Use of molecular markers in breeding for soluble solids content in tomato — a re-examination
Tóm tắt
Through earlier breeding efforts, portions of the genome of the wild species Lycopersicon chmielewskii have been introgressed into the cultivated tomato (Rick 1974). These introgressed chromosomal segments have been reported to increase soluble solids in fruit of certain tomato varieties (Rick 1974). Recently, two of the introgressed segments have been identified with RFLP markers and tested for effects on soluble solids in a single F2 population (Osborn et al. 1987). Based on results from that experiment, it was determined that one of the detected segments contains gene(s) controlling soluble solids and concluded that tomato varieties could be improved for this character by indirect selection for the linked RFLP marker (Osborn et al. 1987). In this report, we have independently tested the association between RFLP and isozyme markers and genes controlling soluble solids and other characters in the above described material. These experiments differ from the previous ones in that a set of 132 molecular markers (isozymes and DNA clones) of known chromosomal position have been used. Three introgressed chromosomal segments from L. chmielewskii have been identified using these markers. They map to the middle and the end of chromosome 7 (> 40 cM apart) and to the end of chromosome 10. The effects of these segments on soluble solids and other horticultural characters were tested in crosses with three different cultivars over a period of two years. Two of the three segments were found to increase soluble solids, however the effect of one of these was dependent on genetic background. Both segments were found to be associated with deleterious characters including increase in fruit pH, lower yield and small fruit. These results confirm the utility of molecular markers for detecting genes underlying quantitative variation but demonstrate the danger in establishing breeding programs around such linkages until the effects of the quantitative genes have been tested in a variety of genetic backgrounds and for associated effects on other characters of agronomic importance.
Tài liệu tham khảo
Bernatzky R, Tanksley SD (1986a) Genetics of actin-related sequences in tomato. Theor Appl Genet 72:314–321
Bernatzky R, Tanksley SD (1986b) Methods for detection of single or low copy sequences in tomato on southern blots. Plant Mol Biol Rep 4:37–41
Bernatzky R, Tanksley SD (1986c) Toward a saturated linkage map in tomato based on isozymes and random cDNA sequences. Genetics 112:887–898
Edwards MD, Stuber CW, Wendel JF (1987) Molecular-marker-facilitated investigations of quantitative-trait loci in maize. I. Numbers, genomic distribution and types of gene action. Genetics 116:113–125
Ellis THN (1986) Restriction fragment length polymorphism markers in relation to quantitative characters. Theor Appl Genet 72:1–2
Falconer DS (1960) Introduction to quantitative genetics. Ronald Press, New York
Hanson WD (1959) Early generation analysis of lengths of heterozygous chromosome segments around a locus held heterozygous with backcrossing or selfing. Genetics 44:833–837
Ibarbia E, Lambeth VN (1969) Inheritance of soluble solids in a large/small-fruited tomato cross. J Am Soc Hortic Sci 96:199–201
Lower RL, Thompson AE (1967) Inheritance of acidity and solids content of small-fruited tomatoes. Proc Am Soc Hortic Sci 91:486–494
Osborn TC, Alexander DC, Fobes JF (1987) Identification of restriction fragment length polymorphisms linked to genes controlling soluble solids content in tomato fruit. Theor Appl Genet 73:350–356
Rick CM (1974) High soluble-solids content in large-fruited tomato lines derived from a wild green-fruited species. Hilgardia 42:493–510
Rick CM, Kesicki E, Fobes JF, Holle M (1976) Genetic and biosystematic studies on two new sibling species of Lycopersicon from interandea Peru. Theor Appl Genet 47:55–68
Soller M, Beckmann JS (1983) Genetic polymorphism in varietal identification and genetic improvement. Theor Appl Genet 67:25–33
Soller M, Brody T (1976) On the power of experimental designs for the detection of linkage between marker loci and quantitative loci in crosses between inbred lines. Theor Appl Genet 47:35–39
Stuber CW, Edwards MD, Wendel JF (1987) Molecular-marker-facilitated investigations of quantitative-trait loci in maize. II. Factors influencing yield and its component traits. Crop Sci 27:639–648
Tanksley SD (1985) Enzyme-coding genes in tomato (Lycopersicon esculentum). Isozyme Bull 18:43–45
Tanksley SD, Iglesias-Olivas J (1984) Inheritance and transfer of multiple-flower character from Capsicum chinense into Capsicum annuum. Euphytica 33:769–777
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 49:11–25
Tanksley SD, Miller J, Paterson A, Bernatzky R (1987) Molecular mapping of plant chromosomes. Stadler Symp (in press)
Zamir D, Tadmor Y (1987) Unequal segregation of nuclear genes in plants. Bot Gaz 147:355–358
Zamir D, Selilaben-Davis T, Rudich J, Juvick JA (1984) Frequency distribution and linkage relationships of 2-tridecanone in interspecific segregating generations of tomato. Euphytica 33:481–488