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1.
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
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B. Kalyana Babu N. Senthil S. Michael Gomez K. R. Biji N. S. Rajendraprasad S. Satheesh Kumar R. Chandra Babu 《Genetic Resources and Crop Evolution》2007,54(2):399-404
Finger millet (Eleusine coracana), an allotetraploid cereal, is widely cultivated in the arid and semiarid regions of the world. Being rich in protein and
calcium, finger millet serves as an important staple food for rural populations in developing tropical countries where calcium
deficiency and anemia are wide spread. Thirty-two finger millet genotypes were fingerprinted using 50 random amplified polymorphic
DNA (RAPD) markers. Out of the total 529 loci generated using the 50 RAPD primers, 479 loci (91%) were polymorphic and informative
to differentiate the accessions. Cluster analysis grouped the 32 finger millet accessions into two major clusters. Among the
32 finger millet genotypes, GEC 182 and CO 12 were distantly related with a low similarity index of 0.315. These two accessions
also differed considerably in days to flowering and grain weight; GEC 182 is early flowering and has bold grains, while CO
12 is late flowering and has smaller grains. These two accessions with higher diversity at molecular level, phenology and
grain weight will be ideal as parents in hybridization programme, to develop improved finger millet varieties suitable for
peninsular region of India. 相似文献
5.
Abdelhameed Elameen Siri Fjellheim Arild Larsen Odd Arne Rognli Leif Sundheim Susan Msolla Esther Masumba Kiddo Mtunda Sonja S. Klemsdal 《Genetic Resources and Crop Evolution》2008,55(3):397-408
Sweet potato (Ipomoea batatas L.) is the fifth most important crop in the developing countries after rice, wheat, maize and cassava. The amplified fragment
length polymorphism (AFLP) method was used to study the genetic diversity and relationships of sweet potato accessions in
the germplasm collection of Sokoine University of Agriculture, Morogoro and Sugarcane Research Institute, Kibaha, Tanzania.
AFLP analysis of 97 sweet potato accessions using ten primer combinations gave a total of 202 clear polymorphic bands. Each
one of the 97 sweet potato accessions could be distinguished based on these primer combinations. Estimates of genetic similarities
were obtained by the Dice coefficient, and a final dendrogram was constructed with the un-weight pair-group method using arithmetic
average. AFLP-based genetic similarity varied from 0.388 to 0.941, with a mean of 0.709. Cluster analysis using genetic similarity
divided the accessions into two main groups suggesting that there are genetic relationships among the accessions. Principal
Coordinate analysis confirmed the pattern of the cluster analysis. Analysis of molecular variance revealed greater variation
within regions (96.19%) than among regions (3.81%). The results from the AFLP analysis revealed a relatively low genetic diversity
among the germplasm accessions and the genetic distances between regions were low. A maximally diverse subset of 13 accessions
capturing 97% of the molecular markers diversity was identified. We were able to detect duplicates accessions in the germplasm
collection using the highly polymorphic markers obtained by AFLP, which were found to be an efficient tool to characterize
the genetic diversity and relationships of sweet potato accessions in the germplasm collection in Tanzania. 相似文献
6.
Pedro Talhinhas José Leitão João Neves-Martins 《Genetic Resources and Crop Evolution》2006,53(3):563-578
Lupinus angustifolius L. is a Mediterranean species, domesticated in the 20th century, representing an important grain legume crop in Australia
and other countries. This work is focused on the collection of wild germplasm and on the characterisation of morphological
and molecular diversity of germplasm accessions. It reports the collection of 81 wild L. angustifolius accessions from the South and Centre of Portugal, available at the ‘Instituto Superior de Agronomia Gene Bank’, with subsequent
morphological and molecular characterisation of a selection of these and other accessions. A multivariate analysis of morphological
traits on 88 L. angustifolius accessions (including 59 wild Portuguese accessions, 15 cultivars and 14 breeding lines) showed a cline of variation on wild
germplasm, with plants from Southern Portugal characterised by earlier flowering, higher vegetative development and larger
seeds. AFLP and ISSR molecular markers grouped modern cultivars as sub-clusters within the wider diversity of wild germplasm,
revealing the narrow pool of genetic diversity on which domesticated accessions are based. The importance of preserving, characterising
and using wild genetic resources for L. angustifolius crop improvement is outlined by the results obtained. 相似文献
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Marker-assisted sampling of the cultivated Andean potato Solanum phureja collection using RAPD markers 总被引：5，自引：0，他引：5
Marc Ghislain Dapeng Zhang Diego Fajardo Zósimo Huamán Robert J. Hijmans 《Genetic Resources and Crop Evolution》1999,46(6):547-555
