Genetic Resources and Modern Agriculture

Abstract

The primary sources of genetic variability that have been stored in genebanks and utilised to stimulate and promote plant breeding in agriculture are mutations accumulated in landraces and lntrogression of genes from exotics. Innovative germplasm conservation and handling methodologies for in situ and ex situ preservation of genetic resources are not available to make possible the optimal maintenance and use of the diversity of wild weeds, arable crops, fruit trees, forest trees, and symbiotic gene pools that can also be applied in developing countries. For many crops, their genetic resources have proved inadequate for significant crop improvement. However, for crops such as rice, maize, cowpea, soybean, amaranth, root and tuber crops, the tropical and sub-tropical fruits which are mainly grown in economicallyemerging countries, the collected and stored genetic resources (although incomplete) have been utilised to breed useful genotypes that have made significant improvements in crop productivity. Recent progress in biology and analysis of the c-onstraints that limit crop productivity have indicated that in some tropical and subtropical areas where cropping is difficult, agriculture systems based on multiple cropping and agroforestry may be convenient for sustainable land use in which crop cultivars can make complete use of e~vironmental resources. Efficient strategies are n~ed for the collection, conservation, evaluation and use of genetic resources for breeding crop cultivars to be grown under multiple cropping and agroforestry systems. Genetic resources represent a universal cause, and awareness for their conservation should be promoted at all levels of human activity, to ensure their availability and use for the genetic improvement of crop cultivars that will face the technical and biological problems posed by current and future agricultural systems.