The Study In Effect Of Low Temperature Storage On Fifteen Herbaceous Peonies Pollen Viability

In order to develop rich new varieties of peony flowers and solve the problems associated with non-synchronised flowering,a study was conducted to investigate pollen viability of fifteen herbaceous peony cultivars.Pollen was stored for more than one year under four storage conditions（4°C,-4°C,-20°C,and-76°C）.In vitro germination and the I₂-KI staining method were used to test pollen viability.For all herbaceous peony cultivars,pollen stored at-76°C showed a significantly slower rate of viability reduction when compared to all the other storage conditions.The differential results obtained using different pollen viability assays confirmed that the in vitro germination test showed lower viability compared to I₂-KI staining method.The main results of this study are as follows:1.Confirmed the optimal method for testing pollen viabilityUsing I₂-KI staining method and the in vitro germination method to test ‘Hongfeng’ pollen viability after storage about one year and the viability were 17.24% and 0.00% respectively.Stored for about a year’s ‘Hongfeng’ pollen and fresh ‘Hongfeng’ pollen hybride with ‘Qihualushuang’ and observe fruit-set rate in fruit mature period.The results showed that both two possessed high fruit-set rate and greater than ‘Qihualushuang’ fruit-set rate under natural pollination.Therefore,I₂-KI staining method for the determination of germination in vitro culture method results more reliable and fast.From the present study,we suggest that herbaceous peony pollen can be stored at 4°C for hand-pollination among cultivars having non-synchronised flowering in a season.2.Confirmed the optimal storage temperature for cross breeding in the same seasonAccording to the peony pollen viability and hybridization validation experiments,in the cross breeding of the season:（1）Earlier flowering varieties ‘Dafugui’ ‘Gaoganhong’ ‘Hongxiuqiu’ ‘Hongfeng’ ‘Fenchijinyu’ pollen can be used to hybridize with the middle flowering varieties ‘Xuefeng’ ‘Hongfushi’ ‘Qingtianlan’ ‘Xueyuanhonghua’ ‘Guifeichacui’ and late flowering varieties‘Bingshan’ ‘Chifen’ ‘Tianshanhongxing’ ‘Dongjingnvlang’ ‘Yangfeichuyu’.（2）Middle flowering varieties ‘Xuefeng’ ‘Hongfushi’ ‘Qingtianlan’ ‘Xueyuanhonghua’ ‘Guifeichacui’ pollen can be used to hybridize with late flowering varieties ‘Bingshan’ ‘Chifen’ ‘Tianshanhongxing’ ‘Dongjingnvlang’ ‘Yangfeichuyu’.（3）Flowering earlier varieties pollen can be stored at 4°C,-4°C,-20°C,and-76°C condition,and more economical stored at 4°C condition.3.Confirmed optimal storage temperature and hybrid combinations for the cross breeding of following season.The cross breeding varieties was confirmed according to the peony pollen viability and cross validation experiment:（1）‘Dafugui’ ‘Gaoganhong’ ‘Hongxiuqiu’ ‘Xuefeng’ ‘Hongfushi’ ‘Xueyuanhonghua’ ‘Guifeichacui’ ‘Bingshan’ ‘Chifen’ ‘Tianshanhongxing’ ‘Dongjingnvlang’ pollen can be stored at 4°C,-4°C,-20°C,and-76°C condition,and 4°C is the most economic condition;（2）‘Fenchijinyu’ ‘Yangfeichuyu’ pollen can be stored at-4°C,-20°C and-76°C,and-4°C is the most economic condition;（3）‘Hongfeng’ ‘Qingtianlan’ pollen can be stored in-20°C and-76°C condition,and-20°C is the most economic condition.