共查询到20条相似文献，搜索用时 31 毫秒
1.
2.
Geoffrey Onaga James Egdane Richard Edema Ismail Abdelbagi 《Journal of Crop Science and Biotechnology》2013,16(1):53-62
A major emphasis in breeding for iron toxicity tolerance in rice is to identify differences that are associated with resistance and harness them for genetic improvement. In this study, thirty accessions, including IRRI gene bank accessions, two varieties from Brazil, 8 cultivars from West Africa and 10 cultivars from Uganda were analyzed for sensitivity to iron toxicity, and genetic diversity using morphological and SSR markers. Two genotypes, IR61612-313-16-2-2-1 and Suakoko 8 showed significantly high resistance with an average score of ≤ 3.5 on 1–9 scale. The SRR markers were highly informative and showed mean polymorphism information content (pic) of 0.68. The PIC values revealed that RM10793, RM3412, RM333, RM562, RM13628, RM310, RM5749, and RM154 could be the best markers for genetic diversity estimation of these rice cultivars. Diversity at the gene level showed an average of 4.61 alleles ranging from 2 to 12 per locus. Mean gene diversity (H) value for all SSR loci for the 30 genotypes evaluated was 0.69 but was decreased to 0.53 when analysis was performed on Ugandan accessions. The low genetic diversity found among the Ugandan accessions is the evidence of a narrow genetic base, and such a scenario has a potential vulnerability for resistance break down. A low correlation was detected between the observed molecular and morphological datasets. This means that a combination of morphological traits and SSR analysis would be required when assessing genetic variation under iron toxic conditions, and could be a practical strategy for breeders when planning crosses. A distinction between the resistant and susceptible accessions in both phenotyping and SSR datasets suggests the presence of unique alleles that could be harnessed for improvement of rice against iron toxicity. 相似文献
3.
4.
5.
Gabriel Borges Mundim José Marcelo Soriano Viana Ciro Maia Geísa Pinheiro Paes Rodrigo Oliveira DeLima 《Euphytica》2013,191(2):291-299
Popcorn inbred lines with more efficient nitrogen use are better able to uptake nitrogen from the soil and convert it into higher grain yield, resulting in lower environmental and economic impacts caused by nitrogen fertilization. The objectives of this study were to (i) identify inbred lines superior in nitrogen use (ii) assess the genetic diversity between popcorn inbred lines under high and low N conditions and (iii) investigate the causal effects of several traits in nitrogen use efficiency (NUE). We evaluated 25 popcorn inbred lines under high and low N, and several traits related to NUE and its components were measured. Efficient and inefficient inbred lines under both N levels were identified and can be useful for generating a segregating population for quantitative trait loci mapping. The genetic diversity assessment based on phenotypic traits grouped the inbred lines into four clusters under both N levels, and the efficient inbred lines were grouped together, as were the inefficient lines. The most divergent inbred lines under high N were classified as efficient and intermediate and can be useful to generate a divergent breeding population with a high frequency of favorable genes for NUE. Nitrogen uptake efficiency (NUpE) was considered the most important trait for NUE. To improve the accuracy of selection for NUE, a selection index involving the total root length (TRL), daily growth and NUpE traits under both N levels is recommended, as these traits had high correlations with and direct effects on NUE. 相似文献
6.
Paula Menna Barreto Dias Bernadette Julier Jean-Paul Sampoux Philippe Barre Miguel Dall’Agnol 《Euphytica》2008,160(2):189-205
The NPGS-USDA core collection with 85 accessions of red clover, an important forage species, is little described. The goal
of the present study was to evaluate the diversity of a set of accessions from the core collection at the morphological and
molecular level in order to extract some valuable accessions for Brazilian red clover breeding programs. Twenty-one morphological
traits, collected in field and greenhouse in South Brazil, and seven SSR markers were used to describe 57 accessions from
the U.S. core collection and one population cultivated in Southern Brazil. Variation between accessions was large for most
of the 21 morphological traits. A cluster analysis based on the morphological traits revealed five distinct clusters that
separated the populations according to flowering earliness, as already described, but also according to persistency, growth
habit and dry matter productivity. Over seven SSR loci, the number of alleles averaged 11.1 alleles per locus. Genetic diversity
measured with SSR markers was high, with a mean expected heterozygosity of 0.86. An analysis of molecular variance revealed
that the largest proportion of variation (83.6%) resided at the within population level. Although the molecular markers also
separated accessions into five clusters, there was no coincidence between the composition of groups found with morphological
and molecular data. Use of genetic diversity in breeding programs requires to use the most promising populations, to combine
positive traits such as persistency and forage yield, and probably to use within population variation to detect valuable genotypes
that could be used as parents of synthetic varieties. 相似文献
7.
