Apple phenology occurs earlier across South Korea with higher temperatures and increased precipitation.

This study examined relationships between temperature, precipitation, geo-topography, and the spring phenology of Fuji and Hongro apple cultivars along spatial gradients across South Korea. Phenology data was gathered from 2011 to 2014 in 42 uniformly managed research orchards which span a range in climate, latitude, and elevation. We used linear models and spatially explicit forecasts to study apple phenology under climate change scenarios. Given dry winters and complex terrain in South Korea, we hypothesized that, in addition to temperature, precipitation and geo-topographic factors influence apple phenology. We also expected responses to climate variation to be similar between (spatial) and within (temporal) orchards, given the controlled conditions and the use of apple clones in this study. With other factors held constant, phenological sensitivity ranged from - 3.2 to - 3.4 days °C-1 for air temperature and - 0.5 to - 0.6 days cm-1 for March precipitation in a combined model. When modeled without temperature, phenology changed by up to 10 days over the full range in March precipitation. Spring temperatures and precipitation in March had very little cross-correlation (r < 0.05), suggesting these patterns are independent; however, in a combined model including temperature, predicted changes in precipitation over the next 80 years have only a small impact on future apple phenology. Combining the best models with climate forecasts for South Korea, spring phenology continues to occur earlier over the next 80 years, mostly due to warming temperatures but with strong variation between regions. This suggests regionally specific climate change adaptation strategies are needed for future apple production in South Korea.

High temperature at veraison inhibits anthocyanin biosynthesis in berry skins during ripening in 'Kyoho' grapevines.

We examined the effects of high temperature (HT) at veraison (the onset of ripening) on coloration and anthocyanin biosynthesis in berry skins of 'Kyoho' grapevines (Vitis labruscana L.). The vines were subjected to control, HT (6 °C higher than the control for 10 days), and intermittent HT (IHT; 6 °C higher than the control for 4 days followed by control temperature for 3 days and then 6 °C higher than the control for another 3 days) conditions from 50 to 60 days after full bloom (DAFB) in temperature-controlled rooms. Under control conditions, berry skins were tinted purple from 55 DAFB and turned to reddish-purple thereafter until 80 DAFB, concurrently with the anthocyanin accumulation. The HT and IHT treatments greatly inhibited the coloration and anthocyanin accumulation, with greater inhibition by the HT treatment. The HT and IHT treatments significantly inhibited the expressions of early (EBGs) and late anthocyanin biosynthetic genes (LBGs), and the transcription factor gene VlMYBA2. Abscisic acid (ABA) contents in the control berry skins increased from 50 DAFB, peaked at 55 DAFB, and decreased thereafter. The HT and IHT treatments reduced the increase in ABA contents, with no significant difference between HT- and IHT-treated vines. Gibberellin (GA) contents decreased during veraison in the berry skins of control and IHT-treated vines, but remained unchanged in those of HT-treated vines. These results suggest that the coloration and anthocyanin biosynthesis in berry skins are associated with changes in the ABA/GA ratio.