Literature Cited:
Gallegly M.E., 1960. Proc Campbell Soup Co., Plant Seminar, U.S.A., 113-135
Laterrot H., 1975. Ann. Amelior. Plantes 25 (2), 129-149
Turkenstein L.J., 1973. Mededeling N° 633.
RFLP polymorphism between two tomato lines
Lefebvre, V., Ferrlere, C., Caranta, C. and Damidaux, R.
Station d'Amelioration des Plantes Maraicheres - I.N.R.A- Avignon, France.
In order to map quantitative traits as soluble solids contents, it would be advantageous to work on
intraspecific cross (Lycopersicon esculentum). The progeny has acceptable agronomic characteristics, good fertility
and the segregations are not skewed compared to progeny of interspecific crosses. The two following lines were
studied
- Plovdiv 43/10, origin Maritsa Institute (Bulgaria), with high soluble solids contents (7 to 7.5 °Brix) and
determinate growth, derived from L. pimpinellifolium (Yordanov et al., 1977),
- Castone, origin INRA/CTCPA Montfavet (France), cultivated in France for paste production with
mechanical harvest (Laterrot and Damidaux, 1994).
A total of 33 tomato low-copy nuclear probes (provided by S. Tanksley of the Cornell University, Ithaca,
N.Y., USA), regularly distributed across the different chromosomes of the interspecific tomato map (Tanksley at al.,
1992) were used to examine the restriction fragment length polymorphism between the DNA of the 2 tomato lines
cut with 8 restriction enzymes (BamHl, Dral, EcoRl, EcoRV, Haelll, Hindlll, Taql, Xbal). DNA extraction, digestion,
electrophoresis, southern blotting and hybridization were performed as Lefebvre et al. (in press) described. Each
probe was not systematically tested with all the digested DNA, leading to an average of 6.6 different restriction
enzymes tested per probe.
Differences between enzymes were detected with respect to polymorphism. No polymorphism was found
with Oral (22 probes), Taql (24 probes) and Hindlll (31 probes). EcoRl, Xbal, EcoRV were the enzymes detecting
the largest amount of polymorphism (4 polymorphic on 29 probes for EcoRl, 4 polymorphic on 31 probes for Xbal, 2
polymorphic on 31 probes for EcoRV). This observation corroborated with the conclusions of Miller and Tanksley
(1990 a) who showed that the enzymes generating the largest genomic fragments as Xbal and EcoRV detected the
largest amount of polymorphism.
Among 219 enzyme-probe combinations tested, 12 (5.5 %) revealed polymorphism between Castone and
Plovdiv 43/10. The polymorphism level with at least one restriction enzyme corresponded to 15.2 % (5 probes
among 33). In fact, the same degree of polymorphism would have been detected if only EcoRl and Xbal had been
used. Indeed when a probe is polymorphic, the polymorphism is often detected with several enzymes. If it
corresponds to a chromosomal rearrangement (insertion/deletion for instance), its segregation in the progeny
would be the same whatever the enzyme used. The 5 polymorphic probes were randomly distributed on the tomato
map.
This preliminary study revealed a weakly higher degree of polymorphism than reported by Miller and
Tanksley (1990 b) who found on average 6% of polymorphic probes with a single restriction enzyme between
modern tomato cultivars. It confirmed the very low level of RFLP within L. esculentum and encourage us to develop
other types of DNA markers.
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