Date of Award

Summer 8-16-2024

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Botany and Plant Pathology

Advisor

Ek Han Tan

Second Committee Member

Paul Collins

Third Committee Member

Andrei Alyokhin

Abstract

Potato (Solanum. tuberosum) is the fourth most cultivated crop worldwide, and the most grown vegetable crop in Maine. Currently, all available commercial potato varieties developed at the University of Maine and in the United States are autotetraploids (2n = 4x = 48). However, potato and its wild relatives exist in a range of ploidy states. In contrast to commercial varieties in the US, many South American landraces and related tuber-bearing Solanum species are diploid (2n = 2x = 24). As a highly heterozygous polyploid, inbreeding in conventional tetraploid potato breeding cycles is impractical, and has prevented breeders from establishing an F1 hybrid breeding system for potatoes. Unlike tetraploid potatoes, diploid potatoes that can be self-fertilized may be used to create inbred lines. With additional ploidy manipulation, inbred potato III development can be expedited. In this work, we test potato haploid inducers (PL-4 and IvP48) to create potato monoploids (2n = 1x = 12) by crossing to selected diploid lines. Five monoploids from three families were produced and identified. Chromosome doubling has been attempted using colchicine treatments to generate a fully inbred diploid potato in one generation. Previous doubled monoploids have been developed with this method, but poor fertility and agronomic traits have hindered their utility in breeding programs. Developing doubled monoploids from improved diploid germplasm can produce more fertile, fully inbred lines to accelerate diploid hybrid potato breeding.

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