Production components and water efficiency of upland cotton cultivars under water deficit strategies

The objective of this work was to study water deficits effect on different phenological phases in the production components and water efficiency of upland cotton cultivars. For this, an experiment was carried out at the Federal University of Campina Grande - UFCG, Pombal county Campus, Paraiba State, Brazil. Treatments were formed from a split-plot arrangement in which plots were 6 water deficit periods (P): (P1 = No deficit; P2 = Deficit in the initial growth stage; P3 = Deficit in the flower bud stage; P4 = Deficit in the flower stage; P5 = Deficit in the boll stage; and, P6 = Deficit in the open boll stage) and, the subplots, 2 upland cotton cultivars (C): (C1 = Brazil Seeds 286 and C2 = BRS 336), in randomized block design, with 4 replicates. Cultivars studied were more tolerant to water deficit in stages of initial growth, flower bud and open boll. Water deficit during flowers and bolls stages in upland cotton cultivars was the most detrimental to production components. Between cultivars tested, their behavior was similar only in cotton seed yield and water-use efficiency being BRS 286 higher than BRS 336 in other analyzed variables, except for mean open boll weight. Key words: Gossypium hirsutum L. r. latifolium H., Hydric stress, agronomic variables.