The potato crop originated in the Andean highlands where numerous farmer's varieties and non-cultivated wild species exist. An Andean potato collection is held in trust at the International Potato Center (CIP) to preserve the biodiversity of this crop and ensure the supply of germplasm for potato improvement worldwide. A core collection representing the biodiversity of the Andean potato germplasm is under construction using morphological, molecular, and geographic data. One of the eight cultivated potato species, Solanum phureja, has been genotyped using the RAPD technique. A protocol suitable for large germplasm collection genotyping has been developed to process numerous samples at reasonable costs. From 106 RAPD primers evaluated, we have selected 12 primers yielding 102 polymorphic markers, which unambiguously discriminated all 128 accessions but 2 that are possible duplicates. The S. phureja germplasm collected throughout the Andean countries appears to have a homogeneous genetic constitution. There was no clear geographic pattern as indicated by cluster analysis of the RAPD data. A sub-group of 20 accessions has been identified on the basis of the marker data and selected to maximize molecular (RAPD) variance and polymorphism. The probability of capturing equal amounts of marker polymorphism in this sub-group of 20 accessions by random sampling is less than 40%. This set accessions represents our first group of accessions that may constitute a core of the S. phureja collection. This tentative core will be challenged for diversity content by alternate markers and agronomic traits. Hence, the methodology for sampling less than 10% of the base collection, proposed for core collections by Brown (1989), can be based on molecular marker data provided cost-efficient fingerprints are developed. 相似文献
9.
Jane M. Marita Julie M. Rodriguez James Nienhuis 《Genetic Resources and Crop Evolution》2000,47(5):515-526
The development of a core collection, one which represents the genetic diversity of a crop with minimal redundancy and increases utility of the collection as a whole, is especially important as the funding for germplasm collections decreases. With limited resources, it is difficult to manage large germplasm collections and disperse genetically diverse germplasm to plant breeders. An algorithm was developed to assist in selection of core collections based on estimates of genetic distance. The criteria for selection of the maximum genetically diverse set were based on rankings of genetic distance between an accession with respect to all other accessions. Depending on the size core which a user wished, a zone around each selected accession was determined and no other accession within these limits was selected. The premise for the algorithm was that the genetic variability represented in the core must be representative of the distribution of genetic distances within the population of interest. In the present study, the algorithm was used with RAPD-marker-based estimates of genetic distance for 270 Theobroma cacao L. accessions and 134 Capsicum accessions that chose a set representing 18.5% of the population and representing the breadth of RAPD-based variation. 相似文献
10.
Establishment of sesame germplasm core collection in China 总被引：14，自引：0，他引：14
Zhang Xiurong Zhao Yingzhong Cheng Yong Feng Xiangyun Guo Qingyuan Zhou Mingde Toby Hodgkin 《Genetic Resources and Crop Evolution》2000,47(3):273-279
A sesame core collection containing 453 accessions was established by assessing genetic diversity of 4251 accessions collected in China. The accessions in the whole collection were grouped based on their origin, varietal and agro-ecological type. A computer program was used to cluster the data of 14 traits from the random small sample. Ward's method was chosen as the desirable method for clustering sesame germplasm resources. A set of technical methods for establishing core collection has been developed through determining the number of selected accessions based on the diversity distribution. The agronomic traits of the pre-selected core collection were investigated and tested in three ecological locations in China for two years. Among six qualitative traits, including plant type and flower color in a total of 5304 accessions, 97.85% was completely the same as the original data, and three quantitative traits, including growth period and plant height, were significantly and positively related with the original data. The representativeness assessment of the final core collection indicated that 35 phenotypes of 10 qualitative traits in the core collection were basically similar to those of the pre-selected core collection. Six feature values such as mean, standard deviation etc. of four quantitative traits including oil content and 1000-seed weight were close to those of the pre-selected core collection. The final core collection possessed a fair representativeness of the pre-selected core collection. 相似文献
11.
Phenotypic diversity was assessed for quantitative and qualitative traits in a salt-tolerant subset of the international safflower
(Carthamus tinctorius L.) germplasm collection originating from 11 countries in three regions (Central Asia, Southwest Asia and Africa) of the
Middle East. Phenotypically, the germplasm, among and within regions, was highly variable, especially for rosette- and yield-related
traits. Frequency of desirable variants of seven agronomically important traits ranged from 14% for long rosette period to
50% for no or few spines. Level of population differentiation was high for number of capitula per plant (30%), whereas most
traits partitioned their diversity (82–87%) within populations. Region-specific nonrandom associations among sets of qualitative
traits and the existence of broad morphological and phenotypic diversity in this germplasm were supported by the large number
of log-linear models needed to describe qualitative trait associations, the high number of principal components needed to
account for total variability, and the low discriminatory power of phenotypic traits among germplasm from regions and countries
in the Middle East. These results suggest that adaptation of the species to the wide spatial and temporal variation in the
Middle East resulted in a multitude of ecotypes and in enormous amount of local variation. A multivariate selection criterion
for high biological and seed yield, long rosette period and no or few spines identified five accessions from Southwest Asia
that can be introduced into subsistence farming systems as a multipurpose crop under saline agriculture. 相似文献
12.
