The role of Trichoderma species as phosphate solubilizing microorganism was studied in vitro, by means of the Modified Pikovskaya's Broth medium (MPB) and in vivo, under greenhouse conditions using Rock Phosphate (RP) as a source of phosphorus (P). In broth medium, Trichoderma strain FR-NST-009 gave the highest P-solubilization (80.25%), followed by FR-NST-353 (77.51%), CB-Pin-01 (66.91%), RB-NST-028 (46.05%), and RB-NST-003 (21.20%) as compared with a control (broth medium non-inoculated with Trichoderma strain) after incubation at room temperature (27 ± 2 o C) for 7 days. In addition, the treatments with Trichoderma species provided the final pH of broth culture lower than the control. Three kinds of organic acids including citric acid, lactic acid and succinic acid were detected by High Performance Liquid Chromatography (HPLC) in all treatments inoculated with Trichoderma strain. Trichoderma species produced citric acid in higher than lactic acid and succinic acid. Production of organic acids by Trichoderma species is one of the mechanisms for phosphate solubilization. In greenhouse conditions, at 60 days after planting, the treatments with Trichoderma strain FR-NST-009+RP provided the percentage of available phosphorus increasing more than the control 1 (with only RP) to 14.91%. However, after 60 days, the available phosphorus in the planting medium continually decreased in all treatments. At 180 days after planting, the treatments with FR-NST-009+RP increased plant height (22.19%), stem circumference (13.81%), leaf number (71.43%), total phosphorus in the rubber tree leaves (18.90%), shoot fresh weight (43.95%), root fresh weight (19.36%), shoot dry weight (39.96%), and root dry weight (21.13%), as compared with the control 1 (with only RP) Furthermore, the treatments with FR-NST-009+RP provided the population of Trichoderma species in the planting medium with 1.78 × 10 5 Colony-Forming Units (CFU) per gram planting medium and gave the root colonization percentages with 100.00%. The selected indigenous strain, FR-NST-009 was Trichoderma harzianum identified by using morphological characteristics.

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In the selection phase of melon breeding programs, genetic variability is a critical component for yield improvement. The goals of this study were to discover the variables that affect melon fruit weight and examine genetic variability, correlation, and path analysis of eight melon varieties. The experiment was arranged as a completely randomized block design with 4 blocks. It was conducted between July and September 2021 at the School of Agricultural Technology, Walailak University, Nakhon Si Thammarat, Thailand. The result found that stem diameter and length, leaf length, width, number, and chlorophyll, day to 50% male and female flowering, and fruit perimeter, height, and weight were highly significant across the varieties. The genotypic coefficients of variation (GCV) of observed variables were all lower than phenotypic coefficients of variation (PCV). Fruit weight (15.462 and 19.865%) had the highest GCV and PCV. High broad-sense heritability was linked to high (H) or moderate (M) genetic advance as a percentage of the mean from stem length (67.606%: H and 21.992%: H), fruit weight (60.586%: H and 24.793%: H), fruit perimeter (76.395%: H and 12.258%: M), and fruit height (69.828%: H and 12.122%: M). The maximum and significant genotypic correlation value was obtained between leaf length and leaf width (r = 1.000). Fruit weight is positively correlated with fruit perimeter (r = 0.940) and fruit height (r = 0.831). According to correlation and path analyses, stem diameter and length, leaf chlorophyll, and fruit perimeter and height were considered variables for fruit weight improvement in the breeding programs. It suggests that the increase in traits with a favorable direct influence on fruit weight may directly contribute to fruit weight.

Leaf spot caused by Cercospora lactucae-sativae is one of the most damaging diseases of ‘Green Oak’ lettuce in Thailand. This study was conducted to estimate the effectiveness of Trichoderma asperellum NST-009, a native strain in Thailand, to manage the leaf spot disease and enhance the growth of ‘Green Oak’ lettuce in a nutrient film technique (NFT) hydroponic system. In vitro tests showed that T. asperellum NST-009 significantly inhibited the mycelial growth of C. lactucae-sativae by 72.50%, and its antifungal metabolite from the culture filtrate of T. asperellum NST-009 inhibited the mycelial growth of C. lactucae-sativae by 93.26%. In the hydroponics experiment, T. asperellum NST-009 reduced the disease severity index by 67.51% compared to the inoculated control and significantly stimulated the growth of the ‘Green Oak’ lettuce in terms of the plant height (8.62%), canopy width (16.67%), leaf number (18.39%), shoot fresh weight (25.71%), root fresh weight (39.26%), and total P in the leaves (31.45%) compared to the control. In addition, T. asperellum NST-009 was found to survive in both the lettuce leaves and roots at 100.00%.

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