Biomass production and bromatologic of silage to aerial parts of twenty accesses of sweet potato

Abstract

Among the diseases that affect the tomato culture, a special attention is given to the seedling damping off due to the damages it causes on the initial phase of the cultivation. We aimed in this study to assess the different concentrations of salicylic acid (SA) on the induction of resistance to the damping off of tomato seedlings and the control of Rhizoctonia solani Kuhn in vitro. The seed treatment of tomato plants was conducted with immersion in SA solutions for 5 minutes under the concentrations of 0.5; 1.0; 1.5 and 2.0 mMe and control (distilled water). Subsequently, we showed them in expanded polystyrene trays containing the substrate Plantmax Florestal®, previously sterilized and inoculated with R.solani, being the experimental unit constituted by 20 cells, in 4 replicates. The experiment was conducted over 14 days in cultivation chamber with control of temperature (23oC ±2), luminosity (photoperiod of 12 hours) and humidity (70% ±10); then we assessed the seed germination, incidence of damping off, seedling length and fresh matter mass. We also quantified in the tissues of the plants the levels of the enzymes phenylalanine ammonia-lyase (FAL), β-1,3-glucanase and chitinase. In the experiment in vitro, the experimental unit was constituted by a Petri dish, in four replicates, being the SA incorporated to the BDA (potato dextrose agar) and assessed the mycelial growth of R.solani. The AS application in the tomato plant seeds do not interfere on the incidence of seedling damping off, but it induces resistance, activating the enzyme β-1,3-glucanase. The SA did not present effect over the R.solani in vitro.