Cultivated groundnut (Arachis hypogaea L.) is an agronomically and economically important oilseed crop grown extensively throughout the semi-arid tropics of Asia, Africa and Latin America. Rust (Puccinia arachidis) and late leaf spot (LLS, Phaseoisariopsis personata) are among the major diseases causing significant yield loss in groundnut. The development of varieties with high levels of resistance has been constrained by adaptation of disease isolates to resistance sources and incomplete resistance in resistant sources. Despite the wide range of morphological diversity observed in the cultivated groundnut gene pool, molecular marker analyses have thus far been unable to detect a parallel level of genetic diversity. However, the recent development of simple sequence repeat (SSR) markers presents new opportunities for molecular diversity analysis of cultivate groundnut. The current study was conducted to identify diverse disease resistant germplasm for the development of mapping populations and for their introduction into breeding programs. Twenty-three SSRs were screened across 22 groundnut genotypes with differing levels of resistance to rust and LLS. Overall, 135 alleles across 23 loci were observed in the 22 genotypes screened. Twelve of the 23 SSRs (52%) showed a high level of polymorphism, with PIC values ≥0.5. This is the first report detecting such high levels of genetic polymorphism in cultivated groundnut. Multi-dimensional scaling and cluster analyses revealed three well-separated groups of genotypes. Locus by locus AMOVA and Kruskal–Wallis one-way ANOVA identified candidate SSR loci that may be valuable for mapping rust and LLS resistance. The molecular diversity analysis presented here provides valuable information for groundnut breeders designing strategies for incorporating and pyramiding rust and late leaf spot resistances and for molecular biologists wishing to create recombinant inbred line populations to map these traits.E.S. Mace and D.T. Phong contributed equally to this work. 相似文献
8.
Huiling Liu Xiping Yang Qian You Jian Song Liping Wang Jisen Zhang Zuhu Deng Ray Ming Jianping Wang 《Euphytica》2018,214(3):48
Sugarcane (Saccharum spp) is an important crop for both sugar and biofuel production. However, the sugarcane breeding process has resulted in modern sugarcane cultivars with a narrow genetic basis. To broaden the genetic basis and promote international collaborations in sugarcane cultivar development, we documented the peidgrees of representative sugarcane culativars widely used in China and the United States of America (USA), recruited more than six thousand simple sequence repeat (SSR) markers for sugarcane, and assessed the genetic diversity and relationships beween representative sugarcane cultivars and their potential ancestry accessions. The SSR gentoyping results indicated that both the USA and Chiniese cultivars had low genetic diversity, specifically the Chinese cultivars. The USA sugarcane cultivars experienced high presure of selection for sugar content as they had the closest relationship with S. officinarum, followed by Chinese cultivars, S. robustum, and S. spontaneum. The sugarcane accessions assessed could be divided into five and four groups through cluster and principal component analysis, respectively. S. spontaneum as a potential ancestor contributing to the stress tolerance of sugarcane cultivars was grouped into distinct clusters, and S. officinarum was grouped with sugarcane cultivars in both countries. S. robustum did not seem to contribute to the sugarcane cultivar development in China, but may have contributed to the USA cultivar development. This study not only provided a collection of easy to use SSR markers, but also detailed genetic diversity and relationship among the cultivars in the two counties, which will be referable to promote international collaboration and broaden the genetic basis of sugarcane cultivars. 相似文献
9.
K. Vijayan P. K. Kar A. Tikader P. P. Srivastava A. K. Awasthi K. Thangavelu B. Saratchandra 《Plant Breeding》2004,123(6):568-572
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. 相似文献
10.
