Characterization of Italian chickpea (Cicer arietinum L.) germplasm by multidisciplinary approach

Characterization of 15 chickpea (Cicer arietinum L.) accessions (6 cultivars, 3 selected lines and 6 landraces) was performed using morphological, agronomic, and technological traits, together with biochemical (seed storage proteins) and molecular markers. Field trials, performed in two different geographical areas of Southern Italy, one in a plain area near Tyrrhenian sea and one in an hilly internal area, revealed a high influence of field location on yield. A wide variation was also registered for technological traits and molecular markers. Microsatellite (SSR) markers grouped chickpea accessions in different clusters, providing useful information on genetic variation and relationships among them, with polymorphic fragments useful to discriminate among all accessions. On the contrary, seed storage protein pattern showed scarce variation resulting very similar among all the accessions considered.     

Variability in leaf and fruit morphology and in fruit composition of chestnuts (<Emphasis Type="Italic">Castanea Sativa</Emphasis> Mill.) in the Nazilli region of Turkey

The aim of this study is to characterize 10 European chestnut (Castanea sativa Mill.) accessions which were selected among 80 accessions at the end of a selection study in Nazilli in Turkey. During the harvest periods in 2001, 2002 and 2003, European chestnut accessions were examined. Nineteen morphological, pomological and biochemical characters were used. Significant genotype×year interaction were found for all traits but one. Multivariate methods, including cluster and principal component analysis were performed to characterize the accessions. The first five principal components account for 86.44% of the total variance of all traits, indicating a high degree of correlation among the characteristics analyzed. High level of phenotypic proximity was found between the accessions N-20-2 and N-5-1 based on pomological, morphological and biochemical characteristics.     

Morpho-agronomic and simple sequence repeat-based diversity in colored rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) germplasm from peninsular India

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.     

Genetic variation in radish (Raphanus sativus L.) germplasm from Pakistan using morphological traits and RAPDs

Genetic diversity of 30 radish (Raphanus sativus L.) accessions was investigated at the phenotypic level with morphological characters and at the DNA level using the random amplified polymorphic DNA (RAPD) technique. Thirty-six morpho-physiological traits were recorded from seedling stage to harvest. The 31 primers used generated 202 RAPD bands, of which 158 (78.2%) were polymorphic. Multivariate procedures were used to classify the germplasm on the basis of phenotypic traits and RAPD fragments. Dendrograms were generated for the Euclidean distance from the morphological data and the Nei's genetic distance from the RAPD markers. Phenotypically, all the accessions were classified into four major groups corresponding to the different forms of cultivated radish. The morphological diversity existing within each of these groups suggested that they should be discriminated into the three botanical convarieties, sativusT (large-rooted), caudatus (pod-type) and oleifer (oilseed-type). Clustering of the accessions did not show any pattern of association between the morphological characters and the collection sites. Instead, landrace groups were associated with their morphological similarities and horticultural uses. On the other hand, the intra-specific genetic relationships of several accessions based on RAPD analysis were related primarily to their collection sites rather than to their phenotypic affinities. The level of polymorphism exhibited by the various convarieties could be exploited in genetic mapping populations to tag economically important traits. These genotypes also could serve as a useful germplasm source for root, leaf, pod and seed. This preliminary study of traditional radish landraces from Pakistan provides useful information regarding their horticultural potential.     

Genetic diversity analysis in Phaseolus vulgaris L. using morphological traits

Common bean (Phaseolus vulgaris) is an important export crop in Kyrgyzstan since the end of the twentieth century. Genetic diversity analysis of common bean populations is useful for breeding programs, as it helps to select genetic material to be used for further crossing. Twenty-seven common bean accessions were analyzed using 13 qualitative morphological traits. In some cases, obtained morphological data were combined with previously published results based on microsatellite markers. The similarity matrices generated from the molecular and morphological data were significantly correlated (r = 0.49, P < 0.01). Cluster analyses based on Dice’s similarity coefficient were constructed based on morphological data and the combined data set of morphology and microsatellite, and both grouped the 27 accessions according to their origin: 15 belonged to the Andean and 12 to the Mesoamerican gene pool. On average, the Andean accessions were less diverse than the Mesoamerican accessions. The average diversity based on the Shannon diversity index for the 13 qualitative morphological traits was 0.05. Overall, this study revealed that qualitative morphological markers are efficient in assigning modern cultivars to their gene pools of origin.     

