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1.
Knowledge of the genetic diversity in the germplasm accessions is important for the efficient germplasm management. We studied
45 colored rice accessions, which had been earlier collected from peninsular India. The accessions were evaluated at two diverse
locations for 12 morpho-agronomic traits and genotyped using 50 simple sequence repeat (SSR) markers. Significant genotypic
variability was observed for all morpho-agronomic traits studied. Dendrogram and principal component analysis based on morpho-agronomic
traits separated the accessions into three clusters. The first two principal components accounted for 82% of the total variation.
The most discriminatory traits were number of grains per panicle, biomass yield, and days to flowering and maturity. The SSR
analysis revealed high polymorphic information content value of 0.84. Though, Mantel test did not show a significant correlation,
yet the classification based on phenotyping and genotyping data showed good agreement for the expression of morpho-agronomic
traits in the formation of clusters. Five accessions had high concentration (> 100 μg/g) of Fe and one of Zn. Our study revealed
the presence of large genetic variation among the colored rice accessions evaluated and moderate agreement between morpho-agronomic
and SSR–based classifications and of these with geographic diversity. 相似文献
2.
Gemechu Keneni Mussa Jarso Tezera Wolabu Getnet Dino 《Genetic Resources and Crop Evolution》2005,52(5):551-561
A field experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study genetic diversity in Ethiopian faba bean
(Vicia faba L.) landraces. One hundred sixty random germplasm accessions were grown in an alpha lattice design with two replications. Data
on 12 traits were collected and analyzed. Significant differences were observed among the accessions for most of the traits
(except number of pods/podding nodes) at each location even though differences pooled over location were mostly non-significant.
Cluster analysis distinguished seven diversity classes of different sizes. Accessions from the northern half of the country
(North and South Wello, North Gonder and North Shewa) were closely related while those from the southern part of the country
(Arsi) were highly diverse. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters.
Some overlapping were encountered between accessions from the northern and those from the southern parts of the country. The
study revealed that accessions from different regions might have similar genetic background and those from the same origin
might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of
genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population.
Genetic distances between most of the clusters were significant that crosses between parents selected out of them are expected
to generate desirable progenies. Future germplasm collection, conservation and utilization strategies should put more focus
not only on inter-regional diversity in the country as a whole but also on intra-regional diversity in Arsi. 相似文献
3.
Faris Hailu Arnulf Merker Harjit-Singh Getachew Belay Eva Johansson 《Genetic Resources and Crop Evolution》2006,53(6):1089-1098
The variability of 2420 plants of tetraploid (2n = 4x = 28, AABB genome) wheat germplasm representing 121 accessions from Ethiopia were evaluated for 23 agro-morphological traits at Debre Zeit Agricultural Research Center area, Akaki substation, during the 2003 main season using multivariate methods. This enabled to assess the extent and pattern of variation of the germplasm with respect to regions, altitude classes and species and to identify the major traits contributing to the diversity. The first three and two principal components explained about 83 and 80% of the total variance among regions and altitudinal class, respectively. In the first principal component plant height, days to heading, the length and density of the spike, and kernel color were the most important traits contributing to variation that explained about 50% of regional variance. Cluster analysis grouped the accessions into 15 clusters, with 9 accessions remaining ungrouped. Based on the observed patterns of variation, it is concluded that there exists great variation in the germplasm, which provides opportunities to be utilized for genetic improvement. 相似文献
4.
Gemechu Keneni Mussa Jarso Tezera Wolabu Getnet Dino 《Genetic Resources and Crop Evolution》2005,52(5):539-549
An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity
in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data
on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except
number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions
were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall
clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C1 to C3. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite
relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among
accessions from different parts of the country. Accessions from different regions might have similar genetic background and
those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily
be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity
in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected
out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages
of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should
focus not only on inter-regional diversity but also on intra-regional diversity. 相似文献
5.
6.
