Priming e a tolerância do sorgo granífero ao estresse hídrico e salino

Abstract

Drought and salinity are the main abiotic factors, which have limited agricultural production worldwide, and can cause great losses mainly in the most critical stages of the crop, such as germination and initial growth. However, investing in strategies such as the use of more tolerant species, such as sorghum, can ensure greater stability of agricultural production. In addition, seed priming, with GA3, may potentiate the tolerance of these genotypes, reducing the damage caused by stresses during germination and establishment of the crop. The objective of this research was to analyze the ability of three sorghum genotypes to germinate and grow under water and saline stress conditions, as well as to evaluate the efficiency of the hormonal priming, with GA3, in improving the tolerance of the genotypes and less sensitive to stress. The research was carried out in two stages, in the first the three genotypes were submitted to 5 levels of water stress (0,0; -0,3; -0,6; -0,9 and -1,2 MPa) and 7 Salinity levels (0.0, 4.0, 8.0, 12.0, 16.0, 20.0 and 24 dS m-1); In the second stage, the seeds of the genotypes, more tolerant and less tolerant, were treated by hormonal priming, by soaking the seeds for 2 hours in GA3 solutions at concentrations of 0,0; 50; 75 and 100 mg/L, with a constant temperature of 25°C, and in a dark environment, and then dried for 24 hours at 30°C. Under the conditions controlling water and saline stress the genotype BRS 330 was the most tolerant, and the L-20 the most sensitive genotypes during the initial phase of the culture. Under the conditions controlling water and saline stress the genotype BRS 330 was the most tolerant, and the L-20 the most sensitive genotypes during the initial phase of the culture, and priming with GA3, at 100 mg/L concentration, improved tolerance of sorghum during the initial phase, water and saline stress conditions, especially the more tolerant genotype. Therefore, the combination of strategies such as the use of more tolerant species or genotypes, and priming with GA3 are efficient in reducing the damages caused by water and saline stresses during germination and seedling growth.