Effects of Cytoplasmic Configurations in Potato
Distinct parental cytoplasms were combined in symmetric tetraploid hybrids of potato by somatic cell fusion. This allowed in the presence of nearly isogenic nuclear genomes to estimate the contribution of mitochondrial (mt) and chloroplast (cp) genomes to yield parameters. Analysis of mt-cp configurations in 144 potato cultivars [2n=4x], a reciprocal population [2n=2x], di-haploid fusion parents [2n=2x] and their respective hybrids [2n=4x] made visible the effects of different cytoplasmic backgrounds and mitochondrial subgenomic rearrangements. Evaluation of cytoplasmic types lead to the assumption, that in starch content the ´wild type´ cytoplasms a and g have a significant advantage to other cytoplasmic types (b, d, e). Genotypes identified by our markers as mt type g were associated with cytoplasmic male sterility. In seed production di-haploids with mt- e were superior to others. In hybrids an interaction of starch content within different mt-cp combinations could be found. In general the highest field performance, measured in starch yield was associated with such cytoplasmic configurations which appeared to a high frequency within a population. This fact is explained by a selection advantage of clones with optimized organellar segregation allready during in vitro phase.

Phenotypic Variability within a Fusion Hybrid Population
Andreas Lössl
Lössl: Cytoplasm Genome Research
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 Acknowledgements: The authors are grateful to Mr. A. Barth, Mrs. E. Gerick,
Mr. C. Kornbauer and Mrs. Ammerseder for technical assistance.
This work was supported by grants of the BMBF under the number 0310768.
Last Update: Jan. 2000