Germinação e desenvolvimento inicial de clones de cajueiro anão-precoce sob condições de salinidade.

Abstract

The work was conducted under greenhouse conditions in the Department of Agricultural Engineering of the Federal University of the Paraiba, Campina Grande, PB, having as objective to study the effects of water salinity in different genotypes of cashew (Anacardium occidentale L.) in the germination phase, and initial growth development of the plants. The treatments consisted of four levels of irrigation water electrical conductivity (ECw: 0.7, 1.4, 2.1 and 2.8 dS m"1) tested in five commercial clones of early-dwarf type (CCP06, CCP09, CCP1001, EMBRAPA50 and EMBRAPA51), in an entirely random block experimental design, in 5x4 factorial scheme, with four replications. The irrigation waters were prepared using NaCl, CaCb^FfeO and MgCl^FfcO, keeping equivalent ratio 7:2:1 among Na:Ca:Mg, respectively. The germination variable evaluated were: days and emerged seedling percentage; growth indices: plant height, leaf number, leaf area, dry weight of the roots, the aerial parts and total (50 and 100 days after the plantation - DAP); physiological indices: absolute growth rate, relative growth rate, net assimilation rate (after 50 the 100 DAP), ratio of leaf area, root / aerial part ratio and water content of leaves (after 50 and 100 DAP). The salinity levels of the irrigation water did not reduce the germination percentage significantly, but prolonged the duration of germination phase. The increase of the saline level of the irrigation water caused significant reduction in the vegetative growth; the plant height, leaf area, dry weight of roots, the aerial parts and total were reduce with the increment of the saline concentration; the growth of the aerial part was affected more by the salinity of than that of roots system. The increment of the salinity had significant increase in the ratio of leaf area, root / aerial part ratio and water content of leves. Increase of ECw beyond 0.7 dS m"), caused linear decrease of absolute growth rate. No interactive effect between clones and water salinity levels for any variable was verified indicating that the effect of the salinity do not depend on the studied genetic materials.