亲本分别与豫豆21和早熟18杂交构建F2:3家系群体。两个群体的抗性遗传分析表明,豫豆25对疫霉根腐病的抗性由一个显性单基因控制,暂定名为RpsYD25。用SSR标记分析两个群体,RpsYD25均被定位于大豆分子遗传图谱N连锁群上。由于Rps1座位已作图在N连锁群,选择Rps1k基因中的一些SSR设计引物,检测RpsYD25与Rps1座位的遗传关系。结果表明,一个SSR标记Rps1k6与RpsYD25连锁,二者之间的遗传距离为19.4 cM。因此,推测RpsYD25可能是Rps1座位的一个新等位基因,也可能是一个新的抗病基因。  相似文献   

12.
AFLP marker associations with agronomic and fiber traits in cotton   总被引：1，自引：0，他引：1  
DNA markers linked with major QTL contributing to traits of importance will be a useful tool for cotton (Gossypium spp.) genetics and breeding. We crossed four photoperiod-sensitive accessions of cotton, G. hirsutum L., with a cultivar, selected day-neutral plants and backcrossed four times to each of the four photoperiod-sensitive accessions, selecting day-neutral plants at each generation. The day-neutral plants from the first cross and the four backcross generations were advanced to the F6. These 20 day-neutral lines and four cultivars were grown in two environments at Mississippi State, MS and scored for seven agronomic and fiber quality traits. They were also scored for AFLP markers using a bulk sample of leaves from each of 24 lines. More than 50 AFLP markers were associated with the seven traits with fewer markers associated with fiber than agronomic traits. However, one to four markers were associated with 22–93% of the phenotypic variability of each of the seven traits. The results suggest that selected markers could be used in marker assisted selection (MAS) in crosses designed to use alleles from exotic accessions or cultivars to develop elite breeding lines for cotton improvement.  相似文献   

13.
In sugarcane breeding programs, parents used in crosses are classified as male or female based on relative amounts of viable pollen produced. Usually the ‘female’ parent produces some pollen, albeit at a lower level than the ‘male’ parent. The possibility of selfing and associated problems have long been recognised by breeders. A high level of selfing may seriously bias estimates of breeding value of parents and affect the reliability of family means for identifying superior crosses. However, there is no reliable information reported indicating the level to which selfing is occurring in sugarcane crosses. The level of selfing was evaluated in eight Australian sugarcane crosses using RAPD markers. The crosses were selected as exhibiting variable levels of performance, as judged by measurements of commercial cane sugar (CCS), cane yield (TCH) and sugar yield (TSH) in plots consisting of random progeny clones. Five to eight male-specific RAPD bands were identified for each cross and used to screen twenty-eight to thirty-eight progeny from each cross. Selfed progeny were identified in each cross on the basis of absence of any male-specific RAPD bands after screening with at least 5 such RAPDs. Levels of selfing ranged from 0 to17.6%, with most of the crosses exhibiting zero or low levels of selfing. Although only a limited number of sugarcane crosses have been studied, this survey suggests that unwanted selfing is not a significant problem in the Australian sugarcane breeding program. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

14.
Manfred Huehn 《Euphytica》1996,91(3):365-374
Summary Based on maximization of selection response, Peek (1986) proposed methodology for determining the optimum number of crosses and progeny per cross in breeding self-fertilizing crops. By this method the total selection response is obtained by adding the individual responses from the two steps of selection: selection between crosses and selection within crosses. In this paper, Peek's approach has been generalized for finite or nonnormal populations. Optimum numbers of crosses are determined by testing capacity, number of selected crosses, number of selected lines from each selected cross, and heritability.In the case selection of the best line from the best cross, the optimum number of crosses increases monotonically with increasing testing capacity (for any given fixed heritability). For increasing heritabilities, however, the optimum number of crosses exhibits relatively flat maxima (for any given fixed testing capacity). These maxima are located at intermediate or sub-intermediate heritabilities.For varying numbers of selected crosses and selected lines from each selected cross the main results are: The optimum number of crosses i) increases with increasing testing capacity, ii) increases with increasing number of selected crosses and iii) decreases with increasing number of selected lines from each selected cross.  相似文献   

15.
亚麻遗传连锁图谱的构建   总被引：2，自引：0，他引：2  
利用DIANE (纤用亚麻栽培种)和宁亚17 (油用亚麻栽培种)为杂交亲本,构建30个F2单株作为作图群体,选用71对SRAP和24对SSR共显性标记构建了全长为546.5 cM,含12个连锁群(LGs)的亚麻遗传连锁图谱,标记均匀分布于12个连锁群,每个连锁群有4~15个标记,标记间平均距离为5.75 cM。结果表明,SRAP标记和SSR标记中共显性标记适合于亚麻遗传连锁图谱的构建,但该图谱覆盖的基因组范围较小,需继续图谱的完整性工作。本研究为今后的亚麻在分子生物学方面的研究提供了基础信息。  相似文献   

