An In vitro pollination technique for detecting self-incompatibility in cruciferous crops

An in vitro pollination procedure was developed as an efficient technique for assaying self-incompatibility of Cruciferous crops. Excised flowers were pollinated in the lab, kept in constant relative humidity chambers at 25℃, and the pollen tubes in the style were counted using fluorescence microscopy after staining with aniline blue the next day. A relative humidity (RH) of 98% was optimum for differentiating self-incompatibility vs. self-compatibility with excellent reproducibility. The number of pollen tubes penetrating to stigma under 98% RH was different from plant to plant and age to age of the flower. However. this variation for flowers of the same plant was highly correlated with seed set. Strongly self-incompatible plants could be selected by selecting for the minimum number of pollen tubes across a wide range of flower age for individual plants. This technique seemed to be widely applicable in the study of self-incompatibility.