Yosuke Kuroda Norihiko Tomooka Akito Kaga S. M. S. W. Wanigadeva Duncan A. Vaughan 《Genetic Resources and Crop Evolution》2009,56(8):1045-1055
Wild soybeans, Glycine soja, are a source of genetic variation to improve soybeans. To improve the efficiency evaluation of conserved germplasm a core
or mini-core collection approach that maximizes allelic diversity in a proportion of the whole collection has frequently been
advocated. The genetic diversity of a wild soybean collection (1,305 accessions) plus Japanese cultivated soybeans (53 accessions)
were analyzed at 20 SSR marker loci. Higher levels of allelic diversity were found in wild soybeans (28 alleles per locus)
than Japanese cultivated soybean (five alleles per locus). The genetic distance between wild soybeans from different regions
reflected their proximity. Accessions from Russia consisted of a diverse array of alleles resulting in accessions being spread
further apart in a PCA plot than accessions from other regions. Accessions of wild soybean from Korea included many rare alleles
and thus had a high representation in the core collection. The two core collections developed here, traditional and mini,
consisted of 192 accessions with 97% of the allelic diversity (14% of the whole collection) and 53 accessions with 62.4% of
the allelic diversity (5% of the whole collection), respectively. 相似文献
13.
Adoption of conservation tillage systems has become more popular in recent years due to erosion control and economics. Weed control is often identified as the limiting factor in the adoption of such systems. Although herbicides are efficient and convenient, the need to reduce herbicide use has been emphasized. Cover crops have become a viable option in this context, but the contribution of cover crops to weed control has not been clearly defined. A 2-year field experiment compared minimum tillage (MT), no-tillage (NT) and conventional tillage (CT) for soybean [Glycine max (L.) Merr.] following paddy rice (Oryza sativa L.) with finger millet (Eleucine corocana L. Gaertn.) as a cover crop. Weed emergence, cover crop biomass, main crop growth and yield were observed. Finger millet effectively controlled weeds but total weed biomass was greater with NT than other tillage methods and seeding method had no effect at early stage of growth. Neither crop growth nor leaf chlorophyll content was affected by finger millet under given tillage treatments. Weed biomass was almost half under MT than NT. Finger millet was able to effectively manage weed biomass under MT to a level achieved under CT without a cover crop at the early stage of growth. Number of seeds per pod and 100 seed weight were not affected by tillage treatments but number of pods per square meter was significantly higher with row seeding than broadcast seeding of finger millet cover crop in 2002. The absence of finger millet under MT in 2003, significantly reduced soybean grain yield. Finger millet can be managed with a single mechanical suppression as a cover crop under MT with no yield reduction. 相似文献
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Axel Diederichsen Peter M. Kusters Dallas Kessler Zenon Bainas Richard K. Gugel 《Genetic Resources and Crop Evolution》2013,60(4):1479-1485
Between 1998 and 2008, numerous projects were conducted by the Canadian national genebank, Plant Gene Resources of Canada, for the regeneration, characterization and evaluation of the whole flax (Linum usitatissimum L.) germplasm collection. The whole collection comprised 3378 accessions and, according to the passport data, several of these were probably genetically very similar or even identical. Therefore, a subset of 381 accessions was selected that represented the diversity found in the whole collection. Sampling accessions from the whole collection was made using characterization and evaluation data and followed six different methods: (1) For seven qualitative characters, each unique combination of character expression was represented by three accessions; (2) for quantitative characters, a fixed number of accessions representing the lowest and highest observed values was included; (3) for stem fibre content, disease ratings, seed vigour and drought tolerance, a fixed number of accessions with desirable performance was included; (4) a subset of the 57 most distinct accessions based on RAPD markers was included; (5) a subset of 40 pure lines that were created based on extreme low and high values for 1000 seed weight, seed oil content and fatty acid profiles was included; (6) a subset of fibre flax cultivars of known relevance in European flax breeding and another subset of flax cultivars of known relevance for North American linseed breeding were included. The goal was to maximize the diversity available in a limited number of flax accessions by preserving the range of variation present in the whole collection, while improving evenness. The core collection was assembled in response to requests by flax breeders. This paper compares distribution parameters in the whole and core collections. 相似文献
17.
