A genetic map of potato : construction and applications

This thesis describes the construction of an integrated genetic map of potato (Solanum tuberosum L.) using molecular, morphological and isozyme markers. A general method for map construction, different from previous methods employed in non-inbred plants, is described using JoinMap 1.4. This basic map was used for various applications in potato genetics. For the purpose of targeted transposon tagging in potato, the integration sites of T-DNA's and transposable elements were determined and were found to cover the entire potato genome. Genetic maps, constructed from seven different potato populations, were compared and aligned. All data were combined and one common core map was constructed with the help of JoinMap 2.0. Furthermore, the genetic map was used to assist in the mapping of the resistance locus GroV1 from S . vernei. This resistance locus, to the potato cyst nematode Globodera rostochiensis pathotype 1, was located on chromosome 5 with molecular (RFU/PCR) markers

Vivipary in the Marlborough rock daisy, Pachystegia insignis (Asteraceae)

Vivipary involves the germination of seeds prior to their dispersal from the parent plant. It requires seed dormancy to be absent and has only been recorded in a very small number of phylogenetically diverse higher plants of varying life forms from a wide range of habitats. This study confirms a lack of seed dormancy in the New Zealand native Marlborough rock daisy, Pachystegia insignis (Hook. f.) Cheeseman (Asteraceae). High frequencies of germination in P. insignis immediately following seed maturation are documented, as well as an instance of prolific vivipary. We provide experimental validation that, when achenes are retained in capitula, vivipary is induced in planta by wet conditions

Sequencing the potato genome: outline and first results to come from the elucidation of the sequence of the world's third most important food crop

Potato is a member of the Solanaceae, a plant family that includes several other economically important species, such as tomato, eggplant, petunia, tobacco and pepper. The Potato Genome Sequencing Consortium (PGSC) aims to elucidate the complete genome sequence of potato, the third most important food crop in the world. The PGSC is a collaboration between 13 research groups from China, India, Poland, Russia, the Netherlands, Ireland, Argentina, Brazil, Chile, Peru, USA, New Zealand and the UK. The potato genome consists of 12 chromosomes and has a (haploid) length of approximately 840 million base pairs, making it a medium-sized plant genome. The sequencing project builds on a diploid potato genomic bacterial artificial chromosome (BAC) clone library of 78000 clones, which has been fingerprinted and aligned into ~7000 physical map contigs. In addition, the BAC-ends have been sequenced and are publicly available. Approximately 30000 BACs are anchored to the Ultra High Density genetic map of potato, composed of 10000 unique AFLPTM markers. From this integrated genetic-physical map, between 50 to 150 seed BACs have currently been identified for every chromosome. Fluorescent in situ hybridization experiments on selected BAC clones confirm these anchor points. The seed clones provide the starting point for a BAC-by-BAC sequencing strategy. This strategy is being complemented by whole genome shotgun sequencing approaches using both 454 GS FLX and Illumina GA2 instruments. Assembly and annotation of the sequence data will be performed using publicly available and tailor-made tools. The availability of the annotated data will help to characterize germplasm collections based on allelic variance and to assist potato breeders to more fully exploit the genetic potential of potat

The inheritance of anthocyanin pigmentation in potato (Solanum tuberosum L.) and mapping of tuber skin colour loci using RFLPs.

Two existing genetic models for anthocyanin pigmentation are compared: the genetic model as proposed by Lunden (1937, 1960, 1974) for tetraploid potato Solanum tuberosum group Tuberosum and the model by Dodds & Long (1955, 1956) for diploid cultivated Solanum species. By crossing well defined genotypes from both genetic sources it was demonstrated that locus R/Rpw and locus D are allelic. Both loci are involved in the biosynthesis of red anthocyanins. We propose to maintain the symbol D for this locus. Tuber skin colour is expressed due to the complementary action of one locus involved in anthocyanin biosynthesis and a second locus involved in tissue-specific regulation of anthocyanin expression. The inheritance of two phenotypes of skin colour was investigated in this study: pigmentation of the epidermis and pigmentation of the cortex. In two different populations the loci determining the two phenotypes were located with RFLPs on the map of the potato genome, at approximately the same position as the earlier mapped PSC locus on chromosome 10. Lunden proposed the symbols E and R for the loci determining these phenotypes. Dodds and Long proposed only one locus I for tuber skin colour without describing these different phenotypes. The identity and nomenclature of the loci studied by the various authors are discussed

The inheritance of anthocyanin pigmentation in potato (Solanum tuberosum L.) and mapping of tuber skin colour loci using RFLPs.

Two existing genetic models for anthocyanin pigmentation are compared: the genetic model as proposed by Lunden (1937, 1960, 1974) for tetraploid potato Solanum tuberosum group Tuberosum and the model by Dodds & Long (1955, 1956) for diploid cultivated Solanum species. By crossing well defined genotypes from both genetic sources it was demonstrated that locus R/Rpw and locus D are allelic. Both loci are involved in the biosynthesis of red anthocyanins. We propose to maintain the symbol D for this locus. Tuber skin colour is expressed due to the complementary action of one locus involved in anthocyanin biosynthesis and a second locus involved in tissue-specific regulation of anthocyanin expression. The inheritance of two phenotypes of skin colour was investigated in this study: pigmentation of the epidermis and pigmentation of the cortex. In two different populations the loci determining the two phenotypes were located with RFLPs on the map of the potato genome, at approximately the same position as the earlier mapped PSC locus on chromosome 10. Lunden proposed the symbols E and R for the loci determining these phenotypes. Dodds and Long proposed only one locus I for tuber skin colour without describing these different phenotypes. The identity and nomenclature of the loci studied by the various authors are discussed