Relación entre los procesos cognitivos, metacognitivos y

Rich genetic resources not only provide valuable genes but are also insurance against future hazards, pests and diseases. Agricultural biodiversity (agrobiodiversity) includes all species and crop cultivars, animal breeds and races, microorganism strains that are used directly or indirectly for food and in agriculture, both in human nutrition and animal feed (including grazing) for domesticated and semi-domesticated animals, and the range of environments in which agriculture is practised (Heywood, 1999). Analysis of genetic diversity in underutilised crops is necessary to find valuable characters, to determine evolutionary history in order to choose appropriate breeding strategies and to monitor genetic erosion (loss of genetic diversity) and gene flow between local and introduced species/cultivars.

In general, most of the diversity is found in landraces, ecotypes or local cultivars that have been developed through unconscious selection over centuries. These ecotypes are adapted to local environments, but they are at risk through replacement by modern cultivars of broad adaptability. Some landraces may represent very ancient, relict forms even from the periods before glaciations as has been proven for the L. perenne ecotype

from the Tatras. The presence of cpDNA and mtDNA haplotypes together with a separate position in transposon based dendrograms as well as the presence of a unique peroxidase allele (Per1-45) suggests that this population has been genetically isolated for a

considerable period of time. During the Quaternary Ice Ages, in contrast to the Alps, relatively small areas were covered by ice sheets in the Tatras. Presumably, perennial ryegrass populations in the Tatras were fragmented and more isolated but they survived the glaciation periods. Furthermore, due to difficult living conditions, and as a result of early protection, the local vegetation has not been disturbed for centuries. Traditional agriculture has prevented the extinction of old genotypes by crossing with modern cultivars (Polok, 2007). Foxtail millet, Setaria italica is another crop, for which higher

intermediate between the three other geographical groups whereas lines from central Europe are genetically uniform (Schontz and Rether, 1999).

Agricultural biodiversity involves also habitats and species outside farming systems but which benefit from agriculture or enhance it. Natural ecosystems form a part of the landscape within which agricultural systems are found and they are a source of valuable genes. They are responsible for soil stabilisation, water and air quality. Mossy peat-bogs that can be found in north-western parts of Europe constitute natural water reservoirs preventing floods and provide poor farmers with food (cranberries, medicinal plants) and fuels. However, the intensive drainage of peat-bogs has resulted in their drying out, and has affected the viability of agriculture in the vicinity and resulted in extinction of some genotypes. The process is well emphasised by disappearance of the relict genotype of Pinus sylvestris f. turfosa inhabiting some Polish peat-bogs both by

invading peat-bogs by typical fast growing, forms of P. sylvestris and erosion of genetic

resources through hybridisation between both forms (Polok et al., 2005).

For centuries, exchange of genetic materials has led to the development of secondary centres of diversity for some crops but also resulted in disappearance of native species. At present agricultural production of developed countries is predominantly based on species originating from other regions. For instance, it is estimated that the whole food production in Australia and North America depends on alien species while Europe is 91% dependent on species from other parts of the world (FAO, 1996). This trend is also followed by minor crops. Even though Europe holds a significant diversity of native plants those that were spread many years ago alongside with the development of primitive agriculture, very often exotic or alien species to native flora are recommended for introduction as alternative crops. Examples include amaranth (Amaranthus ssp.)

promoted in Europe as a nutritionally rich food and alternative source of energy, meadowfoam (Limnanthes alba) as a source of products for the cosmetic industry and

others. The Polish Ministry of Agriculture recommends introducing Solidago canadensis

as a nectar source for honey despite the fact that it is a highly invasive species, supplanting native S. virga-aurea. Moreover, hybridisation of both species may lead to

genetic erosion of native forms. By contrast, Europe is a primary or secondary centre of diversity for many crops that used to be cultivated but are now abandoned or rarely found. This is true for such cereals as emmer (T. dicoccoides), spelt (T. spelta), naked

barley, naked oat (A. nuda), bristle oat (A. strigosa), rye (S. cereale), foxtail millet (S. italica) and buckwheat (Fagopyrum esculentum), which is a pseudocereal. These species

are well adapted to European conditions and could become a basic source for diversifying agriculture and food. For some of them sufficient genetic diversity exists providing rough materials for genetic improvements while others are genetically relatively uniform. An example of the latter is A. strigosa, genetic resources of which are highly homogenous

and ecotypes from different parts of the world are much the same with respect to morphology and DNA profiles (Figure 5).

Figure 5. ISJ profiles of A. strigosa ecotypes

One of the key questions that have to be addressed when considering use of wild species as potential new crops is the availability of genetic material for genetic improvement. If there is not sufficient genetic diversity it should be widened. Induced mutagenesis is one of the most cost effective, simple and uncontroversial methods to reach this goal, but not often used for underutilised species. During mutagenic treatment many point mutations are induced in the genome and the diversity of induced mutants is often higher in comparison with cultivars or ecotypes. In A. strigosa it was possible to select 120 mutant

lines originating from six ecotypes, 51499 (Caucasus), 51578 ecotype (Uruguay), 51584 ecotype (France), 51733 ecotype (Spain), 51730 ecotype (Brazil, old cultivar Saja3), and

A. strigosa var. glabrescens, collected in north-east Poland. Owing to the selection goals,

the majority of lines are dwarf or semi-dwarf, however other mutants were also found (Figure 6). Apart from morphological changes, high diversity of mutants was observed at the DNA level as indicated by ISJ or AFLP profiles (Figure 7). Similarly, induced mutants of pea fell into five morphological categories including dwarf mutants, root mutants characterised by a shorter root system but normal stem height, root mutants with a reduced number of lateral roots, a stem-less mutant (only roots developed), and fasciata

mutants. The AFLP analysis of P. sativum mutants confirmed that chemical mutagens

induce a high number of mutations in the genome. In total, more than 1000 bands were revealed and 51% of them were polymorphic. An average 14% of mutated AFLP loci were observed in each mutant. Once genetic diversity is available, the genetic improvement must be undertaken to obtain cultivars acceptable by farmers.

Figure 6. Examples of A. strigosa mutants

MOLECULAR APPROACHES FOR GENETIC IMPROVEMENT OF