Mapping of a gene conferring alleviation of pollen–pistil incongruity found in an interspecific cross between Cucumis anguria L. and Cucumis melo L. (melon)

In Cucumis, when melon (Cucumis melo L.) was crossed with Cucumis anguria L., PI 320052, at 24–30 °C, pollen tube growth was arrested in the style. However, at 32 °C and 34 °C, the pollen–pistil incongruity was alleviated. Pollen tubes penetrated into ovules and fruit set was observed. However, these studies have not revealed the genetic and molecular mechanism of pollen–pistil incongruity alleviation. This study reveals the mode of inheritance and identifies molecular markers linked with the gene. We developed the F1 and F2 lines from the alleviate line and non-alleviate line, and evaluated the mode of inheritance of the gene. We constructed the linkage map by the phenotypes and conducted simple sequence repeat (SSR) analysis. We demonstrated that the pollen–pistil incongruity alleviation gene is single recessive and that it is located on LG I between CSN221 and SSR19844 at a distance of 3.7 cM and 4.5 cM from CSN221 and SSR19844, respectively. Therefore we assigned the gene as pollen–pistil incongruity alleviation (pia). This is the first report on the mapping of a gene conferring the pollen–pistil incongruity alleviation in interspecific crosses

► Pollen–pistil incongruity in interspecific crosses of Cucumis spp. was studied.
► This pollen–pistil incongruity was alleviated under high temperature conditions.
► The mode of inheritance of the alleviate gene was single recessive.
► The gene was located between two SSR markers, CSN221 and SSR19844, on LG I.