Effect of the genotype on the production of onion haploid plants through in vitro gynogenesis

M.L.FOSCHI, L. MARTÍNEZ, M.T.PONCE AND C. GALMARINI

ACTA HORTICULTURAE

International Society for Horticultura Science

Lugar: Leuven; Año: 2010

0567-7572

Onion (Allium cepa L.), haploid plant production through in vitro gynogenesis allows, after chromosome doubling, the production of truly homozygous plants in less time than using conventional breeding methods. Gynogenetic response and percentage of embryogenesis over time are variable among onion cultivars. In order to evaluate the effect of the genotype in the production of haploid embryos 95 plants of cv. ‘Cobriza INTA’ were randomly chosen. Flowers were collected 3 to 5 days before anthesis and cultured in Petri dishes using a media containing Dunstan and Short (1977) macroelements, Gamborg (1968) microelements, and Murashige–Skoog (1962) vitamins, 2 mg.l-1 BAP, 2 mg.l-1, 2,4-D and 100 g.l-1 sucrose, 7.5 g.l-1 Bacto-Difco-Agar and pH 5.8. Significant differences were found among plants for the percentage of gynogenic embryos, these percentages varied between 0 to 25 %. In order to verify if these differences were maintained over time, bulbs of plants that showed variability in gynogenetic response were re-cultured and their flowers harvested; 6 plants were chosen showing between 3 to 6 % of gynogenic embryogenesis, 4 showing 1 to 1.7 % and 7 varying between 0 to 1 %. In this work the genotype of the onion plant had a significant effect on the production of gynogenic embryos of ‘Cobriza INTA’ cultivar. The relative values of embryogenesis were maintained considering both years, but not in terms of absolute values. The lower values observed during the second year could be due the consequence of environmental factors or less vigour observed in the umbels and seed stalk of the plants that regrew during the second year.