Cytogenetical Studies in the Inbred Lines of Radish (Raphanus sativus L. var. radicola Pers.) and Their Hybrids IV

Germination of pollen grains on stigma

抄録

Pollen germination on the stigmatic surface and further development of pollen tubes in the style have been studied in two inbred lines of radish (Raphanus sativus L. var. radicola Pers.), namely LS-337/24 and LS-337/25, their F₁ and backcross hybrids and the original population in order to understand the mechanism of reduced fertility of the inbred lines. The inbred lines differed significantly among themselves and from the original population in pollen germination on stigma under identical condition of pollination; pollen germination in the inbred lines is much lower in the inbred lines. Pollen grains of LS-337/25 germinated quite well on the stigma of LS-337/24 and the F₁ hybrid LS-337/24×LS-337/25, but the pollen grains of LS-337/24 showed poor germination on the stigma of LS-337/25 and the F₁ hybrid, indicating its genotypic peculiarity. Differences among lines, hybrids and the original population were also noted in style length, stigma morphology and the number of pollen tubes in the style. Possible mechanism of semi-sterility of the inbred lines has also been discussed.