ISHS Acta Horticulturae 299: Forum on Strategies for Horticultural Societies in the 1990's, XXIII IHC
COOPERATION IN GENETIC RESOURCES AND BREEDING PROGRAMS IN FRUIT TREES |
| Author: | J. Huet |
| Abstract:
The collection, maintenance and evaluation populations of domestic cultivars, primitive forms and wild species, finds its justification in plant breeding. Genetic improvement requires enlargement of genetic basis and genes controlling original and main characters which are the objectives of the breeder. The genetic resources and plant breeding are complementary activities. Each of them needs a long time, land, and sufficient research support. If we develop research on genetic resources, we may have the insurance of sufficient breeding programs to utilize the germplasm to its full potential. Without sufficient breeders our collections would be living museums of the phenotypic variability of the species and genus. What is the breeding situation for fruit trees? Varieties and rootstocks of all the cultivated species do not present all the qualities required by nurserymen, growers, market and customers. One of the best examples is the general susceptibility to parasites, diseases and pests. Also the lack of adaptation to particular climatic conditions, low productivity, lack of dwarfing rootstocks for intensive orchards, poor storage aptitude are problems to cope with. Genetic improvement of many species during the last decades has clearly proved the efficiency of genetics and plant breeding. The more demonstrative examples are wheat, barley, corn, sugar-beet, main vegetables, also some fruit species like apple, peach and coffee. What are the chances for breeding success in fruit trees? Are adequate programs to hope for a significant genetic improvement in the next century? Concerning genetic resources in fruit trees I think that we have a fair genetic diversity with differences among the genus and species. A part of this diversity is maintained in collections, repositories, botanical gardens today in the fields and tomorrow also in vitro or by cryopreservation. The total number of these collections in the world is high. They contain mainly cultivars, rarely primitive forms and wild species. International organizations play an important role, like FAO and IBPGR, but also national organizations are important. Another part of this variability exists in several countries in the world as wild trees or autochthonous old varieties. It is particularly the situation of China (Citrus, Actinidia, Malus…) of India (Mango, Pistachio…), of South West of Soviet Union (Prunus, Malus), of East Europe (Pyrus) etc. There are several concerns about the future of some collections because of reduced public funds. Only a few collections are well evaluated with the objective of screening genitors or identification of genes. Such evaluations may include not only botanical characters but also phenotypic compartments of agronomical interest, and genetic markers like isozymes or Restriction Fragment Length Polymorphism (RFLP). Programs of the National Clonal Germplasm Repository (NCGR) in USA illustrate well the importance of these descriptions and evaluations, and the amount of means necessary. Descriptions, | |
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