The pattern of genetic diversity in faba bean collections from Ethiopia and Afghanistan

Summary The pattern of genetic diversity in 106 faba bean accessions from Ethiopia and Afghanistan was analysed. Eight quantitative characters were observed. Differences among origins were highly significant for plant height and yield characters. Principal component analysis and cluster analysis were performed in order to ascertain phenotypic similarities between accessions, which could be useful for sampling in subsequent studies. A core of 21 accessions based on clusters which are assumed to represent a great diversity was defined.     

Autofertility in a pure line faba bean (Vicia faba L.) germplasm collection

Summary A pure line faba bean germplasm collection (BPL) was derived by a process of cyclic single plant progenies starting in 1979 through 1985. In 1985/86, 840 of these pure line accessions from 677 original populations from 41 countries were evaluated for autofertility by comparing the mean of five plants where all flowers were tripped vs. five plants with no tripped flowers for number of seeds produced (seed index). In a replicated trial grown at the same time, seed yield, 100 seed weight, number of pods per plant, seeds per pod, and number of flowers per inflorescence were also evaluated. A high number of BPL accessions failed to set seeds in the screen houses without tripping, the mean seed index measure of autofertility was 0.51 with a C.V. of 74.2%. There were marked differences among countries of origin for autofertility, with Egypt having the highest (SI = 0.94) and the USSR the lowest (SI = 0.26) autofertility, however, most countries expressed a large range, suggesting that breeders should first look in their own material for this trait rather than searching in exotic germplasm. In general, there was a higher level of autofertility in Middle Eastern countries that may be due to natural selection for non-dependency on pollinators for high yield. Contrary to the findings of others, large seeded accessions had a high autofertility (SI = 0.704) compared to small seeded accessions (SI = 0.384), however, both had similar ranges. In general, there was no significant correlations among autofertility and yield and its components. The variability found in this large pure line collection for autofertility is of potential use for developing cultivars not dependent on insect populations for high yield and for developing self-pollinated faba bean.     

Diversity analysis of Central Asia and Caucasian lentil (<Emphasis Type="Italic">Lens</Emphasis><Emphasis Type="Italic">culinaris</Emphasis> Medik.) germplasm using SSR fingerprinting

Diversity analysis was performed among 39 cultivated lentil (Lens culinaris Medik.) accessions of Central Asia and Caucasian origin using five highly polymorphic microsatellite markers. A total of 33 alleles determined ranging from 3 to 8 per locus. Estimated gene diversity value for 33 loci was 0.66. Genetic similarity indices among 39 accessions ranged from 0.24 to 1.0. Cluster analysis using the unweighted pair group method with arithmetic mean method classified accessions into six major groups at 0.5 similarity coefficient. More than half accessions from Tajikistan formed large cluster. On the other hand, a few accessions from each country showed unique genotypes. Overall, most of the accessions, except ones with closely related origin, were distinguished by the present high quality DNA fingerprinting. This molecular diversity information gives important basis for conservation strategy in gene bank and exotic germplasm introduction in breeding programs in Central Asia and Caucasian countries.     

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.     

Increase of potato genetic resources in their center of diversity: the role of natural outcrossing and selection by the Andean farmer

Summary The Andean farmer conserves and maintains the existing genetic diversity of potato cultivars by means of clonal propagation of tubers. However, surveys of traditional farms showed that botanical seed propagation was used for disease elimination, stock rejuvenation and the creation of new cultivars. Electrophoretic surveys based on 542 tubers collected from 18 markets sampled in the Cusco area disclosed a total of 229 different cultivars from diploid, triploid and tetraploid forms of Solanum tuberosum L. These could be classified by isozyme cluster analysis into four major groups and six minor groups. However, they did not agree with groups based on flesh or skin color. It is therefore concluded that all genotypes belong to a single, large gene pool with considerable gene flow between cultivars of different groups. When the samples were grouped by the three most common tuber skin colors, namely red/pink (Q'ompis type), purple (Yana Imilla type), and yellowish/brown (Yuraq Kusi type), similar allozymes were observed in all three classes. The structure of the isozymic phenotypes within each group indicate that they may have been derived as segregants after outcrossing of diverse parental types. In order to provide further evidence for the origin of new types by hybridization, two segregating diploid progenies were generated by crossing purple by yellow skin types. In the resulting F₁, most of the tuber phenotypes observed in the Andean varieties were reproduced in these crosses. It can be concluded that the Andean potatoes form a large and plastic gene pool amplified and renovated by outcrossing followed in some cases by human selection of desirable phenotypes.     

Effect of resolving medium and staining procedure on inter-simple-sequence-repeat (ISSR) patterns in cultivated flax germplasm

We compared ISSR patterns generated by three variants of resolving medium/staining procedure: agarose/ethidium bromide, polyacrylamide/silver staining, and polyacrylamide/SYBR Green I in order to prepare methodology for large-scale screening of genetic diversity in flax (Linum usitatissimum L.) germplasm collections. We found out that polyacrylamide/SYBR Green I system is the most suitable variant for large-scale characterization of genetic diversity within flax germplasm collections.