Genetic variation in Tunisian melon (Cucumis melo L.) germplasm as assessed by morphological traits

The morphological variation and the systematical status of 28 traditional melon including two ancient varieties collected from different geographical and bioclimatic areas of Tunisia were assessed based on 34 qualitative and quantitative traits. Yellow Canary was used as a reference variety. Significant differences among accessions within and among sites of collection were revealed for the majority of traits. The accessions from the Sahel were more polymorphic than those from Tozeur’s oasis. However, the classification of the local accessions according to Munger and Robinson’s varietal groups did not allow clear segregation of several of them because of their high heterogeneity. The principal component analysis (PCA) performed on all measured traits, allowed a distinction among the introduced varieties clustered according to their varietal group, and the local accessions grouped separately according to their geographical origin and bioclimatic zone. Mahalanobis distances among PCA’s groups were significant. The correlation found between Mahalanobis distance matrix and geographical distance matrix among origins corroborated isolation per distance. Conservation strategies should be made appropriately according to origins. Accessions from the Sahel showing the highest polymorphism within and among sites of collection should be firstly preserved.     

Diallel analysis for morphoagronomic descriptors in Physalis angulata L. hybrids

Genetic Resources and Crop Evolution - Physalis angulata L. is an American species with edible fruits that stands out for having high nutritional and pharmaceutical value. The species is found in...     

Pest-managing efficacy of trans-asarone isolated from Daucus carota L. seeds

The bioactive hexane extract of Daucus carota seed yielded 2,4,5-trimethoxybenzaldehyde (1), oleic acid (2), trans-asarone (3), and geraniol (4). Compounds 1-4 were evaluated for their mosquitocidal, nematicidal, antifeedant, and antimicrobial activities. Only trans-asarone was active in the assays performed, causing 100% mortality to fourth-instar mosquito larvae, Aedes aegyptii, at 200 microg mL(-1) and the nematodes Caenorhabditis elegans and Panagrellus redivivus at 100 microg mL(-1). In feeding trials, trans-asarone also caused significant weight reductions of the caterpillars Helicovarpa zea, Heliothis virescens, and Manduca sexta when incorporated into artificial diet at a concentration of 100 microg mL(-1). Also, it exhibited slight activity at 100 microg mL(-1) against the yeasts Candida albicans, Candida parapsilasis, and Candida kruseii.     

Microsatellite markers as a tool for active germplasm management and bridging the gap between national and local collections of apple

Genetic Resources and Crop Evolution - Simple sequence repeat (SSR) microsatellite markers have been extensively used to identify duplication and analyse genetic diversity in germplasm collections...     

Multivariate analysis approach to evaluate a germplasm collection of Hedysarum coronarium L.

Autochthonous germplasm collected in Spain (Ca´diz and Baleares provinces), Italian ecotypes and cultivated material supplied by a commercial firm were analysed by using a multivariate approach applied to a set of morphological traits. According to these analyses the cultivated material could clearly be separated from the autochthonous germplasm. Variation was observed among the traits studied; Principal Stem Diameter, Leaf Area at Flowering and Susceptibility to Oidium were the main traits in grouping and separating sulla (Hedysarum coronarium L.) entries. A new ecotype (Tarifa) could be used in plant breeding as being a source of resistance to Oidium. The multivariate approach appears to be a valid system for germplasm evaluation in sulla with a higher discriminant capacity than multiple single trait analysis.     

Multivariate analysis of Prunus subgen. Cerasus germplasm in Iran using morphological variables

Knowledge of relationships among the cultivated and wild species of Cerasus, a subgenus of Prunus L., is important for recognizing gene pools, identifying pitfalls in germplasm collections and developing effective conservation and management strategies. In this study, morphological characterization of wild Cerasus subgenus species naturally growing in Iran, including P. avium L. (mazzard), P. mahaleb L., P. brachypetala Boiss., P. incana Pall., P. yazdiana Mozaff., P. microcarpa Boiss. subsp. microcarpa, P. microcarpa Boiss. subsp. diffusa and P. pseudoprostrata Pojark. and three commercial species, sweet cherry (P. avium L.), sour cherry (P. cerasus L.) and duke cherry (P. × gondouinii Rehd.) was investigated. Twenty-nine variables were recorded in 95 accessions of these species to detect similarities among them. All studied characteristics were showing a high degree of variability, but it was highly pronounced for plant height, leaf characters especially for dimensions and pubescence as well as for petiole and peduncle length. The majority of significant correlation coefficients were found in the characteristics representing plant size and growth habit with leaf size. Principal component analysis was performed for phenotypical diversity determination and grouping of species. Characters with high discriminating values were those related to growth habit, height, compactness, trunk diameter, leaf dimensions, petiole length, leaf tip and serration, flower color, peduncle length, fruit shape and stone shape. Based on the cluster analysis, species included in two main clusters, first those with large structure (sweet, sour and duke cherries, mazzard and mahaleb), second the other species with small structure which might be potentially suitable for rootstock breeding programs. Scatter plot using two first factors also confirmed the grouping by cluster analysis. The conservation of the highly diverse native populations of Iranian wild Cerasus species is recommended.     