Genetic diversity in 90 Indian soybean cultivars was assessed using 45 SSR markers distributed on 20 soybean chromosomes. Forty-five SSR markers generated 232 alleles with an average of five alleles/locus. The observed frequencies of the 232 alleles ranged from 0.01 to 0.94 with an average of 0.19. The polymorphic information content (PIC) value of the SSR markers varied from 0.10 to 0.83 with an average of 0.61 and about 71% markers have a PIC value of >0.5. In this study, 54 rare alleles including 19 genotype specific alleles were also identified. The observed hetrozygosity for SSR markers ranged from 0 to 0.11 with a mean of 0.10. Cluster analysis grouped the 90 soybean cultivars into three major clusters and principal coordinates analysis (PCoA) results were similar to those of the cluster analysis. A combination of eight SSR markers successfully differentiated all 90 soybean cultivars. The population structure analysis distributed the 90 soybean genotypes into two populations with mean alpha (α) value of 0.1873. In AMOVA analysis, proportion of variation within population was high (88%), whereas only 12% occurred among populations. In cluster and structure analyses, most of the genotypes with similar pedigree were grouped together. Soybean cultivars DS228, MACS-13, LSb-1, Hardee, Improved Pelican, and Pusa-24 were the six most genetically distinct cultivars identified. The study reported a moderate genetic diversity in Indian soybean cultivars and findings would be useful to the soybean breeders in selecting genetically distinct parents for a soybean improvement program. 相似文献
11.
为了探究形态标记和分子标记对短枝木麻黄无性系遗传多样性评价的差异性,本研究分别利用形态标记和分子标记两种方法对109个短枝木麻黄无性系单株进行遗传多样性差异的比较分析。结果表明:12个形态性状的多样性指数(H’)范围在0.347~2.053之间,其中各质量性状差异较大,短枝木麻黄无性系的表型相似度较高。基于形态性状和分子标记的聚类分析结果,分别可将参试的109个短枝木麻黄无性系单株分别聚为13类和22类,而分子标记的聚类结果更为精确。12对EST-SSR标记引物共检测到等位基因50个,平均每个位点3.42个;无性系样本的观测杂合度Ho和期望杂合度He平均为0.867和0.641;群体的平均Shannon多样性信息指数为1.099,分子标记分析表明华南沿海地区短枝木麻黄无性系人工林遗传多样性较低。研究发现两种方法对短枝木麻黄无性系的遗传多样性评估结果的一致性较低,表明华南沿海林木形态性状标记易受环境影响,遗传多样性评价方法应以分子标记法为主。 相似文献
12.
I. Karsai Gy. Vida S. Petrovics E. Petcu B. Kobiljski S. Ivanovska Z. Bedő O. Veisz 《Euphytica》2012,186(1):139-151
The genetic diversity present in the breeding programs of southeast Europe was assessed in a set of 114 winter wheat (Triticum aestivum L.) cultivars using AFLP and SSR markers. The average genetic diversity characterised with the Jaccard’s distance coefficient was 0.605 with an interval of 0.053 and 0.889. The wheat cultivars originating from the four countries differed from each other in their clustering patterns, including the numbers of clusters and the most prevalent cluster, which was breeding program-specific. Hungarian and Romanian cultivars showed closer relationships, and Serbian and Macedonian cultivars grouped together more frequently. The phenotypic variability of the same cultivars was assessed under diverse ecological conditions of the four growing sites, measuring the disease resistance against two foliar diseases, and several agronomic traits. Of the phenotypic traits, powdery mildew and leaf rust responses showed significant associations with genetic diversity, whereas heading date, plant height and yield components did not. Through parallel assessment of genotypic and phenotypic diversity it was possible to separate winter wheat cultivars with similar genotype but diverse phenotype from those with similar phenotype but diverse genotype. This information will allow breeders to make informed decisions in selecting parents for new crosses. 相似文献
13.
本研究利用18对SSR分子标记对20份常用甘蔗亲本进行遗传多样性分析,实验结果表明,共扩增出410条带,每对引物的扩增带数为9～52条,平均23条;遗传相似性为0.522～0.693,平均为0.606,相似系数较低,亲本间遗传差异较大。SSR聚类分析结果表明:以相似系数0.61为标准,可以将20份常用甘蔗亲本分为四类,分类结果与系谱来源基本吻合,磷效率在四类甘蔗亲本材料间存在显著的类型差异。在亲本选配过程中,综合考虑亲本的SSR分子标记及磷效率评价结果,有利于提高亲本选择准确性和培育磷高效基因型。 相似文献
14.
