Thermo-sensitive sterility and self-sterility underlie the partial seed abortion phenotype of Litchi chinensis

摘要

The seed abortion ratio is one of the most important fruit quality factors in Litchi chinensis. However, unstable seed abortion ratio in some cultivars severely affects its market value. Here, seed development of litchi cultivar 'Guiwei' was surveyed in plants from different orchards for five consecutive production years, applying pollen from different sources and involving exposure to different temperatures. The seed weight ranged from & 0.3 g to & 3.0 g and the seed abortion ratio ranged from 12% to 93%. We conclude that 'Guiwei' seed development is thermo-sensitive base on the results that the seed abortion ratio was strongly positive correlated to the average minimum temperature under field conditions and that a significantly higher seed abortion ratio was seen at 22/26 degrees C than at 18/22 degrees C under growth chambers. The pollen source experiment indicated the self-sterillity of 'Guiwei' with self-pollination resulted in & 92% aborted seeds, compared with 40%-80% in outcrossed fruits. Both thermo-sensitive and selfed sterile fruit contributed to the variable seed development phenotype, with temperature having a greater effect than the pollen source. Based on the non-Mendelian control of seed development according to the results of a reciprocal cross, we propose that the partial seed abortion phenotype seen in 'Guiwei' is epigenetically regulated.