甘薯近缘三倍体杂种2n花粉发生和利用的研究

Studies on the Formation and Utilization of 2n Pollen of Closely-Related Triploidy Hybrids of Sweet Potato

将甘薯的近缘野生种Ipomoeatrifida（2x与I．littoralis（4x）杂交，得到三倍体杂种。在三倍体杂种无性系中观察到可被醋酸洋红染色的可育大粒花粉（2n花粉），该花粉频率与花粉母细胞四分体时期的二分体频率呈显著正相关。以三倍体2n花粉系为父本与甘薯杂交，观察到花粉萌发、受精、胚发育和结实，但结实率很低，且种子大多没有生活力。本研究表明，其主要原因有：柱头花粉附着量和花柱中花粉管较少，受精后合子停止发育和胚未能发育成熟。用植物生长调节剂处理对克服子房水平的上述不亲和性有效。

Triploidy hybrids were obtained by I. littoralis(4x)×I. trifida (2x), and giant fertile pollens stainable by acetic-acid carmine were observed in triploid clones. Positive correlation existed between dyad frequency and fertile giant pollen grain frequency in the population of triplody hybrids. Few seeds, most inviable were obtained when triploid clones were used as male parent in crosses with hexaploid sweet potatoes. According to observation on the stigma, style, ovule and embryo of the hybrid, it was concluded that the failure of the fertilization can be attributed to incompatibility between species. PGR treatment had good effects on overcoming this incompatibility.