谷子(Setaria italica Beauv)无融合生殖系SMA-1的发现

Discovery of Apomixis in Foxtail Millet(Setaria italica Beauv)

谷子无融合生殖的胚胎发生研究结果表明；谷子ＳＭＡ－１的无融合生殖为无孢子生殖和二倍 体孢子生殖两种类型。无孢子生殖类型与专性无融合生殖狼尾草相同，单核胚囊经二次有丝分裂形成 四核胚囊，无反足细胞。二倍体孢子生殖类型与磨擦禾相似。胚珠发育不同时期的观察统计表明，该 系前期的无融合生殖频率较高，达１３．３％，在有性、无性的竞争发育中无融合生殖势减弱，到胶囊成 熟期无融合生殖频率减低到５．４％，但一些植株有较高的无融合生殖频率，达２９．４％，加强筛选可能 获得谷子高频率无融合生殖系。

The developmental process of apomictic embryo sac and apomictic pecentage at different developing stage in foxtail millet (Setaria italica Beauv) were studied, using the method of conventional poraffin sectioning. The results indicated that the apomictic development conforms apospory and diplospory. The apospory embryo sacs development looks like buffel grass ; The nucellar cell divided mitotically for two times to produce a 4-nucleate sac without the antipodals. The diplosporous type looks like Eastern gamagrass but the frequence was very low. The ovules were observed in M. M. C; F. M. C; two-nucleate and mature embryo sac stage, statistics showed that the earlier stage had the higher apomictic potential. The apomictic frequence decreased from 13. 3% (M. M. C) to 5. 4% (Mature embryo sac), however, some plant had much higher apomictic frequence, up to 29. 4%. It showed that there are some performing plant in SMA-1. Making a great effort, we could select a high frequence apomictic line.