Grape breeding in tropical and subtropical regions：A review

Grape is a kind of temperate fruit tree，and grape production and new-variety breeding are also mainly distributed in temperate regions with dry and cool climates. However，with the promotion of new grape cultivation techniques such as rain shelter，dormancy breaking and double-harvest-a-year，the grape industry in tropical and subtropical regions has developed rapidly in recent years due to its early maturity and distinct off-season economic benefits. It has become a characteristic and advantageous cultivation area in China. New grape varieties played an important role in promoting the rapid development of grape industry. Based on the research progress at home and abroad，this paper proposed the necessity of grape breeding in tropical and subtropical regions，summarized the current situation of grape industry in tropical and subtropical areas，the main cultivated grape varieties，and the existing problems. Due to the late start of grape breeding in tropical and subtropical regions of China，the main cultivating grape varieties in these regions were still bred in temperate regions. These varieties were not resistant to heat and humidity and exhibited problems such as coloring disorders，quality decline，poor resistance，susceptibility to various diseases and pests，high chilling requirements，uneven germination，and susceptibility to sunburn，indicating their unsuitability to the local environment. Then the advantages of breeding in tropical and subtropical regions were further analyzed. The accumulated temperature in tropical and subtropical areas was high，the growth of seedlings was vigorous，fruiting occurred early，and the breeding efficiency was high. In addition，the wild heat-tolerant grape resources distributed in tropical and subtropical regions were abundant and they were valuable materials for cultivating new varieties with strong heat and disease resistance. The stress conditions in these areas could provide a natural screening environment for the selection of new varieties of heat-tolerant and disease-resistant grapes. The research progress on grape breeding in hot and humid tropical and subtropical regions were summarized，including the basic grape cultivation techniques，breeding institutions and professional technical teams. It elaborated on the solid foundation of the introduction and evaluation of grape germplasm resources in Guangxi. The representative new varieties from the Brazilian grape genetic breeding program and the registration and protection of new grape breeding varieties in Guangxi tropical and subtropical regions were introduced，and the work plan of grape breeding in tropical and subtropical regions of China was put forward. The breeding of new grape varieties with properties such as early maturity， high quality，strong resistance，easy cultivation，resistant to storage and transportation under the adverse climate environment of high temperature，high humidity，frequent rainfall，fewer sunshine hours and fewer winter chilling hours was a guarantee for the healthy，high-quality and sustainable development of the grape industry，and it was of significance to promote new quality productive forces of grape in tropical and subtropical regions.