Muhammad A. Khan Sabine von Witzke-Ehbrecht Brigitte L. Maass Heiko C. Becker 《Genetic Resources and Crop Evolution》2009,56(1):19-30
Patterns of geographical diversity, and the relationship between agro-morphological traits and fatty acid composition were
assessed for 193 safflower (Carthamus tinctorius) accessions representing forty countries. Accessions were assigned to eight groups based on geographical proximity. Cluster
and Principal Component analyses were performed to assess patterns of diversity among the accessions and to select the most
distant accessions from each of eight groups for analysis of randomly amplified polymorphic DNA (RAPD) markers. There was
a large amount of diversity for agro-morphological traits, fatty acid composition, and RAPD markers. Most correlations among
different traits were rather low. Plant height showed a positive correlation with days to flowering (r = 0.63**). Palmitic acid was positively correlated with stearic acid and oleic acid values, and negatively correlated with
linoleic acid (P < 0.01). Oleic acid and linoleic acid showed a strong negative correlation (r = −0.89**). The first three principal components together explained 59% of the variation, however, neither principal component
analysis (PCA) nor marker analysis revealed a clear relationship between diversity pattern and geographical origin. Accessions
from some geographical regions tended to group together, such as accessions from South Western Asia, Central Western Europe,
and the Mediterranean region. The correlation between the morphological matrix and the genetic matrix based on RAPD markers
was not significant (r = 0.027). Wide diversity in safflower germplasm indicates a considerable potential for improving this crop for both agronomic
and quality traits. 相似文献
7.
An investigation was conducted to determine the extent of diversity and relationships among a worldwide safflower (Carthamus tinctorius L.) germplasm collection and to find out adapted accessions that can be used in an organic safflower breeding program in
Germany. A total of 468 accessions was studied under organic farming conditions at Kleinhohenheim experimental station during
the seasons of 2004 and 2005. All the accessions were evaluated for 12 phenotypic traits and three rated diseases. Multivariate
analyses have been used to measure the diversity in a subset of 200 accessions and 11 geographical regions. Generally, the
study showed that there was a large genetic variation within accessions. A coefficient of variation (CV%) for investigated
traits and diseases ranged from 2.9 to 91.0% with the highest CV was recorded for yield/m2, yield/plant and seeds/plant. The
most accessions that originated in Europe revealed relatively better performance compared to non-Europeans. High yielding,
early maturing, and disease tolerant accessions were identified. However, the low oil content (8.7–22.8%) is the primary concern
in this germplasm collection. The degree of heritability varied between 10% for lodging to 86% for plant height. Genotypic
coefficient of correlation (r
g) was slightly higher for many traits than the respective phenotypic coefficient. Oil content and seed yield/m2 were highly
significantly correlated (r
g = 0.78). The genotypic coefficient of correlation showed that selection for seeds/plant and thousand kernel weight was effective
for improvement of seed yield and oil content. The results of the principal component analysis and the clustering pattern
of accessions were consistent with the results of analysis of variance. About 78% of the total phenotypic diversity in the
germplasm was explained on the basis of four principal components and 88% of the total variation among geographical regions
was contributed by the first three principal components. The distribution of the accessions within clusters has no apparent
relationship with the geographical origin. However, many of the European accessions have a tendency to stay together. 相似文献
8.
9.
Genetic diversity was investigated in 73 accessions of emmer wheat (Triticum dicoccon Schrank) from 11 geographical regions using a set of 29 simple-sequence repeat (SSR or microsatellite) markers, representing
at least two markers for each chromosome. The SSR primers amplified a total of 357 different alleles with an average of 12.31
alleles per locus. The number of fragments detected by each primer ranged between 6 (Xgwm1066) and 21 (Xgwm268). Null alleles were detected in nine of the 29 primers used. A high level of gene diversity index was observed. Across the
29 primers, gene diversity ranged from 0.60 (Xgwm46) to 0.94 (Xgwm655), with a mean of 0.82. There was a highly significant correlation (r=0.882; p<0.01) between gene diversity index and the number of loci, showing the number of loci per se is a strong indicator of diversity. Analysis of genetic diversity within and among eleven geographical regions revealed most
of the genetic diversity of the total sample resided within regions. The coefficient of gene differentiation (Gst = 0.27)
showed that the genetic variation within and among the 11 geographical regions was 73 and 27%, respectively. High value of
mean number of alleles per locus was found in Iran (4.86) followed by Morocco (4.10) and Armenia (4.03). On the contrary,
lower mean number of alleles per locus was detected in Yemen (2.83). The average gene diversity index across regions ranged
from 0.52 (Slovakia) to 0.67 (Morocco) with an average of 0.60. Multivariate techniques of principal component analysis and
clustering were employed to examine genetic relationship among the 73 emmer wheat accessions vis-à-vis geographical regions
of collections. The genetic distance coefficients for all possible 55 pairs of regional comparisons ranged from 0.63 (between
Iran and Armenia, Georgia and Azerbaijan, Georgia and Slovakia) to 0.97 (between Morocco and Yemen, Spain and Georgia, and
Turkey and Iran) with a mean of 0.82. From the PCA results, a two dimensional plot of PC1 versus PC2 was constructed. The
scatter plot of the first two principal components which explained altogether 27% of the total variation depicted the presence
of a clear pattern of geographical differentiation except in few cases like accessions from Caucasian region. Similar pattern
of genetic relationships among accessions was observed in cluster analysis. The study provided genetic information of emmer
wheat in relation to geographical regions of origin. The information could be utilized in crop improvement, germplasm conservation
programs, and in further investigation. 相似文献
10.
