RESUMO O presente estudo objetivou avaliar a curva de crescimento das plantas de duas novas cultivares de batata, para melhor conhecer a dinâmica do desenvolvimento das plantas ao longo do ciclo de crescimento vegetativo, e para subsidiar eventuais estratégias diferenciadas de manejo. Os experimentos de campo foram conduzidos em Canoinhas-SC, e Pelotas-RS, na primavera de 2019. Foram avaliadas as novas cultivares de batata BRS F50 - Cecília e BRS F183 - Potira, e a cultivar testemunha amplamente cultivada no país, Asterix. O delineamento experimental foi em blocos completos casualizados com quatro repetições de parcelas compostas por 43 plantas úteis, mais bordaduras. Coletas destrutivas de quatro plantas por parcela foram realizadas aos 28, 42, 56, 70, 84, 98 e 112 dias após o plantio. Foram avaliados caracteres morfoagronômicos ao longo do ciclo da cultura, e ao final, com a colheita de 15 plantas por parcela, foi realizada a determinação da produtividade de tubérculos. Cecília apresentou maior desenvolvimento da parte aérea das plantas e também elevada produtividade de tubérculos. Potira também apresentou boa produtividade de tubérculos, mas ciclo de desenvolvimento das plantas mais tardio, necessitando de estudos mais específicos sobre o manejo diferenciado considerando esta característica. Foi verificado ainda que, em geral, os genótipos com maior desenvolvimento da parte aérea foram mais produtivos. No entanto, nesta análise não se pode considerar apenas os caracteres relacionados à produção de folhas ou mesmo a área foliar, mas a estrutura das plantas como um todo, incluindo o desenvolvimento das hastes.

ABSTRACT The present study aimed to evaluate the plant growth curve of two new potato cultivars, to better understand the dynamics of the plant development throughout the growth cycle, and to subsidize management strategies. Field experiments were carried out in Canoinhas-SC, and Pelotas-RS, in the spring 2019. The new potato cultivars BRS F50 - Cecília and BRS F183 - Potira were compared with the standard cultivar widely grown in the country, Asterix. The experimental design was randomized complete blocks with four replications of plots composed of 43 useful plants, plus borders. Destructive samples of four plants per plot were carried out at 28, 42, 56, 70, 84, 98, and 112 days after planting. Morpho-agronomic characters were evaluated throughout the crop cycle, and the determination of tuber yield was done at its end, harvesting 15 plants per plot. Cecília presented a great development of the aboveground plant parts, and a high tuber yield. Potira also showed a good tuber yield, but was late in the plant development cycle, requiring specific studies on differentiated management of this character. In general, genotypes with a greater development of the aboveground plant parts are more productive, however, in this analysis it is not possible to consider only characters related to the leaf production or even the leaf area, but the plant structure as a whole, including stem development.

ABSTRACT Grafting has been increasingly used to overcome soilborne pathogens. The commercial rootstock hybrids AF-8253 (Sakata) and Fortaleza (Takii), as well as Embrapa’s new hybrid, BRS Acará, were evaluated as rootstocks for the bell pepper hybrids Margarita (Syngenta) and Pampa (Clause) as scions, under natural infestation of Ralstonia pseudosolanacearum, as well as upon artificial inoculation with a) ten Ralstonia isolates, b) one Phytophthora capsici isolate, c) Meloidogyne incognita race 1, and d) Meloidogyne enterolobii (only rootstocks for c and d). Grafted bell peppers consistently showcased a higher productivity than did non-grafted ones under natural R. pseudosolanacearum infestation, and the rootstock genotype affected fruit size distribution. Rootstocks presented higher resistance than did commercial bell pepper hybrids (scions) for 6 out of 10 Ralstonia isolates. AF-8253 and BRS Acará displayed an immune-like response to P. capsici, while Fortaleza was moderately resistant (25% symptomatic plants) and the bell pepper hybrids (scions) were susceptible (100% symptomatic plants). Rootstocks were immune to M. incognita race 1, but slightly (AF-8253 and BRS Acará) or moderately (Fortaleza) resistant to M. enterolobii. Grafting with BRS Acará, as well as with AF-8253 or Fortaleza, is recommended for managing bacterial wilt, Phytophthora blight, and root-knot nematodes.

Abstract Brazilian potato production is based on cultivars originating from the USA and Europe; however, these cultivars were developed under different environmental conditions than those found in Brazil. The aim of this study was to evaluate the adaptability and stability of 18 potato clones (MLG), developed by the Universidade Federal de Lavras, and four cultivars in six environments in the state of Minas Gerais, Brazil. The following traits were evaluated: marketable tuber yield (MTY), specific gravity (SG), and tuber appearance (TA). Clones, environments, and the genotype × environment interaction had significant effects on all traits. The GGE-biplot explained 71.78, 98.13, and 62.86 % of the sum of squares from the G+G×E for MTY, SG, and TA, respectively. Three MLG clones had higher adaptability and stability, as well as better performance, than the cultivars, making them good candidates for release as cultivars.

Abstract: There is evidence of a relationship between the development of the initial fruits and the abortion of reproductive structures in upper nodes of Capsicum annuum (paprika, pepper), which makes its harvest difficult in continuous production systems. In this study, the effect of the sink size during fruiting, growth rate of fruits and rate of CO2 assimilation (A) on three flower removal intensities treatments was evaluated. At the same time, photosystem II (PSII) photochemical activity and fruit growth (size and biomass) were evaluated. The experimental design was completely randomized, with three replications and 16 plants per experimental unit. The maximum flower removal (up to the third flower node) increased fruit diameter, length, fresh weight and dry weight (p≤0.05) compared to the other two treatments (flowers removed at the first or second node). A minimum percentage of fruit with less than 100 g weight was obtained under the same condition. According to A and the photochemical activity, leaf age determines photosynthetic efficiency. The relationship of the latter with the development state of the fruit is not straightforward.

Resumen: En Capsicum annuum (pimentón, pimiento) existen evidencias de una relación entre el desarrollo de los frutos iniciales y el aborto de estructuras reproductivas en nudos superiores, lo cual dificulta la cosecha continua en sistemas de producción. En este estudio se evaluó el efecto de la magnitud de la fuerza de la demanda de asimilados en la fructificación, tasa de crecimiento del fruto y tasa de asimilación de CO2 (A) con tres intensidades de eliminación de flores. Al mismo tiempo, se evaluó la actividad fotoquímica del fotosistema II (PSII) y crecimiento de los frutos (dimensiones y biomasa). El diseño experimental fue completamente aleatorizado, con tres repeticiones y unidades experimentales de 16 plantas. La eliminación máxima de flores (hasta la tercera flor) produjo frutos con diámetro, longitud, peso fresco y peso seco mayor (p≤0.05) que los otros dos tratamientos (eliminación de flores en el primer nudo o hasta el segundo nudo). En esa misma condición se obtuvo el porcentaje mínimo de frutos con peso menor a 100 g. Según la A y la actividad fotoquímica, la edad de la hoja determina la eficiencia fotosintética. La relación de esto último con el estado de desarrollo de los frutos no es directa.