Potassium supply for improvement of cereals growth under drought: A review.

Potassium (K) is an essential macronutrient that determines crop productivity and promotes crop growth under conditions of abiotic stress. In this review paper, peer‐reviewed publications (experimental data) dealing with the role of K administration in the control of cereals growth under drought stress are reviewed and analyzed. Most published research on the impact of K administration on cereals growth under drought focuses primarily on bread wheat (Triticum aestivum L.) and maize (Zea mays L.), along with barley (Hordeum vulgare L.), rice (Oryza sativa L.), pearl millet (Pennisetum glaucum L.), and sorghum (Sorghum bicolor L.). The beneficial effect of K on cereals growth under drought has been related to maintenance of water balance in the crops, increased activity of the antioxidant enzymes, increased synthesis of osmolytes, contribution to a low sodium (Na)/K ratio, extension of the grain filling period, and increase of the grain growth rate and weight. Moreover, K was suggested as a possible way for enhancing nitrogen use efficiency (e.g., bread wheat and sorghum). Nevertheless, the beneficial effect of foliar applied K in dried soil during grain filling differed among bread wheat cultivars, highlighting that the effect of K supply on grain weight may differ depending on application method, that is, administration through the soil or the foliage. Overall, K supply could be exploited as a tool for increasing cereal tolerance to drought, for example, by considering late administration of K through top dressing applications or foliar sprayings. Yet additional information is needed on the rate and the K form, along with the most suitable growth stage for application. Such information could help agronomists develop strategies for high‐quality cereal production in stressful environments. Core Ideas: Administration of K for improving cereals growth under drought has been studied primarily on bread wheat and maize.Most studies on cereals growth under drought refer to K administration trials in controlled environment.The benefits of K on cereals growth under drought have been related primarily to maintenance of water balance.K administration could be exploited as a potential tool for improving cereals tolerance to drought stress.Information on the K rate and form, along with the most suitable growth stage for application is needed. [ABSTRACT FROM AUTHOR]