Drought escape during the late growth stage through early recovery from initial drying stress by hydropriming of upland rice

Abstract

ABSTRACT This study investigated the interactions between soil moisture conditions and seed priming on initial and late growth over 2 years (2017–2018) through field trials and container experiments with regulated soil moisture. Field trials were conducted on rainfed upland rice fields in Uganda, East Africa, where primed and control seeds were planted in triplicate and cultivated. In 2017, the percentage of first heading (head emergence) of hills was higher in priming treatments, and the time for 20% of the hills to achieve the first heading (H20) was significantly earlier than in controls. Additionally, grain ratio (number of fertile grains to sterile grains) and H20 were negatively correlated (P < 0.05). However, the difference in growth parameters between control and priming was not found in the case of 2018. The results suggested that priming reduces the growth period under certain conditions and improves drought escape. Therefore, we investigated the relationship between priming effects on initial growth under soil moisture treatments and subsequent development under waterlogged conditions. After transfer to waterlogged conditions, plants of the primed seeds initially grown in low soil moisture conditions recovered earlier than control plants. Our research concludes that the agronomical impact of hydropriming on upland rice prevents prolonged plant growth under drought by early recovery. Furthermore, it could decrease the yield loss caused by reduced rainfall in the late growth stage.