Pheno-physiological responses of grapevine cultivars vary under the influence of growing season temperature – a study from Pothwar region of Pakistan

Abstract

Grapevines are an environmentally sensitive crop, their phenology and physiological responses are driven under the influence of different climatic factors. Among different climatic variables, growing season temperature (GST) is considered as a key driver of phenology and physiological activities. Rising air temperature due to climate change has posed a serious challenge for sustainable grape production. The grape cultivation has spread to non-traditional viticulture zones such as Pothwar region of Pakistan where lack of knowledge on comprehensive understanding of grapevine cultivars is a key challenge. The objective of the present research was to explore the effect of variable growing season temperature on the timings of key developmental stages and associated vine physiological activities in Pothwar – a new emerging viticulture zone of Pakistan. Four commercial table grape cultivars, ‘Pelette’, ‘Sugraone’, ‘King’s Ruby’ and ‘NARC Black’, were selected for the pheno-physiological monitoring at two study sites in Pothwar region of Pakistan. Data were recorded for key growth stages; budburst, 5 leaf, bloom, berry set, vearison and harvest for the 2019 and 2020 vintages. The results indicated that all developmental stages were attained earlier with less photosynthetic activity (up to 31%) and WUE (up to 29%) for the hotter site Chakwal than Islamabad. The length of growth period, budburst to harvest was longer (up to 21 days) for the relatively colder vintage of 2020 with higher photosynthetic activity (up to 12%) and WUE (up to 13%) than for 2019. Grapevine cultivars showed a distinct variability (up to 19 days) for the ripening time with earlier ripening for ‘Perlette’, whereas higher photosynthetic activity (up to 30%) was recorded for ‘Sugraone’. The results of the present study contribute to an improved pheno-physiological understanding for devising adaptation strategies for climate smart and sustainable viticulture industry.