Baseline Sensitivity of Alternaria alternata and A. arborescens to Natamycin and Control of Alternaria Rot on Stored Mandarin Fruit

Alternaria rot caused by Alternaria alternata and A. arborescens is one of the major postharvest diseases on mandarin fruit in California. In this study, natamycin, a newly registered biofungicide, was evaluated for its potential as a postharvest treatment to control Alternaria rot on mandarin fruit. The baseline sensitivities of A. alternata and A. arborescens to natamycin were determined. EC50 values of natamycin for 70 A. alternata isolates ranged from 0.694 to 1.275 µg/ml (mean = 0.921 µg/ml) in a conidial germination assay, and from 2.001 to 3.788 µg/ml (mean = 2.797 µg/ml) for 40 A. alternata isolates in a mycelial growth assay. EC50 values of natamycin for 30 A. arborescens isolates ranged from 0.698 to 1.203 µg/ml (mean = 0.923 µg/ml) in a conidial germination assay, and from 2.035 to 3.368 µg/ml (mean = 2.658 µg/ml) for 20 A. arborescens isolates in a mycelial growth assay. Control tests on detached mandarin fruit showed that natamycin at both low (460 µg/ml) and high recommended rates (920 µg/ml) significantly reduced disease incidence and severity on mandarin fruit inoculated with Alternaria isolates, regardless of species. High rate of natamycin significantly reduced disease incidence and severity compared to the non-treated control even when natamycin treatment was delayed for 6, 12, and 18 hours after inoculation. Our results suggested that natamycin can be an effective postharvest fungicide for control of Alternaria rot on mandarin fruit.

Impact of the Application of Landfill Leachate on the Germination of Senna macranthera in Different Substrates

Landfill leachate is a potential environmental pollutant. Physicochemical analyses allow identifying its elements while the use of ecotoxicological tests aims to understand the relation with the environment. The germination assay of Senna macranthera in different substrates (filter paper, commercial-SCM, conventional-SCV and organic-SOR) was performed with different doses of leachate. The objective was to identify the potential impact of leachate by determining the concentration able to cause inhibition in 50% of the seeds (LC50) and the values of the no observable effect concentration (NOEC) and the lowest observed effect concentration (LOEC). The LC50 and LOEC occurred in the treatments with 6.25 while NOEC was with 3.125%. The test in substrates, It was not possible to identify the LC50 in the SCM. For the SCV was with 66 and in SOR with 25%. The NOEC and LOEC for SCM and SCV were 25 and 50% and in SOR with 50 and 100%.

EVALUATION OF SULFURIC ACID, BARIUM CHLORIDE, AND SEED GERMINATION ASSAY METHODS AS EARLY PREGNANCY DETECTION INSTRUMENTS IN CATTLE

This study aims to validate and re-evaluate the use of H2SO4, BaCl2, and seed germination assay (SGA) methods to detect early pregnancy in cattle. Validation was carried out in order to find out the actual test performance value, which include accuracy, sensitivity, and specificity.Validation test was done by reacting the urine of pregnant and non-pregnant cattle populations with H2SO4 solution diluted at a ratio of 1 : 4, with 1% BaCl2 solution or through germination of mung bean seeds in Petri dishes. The results of this study indicated that the H2SO4 and BaCl2 methods have poor accuracy (21.88% and 28.13%) with the sensitivity of 81.82% and 100% and specificity of 9.43% and 13.21%, respectively. Meanwhile, the SGA method had a fairly good accuracy (74.55%) with sensitivity and specificity of 45.46% and 81.82%, respectively. Based on these results, the H2SO4, BaCl2, and SGA methods are not recommended for detection of early pregnancy in the field.

Development and Optimization of a Germination Assay and Long-Term Storage for Cannabis sativa Pollen

Pollen viability and storage is of great interest to cannabis breeders and researchers to maintain desirable germplasm for future use in breeding or for biotechnological and gene editing applications. Here, we report a simple and efficient cryopreservation method for long-term storage of Cannabis sativa pollen. Additionally, the bicellular nature of cannabis pollen was identified using DAPI (4′,6-diamidino-2-phenylindole) staining. A pollen germination assay was developed to assess cannabis pollen viability and used to demonstrate that pollen collected from different principal growth stages exhibited differential longevity. Finally, a simple and efficient method that employs pollen combined with baked whole wheat flour and subsequent desiccation under vacuum was developed for the long-term cryopreservation of C. sativa pollen. Using this method, pollen viability was maintained in liquid nitrogen after four months, suggesting long-term preservation of cannabis pollen.

Development and optimization of a germination assay and long-term storage for Cannabis sativa pollen

Pollen viability and storage is of great interest to cannabis breeders and researchers to maintain desirable germplasm for future use in breeding or for biotechnological and gene editing applications. Here, we report a simple and efficient cryopreservation method for long-term storage of Cannabis sativa pollen. Additionally, we have deciphered the bicellular nature of cannabis pollen using DAPI staining. We have also standardized a pollen germination assay to assess the viability of cannabis pollen, and found pollen collected from different principal growth stages exhibits different longevity. Finally, we developed a long-term storage method which includes pollen combination with baked whole wheat flower and desiccation under vacuum for cryopreservation. By using this method, we were able to maintain germination viability in liquid nitrogen after 4 months, suggesting potentially indefinite preservation of cannabis pollen.

Early Seedling Growth as a Tool to Assess the Tolerance of Urochloa brizantha Cultivars to Free Aluminium

In this study we aimed to evaluate changes in germination, early seedling growth, and some biochemical parameters in Urochloa brizantha cultivars (Basilisk, Marandu, MG4, MG5, BRS Piatã, and Xaraés) subjected to five levels of free aluminium toxicity (0, 1, 2, 4, and 8 mmolc dm³ Al³+), and to verify the selection efficiency of aluminium tolerant cultivars. In the germination assay, lots were submitted to germination under simulated stress conditions in the laboratory, to quantify root protrusion, number of normal seedlings, shoot and root length, and dry mass. In the early seedling growth assay, evaluations were done on the seventh day after subjecting seedlings to aluminium stress conditions. Relative growth rate of length, and dry mass of shoots and roots, superoxide dismutase activity (SOD), and concentrations of proline, total antioxidants (TEAC), and malondialdehyde (MDA) were evaluated. During the seedling study period, up to 14 days after sowing, the most tolerant cultivar maintained root growth in aluminium stress conditions, while the most susceptible cultivar reduced root growth, and developed proportionally more shoots, as shoot growth depends on seed reserves. The germination assay indicated interference of the initial seed quality with increasing Al3+ concentrations. The results indicate that the early seedling growth assay, which excluded germination effects, and used the measurement of root attributes, is appropriate for the discrimination of Al3+ tolerant genotypes. The Marandu cultivar was the most similar to the Al3+ tolerance standard Basilisk cultivar.