José Martínez-Calvo Ana Delia Gisbert M. Carmen Alamar Rosa Hernandorena Carlos Romero Gerardo Llácer María L. Badenes 《Genetic Resources and Crop Evolution》2008,55(5):695-703
Loquat species (Eriobotrya japonica Lindl.) originated in China, later was introduced in Japan. However, introduction in Europe occurred much later, in 18th
century, it was introduced as an ornamental tree. Since then, the species was very well adapted to the Mediterranean climate,
mainly in South East of Spain, where is located more than 50% of total European crop production. A European Project titled
‘Conservation, evaluation and collection of underutilized fruit species’ supported surveys and collection of plant material
from these species in the Mediterranean basin countries. One of these surveys resulted in a germplasm collection of loquat
established at IVIA, Valencia, Spain. This collection is being extended with new accessions collected across the world, currently
the collection have 123 accessions under study. Germplasm management needs first a characterization of the plant material
introduced and second diversity studies into the collection that could point out the variability pattern, to establish groups
of accessions with similar traits and the most significant variables. These results allow organizing the information gathered
for further uses. In this paper, 62 accessions from the IVIA germplasm collection were studied. Results from 43 variables
were gathered and data studied by multivariate analysis. The analysis allowed summarizing the data tables with new variables
containing most of the information. These results along with those obtained in the coming years will allow define a nuclear
collection (minimum number of accessions that contained all the variability present in the collection). 相似文献
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Yemen differs considerably from many other countries in its extreme variation in elevation. A set of 229 pearl millet germplasm accessions collected from diverse elevations of Yemen was characterized for 12 morpho-agronomic characteristics at ICRISAT, Patancheru, India. Analysis of variance revealed highly significant differences (P < 0.001) among elevational zones for flowering, plant height and seed weight when evaluated in the post-rainy season and for panicle length and thickness when evaluated in the rainy season. The differential performance of accessions for flowering and plant height during the rainy and post-rainy seasons at ICRISAT, Patancheru reflected the photoperiod and temperature sensitivity of the accessions. Shannon-Weaver diversity indices indicated high diversity from low elevations for flowering and plant height. The results of the present study imply that environmental factors such as elevation, temperature and rainfall are the important determinants of variation patterns of pearl millet in Yemen and pearl millet germplasm from high elevations of Yemen is a good source for early maturity, cold tolerance, short plant height and large seeds. 相似文献
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H. D. Upadhyaya K. N. Reddy C. L. L. Gowda Sube Singh 《Genetic Resources and Crop Evolution》2007,54(6):1167-1184
The pigeonpea core collection developed at ICRISAT genebank consists of 1,290 accessions from 53 countries. The core collection,
which includes selected lines in extra early, early, medium and late maturity groups was evaluated for 18 qualitative and
16 quantitative characters during the 2004 rainy season, to assess the phenotypic diversity and determine the relative importance
of different characters in evaluating pigeonpea germplasm accessions. The four maturity groups differed significantly for
all characters under study. The medium maturity group showed significantly higher mean number of primary, secondary and tertiary
branches, number of racemes, pod bearing length, pods per plant, shelling percent and plot seed yield. Late maturity group
showed significantly higher mean for leaf size, plant height, pod length, seeds per pod and 100-seed weight, indicating this
group as a good source of vegetable pigeonpea. Significant positive correlations were found between number of secondary branches
and pods per plant in extra early group (r = 0.756), late maturity group (r = 0.776) and entire core (r = 0.728) and between number of racemes and pods per plant in all maturity groups and entire core. Principal coordinate and
principal component analysis showed that seven qualitative and nine quantitative traits were important in explaining multivariate
polymorphism. The Shannon–Weaver diversity index (H′) varied for different maturity groups and traits. Phenotypic diversity, averaged over all the 16 characters, increases from
extra early group (0.36 ± 0.04) to late maturity group (0.42 ± 0.04) suggesting that medium and late maturity groups have
greater diversity compared to extra early and early maturity groups. 相似文献
20.
Realizing value of genetic resources of <Emphasis Type="Italic">Allium</Emphasis> in India 总被引：1，自引：1，他引：0
Anjula Pandey Ruchira Pandey K. S. Negi J. Radhamani 《Genetic Resources and Crop Evolution》2008,55(7):985-994
The genetic resources of Allium in India are potential source of genes for widening the crop genetic base. Despite their high economic value, limited number
of germplasm accessions of wild species have been collected and conserved mainly due to difficult access to areas of occurrence.
The present work mainly highlights information on species diversity distribution and utilization of wild Allium species to assess the value of Indian germplasm and prioritization for future collection and conservation programmes. 相似文献