Phylogeny and Identification of Pantoea Species Associated with Bulb Rot and Bacterial Leaf Blight of Onion Crops in Uruguay.

Onion is among the most consumed vegetables in Uruguay, grown in the northwestern and southern regions of the country. The onion supply presents interannual variations associated with significant postharvest losses, mainly caused by bacterial rots. Besides bulb rotting, onion leaf lesions as well as infections on seed-stalks during seed production may be devastating for some varieties under conducive conditions. This research aimed to identify the causal agents of bulb rots and leaf blight of onion crops in Uruguay. Symptomatic bulbs, seeds-stalks, and leaves were collected from commercial fields from 2015 to 2020. Bacterial colonies were isolated and identified at genera level using physiological tests and 16S rRNA gene sequence analysis. A collection of 59 Pantoea spp. isolates was obtained (11 from bulbs and 48 from leaves and seeds-stalks). Multilocus sequence analysis using four housekeeping genes (rpoB, gyrB, leuS, and fusA) allowed the assignment of the isolates to five Pantoea species: P. ananatis, P. agglomerans, P. allii, P. eucalypti, and P. vagans. The last two species were not previously reported as onion pathogens elsewhere. The ability to cause disease symptoms was tested by leaf inoculation and red onion scale assays. P. ananatis isolates showed the highest aggressiveness in both assays. Specific isolates from P. allii (MAI 6022), P. eucalypti (MAI 6036), P. vagans (MAI 6050), and Pantoea sp. (MAI 6049) ranked second in aggressiveness on onion leaves, whereas only three isolates belonging to P. eucalypti (MAI 6036 and MAI 6058) and P. agglomerans (MAI 6045) exhibited the same scale-clearing phenotype as P. ananatis. Leaf inoculation assays were also performed on a set of eight onion cultivars and breeding lines. Overall, P. ananatis MAI 6032 showed the highest aggressiveness in all tested cultivars, followed by P. eucalypti MAI 6036. The presence of new reported bacterial species leads to complex disease management and highlights the need for further studies on virulence factors and the epidemiology of these pathogens.

Integrating consumer perception in the selection of purple-skin sweet potato cultivars.

BACKGROUND: Sweet-potato breeding programs need to integrate sensory characterization and hedonic perception to provide global markets with widely accepted products. The present work aimed to characterize a series of purple-skin sweet potatoes differing in flesh coloration (from pale yellow to slight orange) from a sensory and physicochemical perspective. Uruguayan consumers' perceptions of the genotypes were also explored. Special focus was placed on the influence of flesh color on consumers' expectations and hedonic perception of purple-skin sweet potatoes. RESULTS: Sensory characterization based on projective mapping showed that the evaluated genotypes largely differed in their sensory characteristics in terms of flavor, texture, and color. Soluble solids and the concentration of individual sugars were not good predictors of sensory quality. In the appearance evaluation, consumers associated orange flesh with positive expected sensory characteristics and stronger liking. Flavor (sweetness and typical flavor) and texture (creaminess) were identified as key characteristics influencing consumers' liking and description of sweet-potato samples. Among purple-skin ('criollo or boniato' type) genotypes, INIA Cambará was identified as the closest to the ideal sweet potato and was described with the terms sweet, tasty, creamy, and characteristic flavor. CONCLUSION: Flesh color was identified as a key driver of consumers' sensory and hedonic expectations. Results showed that Uruguayan consumers positively value traditional purple-skin sweet potatoes with orange flesh, as it drives positive sensory expectations. However, after tasting, flesh color does not seem to have a relevant influence on consumer liking.

Selection of promising sweet potato clones using projective mapping.

BACKGROUND: Increasing demand for sweet potato in regions with temperate climates has triggered interest in the development of new cultivars. Breeding of this crop should consider sensory characteristics in order to meet consumers' expectations. This requires the application of simple and cost-effective methodologies that allow quality evaluation from a sensory perspective. RESULTS: With the objective of identifying the key sensory characteristics of different sweet potato genotypes, two commercial cultivars and seven clones were evaluated during three consecutive years using projective mapping by an untrained consumer panel. This methodology allowed the discrimination of the genotypes, identifying similarities and differences among groups based on sensory terms selected by the assessors. Genotypes were differentiated in terms of texture and flavor characteristics (firmness, moisture, smoothness, creaminess, flavor intensity, sweetness and bitterness). Materials for future crossings were identified. CONCLUSIONS: The evaluation of the sensory characteristics of sweet potato clones and cultivars using projective mapping is a quick, cost-effective and reliable tool for the selection of new advanced sweet potato clones with superior sensory characteristics compared to the reference cultivars INIA Arapey and Cuarí. © 2016 Society of Chemical Industry.

Evaluation of the sensory characteristics of strawberry cultivars throughout the harvest season using projective mapping.

BACKGROUND: Strawberry breeding programs should be able to rely on valid and simple methodologies for evaluating sensory quality of new cultivars. In this context, the aim of the present work was to evaluate the applicability of a simple sensory methodology, named projective mapping, to evaluate the sensory characteristics of strawberry cultivars and advanced selections throughout the harvest season. Three strawberry cultivars and two advanced selections were evaluated by an untrained assessor panel using projective mapping in three different moments of the harvest season: June (early season), August (mid-season) and September (peak harvest). Instrumental measurements were also performed. RESULTS: Projective mapping enabled the identification of the main sensory characteristics of the strawberry cultivars and advanced selections, as well as the similarities and differences among them. Sensory characteristics of the five evaluated strawberry cultivars and advanced selections largely varied throughout the harvest season. Simple instrumental measurements were not able to predict the sensory characteristics of the strawberry cultivars, suggesting the importance of sensory methodologies for the evaluation of new cultivars in breeding programs. CONCLUSIONS: Projective mapping consisted of a quick alternative for the evaluation of new cultivars relative to standard commercial cultivars. Its main advantage is that a large number of cultivars can be screened with minimal investment of time and resources.

Application of a check-all-that-apply question for the evaluation of strawberry cultivars from a breeding program.

BACKGROUND: Traditionally, breeding research has been focused on increasing yield and fruit size, improving resistance to diseases, behaviour during transport and increasing postharvest shelf-life. However, consumers' liking is one of the biggest challenges for strawberry breeding programs. In this context, the aim of the present work was to evaluate the application of a check-all-that-apply (CATA) question to study consumers' perception of new strawberry cultivars. RESULTS: Average liking scores were low for a highly appreciated product like strawberries, which could be explained considering unfavourable weather conditions prior to harvest. However, despite the small differences in overall liking scores, significant differences were found in the frequency in which 14 out of the 22 terms of the CATA question were used to describe samples. This suggests that the evaluated CATA question was able to detect differences in consumers' perception of the sensory characteristics of the evaluated cultivars. Moreover, a significant correlation was found between laboratory analyses (firmness, colour, soluble solids and acidity) and consumers' responses to the CATA question, which indicates their validity. CONCLUSIONS: Considering results from the present study, the use of CATA questions could be a simple and interesting methodology to gain insight into consumers' perception of different fruit cultivars.