Tolerância de híbridos cítricos (tangerineira x citrumelo) e balanço de sais no substrato sob águas salinizadas.

Abstract

Due to citrus sensitivity to salinity and the need to obtain tolerant genetic materials for use as rootstocks, an experiment was realized in order to evaluate the tolerance of citrus genotypes, from crossing of Common Sunki mandarin (TSKC) [C. Sunki (Hayata) hort. Ex Tanaka] with Swingle citrumelo (C. paradise Macfad x Poncirus trifoliata) (CTSW), to the saline stress during the rootstock formation. The experiment was set up in greenhouse at Center of Agrifood Sciences and Technology - CCTA, of the Federal University of Campina Grande - UFCG, Pombal city, Paraiba state, Brazil. It was used a randomized block design, with treatments made from factorial scheme, 2 x 23, with 4 replications, being two levels of irrigation water salinity (S1 = 0.3 dS m-1 and S2 = 3 dS m-1), and 23 genotypes, relatives to 20 genotypes relatives to progeny of the cross between the Common Sunki mandarin (TSKC) with Swingle citrumelo, added to three control genotypes (the 'Rampur Santa Cruz' lemon (LCRSTC), the Tropical Sunki mandarin and the hybrid between Volkamer lemon (LVK) with Rampur lemon (LCR) - LVK x LCR - 038. The application of salinized water was started from 90 days after sowing (DAS) until 210 days after sowing, when the substrate was evaluated for chemical characteristic and the genotypes about tolerance to salinity. The use of saline water promoted alterations in the chemical characteristics of the soil, with an increase in the values of electrical conductivity in the saturation extract (CEes) and in the Ca+2, Mg+2, Cl- and K+ values in the saturation extract. Considering the toxicity of sodium and chloride ions, we can highlight the TSKC x CTSW- 055 genotypethat obtained the bigger growth in dry matter under EC of 7.43 dS m-1 and chlorine concentration of 103.75 mmol dm-3 and TSKC x CTSW- 043 which developed at the bigger sodium concentration of 47.93 mmol dm-3. The genotypes TSKC x CTSW- 042, TSKC x CTSW- 043, TSKC x CTSW- 046, TSKC x CTSW – 048 and TSKC x CTSW- 058 also succeeded in developing well at observed Na and Cl concentrations.