Abstract:

This study aims to clarify the impact of compound microbial inoculants applied via foliar spraying on fruit color development, maturation, and quality attributes. Using 4-year-old ‘Fujiminori’ grape and ‘Busan 88’ cherry tomato as experimental materials, and two bacterial agent concentration treatment groups (T1: diluted 500 times, T2: diluted 300 times) and a blank control group (CK) were set up. The plants were sprayed at the initial fruit coloring stage and re-sprayed after 10 days. The coloring process, quality, and yield parameters were measured. The results showed that: (1) the color-promoting effect was significant. Under the T2 treatment, the time required for grapes to reach 90% coloration was 12 days earlier than CK, and the ripening of tomatoes was advanced by 7 days. (2) Fruit quality was significantly improved. Compared with CK, the ‘Fujiminori’ grapes showed a 22.07% increase in total anthocyanins, a 1.69% increase in soluble sugar, and a 27.73% increase in vitamin C content, while titratable acid decreased by 9.38%. For tomatoes, soluble sugar, vitamin C, and lycopene contents increased by 24.80%, 33.91%, and 35.08%, respectively, compared to CK, with titratable acid reducing by 18.82%. (3) Yield was simultaneously enhanced. Compared with CK, the hundred-berry weight and single-cluster weight of grapes increased by 32.93% and 22.25%, respectively, while the single-fruit weight and yield per plant of tomatoes increased by 5.58%-9.44% and 1.37%-5.92%, respectively. (4) Economic benefits were significant. Grapes reached the market 12 days earlier, with the selling price increasing from 8-10 yuan/kg to 20 yuan/kg. Similarly, tomatoes were marketed 7 days earlier, and their price rose from 10-15 yuan/kg to 20 yuan/kg. In conclusion, spraying the 300-fold diluted compound microbial agent synergistically promotes fruit coloration, ripening, and quality improvement, providing technical support for high-quality, efficient, and green cultivation of fruits and vegetables.

Key words: microbial agent, color change, fruit quality, soluble sugar, grape, tomato, spraying