Relationship between Satsuma mandarin yield and meteorological factors in Shizuoka and distribution of alternative flowering indices in Mikkabi production area, Japan

BACKGROUNDBiennial bearing, the biggest factor destabilizing citrus fruit production, is primarily attributed to unfavorable weather changes. However, the relationship between the yield of Satsuma mandarin for more than 50 years and the weather remains poorly understood. Therefore, the present study investigated the effect of meteorological factors, such as average temperature, precipitation, and sunshine duration, on the yield of Satsuma mandarin in Shizuoka Prefecture, Japan. We analyzed fruit production statistics and meteorological observation data from 1961 to 2018. Furthermore, we investigated the alternative indices of flowering and sprouting in each of the 20 districts of Mikkabi Town, Hamamatsu City, Shizuoka Prefecture. RESULTSWe detected a positive correlation between the average temperatures in March and February and yields in Shizuoka and Hamamatsu Cities. All alternative indices, except flowering in the early-maturing cultivar, were significantly lower in the southern than in the northern districts (P < 0.01 or 0.05). Particularly, the alternative index of flowering in the late-maturing cultivar was significantly different between the northern and southern districts (P < 0.01). Furthermore, we found a negative correlation between the mean annual temperature or average temperature from January to April and alternative indices of flowering and sprouting. CONCLUSIONThe findings of our field survey in Mikkabi production area suggest that mean annual temperature may affect the biennial bearing of Satsuma mandarin. (c) 2023 Society of Chemical Industry.