Crescimento e produtividade de variedades de Manihot Esculenta sob déficit hídrico

Abstract

The water deficit is one of the abiotic stresses that most compromises crop productivity and has been intensified over the years due to climate change. Thus, it is important to understand the strategies related to water deficit tolerance in order to select varieties with higher productive potential under conditions of low water availability. The objective of this study was to classify four cassava varieties for tolerance to water deficit and to identify the drought tolerance strategies of these varieties. Experiments were conducted in the experimental and greenhouse field of the State University of Goiás, Campus Ipameri. In the field, two experiments were carried out in consecutive years, in a randomized complete block design (DBC) with four varieties of cassava (Cidade Rica, Comuquem, Formosa and Manteiga). The greenhouse experiment consisted of DBC 5x4, with five water replenishments (20, 40, 60, 80 and 100% of the volume of water related to evapotranspiration) and four varieties of cassava, with four replicates in each experiment. Physiological, biochemical, morphological and productivity evaluations were performed. Data were evaluated by Scott-Knott (5%) and regression for field and greenhouse assessments, respectively. According to the analyzed variables, Comuquem and Formosa stood out for drought tolerance and the varieties Manteiga and Cidade Rica were classified as susceptible to water stress. The tolerance to water stress, observed in the Comuquem variety, is due to an efficient antioxidant desorption system that, together with the accumulation of sugars, allowed the maintenance of water status and higher productivity in relation to the other varieties.