A method for establishing a core collection of Saccharum officinarum L. germplasm based on quantitative-morphological data

A technique is proposed for establishing a representative core collection of S. officinarum accessions from the world collection of sugarcane germplasm maintained at the Sugarcane Breeding Institute-Research Centre, Cannanore, India. In the proposed method, the accessions were first sorted based on their relative contributions to the total variability by means of principal component scores based on a set of quantitative characters. Then, the cumulative proportion of their contributions to the total variance was computed. A logistic regression model was fitted to evaluate the functional relationship between the cumulative proportion of variance and the number of accessions. The size of the core set was decided as the inflection point on that fitted curve, i.e., the point beyond which the rate of increase in cumulative proportion of variability contributed by an accession began to decline. A method for eliminating entries with a high degree of similarity from the selected core set is also proposed.     

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.     

Inter-relation between descriptors and morphine yield in Asian germplasm of opium poppy Papaver somniferum

A set of 208 Indian and two Thai germplasm accessions of opium poppy Papaver somniferum were assessed for variation in 17 morphological characters, seed yield and content and yield of morphine from capsules and peduncles. The germplasm was found to be highly variable for all the characters evaluated. In the harvested peduncles and capsules, 13% was peduncle straw, 61% seeds and the rest capsule husk. The peduncle and capsule straw yields ranged between 0.6–2.2 and 1.4–5.3 g plant^-1, respectively. Morphine content in the peduncle varied between about 0.001–0.24% and that in the capsule from 0.02 to 1.05%. On average basis morphine content in the capsule husk was more than 9-fold higher than the peduncle straw. The plant morphine yields from peduncles and capsules ranged between 1.2 and 28.6 mg plant^-1. Four accessions yielded more than 20 mg of morphine plant^-1. Among these, in one of the accessions about 13% of the morphine was contributed by the peduncle. The plants of high morphine yielding accessions were generally small in height, and bore white flowers and large sized ungrooved capsules with a small number of seeds, on a large peduncle.     

Use of Rhizobium leguminosarum as a potential biofertilizer for Lactuca sativa and Daucus carota crops

Microbial biofertilizers are becoming an effective tool for sustainable agriculture by means of the reduction of the use of chemical fertilizers. However, the knowledge of each specific plant–microorganism interaction is essential for a correct application. In this study, we analyzed the in vitro plant‐growth‐promotion mechanisms of a Rhizobium leguminosarum strain named PEPV16 isolated from Phaseolus vulgaris nodules. This strain was able to produce siderophores and indole acetic acid and to solubilize phosphate. Confocal microscopy showed that this strain was able to colonize the roots of two horticultural crops, Lactuca sativa L. (lettuce) and Daucus carota L. (carrot). Strain PEPV16 was also able to promote the plant growth of both plant species increasing the dry matter of shoots and roots of lettuce and carrots, respectively, as well as to increase the uptake of N and P in the edible parts of both plant species. These data confirmed the suitability of Rhizobium as biofertilizer for nonlegumes.     

Variability in Mucuna pruriens L. germplasm for L-Dopa, an anti parkinsonian agent

Mucuna pruriens L. (Fabaceae) is a popular Indian medicinal plant, which has long been used in traditional Ayurvedic system of Indian medicine for diseases including parkinsonism. The seeds of M. pruriens contain 3,4-dihydroxyphenyl-L-alanine (L-dopa) as a major constituent, an intermediate precursor of the neurotransmitter dopamine. L-dopa extracted from seeds of Mucuna is more effective as drug than the synthetic counterpart. The plant is widely distributed throughout the India and in other parts of the tropics including Central and South America. The present study was aimed to screen thirty-eight accessions of Mucuna germplasm collected from different geographical regions of India for L-dopa content, an effective drug used for Parkinson’s disease. The L-dopa content in seeds of M. pruriens was quantitatively analyzed by high performance thin-layer chromatography (HPTLC) at 280?nm wavelength. Results indicated wide variability among thirty-eight accessions of M. pruriens for seed characters like seed colour, size and shape. The L-dopa content in seeds of M. pruriens ranged between 3.29 and 5.44?% (on dry weight basis) among different germplasm collections augmented from various parts of India. Promising accessions identified having high L-dopa content were IC551549 (5.44?%), IC551514 (5.41?%), IC331536 (5.40?%), IC552857 (5.36?%), IC385844 (5.32?%) and IC439197 (5.32?%). Due to the economic importance of the drug, these promising M. pruriens accessions can be exploited for large scale cultivation for their pharmacological important constituents mainly L-dopa content.