DETERMINAÇÃO DE METODOLOGIA PARA GERMINAÇÃO E VIGOR DE SEMENTES DE Cajanus cajan (L.) Millspaugh

Abstract

Cajanus cajan (L.) Millspaugh, popularly known as pigeon pea is a Fabaceae that was introduced in Brazil for reasons like well development on poor soils conditions, resistance to drought, and it adaptation to the climatic conditions of the country. Thus the goal in this study was to determine a methodology for conducting germination and vigor tests of pigeon pea seeds and verify the performance of those tests by water and salt stress at different temperatures. The study was conducted at the Seed Analysis Laboratory of the Center for Agricultural Sciences, Federal University of Paraíba, in Areia - PB, in a completely randomized experimental design. In the first experiment it was evaluated different volumes of water for wetting the substrate (2,0; 2,5; 3,0; 3,5 and 4,0 times the dry weight of the substrate) and alternating temperatures of 20-30 ° C and constant 25, 30 and 35 ° C. In the second experiment it was simulated water stress condition with polyethylene glycol solutions 6000 (PEG 6000) in six osmotic potential 0,0 (control); -0,2; -0,4; -0,6; -0,8 And -1,0 MPa at temperatures of 20, 25, 30 and 35 ° C. In the third experiment, seeds were subjected to sodium chloride solution (NaCl), using six salinity levels: 0,0 (control); 2,0; 4,0; 6,0; 8,0 and 10,0 dS m-1 at three temperatures 20-30 ° C (alternated) and 25 ac, 30 ° C constant. To evaluate the effect of treatments on the seeds it was determinated the seed water content, germination and vigor tests (first count, germination speed index, length and dry weight of roots and shoots). The wetting the substrate with water volumes of 2,81 and 3,5 times the dry weight of the substrate at temperatures of 30 and 35 ° C respectively is indicated for germination and vigor of pigeon pea seeds. In relation to water stress in 20 ° C the germination of this species was reduced with decreasing the osmotic potential from 0,2 MPa, that same study found less influence on seed vigor when they were in the temperature 30 ° C until the potential of -0,6 MPa. The increase in salinity levels affect seed germination and vigor of pigeon pea seeds, especially around 25 ° C.