Genetically pure Turkish onion (Allium cepa L.) lines

Abstract

Onion (Allium cepa L.) is an economically important Allium species grown all around the world. It is a highly heterozygous biennial diploid plant (2n=2x=16). Onion is a difficult crop plant to work with since onion genetics and breeding studies may take many years to complete. Turkey is among the major onion producing countries where many landraces and open-pollinated (OP) standard cultivars are commonly used in onion production. Production of pure lines is a major challenge in onion improvement programs. We are carrying out a gynogenesis-based doubled haploid (DH) strategy to obtain fully homozygous onion lines that can be used as potential parents in the development of new hybrid onion cultivars. In this study, a total of 10 Turkish OP onion (three standard and seven breeding lines developed from landraces) lines were used in two-year gynogenesis induction experiments. A total of 387 gynogenic plantlets were developed from all of the donor onion lines. About one-fifth of the plantlets continued to grow in in vitro. Dried bulbs were produced from 14 DH gynogenic plants. Thirteen of the bulbs that were re-planted in the greenhouse provided selfed-seeds (between 63 and 880). Seedlings of DH lines grew uniformly and did not show any sign of breeding depression. Bulbs of these pure lines were comparable to the bulbs of OP donor lines in size, color, and other morphological features. These pure onion lines are currently studied for their potential to be used as parental lines in the production of new hybrid onion lines. © 2020 International Society for Horticultural Science. All rights reserved.