Seed priming and shading on emergency and initial growth of Bixa orellana L. seedlings

Abstract

Two experiments were carried out to evaluate the effect of period and temperature of conditioning in the germination of seeds and seedlings growth, and the effect of shading on the seedlings initial growth. In the first one, the seeds was conditioned in the following solutions: 1) PEG 6000 (- 1,0 MPa); 2) PEG 6000 (- 1,0 MPa) + KNO3 (- 1,0 MPa); 3) KNO3 (- 1,0 MPa); 4) water and 5) deionized water, and placed to germinate in BOD regulated to provide temperatures of 10 and 20°C during 0 (control), 6, 12 and 24 h. In the second experiment, the seeds were conditioned in solution of PEG 6000 + KNO3 and in deionized water and placed in BOD regulated to 10°C during 24 h, beyond the control. After this, they were sown in polyethylene bags and placed in greenhouses under 0, 50 or 70% shading. The conditioning at 10°C and in the mix solution of PEG 6000 + KNO3, during 24 h provided the bigger percentage of germination (35.87%). Artificial shade of 50% was the most favorable to emergency and growth of annatto seedlings.