Application of plant growth promoting bacteria enhances the growth of yerba mate (Ilex paraguariensis St. Hil) in greenhouse

Abstract

Yerba mate is an economically and culturally important South American plant. The objective of the present research was to assess the growth promotion capacity of endophytic spore-forming bacteria on Ilex paraguariensis St. Hil in greenhouse. Seedlings were inoculated with Bacillus altitudinis (strains 19RS3 and T5S-T4), Kosakonia radicincitans YD4, and their combinations. Azospirillum brasiliense sp.245 and non-inoculated seedlings were used as controls. Inoculated seedlings were 43.28% higher and had a root collar diameter 12.42% thicker, 28.14% more leaves, and 67.84% more leaf area. Total dry weights were up to 27.66% higher, leaves dry weight 89.80% higher, and shoot dry weight 48.28% higher. They presented 90.77% higher gs, 51.73% higher total chlorophyll content, 39.97% higher chlorophyll a, and 80.87% higher chlorophyll b. Bacillus strains alone or in combinations showed the best results, making them excellent candidates for developing an organic eco-friendly biofertilizing product for yerba mate seedlings in the greenhouse.