Segregation of isozyme markers and cold tolerance in an interspecific backcross of tomato
- 153 Downloads
An interspecific backcross was obtained between the cultivated tomato, L. esculentum, and a high-altitude, cold-tolerant L. hirsutum, using the former as the recurrent pistillate parent. An individual plant of L. hirsutum which possessed maximum allelic differences for enzyme loci, with respect to those of L. esculentum, was selected as the staminate parent. Allelic differences were found at seventeen enzyme loci, marking eight of the twelve chromosomes of Lysopersicon.
Significant distortions in the monogenic segregations were detected at six enzyme loci. Four loci skewed with an excess of esculentum homozygotes and two with an excess of hirsutum heterozygotes. Significant heterogeneity between the segregations of subgroups was found at some loci, when the BC1 population was divided into two subgroups according to their physiological age (plastochron index). This indicates selection at the germination/seedling stage may account for some of the skewness.
Differential growth at low temperatures, measured by increments in the plastochron index, was used as the criterion for cold tolerance. Linkages between segregating enzyme loci and genes responsible for cold tolerance were tested via statistical comparisons of the means of plastochron index increments at low temperatures for esculentum homozygotes vs. those of hirsutum heterozygotes at each locus. A minimum of three quantitative trait loci (QT2) responsible for growth at low temperatures were detected, two had positive effects, and the other, negative. One marker locus, Pgi-1, gave a significant and positive effect only at low temperatures.
Key wordsLow temperature tolerance Plastochron index Isozymes Interspecific backcross Lycopersicon Tomato
Unable to display preview. Download preview PDF.
- Erickson RO, Michelini F (1957) The plastochron index. Am J Bot 44:297–305Google Scholar
- Johnson CM, Stout RR, Broyer TC, Carlton AB (1958) Comparative chlorine requirements of different plant species. Plant Soil 8:337–353Google Scholar
- Khush G, Rick CM (1963) Meiosis in hybrids between Lycopersicon esculentum and Solanum pennellii. Genetica 33:167–183Google Scholar
- Lamoreaux RJ, Chaney WR, Brown KM (1978) The plastochron index: a review after two decades of use. Am J Bot 65:586–593Google Scholar
- Rick CM (1963) Differential cygotic lethality in a tomato species hybrid. Genetics 48:1497–1507Google Scholar
- Rick CM (1969) Controlled introgression of chromosomes of Solanum pennellii into Lycopersicon esculentum: segregation and recombination. Genetics 62:753–768Google Scholar
- Rick CM (1971) Further studies on segregation and recombination in backcross derivatives of a tomato species hybrid. Biol Zentralbl 91:209–220Google Scholar
- Rick CM (1979) Potential improvement of tomatoes by controlled introgression of genes from wild species. In: Proc Conf Broadening Genet Base Crops, Wageningen 1978. Pudoc, Wageningen, pp 167–173Google Scholar
- Rick CM, Fobes JF, Holle M (1977) Genetic variation in Lycopersicon pimpinellifolium: evidence of evolutionary change in mating systems. Plant Syst Evol 127:139–170Google Scholar
- Steel RGD, Torrie JH (1960) Principles and procedures in statistics. McGraw Hill Book Company Inc, New York Toronto LondonGoogle Scholar
- Stephens DG (1949) The cytogenetics of speciation in Gossypium. 1. Selective elimination of the donor parent genotype in interspecific backcrosses. Genetics 34:627–637Google Scholar
- Tanksley SD (1979) An efficient and economical design for starch gel electrophoresis. Rep Tomato Genet Coop 29: 37–38Google Scholar
- Tanksley SD, Rick CM (1980) Isozymic gene linkage map of the tomato: applications in genetics and breeding. Theor Appl Genet 57:161–170Google Scholar
- Tanksley SD, Jones RA (1981) Effects of O2 stresses on tomato alcohol dehydrogenase activity: description of a second ADH coding gene. Biochem Genet 19:397–409Google Scholar
- Tanksley SD, Medina-Filho H, Rick CM (1981) The effect of isozyme selection on metric characters in an interspecific backcross of tomato-basis of an early screening procedure. Theor Appl Genet 60:291–296Google Scholar
- Tanksley SD, Medina-Filho H, Rick CM (1982) Use of naturally occurring enzyme variation to detect and map genes controlling quantitative traits in an interspecific backcross of tomato. Heredity 49:11–25Google Scholar
- Vallejos CE (1979) Genetic diversity of plants for response to low temperatures and its potential use in crop plants. In: Lyons JM, Graham D, Raison JK (eds) Low temperature stres in crop plants Academic Press, London New York, pp 473–489Google Scholar
- Vallejos CE, Lyons JM, Breidenbach RW, Miller M (1983) Characterization of a differential low temperature growth response in two species of Lycopersicon: the plastochron as a tool. Planta (in press)Google Scholar
- Zamir D, Tanksley SD, Jones RA (1982) Haploid selection for low temperature tolerance of tomato pollen. Genetics 101: 128–137Google Scholar