Studies On Relevant Technologies Of Hybrid Pennistum Seed Production By Artificial Pollination

Hybrid Pennistum is interspecific hybrid of female parent Pennisetum americanum Tift23A (2n=14) and male parent P. Purpureum N51(2n=28). Hybrid Pennistum which is the key forage in tropical and subtropical regions has a strong resistance, photosynthetic efficiency and use of a wide range of features. Three line-method can be used in the hybrid seed production of Hybrid Pennistum by impelling florescence synchronization of hybrid parent. The florescence synchronization was unstable inter-annual as the growth and development process of Hybrid parent could be effected by the interaction of light and temperature. Artificial pollination was valid solution of instability in florescence synchronization. In order to promote the application of artificial pollination more widely, several relevant key technologies were researched in this experiment.Variation of pollen vitality of P. Purpureum N51during the scattering stage and the stigma receptivity of Pennisetum americanum Tift23A were studied. Appropriate storage conditions of pollen and method of artificial pollination were also preliminarily researched. The results are as follows:1I2-KI staining method and pollen germination test in vitro was used to detect the pollen viability of P.purpureum. The results shows that the pollen of P.purpureum began to shed1day after spike outstretching the flag leaf wholly and the scattering stage lasted for7days. The pollen viability is relatively high at the first day. The pollen grains were largest at2nd to4th days shedding pollens and the pollen viability was significant highest, then decreased fastly. The pollen grains were very few at the seventh day.2The stigma receptivity of Pennisetum americamum was estimated by benzidine-H2O2method. The observation of stigma morphological character and artificial hybridization in the field were adopted in the study. The stigma receptive stage of Pennisetum americamum lasted for7days. The sequence of stigma receptivity during the stage was as follows:2～3d>1d,4d>5～7d. The seed-setting rate of artificial pollination was extremely significant high when the stigma was at1～4days after stigma outstretching the spike than at5～7days. The average seed-setting rate of artificial pollination was84.1%, significant highest at 2～3days after stigma outstretching the spike. The stigma had highest receptivity when its color was white and its split angle was60°～90°3Low temperature was propitious to the pollen storage. The average pollen viability when the storage temperature was-80℃(71.8%) was significantly higher than that when the storage temperature was-20℃(55.0%).Both in vacuum or in general conditions, the storage effects at-80℃were better than that at-20℃.4Vacuum was propitious to the pollen storage. The average pollen viability storaged in vacuum (66.2%) was significantly higher than that storaged in general conditions (60.6%).The storage effect in vacuum was better than that in general conditions when the the storage temperature was-20℃,while there is no significant difference when the the storage temperature was-80℃.5It is the same with the viability of storage pollen between thawing in40℃water quickly and resuscitating in room slowly.6Bagging method、5%and10%sucrose solution spray method were used for artificial pollination.The seed-setting rate were81.9%、78.5%、83.5%,and there is no significant difference between each other. The seed-setting rate using aqueous spray method was74.3%which was lowest.