Production and their cytological observations of the male sterile lines of Zinnia elegans

中国人. 获得百日草雄性不育系，并探索其花药发育机制，为百日草杂种优势的利用提供一条新途径。采用自交F2代出现的不育材料连续回交获得的不育系再进行兄妹交、可育株自交，结合与多个自交系测交进行不育类型鉴定，并对其细胞学进行研究。获得了百日草深红色单隐性雄性不育两用系AH209AB。正常可育的花药,其药壁由4层细胞构成,即表皮、药室内壁、中层和绒毡层；花粉母细胞减数分裂过程中的胞质分裂为同时型；成熟花粉为三细胞型。雄性不育株花瓣退化或丝状，雄蕊退化成丝状，内无花粉，外观呈绒毛状；花药在造孢细胞组织形成后，没有继续分化产生药壁结构、花粉母细胞及其花粉,为完全的结构性雄性不育类型。该雄性不育系属于无花粉囊型不育系，在F1代种子生产上具有重要的利用价值。

英语. In order to find out a new pathway for utilizing heterosis of Zinnia elegans and accelerate breeding process, the mechanism of anther development of a male sterile line was explored. Backcross, sibmating, selfing of fertile plants and testcross with inbred lines were analyzed and identified in the field, and cytomorphology was observed. Recessive nucleus male sterile line AH209AB that capable of being a maintainer was obtained by successive backcrosses with male sterile plants and fertile F1 plants as male parents. Cytological and anatomical studies indicated that: (1) The wall of normal anther was constituted of four layers of cells such as epidermis, powder chamber wall, middle level and tapetum cells. The process in meiosis of pollen mother cell in Zinnia elegans was normal, and cytoplasm divided simultaneously. Mature pollen grain was tri-cellular type. (2) The petal of male sterile plant degenerated as a thread-like structure, the stamens were villiform in appearance and no pollens were formed. The result showed that the anther of male sterile plant no longer proceed to differentiate spore mother cell and the pollen sac after the formation of the tissue of sporogenous cells, there was no evident boundary between tapetum cell, middle lamella and inner wall of PMC, tapetal cells did not develop from the very beginning. So the abortion type was completely structural male sterility. The male sterile line belongs to non-sporange male sterile type and is of great use in F1 seeds production.