PLANT PHYSIOLOGY , Vol 115, Issue 4 1453-1459, Copyright © 1997 by American Society of Plant Biologists
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DEVELOPMENT AND GROWTH REGULATION |
Evidence from Polygene Mapping for a Causal Relationship between Potato Tuber Dormancy and Abscisic Acid Content
I. Simko, S. McMurry, H. M. Yang, A. Manschot, P. J. Davies and E. E. Ewing
Department of Fruit and Vegetable Science (I.S., S.M., H.-M.Y., A.M., E.E.E.), and Section of Plant Biology (P.J.D.), Cornell University, Ithaca, New York 14853
In previous studies polygene mapping of a backcross population derived from
haploid potato (Solanum tuberosum) and a diploid wild species (Solanum
berthaultii) showed at least eight quantitative trait loci (QTLs)
associated with tuber dormancy. The same population was mapped for abscisic
acid (ABA) content in tubers so that any QTLs identified could be compared
with those detected previously. At least three distinct loci on three
chromosomes (2, 4, and 7) were associated with variation in ABA content.
One of the QTLs was detected only as a main (single locus) effect, and two
QTLs were found through two-locus interaction analysis (epistasis).
Interaction between QTLs at markers TG234 (chromosome 2) and TG155
(chromosome 4) explained 20% of total phenotypic variance for this trait.
The interaction closely resembled one previously detected for dormancy,
suggesting an association between high ABA content and long tuber dormancy.
Although relationships between ABA level and dormancy could be demonstrated
through polygene mapping, there was no indication of a relationship between
these traits when they were subjected to a conventional correlation test.
This illustrates the usefulness of polygene mapping as a tool to identify
possible associations between hormone levels and plant development.