16.
Breeding in oil palm aims mainly at improving palm oil yield. Short palms are also desired because they are easy to harvest and increase the economic life of the plantation. A total of 23 progenies from Deli × La Mé and Deli × PO 1097 P (Yangambi) crosses were field tested at La Dibamba Oil Palm Research Centre in Cameroon from 1988 to 1998. Oil yield components were measured on per palm basis from 3 to 9 years after planting, and the vertical growth at 6 years after planting. The mean oil yield of the trial was average, representing 102% of the control (3.515 t/ha), and the mean height 6 years after planting was 101% that of the control (88.0 cm). The analysis of variance detected differences among progenies for various yield parameters and vertical growth. The comparison of means showed clear separation of groups of progenies for oil yield at the juvenile period (3–5 years after planting). At maturity (6–9 years after planting), the groups of progenies were overlapping indicating that progenies were comparable each other. However, four precocious progenies and high oil yielding at maturity (119–122% of the control) in absolute values can be released to planters. Though their vertical growth represented 116–127% of that of the control, short pisifera palm are expected from parental selfs or crosses given the intrinsic heterozygosity of oil palm.  相似文献   

17.
Sex-linked SSR markers in hemp   总被引：3，自引：0，他引：3  
J. Rode    K. In-Chol  B. Saal    H. Flachowsky    U. Kriese  W. E. Weber 《Plant Breeding》2005,124(2):167-170
Hemp is a dioecious plant with sex chromosomes X and Y, the male sex being heterogametic. The quality of the fibre depends on the sex type. The sex chromosomes can be characterized by molecular markers. In this report, sex‐linked simple sequence repeat (SSR) markers are described. One SSR marker was polymorphic in both the populations derived from single crosses, two other markers in but one of the two populations. Three alleles were detected for two SSR markers indicating polymorphism not only between X and Y, but also between different X chromosomes. In addition, several sex‐linked RAPD markers were detected in one population. Recombination within the sex chromosomes was observed for nearly all markers.  相似文献   

18.
选取53个SSR标记,分析了55份参试水稻种质的遗传多样性和亲缘关系,以期为选配组合与改良亲本提供参考.本试验共检测到267个等位变异,平均每个位点等位变异数为5.04个,变化范围为4～7个;53个SSR标记的多样性指数(PIC)平均为0.624,变化范围是0.287～0.786.55份不同材料大体上可分为籼稻和粳稻两大类,各品种间遗传距离在0.588～0.996之间.明恢86与53份供体亲本间的相似性系数为0.655～0.850,蜀恢527与53份供体亲本间的相似性系数为0.640～0.873.试验结果表明检测SSR多态性是研究水稻品种之间遗传差异的高效、准确的手段之一,为高代回交导入群体的有利基因发掘和利用提供了有益的参考.  相似文献   

19.
The improvement of cotton fiber quality has become more important because of changes in spinning technology. Stable quantitative trait loci (QTLs) for fiber quality will enable molecular marker-assisted selection to improve fiber quality of future cotton cultivars. A simple sequence repeat (SSR) genetic linkage map consisting of 156 loci covering 1,024.4 cM was constructed using a series of recombinant inbred lines (RIL) developed from an F2 population of an Upland cotton (Gossypium hirsutum L.) cross 7235 × TM-1. Phenotypic data were collected at Nanjing and Guanyun County in 2002 and 2003 for 5 fiber quality and 6 yield traits. We found 25 major QTLs (LOD ≥ 3.0) and 28 putative QTLs (2.0 < LOD < 3.0) for fiber quality and yield components in two or four environments independently. Among the 25 QTLs with LOD ≥ 3, we found 4 QTLs with large effects on fiber quality and 7 QTLs with large effects on yield components. The most important chromosome D8 in the present study was densely populated with markers and QTLs, in which 36 SSR loci within a chromosomal region of 72.7 cM and 9 QTLs for 8 traits were detected.  相似文献   

20.
Elaeis oleifera or ‘caiaué’, a close relative of oil palm (E. guineensis), has some agronomic traits of great interest for the oil palm genetic breeding such as slow growth, oil quality (mostly unsaturated) and disease resistance. An analysis of a Brazilian oil palm germplasm collection was carried out using RAPD (Random Amplified Polymorphic DNA) markers with the objective of understanding the genetic variation of ‘caiaué’ accessions collected in the Amazon Forest in the last two decades. A sample of 175 accessions obtained along the Amazon River Basin was analyzed and compared to 17 accessions of oil palm from Africa. Ninety-six RAPD markers were used in the analysis, of which fourteen were shown to be specific to oil palm, while twelve were specific to ‘caiaué’. Results showed that the Brazilian ‘caiaué’ accessions studied have moderate levels of genetic diversity as compared to oil palm accessions. The data allowed the establishment of similarity groups for ‘caiaué’ accessions, which is useful for selecting parental plants for population breeding. Cluster analysis showed that, in general, genetic similarities are not correlated to geographical distances, but consistent with geographical dispersal along the Amazon River network. AMOVA showed that most of the genetic variation is found within populations, as expected for anallogamous and long-lived perennial species. The study provides important information to define strategies for future collection expeditions, for germplasm conservation and for the use of E. oleifera in breeding programs. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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