Cucurbits are important economic crops worldwide. However, the cucurbit leaf curl disease (CuLCD), caused by whitefly-transmitted begomoviruses constrains their production. In Southeast Asia, three major begomoviruses, Tomato leaf curl New Delhi virus (ToLCNDV), Squash leaf curl China virus (SLCCNV) and Squash leaf curl Philippines virus (SLCuPV) are associated with CuLCD. SLCuPV and SLCCNV were identified in Luzon, the Philippines. Here, the genetic diversity and geographic distribution of CuLCD-associated begomoviruses in the Philippines were studied based on 103 begomovirus detected out of 249 cucurbit samples collected from 60 locations throughout the country in 2018 and 2019. The presence of SLCCNV and SLCuPV throughout the Philippines were confirmed by begomovirus PCR detection and viral DNA sequence analysis. SLCuPV was determined as a predominant CuLCD-associated begomovirus and grouped into two strains. Interestingly, SLCCNV was detected in pumpkin and bottle gourd without associated viral DNA-B and mixed-infected with SLCuPV. Furthermore, the pathogenicity of selected isolates of SLCCNV and SLCuPV was confirmed. The results provide virus genetic diversity associated with CuLCD for further disease management, especially in developing the disease-resistant cultivars in the Philippines as well as Southeast Asia.

Pepper yellow leaf curl Thailand virus (PepYLCTHV) causes leaf curl disease in chili production regions of the tropics and subtropics. Information on PepYLCTHV disease severity and resistance in chili pepper is still limited in Thailand. This study reports PepYLCTHV disease severity through graft inoculation and selection of single resistant plants for use in a chili breeding program. Twenty-one chili genotypes consisting of the local cultivar (5) collected from Thailand, breeding lines (9) developed at Khon Kaen University (KKU), Thailand and improved lines (7) obtained from the World Vegetable Center, Taiwan were used in this study. Forty-five-day-old seedlings of all the genotypes were graft inoculated with PepYLCTHV in a randomized complete block design (RCBD) with three replications and 10 plants per replication and kept in a plastic net house. Disease symptoms were scored at 20, 27, 34, 41 48, and 55 days after graft/inoculation (DAI). Disease severity was visually recorded using 0-5 scores. Results showed that the disease severity of 21 chili genotypes significantly differed at 48 days after grafting. High resistance and stability were shown by 9853-123 genotypes. Two genotypes, PSP11-7 and PSP11-10-1, showed resistant reaction with disease severity scores of 1.9 and 1.8, respectively. However, among 21 chili genotypes or 630 grafted plants, 302 plants were successfully grafted inoculated plants. Therefore, from the results of this work, highly resistant plants (69 single plants) can be selected, selfed and advanced for breeding.

The use of biostimulants derived from protein hydrolysates (PH) is now recognized as an effective strategy to promote sustainable vegetable production. This study aimed to evaluate the effects of the foliar application of PH derived from hempseed press cakes on Red Oak lettuce cultivated under greenhouse conditions. Foliar applications of PH at concentrations ranging from 0% to 7.5% (w/v) were compared with water (control) and a commercial product (Germinate^®), applied weekly until 35 days after transplanting (DAT). Growth parameters, including plant height, plant width, leaf number, and leaf length and width, were recorded at 14 DAT and subsequently recorded weekly until harvest. Moreover, the fresh and dry weight, chlorophylls, mineral contents, antioxidants, and their activities in the harvested plants were determined. The results showed the positive effects of the hempseed press cake-derived PH on growth, yield, mineral contents, antioxidants, and antioxidant activities. In particular, the foliar application of PH at a concentration of 7.5% (w/v) is recommended to improve the yield and nutritional values in Red Oak lettuce. This study reports the first detailed research on the use of PH derived from hempseed press cakes for lettuce and may offer a sustainable alternative for vegetable production.

Chili peppers (Capsicum annuum L.) are an economically important crop worldwide. Pepper yellow leaf curl Thailand virus (PepYLCTHV), a Begomovirus causing yellow leaf mosaic disease of chili pepper, has been reported to incur 95% economic loss under epiphytotic conditions. Thirty-one chili genotypes were screened for resistance to PepYLCTHV disease through inoculation using 10–15 viruliferous whiteflies per plant. We purified two resistant lines (PEP6 and PEP12) through four generations of selfing and selection. At 28 days after inoculations, two chili genotypes (PEP6 and PEP12) had low disease severity and percentage of disease incidence (DI) compared to four susceptible checks, viz., Yodsonkeam80, Homsupan, Huareau12, and Pong Charian, which had a disease severity score of 5 with 100% DI. Thirty initial plants of PEP6 showed an average disease severity of 3.64 with 69.33% DI, and PEP12 showed an average disease severity of 3.83 with 77.67% DI. From these populations, we selected nine highly resistant plant of PEP6 and seven plants of PEP12 having a disease severity of 0 through pure-line selection for four selfing generations. The ratio of resistance (R) to susceptibility (S) consequently decreased. In PEP6, the ratio decreased from 1R:2S to 1R:1S, while in PEP12 the ratio decreased from 1R:3S to 1R:1S. These lines have potential for release as resistant lines for improving chili pepper resistance to PepYLCTHV and for developing makers associated with the resistant trait.

Chili peppers (Capsicum annuum L.) are economically important crop worldwide. Pepper yellow leaf cure Thailand virus (PepYLCTHV), a Begomovirus causing yellow leaf mosaic disease of chili pepper has been reported to damage 95% economic loss under favorable epidemic conditions. Thirty-one chili genotypes were screened for resistance to PepYLCTHV disease through challenge inoculation using 10-15 viruliferous whiteflies per plant. We purified two resistant lines (PEP6 and PEP12) through four generations of selfing and selection through challenged inoculations. At the 28 days after inoculations two chili genotypes showed symptoms less based on disease severity and percentage of disease incidence of 30 plants PEP6 showed a disease severity 3.64 with 69.33 % DI and PEP12 showed a disease severity 3.83 with 77.67 % DI. PEP6 and PEP12 were selected for pure-line development for four cycles.Both varieties showed an increase in percentage of the resistant plant 12.78 % and 16.77 %, respectively. These lines have potential for release as resistant lines for improvement chili pepper resistance to PepYLCTHV and for developing maker associated with the resistant trait.