科研之友
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摘要
A cultivated diploid potato breeding population has been selected for adaptation to growing, tuberizing (under relatively long days), and storing (including long dormancy) under New Brunswick conditions. In this population, a mutant was discovered that appeared similar to the earlier described droopy mutant, which is deficient in abscisic acid and is unable to regulate water loss from its leaves. The physiology and genetics of the newly discovered mutant were studied and compared in detail with the description of droopy. This mutant has a longer tuber dormancy than the original droopy. In families segregating for droopy and normal, similar dormancies and endogenous abscisic acid levels in tubers were observed between droopy and normal genotypes. The effect of the mutant gene appears to be tissue specific, affecting aboveground plant parts only. A test for allelism indicated that this mutant is allelic to droopy. Classical linkage analyses confirmed previously reported close linkage between the Dr (droopy) and the S (incompatibility) loci. The Dr locus has been mapped in this study to the top of chromosome I. Several test crosses indicated reciprocal differences in the segregation ratios between droopy and normal. In keeping with the droopy (drdr) genotype, drought-stressed leaves of the mutant were incapable of increasing abscisic acid production compared to the normal. This mutant, with its apparent developmentally restricted expression, may be useful in elucidating the genetic and physiological processes associated with such major events as tuberization, response to drought stress and tuber dormancy.
- 出版日期2001-8