Tiny Motlhaodi Mulatu Geleta Stephen Chite Moneim Fatih Rodomiro Ortiz Tomas Bryngelsson 《Genetic Resources and Crop Evolution》2017,64(3):599-610
Cultivated sorghum [Sorghum bicolor (L.) Moench] is an important food security crop in the semi-arid regions of the world including Asia and Africa. Its genetic diversity is contained mostly in traditional varieties and modern cultivars used by farmers. In this study, agro-morphological traits and molecular markers were used to assess genetic diversity in 22 accessions of cultivated sorghum from five countries (Botswana, Namibia, Swaziland, Zambia and Zimbabwe) in the Southern African Development Community (SADC) region. The study revealed a significant variation among 22 accessions in both qualitative and quantitative morphological traits, indicating the accessions’ promising potential as breeding material. For molecular analysis, 11 microsatellite primer-pairs were used, and generated a total of 70 alleles across 20 accessions. Analysis of molecular variance revealed a high level of genetic variation; 67 % among the accessions and 10 % among the five countries. The patterns of genetic diversity and the relationships observed in this study should provide insights for genetic resource conservation and utilization of sorghum germplasm in the SADC region. 相似文献
11.
Pigeonpea is an important pulse crop grown by smallholder farmers in the semi-arid tropics. Most of the pigeonpea cultivars
grown to date are selections from the landraces, with a narrow genetic base. With the expansion of the crop to newer areas,
problems of local importance are to be addressed. Hence, an economically feasible and faster germplasm evaluation mechanism,
such as a core collection, is required. This article describes the development of core collection from 12,153 pigeonpea accessions
collected from 56 countries and maintained at ICRISAT, Patancheru, India. The germplasm accessions from 56 countries were
placed under 14 clusters based primarily on geographic origin. Data on 14 qualitative morphological traits were used for cluster
formation by Ward’s method. From each cluster ≈10% accessions were randomly selected to constitute a core collection comprising
1290 accessions. Mean comparisons using Newman–Keuls test, variances’ comparisons by Levene’s test, and comparison of frequency
distribution by χ2-test indicated that the core collection was similar to that of the entire collection for various traits and the genetic variability
available in the entire collection is preserved in the core collection. The Shannon–Weaver diversity index for different traits
was also similar for both entire and core collection. All the important phenotypic associations between different traits available
in the entire collection were preserved in the core collection. The core collection constituted in the present study facilitates
identification of useful traits economically and expeditiously for use in pigeonpea improvement. 相似文献
12.
13.
Variation among Spanish faba beans cultivars: taxonomic and evolutionary implications 总被引:1,自引:0,他引:1
Summary Univariate and multivariate analysis were used to examine phenotypic variability within a Spanish faba bean germplasm collection maintained at the Centro de Investigación y Desarrollo Agrario, Córdoba, Spain.The analysis of 158 Spanish faba bean accessions and 12 quantitative traits indicated highly significant differences among botanical groups for 8 characters and among geographic regions for 10 characters. An east to west clinal pattern of variation for some characters was detected.In order to identify the main characters which account for the major variation, the same collection was subjected to principal component analysis for 12 quantitative traits. Reproductive and plant height characters appeared to be the major sources of diversity.To determine the importance of both geographic and botanical variation among the Spanish cultivars, discriminant analysis was applied. According to these analyses, plant height, height of the lowest pod-bearing node, pod length and 100 seed weight, were important traits discriminating among different geographic regions. The main character discriminating among botanical groups was the 100 seed weight.Our results fit in a pattern in which both agroecological and anthropological causes could have played a role in the observed variation. This analysis can help plant breeders in choosing the most favorable accessions in plant breeding. 相似文献
14.
