Frequencies of irrigation in millet crop under salt stress/Frequencias de irrigacao na cultura do milheto sob estresse salino

The semi-arid region faces problems related to water deficit and the presence of brackish water that compromise crop performance. Therefore, irrigation frequency can enhance the growth of agricultural crops of interest even under salt stress conditions. In this context, the objective of the present study was to evaluate different irrigation frequencies with water of higher and lower salinity on the agronomic performance of millet. The experiment was conducted from September to November 2020, in the experimental area of the Auroras Seedling Production Unit, belonging to the Universidade da Integracao Internacional da Lusofonia Afro-Brasileira, Redencao, Ceara, Brazil. The experimentaldesign used was completely randomized in a 4 x 2 factorial arrangement, with five repetitions. The first factor corresponded to four irrigation frequencies (Fl - daily irrigation; F2 - irrigation every two days; F3 - irrigation every three days; F4 - irrigation every four days) and the second factor consisted of two levels of electrical conductivity of irrigation water (0.3 and 5.0 dS [m.sup.-1]). Salt stress (5.0 dS [m.sup.-1]) negatively affected leaf area, plant height, stalk diameter, panicle length, and leaf, stem, panicle, and total dry mass of millet, under daily and four-day irrigation frequencies. Increasing the interval in irrigation frequency to beyond two days negatively affects the agronomic performance of millet crop, regardless of the electrical conductivity of water used (0.3 or 5.0 dS [m.sup.-1]). Under salt stress conditions, adopting irrigation frequencies between two and three days can be a viable alternative for irrigation management in pearl millet crop. Key words: Pennisetum glaucum, abiotic stresses, salinity, irrigation management A regiao semiarida apresenta problemas relacionados ao deficit hidrico e presenca de agua salobra que comprometem o desempenho das culturas. Assim, a frequencia de irrigacao pode promover melhores condicOes de desenvolvimento das culturas de interesse agricola mesmo em condicOes de estresse salino. Neste sentido, objetivouse avaliar diferentes frequencias de irrigacao com agua de maior e menor salinidade sobre desempenho agronomico do milheto. O experimento foi realizado no periodo de setembro a novembro de 2020, na area experimental da Unidade de Producao de Mudas Auroras, pertencente a Universidade da Integracao Internacional da Lusofonia Afro-Brasileira, Redencao, Ceara. O delineamento experimental utilizado foi inteirament