Improved Culture System for Microspores of Barley to Become a Target for DNA Uptake

For the winter barley cultivar ‘Igri’, a microspore isolation and regeneration procedure is described which allows the production of such vigorous micro-spore fractions that this single-cell system can be used as a target for DNA uptake. Up to 60 % of the vigorous microspores isolated from the anther, and cultured in liquid modified MS medium, formed embryoids and/or calli. Such preparations were used for trials in DNA uptake with the plasmid pBI 221. Transformation trials were performed with polyethylene glycol as the inducing agent. With this treatment, a relative increase of fluorescence could be shown under UV light indicative of transient expression of the uidA gene.     

Haploid Production from Barley Yellow Dwarf Virus Resistant Clones of Lolium

The investigation was earned out to obtain double haploid homozygous lines of Lolium. Lolium multiflorurm ssp. gaudini cv. ‘Liwelo’, 44 clones and five different cultivars (cv.) of L. perenne were tested with regard to their anther culture response on a solid medium. Callus production and plant regeneration of the different genotypes were investigated. Within L. m. ssp. gaudini green plants have been obtained. In L. perenne significant genotypical differences in the in vitro reaction could be demonstrated. A high-responding genotype was selected which produced a maximum of 20 % green plants. A variety × temperature interaction was found for the L. perenne varieties ‘Premier’ and ‘Barlenna’. The production of 34 green plants out ot eight clones enables a first analysis to be made of the inheritance of Barley Yellow Dwarf Virus resistance in L. perenne.     

Comparative Value of Androgenetic Doubled Haploid and Conventionally Selected Spring Barley Lines

Androgenetic doubled haploid spring barley lines (DH-lines) were compared in field experiments with their pedigree-selected sister lines (PD-lines). The PD-lines resemble a selected proportion of 1 % (10^?2) or less of the original complete F₂-population. By comparison, an average of 10 DH-lines were recovered from 10,000 anthers X > 1,000 microspores, i.e. at least 10⁷ microspores per cross. The average success rate was therefore approximately 10^?6. Both PD- and DH-families showed similar levels of performance with regard to all the characters studied, although no conscious selection had been applied in deriving doubled haploid progeny. Therefore, it is concluded that the regenerated microspore-progenies may be the result of unconscious selection among the large numbers of microspores cultured.     

Monohaploid plants from anthers of a dihaploid genotype of Solanum tuberosum L.

Summary Monohaploid Solanum tuberosum plants were produced from the anthers of a dihaploid genotype. From another dihaploid genotype plants containing 36 chromosomes were obtained. For plantlet production anthers containing pollen at the uninucleate microspore stage were inoculated on a Linsmaier and Skoog-based medium supplemented with 1 mg/1 indole-3-acetic acid and 1 mg/1 benzyl aminopurine.Anthers from donor plants grown either in the summer or in the winter responded similarly on a range of media. Anther response in the form of callus induction and root formation was at least partly dependent on the genotype of the donor dihaploid plant.     

Combination of resistances to barley yellow mosaic virus and Rhynchosporium secalis by recurrent selection with repeated haploid steps

The aim of this investigation was the incorporation of resistance to BaYMV and Rhynchosporium secalis into German winter barley varieties together with the maintenance of their high agronomic characters. The agronomic value of DH-lines after two backcrosses and three haploid steps were compared with the original parents. Lines with similar or superior results could be selected for all the agronomic features evaluated. This method of recurrent selection with repeated haploid steps can therefore lead to the development of lines useful for practical purposes.