[The effects of homo- and heterozygosity for isoenzyme loci in tomato crossing over]
1993
Ursul, S.V. | Zhuchenko, A.A. | Denisova, F.Sh. | Levites, E.V.
An attempt has been made to study the nature of genetic differences in the crossing over rate in marker segments of tomato chromosomes 4 and 11. To this end, an interspecific cross between the multimarker line Mo628 (Lycopersicum esculentum Mill.) and L. hirsutum var. glabratum Mull. was made using a number of isoenzyme markers and the backross genetic analysis. The maximum reduction in the crossing-over rate in the segment ful-e (chromosome 4) has been revealed in the presence of heterozygosity for the locus Adn-1 (chromosome 4) (for +/+-rf=29.96+/-2.53%; for -/+-rf=23.41+/-1.38%) and in the segment hl-a (chromosome 11) with heterozygosity for the locus Aat-2 (chromosome 7) (for +/+-rf=19.28+/-1.47%; for -/+-rf=9.02+/-0.84%). Also, high degree of quasi-linkage between isoenzyme loci of the "cultivated" and "wild" types was found during chromosome segregation in meiosis of the F1 hybrids between L. esculentum and L. hirsutum var. glabratum. The possibility is discussed of the presence in tomato of some herefore unknown genetic factors linked to the Adh-1, Aat-2 loci, significantly affecting crossing-over in the segments under study.
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