Genetic Diversity Among Traditional Ethiopian Highland Maize Accessions Assessed by Simple Sequence Repeat (SSR) Markers

Over the past three centuries, maize has become adapted to complex environmental conditions in the highlands of Ethiopia. We analyzed 62 traditional Ethiopian highland maize accessions, using 20 simple sequence repeat (SSR) markers and 15 morphological traits, to assess genetic diversity and relationships among these accessions and to assess the level of correlation between phenotypic and genetic distances. The accessions varied significantly for all of the measured morphological traits. The average number of alleles per locus was 4.9. Pair-wise genetic dissimilarity coefficients ranged from 0.27 to 0.63 with a mean of 0.49. Ward minimum variance cluster analysis showed that accessions collected from the Northern agroecology were distinct from the Western and Southern agroecologies. However, there was no differentiation between the Western and Southern accessions. This suggested gene flow between these regions. The relationship between morphological and SSR-based distances was significant and positive (r = 0.43, p = 0.001). The high genetic diversity observed among these set of accessions, suggests ample opportunity for the development of improved varieties for different agroecologies of Ethiopia. From conservation perspective, sampling many accessions from all agroecologies would be an effective way of capturing genetic variation for future collections and conservation.     

Diversity of Nordic Landrace Potatoes (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Revealed by AFLPs and Morphological Characters

The management of genebank collections of cultivated potato is costly due to the need for in vitro maintenance and virus eradication. Therefore, it is important to set up conservation strategies, which prevent duplicates entering the collections. In this study, 32 Nordic potato landraces were studied for 57 morphological traits and analysed for amplified fragment length polymorphism (AFLP). Most landraces could be distinguished based on the morphological characters, except five accessions. Using five primer combinations to generate 114 reproducible AFLPs, of which 63 (55%) were polymorphic, the five morphologically indistinguishable accessions were placed into two groups with identical AFLP patterns, suggesting that some of the accessions were redundant for long-term preservation. The AFLP data showed that the Nordic collection of potato landraces is composed of genetically different clones, and morphological analysis revealed a wide range of variability. This variability seems to be distributed randomly over the Nordic region since the cluster analysis based on AFLPs and morphological traits revealed no grouping based on the country of origin. Principal component analysis suggests that fewer morphological traits than used in this study will be sufficient to discriminate between different genotypes of cultivated potato (Solanum tuberosum L.). Future possibilities for rationalising potato collections are discussed.     

南瓜栽培品种的SSR分子标记分析及农艺性状多样性研究

为了研究南瓜栽培品种的遗传多样性,本研究利用43个简单序列重复(SSR)分子标记,对35份南瓜育成品种及地方品种进行了分子标记分析,并调查了农艺性状。结果表明,43个SSR标记均能扩增出多态性条带,共检测到155个等位基因,平均每个标记能检测到3.6个等位基因,多态性信息含量(PIC)为0.130 8~0.775 4,平均值为0.487 2。利用非加权组平均法(UPGMA)进行聚类分析,结果表明35份材料可分为三大类,分别与中国南瓜、印度南瓜和美洲南瓜三个种吻合,且印度南瓜与美洲南瓜之间的亲缘关系较近。农艺性状调查结果表明,不同栽培种之间以及同一栽培种内的不同品种之间,都发现有农艺性状差别明显的情况。本研究为南瓜种质资源的保护、品种指纹图谱的建立及分子育种提供了理论依据。     

Variation and phylogeny of the triploid cultivated potatoSolanum chaucha Juz. et Buk. based on RAPD and isozyme markers

Ninety four accessions of the cultivated triploid potatoS. chaucha were analyzed and classified in genotypic groups using 9 isozyme loci and RAPD markers disclosed by 20 arbitrary 10-mer primers. Eight isozyme loci out of nine were polymorphic. A total of 22 allozymes were analyzed but none of them were specific for any genotypic group. About half (52%) of the 102 RAPD markers scored, were polymorphic, all of them showing polymorphism among groups and rarely within groups. Eighteen RAPD markers were specific for certain genotypes. The isozyme markers showed a certain amount of intra group variation which made classification less reliable than with RAPD markers. A total of 10 triploid genetic groups were discriminated using both techniques together. A single primer was found to be sufficient to distinguish all 10 groups. All varieties of a single group are considered to have been derived from the same cross and then clonally propagated, even though there is a high amount of morphological variation within a single genotypic group due probably to somatic mutations. RAPD markers have been shown to be more reliable in the classification of triploid potato varieties than other genetic markers like isozymes, proteins and morphological traits.