Twenty landraces of cowpea (Vigna unguiculata (L.) Walp.) scattered throughout Algeria were compared through morphological and genetic characterization. At the morphological level, for qualitative characters there was no intra-landrace variation and for quantitative characters the variations were low except for landrace NAG2 Three different cultigroups were located in Algeria: Biflora that was dominant in the Sahara, Melanophtalmus in the North and Unguiculata including one landrace in Kabylia and two in Sahara. The AMOVA analysis indicated that the genetic variation was lower within than among agro-ecological regions. A Mantel test, revealed a correlation between the qualitative morphological data and the geographical data (R = 0.28; P \ 0.01), indicating that the degree of morphological change among landraces was roughly proportional to the geographical distances separating them.Genetic diversity was analyzed by using 11 random amplified polymorphic DNA (RAPD) and 12 intersimple sequence repeat (ISSR) markers. No intralandrace variability was found. The eleven RAPD primers yielded 77 bands, of which 45 (58.44%) were polymorphic; the genetic similarity ranged from 66.0 to 96.7%. The twelve ISSR primers provided a total of 104 bands, of which 65 (62.5%) were polymorphic; the genetic similarity ranged from 62.8 to 97.8%. cluster analysis showed a good match between genetic background and geographical distribution, which was confirmed by the results of the Mantel test. In particular, geographical data and genetic data were found to be correlated: (R = 0.33; P \ 0.01) for RAPD, (R = 0.37; P \ 0.01) for ISSR, and (R = 0.33; P \ 0.01) for a combined RAPD-ISSR dataset. Moreover, despite the absence of significant correlation between morphological and RAPD data (R = 0.14; P = 0.14), significant correlations between morphological data and both ISSR (R = 0.27, P \ 0.05) and a combined RAPD-ISSR dataset (R = 0.22, P \ 0.05) were noted. ISSR markers were better linked to morphological variation than were RAPD markers. However, despite this, genetic distances among these landraces were found to be essentially the same no matter which markers were used.

a b s t r a c tTo set up a rational collecting strategy for germplasm of the edible-seeded cucurbit Cucumeropsis mannii, a study was conducted using 24 morphological and seven putative enzyme markers to determine the intra-specific variability from 16 and 22 accessions (representing three cultivars), respectively. The analysis of variance, showed a significant difference between the three cultivars. Principal component analysis pointed out a variation among individuals, mainly on the basis of flower, fruit, and seed size. Dendrogram with UPGMA method allowed clustering of the cultivars. Genetic diversity indices estimated equalled: 9.96% for the proportion of polymorphic loci (P), 1.10 for the number of alleles (A) and 0.023 for observed heterozygosity (H o ). The level of the within accessions genetic diversity (H S ¼ 0.078) was higher than among accessions (D ST ¼ 0.042). Nei's genetic distances between the three cultivars were also low (0.079-0.147), indicating a high degree of similarity of the analysed cultivars.Crown

Andean tuber crop species oca (Oxalis tuberosa Molina), ulluco (Ullucus tuberosus Caldas), and mashua (Tropaeolum tuberosum Ruiz & Pav.) play major roles in Andean communities. These species show high variability but are threatened with genetic erosion. To study the management of genetic resources of neglected vegetatively propagated crop species, we studied genetic diversity and structure of these species in an in situ diversity microcenter (Huanuco, Peru). A sample of 15 varieties of oca, 15 of ulluco, and 26 of mashua was analyzed with the inter simple sequence repeats (ISSR) molecular markers. Mean genetic distances and global genetic diversities were high for the three species, with higher values for mashua than for oca and ulluco. Assignment technique divided both oca and ulluco samples into two genetic clusters; the mashua sample probably belongs to a single genetic cluster. Inter simple sequence repeats (ISSR) technique showed intravarietal genetic variability for most varieties, suggesting an underestimation of the in situ genetic variability. These results are discussed considering how variation in breeding systems and farmers' practice influenced patterns of genetic diversity. Our findings confirm the hypothesis of a considerable amount of variability found in neglected Andean tubers and are essential to deserve adequate conservation strategies and to maintain genetic resources of neglected Andean tuber crop species under a threat of genetic erosion.

