Possibilities of using wild lettuce forms originating from the spontaneous Yugoslav flora in the selection for virus diseases of Lactuca sativa L

Abstract

An investigation was carried out with aims to create lettuce cultivars (Lactuca sativa L.) resistant to pathogens, such as the causal agents of plant diseases, and especially that of virus diseases. The spontaneous flora in the localities of Pomoravlje and Sumadija were investigated for this propose where resistant genotypes of the species Lactuca sp. could be found. The interspecies hybrids Lactuca virosa L. x Lactuca sativa L., L. saligna L. x L. sativa L., were investigated as a possible source of genetic variability. L. saligna L. and L. virosa L. represented only a part of the population related to L. sativa L. Wild varieties of this species belong to the weed flora. After crossings, variable achenes were obtained only between L. sativa L. x L. saligna L. In the first crossings, as many as two populations of L. saligna L. were used, one with and the other without anthocyanin, but the seedlings of L. saligna L. without anthocyanin decayed after being taken out in the field. In the process of the selection of F-1 generation, 31 plants emerged. However, only 19 plants survived after transplanting in the field. In 9 plants the fertility was provoked by colhicyn, but the percentage of fertile achenes was low as compared to the number of achenes that were not viable. The collection of the genotypes of Lactuca sp. for the gene bank and further investigations on the possibilities of crossing them with the cultivated lettuce (Lactuca saliva L.), the selection programmes on lettuce could be improved. Eventually, the final aim of obtaining a cultivar with the built-in genes of resistance to virus diseases and acceptable morphological characteristics would be achieved.