ARS | Publication request: GENOTYPIC AND ENVIRONMENTAL EFFECTS ON GYNOGENIC HAPLOID INDUCTION IN ONION

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 8, 2002
Publication Date: December 15, 2002
Citation: Jakse, M., Borut, B., Havey, M.J. 2002. Genotypic and environmental effects on gynogenic haploid induction in onion. Meeting Abstract.

Technical Abstract: In vitro culture of unpollinated flowers is an efficient procedure to produce haploids of onion. However several bottlenecks remain limiting the production of doubled haploids, especially the low gynogenic response of most onion populations and poor efficiency of chromosome doubling. We studied frequencies of gynogenic haploid induction among progenies from crosses among responsive and non-responsive lines and the phenotypic correlations among haploid regenerants from parental plants and selfed progenies. Hybrid progenies from crosses between responsive and non-responsive onion inbred lines showed increased gynogenic abilities over that of the non-responsive parent. S1 progenies of highly responsive plants segregated for both responsive and non-responsive progenies. S1 families from non-responsive plants were non-responsive. These studies indicate an additive genetic component may control responsiveness to gynogenic haploid induction in onion. Significant correlations were observed for the frequencies of haploid regenerants produced by the same plants over two years, indicating a relatively small environmental effect on haploid production. For chromosome doubling experiments, embryos were treated with various concentrations of amiprophos-methyl (APM) or oryzalin in liquid for short times under partial vacuum or longer times at normal air pressure or on solid media. In general, APM was more efficient and less toxic than oryzalin. Based on treatments of over 7000 embryos in 2001, we concluded that application of 50 mM APM was superior to 25 or 75 mM, and treatments in liquid medium for 1 or 2 days were superior to the same treatments on solid media.