-The objective of this work was to evaluate the gas exchange, leaf temperature, yield and water use efficiency in 'Tommy Atkins' mango under irrigation deficit strategies. The experimental design was randomized block, with seven treatments with regulated deficit irrigation (RDI) under micro-spray and five treatments with partial root-zone drying (PRD) under drip irrigation. The treatments on RDI consisted of application of 100, 75 and 50% of ETc at the stages S1 (beginning of flowering to fruit set) S2 (fruit development) and S3 (fruit physiological maturation). The treatments on PRD consisted of application of 100, 80, 60 and 40% of ETc, in the same three stages, alternating the irrigation side every 15 days. The regulated deficit irrigation causes less negative interference in gas exchange than the partial root-zone drying, and the climate factors affect the gas exchange and leaf temperature of 'Tommy Atkins' mango more than the regulated deficit irrigation. The partial root-zone drying irrigation with 60 and 40% of ETc causes a decrease in the 'Tommy Atkins' mango yield. The regulated deficit irrigation up to 50% of ETc, applied at the fruit maturation stage, maintain the yield and water use efficiency.Keywords: Water deficit. Irrigation management. Mangifera indica. Gas exchange. PARÂMETROS FISIOLÓGICOS E PRODUTIVOS EM MANGUEIRAS 'TOMMY ATKINS' SOB ESTRATÉGIAS DE DÉFICIT DE IRRIGAÇÃORESUMO -Objetivou-se com este trabalho avaliar as trocas gasosas, temperatura foliar, produtividade e eficiência de uso da água em mangueira "Tommy Atkins" sob irrigação com déficit. O delineamento experimental foi em bloco casualizado, com sete tratamentos para a irrigação com déficit controlado (RDI) sob microaspersão e com cinco tratamentos para a irrigação lateralmente alternada (PRD) sob gotejamento. No manejo RDI os tratamentos consistiram da aplicação de 100, 75 e 50% da ETc nas fases F1 (início da floração até o pegamento dos frutos), F2 (desenvolvimento do fruto), e F3 (maturação fisiológica do fruto). No manejo pelo PRD os tratamentos consistiram da aplicação de 100, 80, 60 e 40% da ETc nas três fases com alternância do lado irrigado de 15 dias. Verificou-se que a irrigação com déficit controlado causa menos interferências negativas nas trocas gasosas que a irrigação lateralmente alternada e as trocas gasosas e temperatura foliar da mangueira "Tommy Atkins" sofrem maiores influências de elementos do clima que da irrigação com déficit controlado. A irrigação lateralmente alternada com 60 e 40% da ETc ocasiona queda na produção da mangueira "Tommy Atkins". Irrigação com déficit controlado com até 50% da ETc aplicados na fase de maturação do fruto mantem a produtividade e a eficiência de uso da água.Palavras-chaves: Déficit hídrico. Manejo da irrigação. Mangifera indica. Trocas gasosas.

ABSTRACT:With the limited availability of water in semi-arid regions, it is necessary that irrigation is accurate and there is high water use efficiency.This study aimed to evaluate the regulated deficit irrigation (RDI) and partial rootzone drying (PRD) in yield, water use efficiency and gas exchange of 'Tommy Atkins' mango tree in semi-arid conditions. The experimental design was a randomized block with seven treatments for RDI under micro sprinkler and five treatments for the PRD under drip. Treatments were applied in phases PI -early blooming to early fruit expansion, PII -early expansion to early physiologic ripening and in phase III -physiologic ripening of fruits, with application of the RDI of 100, 75 and 50 % of ETc in different combinations of phases and application of PRD 100, 80, 60 and 40 % of ETc in three phases with the partial rootzone druing at 15 days. Photosynthesis, carboxylation efficiency and quantum efficiency of photosynthesis are lower in PRD 40% ETc at 8 a.m. compared to full irrigation and PRD 80 % of ETc. Phases of expansion and fruit ripening are more appropriate for application of RDI with 50 % and 75% of ETc without loss to the crop yield of 'Tommy Atkins' mango tree and greater water use efficiency. The strategy of partial rootzone drying, PRD, every 15 days with 40 % of ETc, provides greater WUE.

The increasing water demand of crops in response to climate change; the prospect of expanded irrigated areas; the population growth; and competition with multiple uses of water affect the availability of water resources for agriculture. Thus, measures are required that involve the adoption of irrigation-management strategies able to increase water savings without compromising crop yield, especially in semi-arid conditions, where water resources are limited, and in large-scale commercial cultivation such as in 'Tommy Atkins' and 'Palmer' mango, the second most widely grown irrigated fruit crop. The objective of this study was to examine the influence of irrigation systems (drip and micro-sprinkler) and deficit-irrigation strategies on the yield and water use efficiency (WUE) of 'Tommy Atkins' and 'Palmer' mango trees. The study was developed through two experiments conducted in the Irrigated Perimeter of Ceraíma, located in municipality of Guanambi - BA, Brazil. Two trials were carried out in a completely randomized design. For the 'Tommy Atkins' cultivar, 12 strategies were tested, involving regulated deficit irrigation (RDI) by micro-sprinkler irrigation and partial rootzone drying (PRD) by drip, in three production cycles. For ‘Palmer’ mango, 10 irrigation strategies were evaluated under the same previously described conditions, in only one production cycle. The reduction in water application in RDI was 25 and 50% of the crop evapotranspiration (ETc); and, in PRD, 20, 40 and 60% ETc. ‘Tommy Atkins’ mango achieved higher yields under micro-sprinkler irrigation with full irrigation and in the strategies involving the application of 50 and 75% ETc in stages II and III. These two strategies also provided greater WUE, along with PRD40. Water use efficiency was lower in the third evaluation cycle when compared with the first. ‘Palmer’ mango showed higher yields and WUE under drip irrigation, with the best yields achieved with full irrigation and in the strategies of PRD100, 80%, 60% and RDI with 50% ETc in stage III. The best WUE was obtained in PRD with 60 and 40% ETc.

SUMMARY:We aimed to understand two strategies of deficit irrigation and their effects on yield and water-use efficiency (WUE) in 'Tommy Atkins' mango trees, for three consecutive cycles. In the experiment with Regulated Deficit Irrigation (RDI), the treatments were: T1, full irrigation at every fruit development stage, 100% of ETc; T2, 100% of Etc at stages II and III Rootzone Drying (PRD) for the three crop stages: T1, 100% of ETc, conventional dripping irrigation; T2, 100%; T3, 80% of ETc; T4, 60% of ETc and T5, 40% of ETc. As for the treatments T2, T3, T4 and T5, the side to be irrigated was alternated every 15 days. At the end of 3 production cycles, we observed a reduction in productivity when RDI was applied at SI.The water-use efficiency was higher in the first cycle in relation to the third cycle under RDI.The PRD with 80% of ETc maintains the productivity and with 40% of ETc, increases WUE. KEYWORDS: evapotranspiration, fruit production, Mangifera indica IRRIGAÇÃO COM DÉFICIT EM CICLOS CONSECUTIVOS