Vol. 5, Issue 2, Part B (2023)

The propagation of red pulp guava (Psidium guajava L.) through softwood grafting is one of the most promising techniques for maintaining varietal purity and ensuring rapid orchard establishment. However, grafting success remains inconsistent due to complex physiological, biochemical, and environmental constraints that influence graft union formation. Among these, the activity of rhizospheric microflora surrounding the rootstock plays a crucial but often overlooked role. The present investigation aimed to evaluate the influence of beneficial soil microorganisms on the success of softwood grafting in red pulp guava under controlled nursery conditions. A combination of plant growth-promoting rhizobacteria (PGPR) such as Azospirillum brasilense, Bacillus subtilis, and Pseudomonas fluorescens, along with fungal symbionts like Trichoderma harzianum and Glomus intraradices, was introduced into the rhizosphere prior to grafting. Their effects on graft take-percentage, callus development, scion sprouting, and subsequent plant vigor were systematically studied.

Results revealed a remarkable improvement in graft success rate and early scion growth in microbially inoculated treatments compared to the uninoculated control. Enhanced enzymatic activities related to oxidative stress regulation, greater accumulation of soluble carbohydrates at the graft interface, and higher microbial biomass carbon were recorded. These findings indicate that a biologically enriched rhizosphere contributes to better vascular connectivity and reduced graft incompatibility. The integration of rhizospheric microflora into nursery management therefore represents a sustainable biotechnological strategy to improve propagation efficiency in guava. The study highlights the physiological mechanisms underpinning microbe-mediated graft union success and proposes future applications of bioinoculants in perennial fruit propagation systems.