Salinidade no substrato e tolerância de híbridos de tangerineira com trifoliata na fase de porta-enxerto.

Abstract

ABSTRACT - In saline conditions, the growth, development and production of citrus plants can be reduced, attributable to the effect of toxic ions, mainly chlorine, sodium and boron, however, it is possible to cultivate these plants when using rootstocks that tolerant. The objective of this study was to study the salt balance in the substrate used in the cultivation of citrus plants under irrigation with salinized water during the rootstock formation phase, as well as the tolerance of the plants to the salinity of the water. For this purpose, two water salinity levels were studied, using water with electrical conductivity (ECa) of 0.3 and 3.0 dS m-1, applied to 23 citrus genotypes used as rootstock, which resulted in 46 treatments and 4 replications in a randomized complete block design. The plants were grown in plastic bags with a volume of 2 dm 3, which were filled with commercial substrates based on vermiculite, pine bark and humus, in a ratio of 1: 1: 1. The plants were irrigated with two levels of salinity of 0.3 and 3.0 dS m-1, the second one being prepared in the equivalent ratio 7: 2: 1, between Na: Ca: Mg, respectively. The application of the waters with different CEs started 90 days after sowing (DAS) and lasted up to 180 DAS. The increase in salinity of the water reduced the phytomass of the genotypes TSKc X (LCR x TR) -73, TSKFL X (LCR x TR) -18, which were classified as sensitive. The genotypes SUNKI TROPICAL and TSKC X (LCR x TR) -29 obtained the greatest accumulation of total dry matter and were considered tolerant.