Growth and nutrition of ‘Imperial’ pineapple nursery plants associated with the fungus Piriformospora indica and herbicide application

The low supply of healthy and quality nursery plants has been an obstacle to the growth of pineapple crop in Brazil. The research was carried out with the aim of evaluating mycorrhizal association, growth and nutrient uptake of ‘Imperial’ micropropagated pineapple plants inoculated with the fungus Piriformospora indica in cultivation with herbicide application. The 2 x 4 factorial scheme was used, being the factors the two inoculations: inoculated nursery plants with the fungus P. indica and without inoculation and four doses of herbicides: 0, 1.5, 3.0 and 6.0 L ha-1 for ametryn, 0, 1.6, 3.2, 6.4 L ha-1 for diuron and 0, 0.4, 0.8 and 1.6 L ha-1 for sulfametrazone distributed in a completely randomized design with three replications. The doses of herbicides were applied to substrate before planting. The inoculation with the fungus P. indica was made at the time of planting, placing in the substrate 5 mm mycelial discs containing fungal structures. At 150 days after inoculation evaluations were made by analysis of colonization, determination of N, P and K levels and of nursery plants growth. Data were subjected to analysis of variance and regression. The association of fungus P. indica with ‘Imperial’ pineapple nursery plants was observed with the application of all herbicides. ‘Imperial’ pineapple nursery plants associated with P. indica fungus showed higher levels of nutrients and growth. The use of herbicides in high doses interfered in growth and nutrient uptake by mycorrhizal pineapple nursery plants.