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The establishment and application of a two-crop-a-year cultivation system depends on the particularity of climatic conditions in subtropical regions. The different temperature, light, and water conditions throughout the growing season of summer and winter grapes are the fundamental reasons for differences in primary and secondary metabolites. We performed ultra-high-performance liquid chromatography–triple quadrupole mass spectrometry (UPLC-QQQ-MS)-based metabolomics on 'Kyoho' grapes under a two-crop-a-year cultivation system. In total, 1062 metabolites were identified and classified into 10 different categories, while flavonoids were the largest group, with 285 metabolites. Moreover, 876 metabolites were different among the four developmental stages, and 551 were different between the summer and winter grapes during the same growth period. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) clearly distinguished developmental and growth-season differences based on the detected metabolites. Of note, flavonoids were the most important compounds responsible for the differences in berry composition during the growth and developmental seasons. The content of most flavonoids was higher in the winter grapes, but some were also found at higher levels in summer grapes, such as kaempferol-4′-O-glucoside, leucocyanidin, and cyanidin-3-O-glucosylglucoside. Additionally, myricetin-3-O-arabinoside was consistently higher in winter grapes than in summer grapes during all four developmental stages. The extreme high temperature and higher relative humidity were important reasons for the lower flavonoid content in the summer grapes than in the winter grapes. Moreover, the stronger light intensity in the early development of the winter grapes had a positive effect on the accumulation of flavonoids, especially flavonols and flavan-3-ols. This study provides new insights into the metabolism of flavonoids in grapes under a two-crop-a-year cultivation system and explores the climatic causes of the differences in the metabolites in the two crops of grapes. [ABSTRACT FROM AUTHOR]

The establishment and application of a two-crop-a-year cultivation system depends on the particularity of climatic conditions in subtropical regions. The different temperature, light, and water conditions throughout the growing season of summer and winter grapes are the fundamental reasons for differences in primary and secondary metabolites. We performed ultra-high-performance liquid chromatography–triple quadrupole mass spectrometry (UPLC-QQQ-MS)-based metabolomics on ‘Kyoho’ grapes under a two-crop-a-year cultivation system. In total, 1062 metabolites were identified and classified into 10 different categories, while flavonoids were the largest group, with 285 metabolites. Moreover, 876 metabolites were different among the four developmental stages, and 551 were different between the summer and winter grapes during the same growth period. Hierarchical clustering analysis (HCA) and principal component analysis (PCA) clearly distinguished developmental and growth-season differences based on the detected metabolites. Of note, flavonoids were the most important compounds responsible for the differences in berry composition during the growth and developmental seasons. The content of most flavonoids was higher in the winter grapes, but some were also found at higher levels in summer grapes, such as kaempferol-4′-O-glucoside, leucocyanidin, and cyanidin-3-O-glucosylglucoside. Additionally, myricetin-3-O-arabinoside was consistently higher in winter grapes than in summer grapes during all four developmental stages. The extreme high temperature and higher relative humidity were important reasons for the lower flavonoid content in the summer grapes than in the winter grapes. Moreover, the stronger light intensity in the early development of the winter grapes had a positive effect on the accumulation of flavonoids, especially flavonols and flavan-3-ols. This study provides new insights into the metabolism of flavonoids in grapes under a two-crop-a-year cultivation system and explores the climatic causes of the differences in the metabolites in the two crops of grapes.

[Objective] To explore the effects of weather factors such as temperature, precipitation and sunshine hours on the incidence of powdery mildew in winter grapes harvested twice a year under rain-shielding cultivation mode, and provide theoretical basis for the prevention and control of powdery mildew in winter grapes harvested twice a year. [Methods] Before the harvest of winter grapes in 2017 and 2018, the field natural identification method was used to investigate the incidence of powdery mildew in 14 grape varieties/plants under the sheltered cultivation mode, combining 2017 and 2018 September 1 The meteorological monitoring data from December 31 to December 31 is used to analyze the correlation between meteorological factors, the incidence of grape powdery mildew and the disease index. [Results] During the harvest of winter grapes in 2017, the incidence of powdery mildew in 11 grape varieties/lines was lower than in 2018, and the disease index of powdery mildew in 9 grape varieties/lines was lower than in 2018. The precipitation and the number of rainy days from September 1 to December 31, 2017 were greater than those of the same period in 2018; the number of days in the suitable temperature range for powdery mildew (20.0-27.0°C) in 2017 was less than in 2018; the total accumulated temperature in 2017 was slightly Higher than 2018; 2017 had more sunshine hours than 2018; the two-year average daily relative humidity in 2017 and 2018 was suitable for powdery mildew fungus conidia germination. [Conclusion] The main reasons for the occurrence of powdery mildew in grapes in the winter of 2018 are the main reasons why the occurrence of powdery mildew in grapes in the winter of 2018 is more serious than that in 2017. [ABSTRACT FROM AUTHOR]

[Objective] The study aims to understand the effect of held sticky card on the grape thrips trapping and the occurrence regularity under two-crop-a-year grape cultivation system in Guangxi and provide reference for the effective control of grape thrips. [Method] During the two growing seasons of Guangxi grapes, the grape thrips trapping effect was evaluated by different kinds (blue, yellow and yellow pheromones), spacing(3, 4, 5 m)and heights (1, 1.5, 2 m) of sticky card for ‘ Guipu No. 3 ’ grapes. [Result ] Under two-crop-a-year grape cultivation system,the trapping effect of blue sticky card was better than the yellow and yellow pheromones sticky card; blue sticky card spacing in 4 m showed better grape thrips trapping effect than those in 3 and 5 m; The suspension height of 2 m presented the best trapping effect of grape thrips; The trapping effect of blue sticky card could reach 45.8% -49. 6 % . The grape thrips increased rapidly during the period of flowering, and reached the peak in the young fruit stage, then the grape thrips larvae decreased gradually after fruit enlargement period. [Conclusion] Under two-crop-a-year grape cultivation system, the grape thrips of the second growing season were higher than those of the first growing season. The grape thrips increased rapidly during the period of flowering, and reached the peak in the young fruit stage, then the grape ihrips larvae decreased gradually alter fruit enlargement period, the control effect of grape thrips trapping could reach 49.6 % by hanging blue sticky card of 2 m height and 4 m spacing. [ABSTRACT FROM AUTHOR]

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