Advances in legume systematics : 8. Legumes of economic importance

Cowpea gene pool organization is discussed on the basis of morphological and isoenzymatic data. A hypothesis for a single domestication of cowpea in North-East Africa is presented. (Résumé d'auteur

Répartition des cultivars de niébé Vigna unguiculata (L.) Walp. du Cameroun : influence du milieu et des facteurs humains

Cowpea landraces were surveyed in Cameroon. 4000 accessions were collected from nearly 900 places. These accessions belong to four cultigroups, namely CG Textilis and CG Melanophthalma (in the Sudano-Sahelian area), CG Biflora (mainly in the Mandara Mountains), CG Unguiculata (in the Guinean area, where it was introduced one or two hundred years ago). Pod and seed characters allowed sorting of accessions into one hundred cultivars, which were mapped. Cultivar spread is limited by both ecological and human constraints. The maps show preferential areas of exchange resulting from ethnic distribution, interchange and migration.Le niébé au Cameroun a fait l'objet d'une enquête variétale. Celle-ci a permis de réunir plus de 4000 numéros de collection, appartenant à 4 cultigroupes. CG Textilis et CG Melanophthalma sont représentés dans la zone soudano-sahélienne. L'aire de CG Biflora est pratiquement réduite aux monts Mandara. CG Unguiculata se rencontre surtout en zone guinéenne où son introduction ne remonte pas à plus de deux siècles. Ces 4000 numéros ont été attribués à une centaine de cultivars au vu de leurs graines et de leurs gousses, et ces cultivars ont été cartographies. Les répartitions observées reflètent l'importance de certaines contraintes écologiques, mais surtout celle de facteurs humains. Ces cartes matérialisent des zones d'échanges préférentielles et sont le reflet de la répartition des différents groupes humains, de leurs relations et de leurs mouvements.Pasquet Rémy S., Fotso Martin. Répartition des cultivars de niébé (Vigna unguiculata (L.) Walp.) du Cameroun : influence du milieu et des facteurs humains. In: Journal d'agriculture traditionnelle et de botanique appliquée, 36ᵉ année, bulletin n°2,1994. Phytogéographie tropicale : réalités et perspectives. Propos d'ethnobiologie, sous la direction de Jacques Barrau et Bernadette Lizet. pp. 93-143

Аналіз сучасних підходів до визначення поняття “регіон”

Мета статті. Дослідити основні підходи до трактування поняття “регіон”

Allozyme diversity of cultivated cowpea Vigna unguiculata (L.) Walp

A survey of allozyme variation in cultivar-groups of cowpea (#Vigna unguiculata (L.) Walp.) was undertaken by examining 21 enzyme systems encoded by 36 loci in 271 accessions representing the five cultivar-groups. Very low levels of variation were found within accessions, which is typical of self-pollinating species. Little variation was also found among accessions. Compared with other legume crops, #V. unguiculata is depauperate in allozyme variation. We found an average of 1.61 alleles per locus with 42% of the loci polymorphic and a total heterozygosity of 0.061. Of the variation present, 90% was found within cultivar-groups, while 10% was among cultivar-groups. Data analyses revealed continuous variation among cultivar-groups and geographic regions with the accessions failing to segregate into discrete morphophysiological or geographic clusters. However, evolved cultivar-groups (cv.-gr. #Melanophthalmus and cv.-gr. #Sesquipedalis) appear to be less diverse than their putative primitive cultivar-group progenitors. Due to lack of availability of critical material, no clear center of origin can be established. However, the data presented suggest that Northeast Africa could be a possible center of domestication. (Résumé d'auteur

Genetic relationships among subspecies of Vigna unguiculata (L.) Walp. based on allozyme variation

The cowpea (#Vigna unguiculata (L.) Walp.) is a morphologically and genetically variable species composed of wild perennial, wild annual, and cultivated forms that are mainly used for edible seeds and pods. In this study, genetic variation in 199 germplasm accessions of wild and cultivated cowpea was evaluated using an allozyme analysis. The results from this survey showed that wild cowpea exhibits genetic variation perfectly fitted with the existing morphological classification. The cowpea gene-pool is characterized by its unusually large size. It encompasses taxa (ranked as subspecies) that could be considered as different species considering the high genetic distances observed between accessions belonging to different taxa. These subspecies can be classified into three groups characterized by their breeding systems : perennial outcrossers, perennial out-inbreds, and inbred annuals. Allozyme data confirm this grouping. Perennial outcrossers look primitive and are more remote from each other and from perennial out-inbreds. Within this large gene-pool, mainly made of perennial taxa, cultivated cowpeas (ssp. #unguiculata var. #unguiculata) form a genetically coherent group and are closely related to annual cowpeas (ssp. #unguiculata var. #spontanea$) which may include the most likely progenitor of cultivated cowpeas. (Résumé d'auteur