Summary

Symmetric somatic cell fusion allows in the presence of nearly isogenic nuclear genomes to estimate the contribution of plasmones to yield parameters. Distinct mitochondrial (mt) and chloroplast (cp) genomes were combined in tetraploid hybrids of potato.
Analysis of mt-cp configurations in 144 potato cultivars [2n=4x], a reciprocal population [2n=2x], 2x 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).
This results from the experiments with a reciprocal population, 180 di-haploids, and from cultivar comparisons. 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 a correlation of starch content with different mt-cp combinations could be found.
In general these cytoplasmic configurations which appeared to a high frequency within a population, were associated with the highest field performance. This fact is explained by a selection advantage of clones with optimized organellar segregation allready during in vitro phase.

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Andreas LÖSSL, 15.04.2010