Comparative microsatellite linkage analysis and genetic structure of two populations of F6 lines derived from Lycopersicon pimpinellifolium and L. cheesmanii

Irene Villalta (1, 2) , A. Reina-Sánchez (3) , J. Cuartero (3) , E. Carbonell (3) , M. J Asins (4)

1 IRBI - Institut de recherche sur la biologie de l'insecte
2 EBD - Estación Biológica de Doñana
3 CSIC - Consejo Superior de Investigaciones Cientificas [España] = Spanish National Research Council [Spain]
4 IVIA - Instituto Valenciano de Investigaciones Agrarias - Institut Valencià d'Investigacions Agraries - Valencian Institute for agricultural Research

A population of recombinant inbred lines (RILs) has several advantages over its F 2 population counterpart with respect to quantitative trait loci (QTLs) and genomic studies. The objective of the investigation reported here was the comparative characterization by simple sequence repeat (SSR) and sequence characterized amplified region (SCAR) markers of two populations of F 6 lines derived from Lycopersicon pimpinellifolium (P population, consisting of 142 lines) and L. cheesmanii (C population, consisting of 115 lines) and sharing the female parent, L. esculentum var. cerasiforme. Almost the same percentage of polymorphic markers was found for each population although a different set of markers was involved. The proportion of SSR primer pairs (93 in total) that resulted in poly-morphism for the main band was larger (55-56%) than for SCAR ones (13-16%). The C population showed the largest proportion of markers with zygotic and gametic segregation distortion, which is in agreement with the larger genetic distance reported between L. esculentum and L. cheesmanii than with the former and L. pimpi-nellifolium. Zygotic distortion corresponded primarily to an excess of heterozygotes in both populations, suggesting that the increment of homozygosity was the main factor limiting viability/self-fertility of the lines. Despite both populations sharing the female parent, P alleles were slightly favored in the P population while E alleles were the most frequently fixed in the C population. A linkage map for each population was obtained, with the average distances between consecutive markers being 3.8 cM or 3.4 cM depending on the population. Discrepancy between the maps for the location of only four markers on chromosomes 3, 6 and 10 was observed. Two possible causes of this discrepancy were investigated and can not be discarded: (1) the presence of duplicated markers and (2) segregation distortion caused by the selective advantage of gametes carrying one of the two alleles. This marker characterization of both populations will continue and will enable the comparative QTLs and candidate gene analysis of complex traits towards a more efficient utilization of genetic resources and breeding strategies.

Domaines: Amélioration des plantes; Génétique des plantes

Irene Villalta, A. Reina-Sánchez, J. Cuartero, E. Carbonell, M. J Asins. Comparative microsatellite linkage analysis and genetic structure of two populations of F6 lines derived from Lycopersicon pimpinellifolium and L. cheesmanii. TAG Theoretical and Applied Genetics, 2005, 110 (5), pp.881-894. ⟨10.1007/s00122-004-1906-3⟩. ⟨hal-02140672⟩