Research on the Emasculation Technology by Hot Water about Sugarcane Tassels

  Objective  Orthogonal tests on temperature, time and varieties were conducted for the effects of emasculation technology by hot water in this study, which contributed to explore the suitable emasculation schemes of female parents, reduce self-fertilization ratio and improve the hybrid seed fertility of sugarcane tassels.

  Method  The tassels of ROC22, Ke 5 and Guitang 02-619 with numerous pollen were treated at 48℃, 50℃ and 52℃ for 3 min, 5 min and 7 min according to the design scheme from L₉ (3⁴) orthogonal table. Among 6 tassels (one tassel per plant), 3 tassels were self-pollinated and the other 3 tassels were cross-pollinated (fresh exogenous pollen was granted artificially), the results of which were analyzed to calculate the emergence rate of self-pollinated and cross-pollinated hybrids.

  Result  The emergence rate of ROC22, Ke 5 and Guitang 02-619 were gradually decreased with the increasing of temperature and time, and the ratio of pseudohybrids appeared to change with fluctuating. In addition, the pseudohybrids ratio was lowest (0.12) when cultivars were treated at 50℃ for 3 min. The variance analysis results showed that emergence number of self-pollinated seeds/emergence number of outcrossed seeds (M value) can be used to identify the effects of emasculation technology by hot water, the effect of emasculation technology by hot water was more significant when M value was higher. The temperature and time influenced on M value significantly, but different varieties had no difference.

  Conclusion  The emasculation effect of sugarcane tassels being treated at 50℃ for 3min was better when the unspread branches and mature or being mature branches were removed before tassel emasculation, which significantly increased the seed setting percentage of hybridization.