Kebebew Assefa Hailu Tefera Arnulf Merker Tiruneh Kefyalew Fufa Hundera 《Genetic Resources and Crop Evolution》2001,48(1):53-61
One thousand and eighty tef, Eragrostis tef (Zucc.) Trotter, entries representing 36 populations collected from six central and northern regions of Ethiopia were evaluated at Debre Zeit Agricultural Research Center during the 1995 main season to assess the quantitative trait diversity in the germplasm with respect to collection regions and altitude zones. Hierarchical analysis of variance showed large (p 0.01) variations within populations, and among populations within regions and altitude zones in all the 14 traits studied. The variations among regions were significant (p 0.05) for number of main shoot culm nodes, and panicle branches and spikelets. But only days to maturity, number of culm nodes, diameters of the two basal culm internodes, and harvest index depicted discernible (p 0.05) clinal variability. The 36 populations clustered into six major (75% similarity level) groups consisting of two up to 15 populations. Five principal components (PCs) explained about 81% of the entire phenotypic diversity among the populations. Of these, the first three PCs accounted for about 65% of the gross variance. About 31% of the total variance explained by the first PC alone originated chiefly from variability in main shoot panicle grain yield and length, culm length and diameter of the two basal culm internodes. Likewise, about 23% the variance accounted for by the second PC was due mainly to variations in grain and shoot phytomass yield/plant, and harvest index. Overall, the study demonstrated that tef is a highly versatile crop species and the enormous wealth of quantitative trait diversity in the germplasm indicates immense potential for the genetic improvement of the crop through breeding. 相似文献
15.
Alireza Pour-Aboughadareh Mostafa Mahmoudi Mohammad Moghaddam Jafar Ahmadi Ali Ashraf Mehrabi Seyed Siamak Alavikia 《Genetic Resources and Crop Evolution》2017,64(3):545-556
Genetic erosion in cultivated wheat provides a good reason for studying genetic diversity in crop wild relatives. In the present study, genetic diversity of 32 accessions belonging to T. boeoticum species collected from different parts of Iran were evaluated using 13 morphological traits as well as ten inter-simple sequence repeat primers. Statistical analysis for morphological traits showed significant differences among accessions (except number of fertile tillers and total tillers per plant). In principal component analysis, the first three PCA showed 82.65 % of the total morphological variation. Based on the morphological traits, accessions were separated into two main groups by cluster analysis. In molecular analysis, polymerase chain reactions amplified 105 DNA fragments, out of which, 95 (90.47 %) were polymorphic. From geographic perspective, the accessions sampled from western and southwestern of Iran showed the highest and lowest polymorphism, respectively. However, the maximum values of effective number of alleles (Ne), Nei’s gene diversity (He) and Shannon’s information index (I) was related to accessions collected from NW regions. Also, according to cluster analysis and PCoA plot genetic diversity was not related to geographical distribution. Overall, our results revealed a remarkable level of genetic diversity among studied Iranian T. boeoticum accessions; especially accessions collected from Kermanshah and Lorestan provinces, which can be of interest for future breeding programs. So, conservation of germplasm of these areas is recommended. 相似文献
16.
M. Fergany Balvir Kaur A. J. Monforte M. Pitrat C. Rys H. Lecoq N. P. S. Dhillon S. S. Dhaliwal 《Genetic Resources and Crop Evolution》2011,58(2):225-243
We present here the first comprehensive genetic characterization of melon landraces from the humid tropics of southern India.
The genetic diversity among 50 melon landraces collected from 3 agro-ecological regions of southern India (6 agro-ecological
sub-regions) was assessed by variation at 17 SSR loci, morphological traits of plant habit and fruit, 2 yield-associated traits,
pest and disease resistance, biochemical composition (ascorbic acid, carotenoids, titrable acidity) and mineral content (P,
K, Fe, Zn). Differences among accessions were observed in plant and fruit traits. Melon germplasm with high titrable acidity,
higher than average amounts of mineral content and resistance to Cucumber mosaic virus, Zucchini yellow mosaic virus, powdery
mildew (races 1, 2, 3, 5), Fusarium wilt (races 1, 2), Aphis gossypii and leafminer was recorded in the collection. A high level of genetic variability in melon germplasm was suggested by the
SSR analysis. Comparative analysis using SSRs of the genetic variability between Indian melons from north, south, and east
regions and reference accessions of melon from Spain, France, Japan, Korea, Iraq, Zambia showed regional differentiation between
Indian melon accessions and that Indian germplasm was weakly related to the melon accessions from other parts of the world,
suggesting that an important portion of the genetic variability found within this melon collection has not been used yet for
the development of new cultivars. Additional collections of acidulus melon germplasm should be made in southern India and adequate management of this important genetic resource is clearly a
necessity. 相似文献
17.
