Pseudomonas syringae pv. tomato, the bacterial agent for tomato speck disease, can cause serious epidemics with high leaf moisture, mild temperatures, and cultural practices allowing bacterial dissemination among host plants. Boron is an essential micro-nutrient for plant growth and health in agricultural production. In this study, the effectiveness of 14 different Boron compounds at 5 different doses (1, 5, 10, 20 and 40 mM) against P. s. pv. tomato at a concentration of 108 CFU ml-1 in vitro was evaluated and the most successful 4 different Boron compounds (Ammonium tetrafluoroborate, Sodium tetrafluoroborate, Zinc borate and Disodium octaborate tetrahydrate) were coated with 5 mM doses infected cv. H2274 tomato seeds to determine bacterial populations and seed emergence rates in the seeds. Among the 14 different Boron compounds used in the experiments, Disodium octaborate tetrahydrate was the most successful active ingredient 92% ratio in inhibiting P. s. pv. tomato populations in tomato seeds, while 39% success was achieved with sodium tetrafluoroborate applications. According to the results of the research, it is thought that some Boron compounds can be an economical, effective and environmentally friendly chemical in reducing P. s. pv. tomato in tomato seeds within the scope of good agricultural practices.

Se evaluó una población de medios hermanos (B1PD280) proveniente del cruzamiento del parental resistente al deterioro fisiológico poscosecha (DFP) CW429-1 (Manihot esculenta x M. walkerae), y ocho genotipos élite utilizados como padres recurrentes susceptibles. Se evaluaron cinco raíces por genotipo, 7 y 14 días después de la cosecha (d.d.c.) mediante una escala (0 - 100%). Los resultados mostraron reducción significativa de DFP (entre 10% y 46% en relación con los parentales recurrentes). Cincuenta y un genotipos tuvieron alto y medio nivel de resistencia (0 - 35%), 22% y 20% de ellos correspondieron a individuos sin síntomas 7 o 14 d.d.c., respectivamente. Se estableció una posible correlación entre DFP (14 d.d.c.) y escopoletina (0.523, P < 0.001) y materia seca (0.288, P < 0.001). | The accelerated Physiological Postharvest Deterioration (PPD) process limits the potential of cassava crop, diminishing its palatability and commercial value within 24-72 hours after harvest. A source of genes for drastic delay of PPD was identified in an inter-specific hybrid (CW429-1) between Manihot esculenta (cultivated cassava) and Manihot walkerae. The aim in this study was to evaluate the introgression of the resistance to PPD from the donor parent CW429-1 in cassava. A half-sib (BIPD280) population from resistant parental CW429-1 and 8 elite CIAT genotypes, used as susceptible recurrent parents, was developed and evaluated. The method proposed by Wheatley et al. (1985), with some modifications was used to quantify PPD. Five roots per genotype were evaluated 7 and 14 days after harvest (DAH), following a scale (0 - 100%), other relevant traits were evaluated. Results showed significant reduction of PPD (between 10-46% of PPD in relation to the recurrent parents). About 51% of genotypes were found to have high to medium level of resistance (0-35% PPD) of which 22 and 20% genotypes correspond to individuals without PPD after 7 and 14 DAH, respectively. A positive correlation was found between PPD (14 DAH) and scopoletin (0.523, p<0.001), and with dry matter (0.288, p<0.001). These preliminary results indicated that the scheme for introgressing PPD resistance was successful, that confirm the potential of the wild cassava in the scheme of cassava breeding.