Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 4pg1
INTROGRESSION OF USEFUL GERM PLASM FROM SOLANUM LYCOPERSICOIDES
AND S. RICKII VIA ALIEN ADDITION AND INBRED BACKCROSS LINES.
Roster T. Chetelat, Pedro Cisneros, Charles M. Rick and Joseph
W. DeVerna 1 Dept. of Vegetable Crops, U.C. Davis, Davis, CA
95616 1 Campbell Soup R&D, 28605 County Rd. 104, Davis, CA 95616
Solanum lycopersicoides and S. rickii, two tomato-like wild
nightshade species, possess traits that are valuable for tomato
improvement and not known in other germ plasm sources: tolerance
of extreme drought and low temperatures and resistance to certain
diseases. This study is intended to derive sets of alien
chromosome addition lines (ALs) and inbred backcross lines
(EBLs) representing the genomes of these nightshades in a tomato
background. The ALs and EBLs will be useful for linkage studies
of monogenic traits from the nightshades or genes cloned from any
tomato species. They also provide breeders with advanced
derivatives that obviate starting with the nightshades
themselves. A complete set of S. lycopersicoides ALs was derived
by means of a sesquidiploid intergeneric hybrid and L.
pennellii-derived bridging lines used to overcome hybrid
sterility and unilateral incompatibility. An analogous
cytogenetic strategy is being employed to synthesize S. rickii
ALs. These will be propagated vegetatively in vitro to avoid
problems of recombination and low transmission. From an
unusually fertile F1 L. esculentum x S. lycopersicoides hybrid,
large backcross populations were obtained. BC2 and BC3 relies
will be self-pollinated to produce a set of IBLs representing the
nightshade genome via segmental substitutions. A linkage map of
the S. lycopersicoides genome was constructed based on isozyme
and RAPD markers. A shared RAPD polymorphism rate of 32% was
observed between S. rickii and S. lycopersicoides, indicating
that the map can be applied to both genomes.
Research supported in part by USDA grant #91-37300-6382.
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