The Characteristic of Microspore Development in Temperature-sensitive Male Sterile Line on Chinese Cabbage

The microspore will be malformation and retrogress at each stage of development in temperature-sensitive male sterile line on Chinese cabbage when producing seed with two-line method. The four major types of malformation and retrogression were as follow: The first, the anther can't develop even before sporogonium differentiation, which belongs to non-pollen type. The second, sporogonium differentiates into abnormal corners, then disintegrates or increases in cell size and aggregates into parenchyma cells. The third, at the period of tetrad, both tapetum and microspore retrogressed, which result in only empty clinandrium cavity and relic. The fourth, at the period of mature pollen grain, the microspore was malformation, anther locule constricted into falcate, abnormal microspore crowded in the whole anther locule out of order.