Guangshu Ma

The issue of ongoing cropping barriers is getting worse as China’s melon planting area steadily grows, and the melon industry’s sustainable growth is being negatively impacted by the steadily diminishing yield and quality of the fruit. Trichoderma is a probiotic that can enhance the physiological traits of crops, encourage their growth, and raise their yield and quality. It is yet unknown, though, how Trichoderma influences the growth, physiological traits, and yield of melon grown on soils continuously cropped to melon. Trichoderma viride kf57 agents at 1.0 × 10⁴, 8.0 × 10⁴, 6.4 × 10⁵, and 5.12 × 10⁶ CFU/g and no Trichoderma viride agents (CK) were utilized as treatments. At the seedling and fruiting stages, a pot experiment and a bedding experiment were conducted to study the physiological properties and yield of melon under varying concentration of Trichoderma viride kf57 agents. As a result of the application of T. viride agents, the indexes of melon seedlings were all significantly improved. The treatment of 6.4 × 10⁵ CFU/g had the best promoting effect on the morphology of melon seedlings, and the plant height, stem diameter, leaf area, fresh weight of whole plant, dry weight of whole plant, root shoot ratio, and strong seedling index of melon seedlings increased by 90.39, 46.30, 37.55, 81.35, 100.62, 51.47, and 240.00%, respectively, compared with CK. The results showed that different amounts of T. viride agents could improve physiological and biochemical indices of melon leaves during the fruiting stage; the treatment of 6.4 × 10⁵ CFU/g was the most effective; chlorophyll content, nitrate nitrogen content, sucrose content, reducing sugar content, free proline content, nitrate reductase (NR) activity, peroxidase (POD) activity, and superoxide dismutase (SOD) activity of melon leaves increased at 30 days after melon pollination. Melon quality and yield was also enhanced by the use of T. viride agents, with the treatment of 6.4 × 10⁵ CFU/g T. viride agents having the best boosting effects. The melon fruit’s transverse diameter, vertical diameter, single fruit weight, and yield all increased. The amount of soluble solids, vitamin C, soluble protein, soluble sugar, and sugar acid ratio also increased. In conclusion, by promoting the morphology of melon grown on soils continuously cropped to melon seedlings, T. viride agents can improve the physiological characteristics of melon grown on soils continuously cropped to melon and improve the production and quality qualities of melon. When using T. viride kf57 agents, 6.4 × 10⁵ CFU/g is the highest effective dosage. The study revealed that T. viride agents had significant potential as biological agents as they showed good results in melon yield and quality formation, as well as in enhancing seedling quality.