Comparison of phenotypic and molecular marker-based classifications of hard red winter wheat cultivars 总被引：8，自引：0，他引：8
H. Fufa P. S. Baenziger B.S. Beecher I. Dweikat R. A. Graybosch K. M. Eskridge 《Euphytica》2005,145(1-2):133-146
Genetic diversity is the basis for successful crop improvement and can be estimated by different methods. The objectives of
this study were to estimate the genetic diversity of 30 ancestral to modern hard red winter wheat (Triticum aestivum L.) cultivars adapted to the Northern Great Plains using pedigree information, morphological traits (agronomic measurements
from six environments), end-use quality traits (micro-quality assays on 50 g grain or milled flour samples for the six environments),
and molecular markers (seed storage proteins separated using SDS-PAGE, 51 SSRs, and 23 SRAP DNA markers), and to determine
the relationships of genetic distance estimates obtained from these methods. Relationships among diversity estimates were
determined using simple (Pearson) and rank (Spearman) correlation coefficients between distance estimates and by clustering
cultivars using genetic-distances for different traits. All methods found a wide range in genetic diversity. The genetic distance
estimates based on pedigree had the highest values due to possible over-estimation arising from model assumptions. The genetic
diversity estimates based on seed storage protein were lowest because they were the major determinants of end-use quality,
which is a highly selected trait. In general, the diversity estimates from each of the methods were positively correlated
at a low level with the exceptions of SRAP diversity estimates being independent of morphologic traits (simple correlation),
SDS-PAGE, and SSR diversity estimates (rank correlation). However, SSR markers, thought to be among the most efficient markers
for estimating genetic diversity, were most highly correlated with seed storage proteins. The procedures used to accurately
estimate genetic diversity will depend largely upon the tools available to the researcher and their application to the breeding
scheme. 相似文献
15.
Phosphorus use efficiency (PUE) evaluation based on shoot dry weight in the early stages of plant development can be a useful measure to identify genotypes that are superior in phosphorus (P) use. The objectives of this study were to (i) identify inbred lines that are efficient and inefficient in P use, (ii) assess the genetic diversity among the inbred lines based on traits related to PUE, (iii) investigate the relationship among traits related to PUE and its components and (iv) estimate the expected responses to selection for increasing PUE. Twenty‐three S6 popcorn inbred lines were evaluated under high and low P, and several traits related to PUE and its components were measured. Efficient and inefficient inbred lines under each P level were identified, and the genetic diversity assessment grouped these inbred lines in opposite clusters. Phosphorus acquisition efficiency (PAE) was the most important component of PUE in the early stages of plant development, and the direct selection for PAE seems to be the best method for increasing PUE in these stages. 相似文献
16.
Kelly D. Chenault Andrea L. Maas John P. Damicone Mark E. Payton Hassan A. Melouk 《Euphytica》2009,166(3):357-365
The production of cultivated peanut, an important agronomic crop throughout the United States and the world, is consistently
threatened by various diseases and pests. Sclerotinia minor Jagger (S. minor), the causal agent of Sclerotinia blight, is a major threat to peanut production in the Southwestern US, Virginia and North
Carolina. Although information on the variability of morphological traits associated with Sclerotinia blight resistance is
plentiful, no molecular markers associated with resistance have been reported. The identification of markers would greatly
assist peanut geneticists in selecting genotypes to be used in breeding programs. The main objective of this work was to use
simple sequence repeat (SSR) primers previously reported for peanut to identify a molecular marker associated with resistance
to S. minor. Out of 16 primer pairs used to examine peanut genomic DNA from 39 different genotypes, one pair produced bands at approximately
145 and 100 bp, consistent with either S. minor resistance or susceptibility, respectively. Cloning and sequencing of these bands revealed the region is well conserved among
all genotypes tested with the exception of the length of the SSR region, which varies with disease resistance levels. This
is the first report of a molecular marker associated with resistance to Sclerotinia blight in peanut. The identification of
this marker and development of a PCR-based screening method will prove to be extremely useful to peanut breeders in screening
germplasm collections and segregating populations as well as in pyramiding S. minor resistance with other desirable traits into superior peanut lines. 相似文献
17.
