Halo-priming em cultivares de feijão-caupi submetidas ao estresse salino

Abstract

The use of tolerant to salinity cultivars and techniques that promotes good agricultural yields in saline soils is important. The objective was to evaluate the activation of defense responses to salt stress induced by halo-priming in plant cowpea cultivars, coming from pre-conditioned seeds. The experiment was carried out in randomized completely design in a greenhouse in a factorial 3x4 and 2x3x3, with three repetitions. The plot was represented by a pot, size 3 dm3, with one plant per pot. Were used two (2) levels salinity: E0, with 0 mmol NaCl and E1 with 60 mmol NaCl in the nutrient solution; three (3) halo-priming levels: HP0, no priming, HP1 immersion in solution with 30 mmol NaCl for 2 hours and HP2, immersion in 60 mmol NaCl for 2 hours; and four (4) cultivars, C1: Canapu, C2: Epace 10; C3: IPA 206 and C4: IPA Miranda 207. The treatment salt stress (E1) started 20 days after planting. They were made germination index evaluation (GI) and emergence speed index (ESI), before the start of the salt stress treatments. After the salt stress treatments, at 60 days after planting, the following biometric evaluations (plant height, stem diameter, dry weight of shoot and root dry weight), percentage reduction evaluation of shoot and chemical evaluations of sodium and potassium. Statistical analysis was done using analysis of variance and average comparison tests, using the electronic program SISVAR. Better results were seen for germination speed index in the Miranda IPA 207 and IPA 206 cultivars when subjected to halo-priming. The height of the main branch was significantly reduced in salt stress situation. The treatments with the presence of halo-priming increased the average stem diameter in Epace 10 and IPA 206 cultivars. The halo-priming with 30 mmol of NaCl for 2 hours significantly increased the root dry weight of cultivars. For dry weight of shoots to grow Canapu had the highest average under salt stress and absence of halo-priming. To the sodium content in the plant, best responses were observed when using the halo-priming 30 mmol NaCl. To the potassium content to cultivate Canapu showed better responses when used halo-priming 60 mmol NaCl. Conclude that the cultivar Canapu is moderately tolerant to irrigation water with salt concentration of 60 mmol NaCl in the vegetative phase. The halo-priming with a concentration of 30 mmol of NaCl can be given to remediate the salt stress in cultivating Canapu.