Trebbi D.,Geneticlab Srl |
Papazoglou E.G.,National and Kapodistrian University of Athens |
Saadaoui E.,National Water Research Institute |
Vischi M.,University of Udine |
And 6 more authors.
Industrial Crops and Products
The aim of this work was to estimate the genetic diversity among 273 Jatropha curcas L. accessions and to develop a new SNP-based multi-allelic marker assay (Intra-Locus SNP Haplotype, or LSH) to enhance the genetic discriminatory power of the SNP marker system. The accessions were collected in 15 countries of 3 continents (Africa, Asia and America) and analyzed with SSR, EST-SSR and SNP markers. Cluster analysis revealed the presence of two main genetic groups with an extreme high genetic uniformity and homozygosity of accessions grown in all countries of Africa, Asia, South America, and in some states of Mexico. Differently, an increased genetic variability and heterozygosity was observed in other states of Mexico and Guatemala. The newly developed LSH assay successfully identifies multiple alleles at the same locus and increased the average polymorphic information content of the SNP system. These results confirm the general idea recognizing the Central America region as the center of origin of the species and the genetic homogeneity of the world-wide cultivated accessions, and propose a new powerful SNP-based multi-allelic marker assay for enhancing genetic diversity analysis and selection methods in breeding programs. © 2015. Source
Ambrosi D.G.,University of Padua |
Galla G.,University of Padua |
Purelli M.,Geneticlab Srl |
Barbi T.,Geneticlab Srl |
And 4 more authors.
Jatropha curcas L. (2n = 2x = 22) is becoming a popular non-food oleaginous crop in several developed countries due to its proposed value in the biopharmaceutical industry. Despite the potentials of its oil-rich seeds as a renewable source of biodiesel and an interest in large-scale cultivation, relatively little is known with respect to plant reproduction strategies and population dynamics. Here, genomic DNA markers and FCSS analyses were performed to gain insights into ploidy variation and heterozygosity levels of multiple accessions, and genomic relationships among commercial varieties of Jatropha grown in different geographical areas. The determination of ploidy and the differentiation of either pseudogamous or autonomous apomixis from sexuality were based on the seed DNA contents of embryo and endosperm. The presence of only a high 2C embryo peak and a smaller 3C endosperm peak (ratio 2:3) is consistent with an obligate sexual reproductive system. Because of the lack of either 4C or 5C endosperm DNA estimates, the occurrence of gametophytic apomixis seems unlikely in this species but adventitious embryony cannot be ruled out. The investigation of genetic variation within and between cultivated populations was carried out using dominant RAPD and Inter-SSR markers, and codominant SSR markers. Nei's genetic diversity, corresponding to the expected heterozygosity, was equal to H e = 0.3491 and the fixation index as low as F st = 0.2042. The main finding is that seeds commercialized worldwide include a few closely related genotypes, which are not representative of the original Mexican gene pool, revealing high degrees of homozygosity for single varieties and very low genetic diversity between varieties. © 2010 by the authors; licensee MDPI, Basel, Switzerland. Source