Development of Core Subset of Finger Millet Germplasm Using Geographical Origin and Data on 14 Quantitative Traits

Finger millet [Eleusine coracana (L.) Gaertn.] is an important cereal food crop in Africa and South Asia. It is a hardy crop that can be grown in very diverse environments from almost at sea level to about 2400 m.a.s.l. Finger millet has an excellent food value as its seeds contain protein ranging from 7 to 14% and are particularly rich in methionine amino acid, iron, and calcium. Despite all these merits, this crop has been neglected from the main stream of crop improvement research. One of the means to boost its production and productivity is to enhance utilization of finger millet germplasm to breed superior varieties. Keeping this objective in view, a core subset of finger millet germplasm (622 accessions) based on origin and data on 14 quantitative traits was developed from the entire global collection of 5940 accessions held in the genebank at ICRISAT, Patancheru, India. The comparison of means, variances, frequency distribution, Shannon-Weaver diversity index (H′) and phenotypic correlations indicated that the core subset represents the entire collection. These tests indicated that sampling was optimal and the diversity has been captured very well in the core subset. The correlation analysis indicated that panicle exsertion and longest finger length could be given lower priority in the future germplasm evaluation work of finger millet.     

Diversity of Nordic Landrace Potatoes (<Emphasis Type="Italic">Solanum tuberosum</Emphasis> L.) Revealed by AFLPs and Morphological Characters

The management of genebank collections of cultivated potato is costly due to the need for in vitro maintenance and virus eradication. Therefore, it is important to set up conservation strategies, which prevent duplicates entering the collections. In this study, 32 Nordic potato landraces were studied for 57 morphological traits and analysed for amplified fragment length polymorphism (AFLP). Most landraces could be distinguished based on the morphological characters, except five accessions. Using five primer combinations to generate 114 reproducible AFLPs, of which 63 (55%) were polymorphic, the five morphologically indistinguishable accessions were placed into two groups with identical AFLP patterns, suggesting that some of the accessions were redundant for long-term preservation. The AFLP data showed that the Nordic collection of potato landraces is composed of genetically different clones, and morphological analysis revealed a wide range of variability. This variability seems to be distributed randomly over the Nordic region since the cluster analysis based on AFLPs and morphological traits revealed no grouping based on the country of origin. Principal component analysis suggests that fewer morphological traits than used in this study will be sufficient to discriminate between different genotypes of cultivated potato (Solanum tuberosum L.). Future possibilities for rationalising potato collections are discussed.     

Nematode diversity and distribution in the southern maritime Antarctic—clues to history?

Nematode worms are one of the most important soil faunal groups in Antarctica. However, relatively little is known about their wider distribution, biogeography and history in the region, and taxonomic information remains confused or incomplete. Here, we hypothesise that the Alexander Island (southern maritime Antarctic) fauna includes elements that have survived (at least) the period of Pleistocene glaciation in situ, forming a regional centre of endemism and biodiversity hotspot. We describe nematological surveys carried out across a latitudinal gradient between 68 and 77°S along the southern Antarctic Peninsula, comparing the data obtained with the maritime Antarctic fauna described in the few previous studies between northern Marguerite Bay and the South Orkney Islands (60-68°S). In general, our survey supports previous findings of a lack of overlap at species level between the maritime and continental Antarctic biogeographical zones, with the large majority of specimens obtained from all survey sites being attributable to known maritime or new and currently endemic taxa. However, collections from Alexander Island, Alamode Island and the most westerly site sampled, Charcot Island, include specimens morphologically very close to two known continental Antarctic species, which may indicate a link between the two regions. The fauna obtained at the northern study sites (ca. 68°S, Adelaide Island, Marguerite Bay) closely matches that described previously. However, in contrast with widely described patterns of decreasing diversity in other Antarctic biota, species richness increased markedly at locations on Alexander Island (ca. 72°S), including a substantial element of undescribed species (50% of taxa across all locations, 40% of taxa found on Alexander Island). Finally, the most southerly samples obtained, from inland nunataks in Ellsworth Land (75-77°S), indicate a fauna that does not include nematodes, which is exceptional not only in an Antarctic context but also for soils worldwide.     

Rice genetic diversity at farm and village levels and genetic structure of local varieties reveal need for in situ conservation

Rice genetic diversity partitioning between farms, varieties and, within-variety diversity, were analysed in two villages of Maritime Guinea with contrasted agroecological conditions. One thousand and two hundred individual plants belonging to 45 accessions collected in eight farms were genotyped using 10 SSR markers. The molecular variance was evenly shared between and within accessions, while the farm effect was almost nil. Local varieties had a multi-line genetic structure. The number of multilocus genotypes was proportional to the utilisation rate of the variety in the village. The F _ST values between different accessions of each variety were significant which indicated low genetic consistency in the variety names. This varietal structure could mainly be explained by the migration phenomenon and the high varietal turnover. Compared to allelic diversity, multilocus genotypic diversity seemed to be the most suitable indicator of the quantitative distribution of diversity at different management scales (accession, farm and village). The within- and between-farm F _ST values were in the same order of magnitude. The within-farm diversity was not farm-specific but quantitatively high, i.e. up to 50% of the total genotypic diversity of a given village. Given the relative importance of the within-variety diversity, the in situ approach stands out as the most effective solution. As farms do not host specific diversity the in situ approach could be implemented by working with a small number of farms.     

