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Second cycle gynogenesis in onion, Allium cepa L., and genetic analysis of the plants
Author(s) -
Javornik B.,
Bohanec B.,
Campion B.
Publication year - 1998
Publication title -
plant breeding
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.583
H-Index - 71
eISSN - 1439-0523
pISSN - 0179-9541
DOI - 10.1111/j.1439-0523.1998.tb01939.x
Subject(s) - biology , ploidy , rapd , embryo , cultivar , allium , doubled haploidy , genetics , botany , horticulture , gene , genetic diversity , population , demography , sociology
Haploid induction in onion via gynogenesis provides inbred lines that can be used in production of hybrid cultivars. Despite several successful reports, the gynogenic induction rate is still relatively low, ranging mainly from 0.5 to six embryos per 100 cultured flowers. In the present study, gynogenesis was induced in selfed progeny of three genetically homozygous and stable fertile doubled haploid lines previously obtained through in vitro gynogenesis. The aims were to acquire information on whether the gynogenic responsiveness of a particular heterozygous cultivar is correlated with higher or lower gynogenic capacity in the second cycle of gynogenesis, to evaluate the non‐genetic component of the variability, and to monitor by random amplified polymorphic DNA (RAPD) analysis the onset of eventual gametoclonal variation induced during the gynogenic processes. The results from the gynogenic induction of 9708 flowers showed significant differences among three lines, one of them being extremely responsive, showing a mean yield of 118.3 haploid embryos per 100 cultured flowers (118.3%). The high embryo yield of this line was determined by the line's particular genotype. However, the induction rate of gynogenic embryos obtained within 24 genetically uniform donor plants of this responsive line varied from 67 to 196% and this variation can be attributed to uncontrolled environmental conditions. A total of 157 plants sampled from two lines and obtained through a first (RI) and a second (SCG) cycle of gynogenesis, was analysed by RAPDs. The single band profiles were compared either between or within the RI and SCG plants of each line. A total number of 4600 RAPD fragments were scored and no variation was found in the highly responsive line, while in the less responsive one, minor changes were detected for the presence/absence of two RAPD bands. These results indicate high genetic stability of onion homozygous lines passed through two cycles of gynogenesis.