Research progress on sex control of chestnut flower buds

Chestnut(Castanea mollissima Blume) is a monoecious plant with unisexual flowers. The flowers of chestnut are arranged in long catkins of two kinds,one is made of only male flowers,and the other is called mixed inflorescence which can differentiate into both male and female flowers. Chestnut bears unbalance male and female flowers,in practice,there are too many male flowers but very few female flowers,which constraints the output of chestnut fruits. Since 70 s of last century,the morphological and physiological research on chestnut flower buds differentiation was developed rapidly,and it was confirmed that the mixed flower buds of chestnut were plastic. And plant growth regulators and nutrition of trees had significantly effects on the sex differentiation of the flower buds. Thus,female flowers as well as the output of fruits were increased by using phytohormone,increasing application of P,K fertilizer,application foliage of B fertilizer or reasonable trimming. Recently,molecular biology study of chestnut flower bud differentiation was conducted regularly. However,the research in chestnut was relatively slow and huge gap should be filled in comparison with research in other plants. Herein,we summarized the progress of the studies on sex control of flower bud differentiation in chestnut,and presented the research shortage and difficulty as well as future research prospects in order to provide reference information for sex control of flower buds in chestnut.