Female flowers with short ovaries in 'Lemon' cucumber (Cucumis sativus L.) plants and their progeny carrying the mm gene (CS-ACS2 gene with c.97G > T mutation): a novel trimonoecious phenotype

Abstract Analysis of the sex expression in 10 ‘Lemon’ (mmff) cucumber plants (Cucumis sativus L.), known to be andromonoecious, revealed that 3 plants produced female flowers with short ovaries, resembling bisexual flowers, after producing male and bisexual flowers. To investigate the heredity pattern governing these aberrant female flowers with short ovaries, F₁ hybrid plants (MmFf) were generated through a cross between ‘Dokanari-sennari’ (MMFF) and ‘Lemon’ (mmff), and individuals 4 (mmff) and 45 (mmFF) were meticulously selected from a pool of 45 F₂ segregants. Analysis of the sex expression in both 10 F₅ plants (mmff) derived from the F₂ individual 4 (mmff) and 10 F₄ plants (mmFF) derived from the F₂ individual 45 (mmFF) revealed that 8–9 plants produced female flowers with short ovaries after producing male and bisexual flowers. Notably, no female flowers with short ovaries were produced in the plants carrying the M gene, such as ‘Dokanari-sennari’ (MMFF), 8 F₁ hybrid plants (MmFf), and the 29 F₂ segregants (M-F-, M-ff). Thus, female flowers with short ovaries may be produced in some ‘Lemon’ (mmff) cucumber plants and their progeny, particularly those carrying the mm gene (CS-ACS2 gene with c.97G > T mutation), after the production of male and bisexual flowers. However, no clear genetic rules governing the occurrence of these female flowers with short ovaries were observed. This is the first report on trimonoecious cucumber plants displaying male flowers, bisexual flowers with short ovaries, and female flowers with short ovaries, all on the same plant, under the influence of the mm gene (CS-ACS2 gene with c.97G > T mutation).