Vincent Lombard Benoit Tireau Françoise Blouet David Zhang Claire P. Baril 《Euphytica》2002,125(1):121-127
The ability of AFLP markers to assess the uniformity of rapeseed inbred line varieties was investigated in the context of
plant registration. Three candidate varieties were chosen on a scale of morphological heterogeneity in the field. Thirty rows
per variety were characterized with 4 primer combinations (173 markers). Principal component analysis and distribution of
pairwise Rogers' distances between rows revealed exactly the same off types as those observed in the fields. The Nei's genetic
diversity computed from the binary data matrix revealed the same diversity level as the one observed with morphological traits:
the Nei's diversity value for the most homogeneous variety, a microspore-derived doubled haploid line, was 0.0011, whereas
the value for the most heterogeneous variety was 0.0706. The similarity between the results with AFLP markers and morphological
traits showed that AFLP markers associated with adapted data analysis tools (PCA, Nei's diversity index, genetic distance
distribution) are very useful to assess the uniformity of candidate varieties in the context of plant registration.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
番茄遗传资源的聚类分析研究 总被引：2，自引：0，他引：2
通过测定番茄品质特性的遗传多样性和分子标记的多态性,对番茄品种资源进行了聚类分析。结果表明,品质特性聚类分析和分子标记聚类分析最后都形成了四大类群,而且都把果实硬度大、软化速度慢、果型长圆、含水量低、可溶性固形物含量高的加工番茄聚合在了一起,说明一些分子标记可能和控制番茄加工品质特性的基因有比较紧密的连锁关系。分子标记更能灵敏地区分不同品种间的遗传差异。不同类群间品质性状的差异明显大于群内不同品种间的差异,说明聚类分析是鉴别品种资源遗传差异程度、筛选核心资源的有效手段。 相似文献
19.
E. M. Agbicodo C. A. Fatokun S. Muranaka R. G. F. Visser C. G. Linden van der 《Euphytica》2009,167(3):353-370
This review presents an overview of accomplishments on different aspects of cowpea breeding for drought tolerance. Furthermore
it provides options to enhance the genetic potential of the crop by minimizing yield loss due to drought stress. Recent efforts
have focused on the genetic dissection of drought tolerance through identification of markers defining quantitative trait
loci (QTL) with effects on specific traits related to drought tolerance. Others have studied the relationship of the drought
response and yield components, morphological traits and physiological parameters. To our knowledge, QTLs with effects on drought
tolerance have not yet been identified in cowpea. The main reason is that very few researchers are working on drought tolerance
in cowpea. Some other reasons might be related to the complex nature of the drought stress response, and partly to the difficulties
associated with reliable and reproducible measurements of a single trait linked to specific molecular markers to be used for
marker assisted breeding. Despite the fact that extensive research has been conducted on the screening aspects for drought
tolerance in cowpea only very few—like the ‘wooden box’ technique—have been successfully used to select parental genotypes
exhibiting different mechanisms of drought tolerance. Field and pot testing of these genotypes demonstrated a close correspondence
between drought tolerance at seedling and reproductive stages. Some researchers selected a variety of candidate genes and
used differential screening methods to identify cDNAs from genes that may underlie different drought tolerance pathways in
cowpea. Reverse genetic analysis still needs to be done to confirm the functions of these genes in cowpea. Understanding the
genetics of drought tolerance and identification of DNA markers linked to QTLs, with a clear path towards localizing chromosomal
regions or candidate genes involved in drought tolerance will help cowpea breeders to develop improved varieties that combine
drought tolerance with other desired traits using marker assisted selection.
相似文献
20.
Genetic diversity in a crop species is basic to improvement of the species and can be estimated at the molecular level. The
objective of this study was to estimate genetic diversity within and between spelta and macha wheats. Random amplified polymorphic
DNA (RAPD) analysis was conducted on 69 spelta and 32 macha wheat accessions. The classification of spelta and macha accessions,
based on Jaccard genetic similarity coefficients for RAPD markers, was consistent with their geographic origin. The results
indicated that the germplasm of macha wheat was more diverse than that of spelta wheat. In the dendrogram of macha wheat,
four spelta-like accessions grouped together, separate from the remaining macha accessions, suggesting that these accessions
were misclassified. In addition, accessions with identical RAPD patterns were found, indicating that these accessions were
probably duplicated. Thus RAPD analysis can be used to estimate genetic diversity and identify duplicate accessions in wheat
germplasm collections.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献