N. P. S. Dhillon R. Ranjana Kuldeep Singh I. Eduardo A. J. Monforte M. Pitrat N. K. Dhillon P. P. Singh 《Genetic Resources and Crop Evolution》2007,54(6):1267-1283
Diversity among 36 snapmelon landraces, collected from 2 agro-ecological regions of India (9 agro-climatic sub-regions), was
assayed using RAPD primers, morphological traits of plant habit and fruit, 2 yield-associated traits, pest and disease resistance
and biochemical composition (TSS, ascorbic acid, titrable acidity). Typical differences among accessions were observed in
plant and fruit characteristics and snapmelon germplasm with high titrable acidity and possessing resistance to downy mildew,
Cucumber mosaic virus, Zucchini yellow mosaic virus, Papaya ringspot virus, Aphis gossypii and Meloidogyne incognita was noticed in the collection. RAPD based grouping analysis revealed that Indian snapmelon was rich in genetic variation
and region and sub-region approach should be followed across India for acquisition of additional melon landraces. Accessions
of var. agrestis and var. momordica clustered together and there was a separate cluster of the accessions of var. reticulatus. Comparative analysis of the genetic variability among Indian snapmelons and an array of previously characterized reference
accessions of melon from Spain, Israel, Korea, Japan, Maldives, Iraq, Pakistan and India using SSRs showed that Indian snapmelon
germplasm contained a high degree of unique genetic variability which was needed to be preserved to broaden the genetic base
of melon germplasm available with the scientific community.
N. P. S. Dhillon and Ranjana contributed equally to this work and are considered the first authors. 相似文献
18.
Jinggui Fang Chih-Cheng T. Chao Philip A. Roberts Jeffrey D. Ehlers 《Genetic Resources and Crop Evolution》2007,54(6):1197-1209
Cowpea is an important grain legume and hay crop of many tropical and subtropical regions, especially in the dry savanna region
of West Africa. The cowpea gene pool may be narrow because of a genetic bottleneck during domestication. Genetic variation
within specific breeding programs may be further restricted due to breeding methods, ‘founder effects’ and limited exchange
of germplasm between breeding programs. Genetic relationships among 60 advanced breeding lines from six breeding programs
in West Africa and USA, and 27 landrace accessions from Africa, Asia, and South America were examined using amplified fragment
length polymorphism (AFLP) markers with six near infrared fluorescence labeled EcoRI + 3/1bases/MseI + 3/1bases primer sets. A total of 382 bands were scored among the accessions with 207 polymorphic bands (54.2%). Despite
a diverse origin, the 87 cowpea accessions shared a minimum 86% genetic similarity. Principal coordinates analysis showed
clustering of breeding lines by program origin, indicating lack of genetic diversity compared to potential diversity. Accessions
from Asia and the Americas overlapped and were distinct from West African breeding lines, indicating that germplasm from Asia
and the Americas have common origins outside West Africa. US and Asian breeding programs could increase genetic variability
in their programs substantially by incorporating germplasm from West Africa, while national programs in West Africa should
consider introgression of Asian germplasm and germplasm from other parts of Africa into their programs to ensure long-term
gains from selection. 相似文献
19.
Wild melon diversity in India (Punjab State) 总被引:1,自引:1,他引:0
Anamika Roy S. S. Bal M. Fergany Sukhjeet Kaur Hira Singh Ajaz A. Malik Jugpreet Singh A. J. Monforte N. P. S. Dhillon 《Genetic Resources and Crop Evolution》2012,59(5):755-767
We present here the first comprehensive genetic characterization of wild melon accessions from northern India. The genetic diversity among 43 wild melon accessions collected from the six agro-ecological regions of the Punjab State of India was assessed by measuring variation at 16 Simple Sequence Repeat (SSR) loci, morphological traits of plant habit and fruit morphological traits, two yield-associated traits, root nematode resistance and biochemical composition (ascorbic acid, carotenoids, titrable acidity). Variation among accessions was observed in plant habit and fruit traits and wild melon germplasm with high acidity and elevated carotenoid content and possessing resistance to Meloidogyne incognita was identified in the collection. A high level of genetic variability in wild melon germplasm was suggested by SSR analysis. Comparative analysis using SSRs of the genetic variability between wild melons from the north and other melons from the south and east regions of India and also reference accessions of cultivated melon from Spain, Japan, Korea, Maldives, Iraq and Israel, showed regional differentiation among Indian melon accessions and that Indian germplasm was not closely related to melon accessions from other parts of the world. A highly drought tolerant accession belonging to var. agrestis Naud. was also identified. 相似文献