Melon damping off, which has a negative impact on melon quality and yield, can be safely and effectively managed with Trichoderma. Melon cultivar ‘Longtian No. 1’ was evaluated at both the adult and seedling stages in a pot experiment. The Rs and PD liquids were utilized as CK1 and CK2, respectively. Trichoderma viride Tv286 treatments T1B, T2B, T3B, and T4B were used based on Rs at concentrations of 10⁴, 10⁵, 10⁶, and 10⁷ CFU·g⁻¹, respectively. The impact of several treatments on the antioxidant system and seedling quality of melon were assessed at 15, 25, and 35 days after sowing. We examined the effects of several treatments on melon quality, yield attributes, and physiological and biochemical markers during the adult stage at 10, 20, and 30 days after pollination. The effects of several treatments on melon damping off were also studied. Applying T. viride Tv286 at different rates effectively increased the activities of enzymes, including catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), and polyphenol oxidase (PPO), in the leaves of melon seedlings, significantly reduced the malondialdehyde (MDA) content, and improved the root–shoot ratio and seedling strength index. In terms of its influence on promoting the effect of antioxidant system indicators, T3B performed well. Melon seedlings treated with T3B showed higher CAT, POD, SOD, APX, and PPO activities in their leaves 35 days after sowing compared to CK1 (189.74, 169.61, 175.36, 224.20, and 477.39%, respectively). The strong seedling index and root–shoot ratio showed improvements of 130.43 and 79.71%, respectively, and the MDA content dropped by 35.66% at 35 days after sowing compared to CK1. Varying the rates at which T. viride Tv286 was applied increased the nitrate reductase (NR) activity and nitrate nitrogen, proline (Pro), chlorophyll, soluble sugar, and soluble protein contents in mature melon leaves, increasing melon quality and yield. T3B is the most effective marketing campaign. Compared to CK1, mature T3B leaves had higher NR activity, nitrate nitrogen content, chlorophyll content, soluble sugar content, soluble protein content, and Pro content 30 days after melon pollination (100.40, 135.17, 68.59, 93.65, 158.13, and 238.67%, respectively). The soluble solids, soluble protein, soluble sugar, vitamin C contents, and yield of melon fruit increased by 50.07, 126.82, 60.62, 70.79, and 61.45%, respectively, at 30 days after melon pollination compared to CK1. Optimal management of melon damping off can be accomplished with the application of T. viride Tv286 at different concentrations, with T3B exhibiting the best effect. The control effects reached 90.48 and 72.99% at the seedling and adult stages, respectively. Overall, T. viride Tv286 improved seedling quality, damping off control efficacy, melon yield and quality, and the antioxidant system during the seedling stage and enhanced physiological and biochemical characteristics during the adult stage. This study indicates the potential of T. viride Tv286 conidia as a biological control agent because it can prevent plant disease, increase yield, and improve quality.

At the seedling and adult plant phases, pot experiments were carried out to enhance the physiological-biochemical characteristics of cucumber, guarantee its high yield, and ensure its cultivation of quality. Trichoderma harzianum conidia agents at 10⁴, 10⁵, 10⁶, and 10⁷ cfu g⁻¹ were applied in accordance with the application of Fusarium oxysporum powder at concentrations of 10⁴ cfu/g on the protective enzyme activity, physiological and biochemical indices, seedling quality, resilience to Fusarium wilt, quality, and yield traits. Fusarium oxysporum powder at 10⁴ cfu g⁻¹ was used to treat CK1, while Fusarium oxysporum powder and T. harzianum conidia agents were not used to treat CK2. The results show that different T. harzianum agents improved the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and peroxidase (POD) in cucumber seedlings, improved chlorophyll content, root activity, root-shoot ratio, and seedling strength index, and decreased malondialdehyde (MAD) content (P < 0.05). T3, a combination of 10⁴ cfu g⁻¹ Fusarium oxysporum powder and 10⁶ cfu g⁻¹ T. harzianum conidia agents, had the greatest promoting effect. The effects of different T. harzianum conidia agents and their application amounts on the control of cucumber Fusarium wilt were explored. T3 had the best promotion impact, and the control effect of cucumber Fusarium wilt at seedling stage and adult stage reached 83.98% and 70.08%, respectively. The quality index and yield formation of cucumber were also increased by several T. harzianum agents, with T3 having the strongest promotion effects. In comparison to CK1, the soluble sugar, Vc, soluble protein, and soluble solid contents of T3 cucumber fruit were 120.75%, 39.14%, 42.26%, and 11.64% higher (P < 0.05), respectively. In comparison to CK2, the soluble sugar, Vc, soluble protein, and soluble solid contents of T3 cucumber fruit were 66.06%, 24.28%, 36.15%, and 7.95% higher (P < 0.05), respectively. In comparison to CK1 and CK2, the yields of T3 cucumber were 50.19% and 35.86% higher, respectively. As a result, T. harzianum agents can enhance the physiological and biochemical traits of cucumber seedlings, raise the quality of cucumber seedlings, have a controlling impact on Fusarium wilt, and increase the yield and quality of cucumber fruit. The greatest effectiveness of T3 comes from its use. In this study, Trichoderma harzianum conidia agents demonstrated good impacts on cucumber yield formation and plant disease prevention, demonstrating their high potential as biocontrol agents.