Effects of rhizobacteria and substrates in the physiological quality of lettuce seeds

Abstract

The objective of this work was to evaluate the production and physiological quality of lettuce seeds, cultivar Grand Rapids TBR, produced by plants treated with rhizobacteria and cultivated on different substrates. The experimental design was a randomized block in a factorial 3x5, involving seed treatment with rhizobacteria Bacillus pumilus 01 and B. subtilis 34, and the control (no treatment) and five substrates: soil+sand+Bioplant^® (1:1:1), soil+manure (2:1), soil+manure+sand (1:1:1), soil+Bioplant^® (2:1) and Bioplant^®, with five repetitions. For inoculation, the seeds were immersed in the bacterial suspensions (OD₅₄₀= 0.5) kept under constant stirring for 15 minutes, and immediately seeded. After harvesting, cleaning and separation, the seeds were weighed for yield evaluation and then submitted to the determination of the water content and germination and vigor tests (first germination count, seedling emergence, rate of emergence and accelerated aging). The inoculation of seeds with the rhizobacteria B. pumilus 01 and B. subtilis 34, and the use of the substrate soil+manure+sand (1:1:1), provide higher seed yield. Seeds treated with the rhizobacterium B. pumilus 01 and cultivated in the substrates soil+manure+sand (1:1:1) and soil+Bioplant^® (2:1) induced the production of better physiological quality lettuce seeds.