Norihiko Tomooka

Phylogeny of Vicia Subgenus Vicia (Fabaceae) Based on Analysis of RAPDs and RFLP of PCR-Amplified Chloroplast Genes

We report the results of two methods of DNA analysis to elucidate phylogenetic relationships among 29 Vicia subgen. Vicia species in comparison with two species of subgenus Vicilla sect. Vicilla. The methods employed were RAPD analysis of total genomic DNA and PCR-RFLP analysis of five chloroplast genes, rbcL, rpoB, 16S, psaA and trnK. The results of each method were similar and complementary, and support the current taxonomic systems of subsp. Vicia. According to RAPD and PCR-RFLP analysis the Narbonensis complex can be considered a well separated section, which may be related to section Vicia. Sections Vicia, Atossa and Wiggersia are separate, but closely related sections. Species of the section Hypechusa form a single monophyletic section, where V. lutea, V. anatolica and V. hyrcanica are quite remote from other species. Our results suggest that within the subgenus Vicia, V. faba is more closely related to V. bithynica and that these two species are most closely related to section Peregrinae. We found that PCR-RFLP of cp DNA provided more precise information concerning relationships between Vicia sections than RAPD analysis. However, RAPD analysis was more informative concerning diversity of closely related Vicia taxa, such as the variable groups, section Narbonensis and V. sativa aggregate.

Population diversity of the Vicia sativa agg. (Fabaceae) in the flora of the former USSR deduced from RAPD and seed protein analyses

The genetic diversity of 58 wild and weedy populations representing taxa within the V. sativa aggregate from the former USSR, 4 cultivars of V. sativa, 2 accessions of V. cordata and 3 accessions of V. macrocarpa from Mediterranean countries were analysed using randomly amplified DNA fragments (RAPDs) and seed protein electrophoresis (SDS-PAGE). Interspecific variation between taxa in the V. sativa aggregate could readily be detected using both techniques. RAPDs and seed protein patterns were found to be an effective means of identifying accessions that cannot be identified clearly by morphological criteria alone. RAPD and seed protein analysis revealed a clear relationship between observed genetic variation of populations and their geographical distribution. Populations from each region had their own gene pools. Geographical variation was detected in V. segetalis. The degree of genetic divergence between local populations was usually related to proximity. In several locations where wild and weedy populations of different V. sativa agg. taxa grow sympatrically, intermediate forms could be detected at the DNA and protein levels. Both RAPD and seed protein analysis support the view that the V. sativa aggregate consists of 8 taxa warranting recognition at the species level. Several species in this aggregate are evolving intra-specific groups which can readily be detected at the molecular level.

Collecting the Wild Relatives of Crops in the Tropics

There remains much that is not known about wild relatives of major crops. Hence the need for further collecting and study of these wild genetic resources is warranted. In recent years international and legal aspects of collecting and using germplasm have changed and need to be considered carefully in the preparatory phase of collecting. In addition, improved ability of collectors to document, map and sample plant populations (i.e. taking DNA samples) has added new dimensions to collecting. A wealth of information on the wild relatives of crops can be found from web-based databases that can help guide in planning collecting missions. To the extent possible collectors of plant germplasm need to promote the characterization and evaluation of collected materials.

Eco-Geographic Analysis

Within the field of genetic resources science one area that is developing rapidly, with advances in computer hardware, software and associated databases, is the application of geographic information systems (GIS) to understand issues related to conservation, evaluation and use of plant genetic resources. The database developed for Vigna subgenus Ceratotropis consisting of herbarium and passport data, includes information on the location of populations. This geo-referenced data can be used as the basis for looking at commonality and differences among locations for a wide variety of cultural, geographic and ecological attributes such as altitude, climate, ethnobotany, soil and vegetation (Guarino et al., 2002). Ethno-ecogeographic extrapolation requires care for the following reasons: Data on site location from herbarium specimens and passport data have varying levels of accuracy. Thus, while sites of recently collected germplasm may have been determined using a global positioning system (GPS), samples collected 15–20 years ago rarely have sites located so accurately. The data grids to which site location can be matched varies in size from region to region. Map grid size may be very fine, such as 1 ’ square for some information but less fine for other information. In addition, map grids into which populations may be placed are fixed thus populations growing close together may fall into different grids. Asia is a difficult continent to analyze because it is non-contiguous and larger than South America and Africa.

Research and Future Perspectives

In this final chapter a series of research topics are discussed that are particularly relevant to the conservation, evaluation and use of the Asian Vigna. The final section of the chapter discusses future research perspectives for the Asian Vigna.