A preliminary study of the genetic diversity of Bolivian oca (Oxalis tuberosa Mol.) varieties maintained in situ and ex situ through the utilization of ISSR molecular markers Marie Malice AE Nicolas Martin AE Audrey Pissard AE Jorge A. Rojas-Beltran AE Antionio Gandarillas AE Pierre Bertin AE Jean-Pierre Baudoin Abstract ISSR molecular markers have been used to investigate genetic diversity of oca (Oxalis tuberosa Mol.), an Andean neglected tuber crop species. Sampling procedure allowed a preliminary study of the genetic diversity at the intra-and intervarietal levels. Twenty tuber lots conserved in situ in the microcentre of Candelaria and ex situ in the Toralapa Centre (Bolivia) were identified. Four ISSR primers amplified a total of 25 fragments of which 17 (68%) were polymorphic. These experiments show that the structure of oca varieties is mainly based upon vernacular names with a greater differentiation among tuber lots than within them, supporting agromorphological data. ISSR technique enlightened the existence of heterogeneous varieties in oca and divergence between in situ and ex situ conservation strategies. These observations are potentially linked to the different ways of management of tubers in these two conservation systems.

Taxonomie locale et analyse des critères des paysans pour caractériser les différents écotypes d'oignons (Allium cepa L.) du Niger Résumé L'oignon est une production maraîchère bien ancrée au Niger qui a acquis depuis longtemps une réputation de qualité. Au Niger, de nombreuses études ont porté sur la production et la filière de l'oignon. En revanche, très peu de recherches ont été consacrées à la diversité nommée des écotypes d'oignons. Ce travail a pour but d'inventorier les différents types d'oignons cultivés au Niger. Ainsi, 11 sites situés dans les principales zones de production d'oignon au Niger ont été visités. Dans chaque site, des entretiens individuels ont été conduits avec 10 producteurs qui ont une bonne connaissance des différents types d'oignons de la zone en particulier et du Niger en général. La caractérisation des écotypes du Niger a été réalisée en se basant sur les descripteurs du genre Allium établis par Bioversity International (ex-IPGRI). Cinquante-deux écotypes nommés ont été inventoriés, mais après analyse et regroupement des synonymes, il ressort que 17 écotypes sont cultivés au Niger. Les principaux critères des paysans pour caractériser un écotype local sont la couleur des bulbes et la zone de provenance.Mots clés : Allium cepa L. ; diversité génétique dans l'espèce ; écotype ; oignon ; Niger ; taxonomie.Thèmes : productions végétales ; ressources naturelles et environnement. Abstract Folk taxonomy of Niger onion diversity and analysis of farmer criteria for characterizing the different ecotypesThe onion is a very important crop in Niger, which has developed a reputation of high quality for ages. In Niger, many analyses have been carried out concerning onion production, but very little research has been done on onion ecotypes. The aims of this work were to identify the different types of onion produced in Niger. About a dozen sites were visited in the main area of mass production of onion in Niger. Interviews were conducted with ten producers on each site visited. These producers have a good knowledge of the different types of onions produced in the area and all over the country. Descriptors for Allium, established by Bioversity International (ex IPGRI), have been used to characterize the onion ecotypes. Fifty two locally named ecotypes were identified, but after analysis and grouping by synonyms, it was found that 17 of them were produced in Niger. The main criteria for a local ecotype naming are the colour of the onion bulb and the production area. Pour citer cet article : Abdou R, Malice M, Bakasso Y, Saadou M, Baudoin JP, 2014. Taxonomie locale et analyse des critères des paysans pour caractériser les différents écotypes d'oignons (Allium cepa L.) du Niger. Cah Agric 23 : 166-76.

No abstract

Plant breeding is intended to seek for ways of realizing a genetic structure adapted to criteria and population needs. In this context, cross-pollinations are for great interest. They offer the means of creating a wide genotypic variability. However, a limited number of species are able to undergo hybridization studies. In Phaseolus L., improvement can be envisioned by either exploiting the primary genetic pool of the species, or the genetic variability of other species. In fact, there are wild or wild-like species more resistant to stresses or diseases than the cultivated ones. The methods of embryo rescues facilitate the interspecific crosses and contribute to exploiting the available genetic diversity within plant germplasm. Difficulties related to obtaining hybrids in grain legumes, and Phaseolus L. in particular, are reported in this research. It is possible to avoid the incompatibility barriers based on their appearance time. When they are pre-zygotic, the use of growth regulators during pollination is recommended. The in vitro explants culture is the most usual method to overcome the post-zygotic barriers. The mechanisms leading to abortion of hybrid embryos, as well as adequate methods to overcome the interspecific incompatibilities should be subjected to further studies.