Tomato: a crop species amenable to improvement by cellular and molecular methods

Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

Primary production within the euphotic layer of the Norwegian Sea in July 1997: measurements by different methods

Results of primary production measurements obtained by different methods are presented. These methods are radiocarbon and oxygen modifications of the flask method, as well as fluorometric procedure with a PrimProd submersible probing fluorometer (produced at the Biological Department, Moscow State University). The research was carried out during a complex expedition aboard R/V Akademik Boris Petrov to the Norwegian Sea in July, 1977. Distributions of primary production values measured by different methods were correlated with other oceanographic data. Then a comparison of obtained values by the above-mentioned methods was performed