Plant conservation: old problems, new perspectives

Nature conservation has changed from an idealistic philosophy to a serious technology(J. Harper, 1992)A review is given of the major conceptual changes that have taken place during the last 50 years in our understanding of the nature of plant conservation and of the principal methodological advances in undertaking conservation assessments and actions, largely through the incorporation of tools and techniques from other disciplines. The interrelationships between conservation and sustainable use are considered as well as the impact of the development of the discipline of conservation biology, the effects of the general acceptance of the concept of biodiversity and the practical implications of the implementation of the Convention on Biological diversity. The effect on conservation policy and management of the accelerating loss or conversion of habitats throughout the world and approaches for combating this are discussed.     

Soil-living parasitic Hymenoptera: comparison between a forest and an open landscape habitat

Community structures and local diversity patterns of parasitic Hymenoptera with soil and leaf litter hosts were studied in a German beech forest and a meadow. Hymenoptera appeared to be one of the most species-rich taxa associated with the soil. Eighty-eight species were found in the meadow (total density of 128 ind. m⁻² yr⁻¹) and 188 species (149 ind. m⁻² yr⁻¹) in the forest. The mean parasitism rates were above 60% for parasitoids of mycetophagous Diptera and between 7% and 26% for parasitoids of saprophagous Diptera. Species overlap between both habitats was higher than expected from a random sample model. Species common to both habitats were primarily parasitoids of predatory Coleoptera. High mean densities of these species support the hypothesis of a positive correlation between local abundance and range size.     

Reptile diversity and rodent community structure across a political border

The peace treaty between Israel and Jordan found the Arava desert ecosystem, shared by the two countries, in a state of developmental dichotomy. On the Israeli side, vast lands have been settled and transformed into agricultural fields, while the Jordanian side has remained relatively intact and inhabited by only a few traditional and pastoral societies. This study examined the effect of different landscape units and proximity to agriculture on reptile diversity and rodent community structure on both sides of the border. It appears that in addition to the effect of proximity to agricultural fields and landscape habitat, the border between the two countries may play a role in determining diversity on the respective sides. While reptile abundance was generally higher on the Israeli side of the border, diversity was found to be significantly higher on the Jordanian side. Rodent community structure also revealed significant differences between the two sides of the border, mainly due to the more favorable conditions for psammophilic gerbils in Jordan. When comparing Western society with pastoral traditional society, it appears that development activities of the former have altered diversity and community structure of the taxa studied in the Arava. We suggest that in addition to the effects of habitats and human disturbances, such as modern agricultural practices, cultural differences between societies should be considered when conservation plans are developed for cross-border ecosystems.     

The diversity and sustainable development of crop genetic resources in the Lancang River Valley

This paper reviews the status of crop genetic resources in Yunnan province of China from 1978 to 1999. Results are presented of same research in the field of the diversity of cultivated and wild crop. Yunnan is one of the centre of origin or genetic diversity of more than 200 cultivated and wild crops. There are over 500 cultivated plants which account for over 80% of the total in China and more than 650 species of wild crops. In addition, there are more than 440 species of main wild flowers. According to our recently researches there are abundant species, subspecies and varieties of crop genetic resources in Yunnan Province. The Lancang River Valley is the richest genetic diversity centre of rice, maize, wheat, barley, buckwheat, legumes, ramie, sugarcane, vegetable, tea, actinidia and so on. For example, there are 59 varieties (including all varieties of Oryza sativa L. in China) in 5933 accession of Yunnan indigenous rice. The Lancang River Valley is one of the centre for genetic diversity of rice resources and a rich region for elite and rare rice resources of Yunnan, too. In order to protect the highly endangered crop genetic resources in the Lancang River Valley, it is necessary and very important to set up a collection, conservation, utilization and research system, enhancing their protection and utilization, in situ- and ex situ-conservation, farm management and sustainable production.     

湖南衡南县紫色土土壤动物研究

通过对衡南县紫色土5种生境中的土壤动物进行调查研究,共获得土壤动物1657只,隶属于4门9纲37目,其中优势类群2类,常见类群11类。探讨了5种生境中土壤动物群落结构特征,并进行了多样性、均匀性及相似性分析。     

Genealogical Analysis of Diversity of Russian Winter Wheat Cultivars (Triticum aestivum L.)

With the aid of genealogical analysis the genetic diversity of Russian winter Triticum aestivum L. wheat cultivars was studied. The change of diversity in time from 1929 to 2002 shows an increase in diversity of Russian cultivars due to the use of foreign material in the breeding programs. At the same time, the genetic erosion of the released diversity occurred. In the 1950s and the 1960s about 50% of the Russian local and old varieties had dropped out of the pool of landrace ancestors. The set of the modern cultivars included in the Russian Official List 2002 has a cluster structure. The overwhelming majority (96%) are the descendants of cultivars Bezostaya 1 and/or Mironovskaya 808. The low diversity of cultivars recommended for cultivation in the Central and Volga-Vyatka regions is apparent. This situation can result in losses of a yield due to a uniform susceptibility to pathogens.