A genetic map of lettuce (Lactuca sativa L.) with restriction fragment length polymorphism, isozyme, disease resistance and morphological markers

• Published in: Genetics (Austin) Vol. 116; no. 2; pp. 331 - 337
• Main Authors: Landry, Benoit S, Kesseli, Rick V, Farrara, Barry, Michelmore, Richard W
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Genetics Soc America 01.06.1987; Genetics Society of America
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; bremia; chromosome; chromosomes; Classical and quantitative genetics. Population genetics. Molecular genetics; Classical genetics, quantitative genetics, hybrids; cromosomas; disease resistance; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; genetic markers; Genetics and breeding of economic plants; Genetics of eukaryotes. Biological and molecular evolution; hidrolasas; hydrolase; hydrolases; Investigations; isoenzimas; isoenzyme; isoenzymes; Lactuca sativa; marcadores geneticos; marqueur genetique; polimorfismo; polymorphism; polymorphisme; Pteridophyta, spermatophyta; resistance aux maladies; resistencia a la enfermedad; Vegetals; Genetic mapping; Vegetals; Disease; Enzyme; Restriction fragment; Compositae; Resistance; Vegetable crop; Dicotyledones; DNA; Angiospermae; Restriction map; Spermatophyta; Lactuca sativa; Polymorphism
• ISSN: 0016-6731; 1943-2631; 1943-2631
• DOI: 10.1093/genetics/116.2.331

A detailed linkage map of lettuce was constructed using 53 genetic markers including 41 restriction fragment length polymorphism (RFLP) loci, five downy mildew resistance genes, four isozyme loci and three morphological markers. The genetic markers were distributed into nine linkage groups and cover 404 cM which may be 25-30% of the lettuce genome. The majority (31 of 34) of the RFLP probes detected single segregating loci, although seven of these may have been homologous to further monomorphic loci. When several loci were detected by a single probe, the loci were generally linked, suggesting tandem duplications. One probe, however, detected loci in three linkage groups suggesting translocations. The five downy mildew resistance genes (Dm1, Dm3, Dm4, Dm5/8 and Dm13), segregating in the Calmar x Kordaat cross, represented each of the four resistance gene linkage groups. Dm5/8 is flanked by two cDNA loci, each located 10 cM away. These flanking markers will be used to study the source of variation in downy mildew genes and are also part our strategy to clone resistance genes.