Tolerância de frutos de pessegueiro a geadas

Abstract

RESUMO -Este trabalho teve como objetivo avaliar a tolerância de frutos de pessegueiro aos danos ocasionados pela geada. A geada ocorreu no dia 5 de setembro de 2006, sendo que a temperatura mínima, a 1,5 m do solo, foi de -1,06°C. Foram avaliados 28 genótipos de pessegueiro em diferentes estádios fenológicos. O delineamento experimental foi o inteiramente casualizado, com três repetições (plantas de pessegueiro), procedendo-se à avaliação em seis ramos por planta. No dia em que ocorreu a geada, foram mensurados o número de frutos por ramo, diâmetro sutural médio dos frutos, número total de gemas vegetativas, percentual de brotação e percentual de brindilas formadas a partir das gemas brotadas. Uma segunda avaliação foi realizada 15 dias após a primeira, para avaliar o percentual de queda de frutos e o diâmetro sutural médio dos frutos remanescentes. Genótipos bem enfolhados e cujos frutos apresentavam endocarpo endurecido, no momento da ocorrência da geada, foram tolerantes ao dano ocasionado pelo frio; frutos com diâmetro sutural inferior a 20 mm foram suscetíveis à geada, enquanto frutos com diâmetro sutural superior a 30 mm apresentaram boa tolerância, independentemente do genótipo avaliado. Termos para Indexação: danos por congelamento, danos por frio, frutificação, Prunus persica. FRUIT FROST TOLERANCE IN PEACHABSTRACT -The aim of this work was to evaluate the fruit damage tolerance in different peach tree genotypes after natural freeze. The frost happened on September 5, 2006, and the minimum temperature, 1.5 meters over soil, was -1.06°C. Twenty-eight peach tree genotypes, in different stages of development, were evaluated, in a completely random design, in three replication (plants) and six branches by plants. Immediately after frost, we measured the number of fruits per branches, average fruit suture diameter, percentage of sprouts and percentage of twigs in formation. A second evaluation was accomplished fifteen days after the first one in order to assess the percentage of fruit drop and the average remaining fruit suture diameter. Genotypes with good leafing and hard pit (endocarp) during frost have freeze tolerance; fruits with suture diameter lass than 20 mm are susceptible to frost damage, while fruits with suture diameter superior to 30 mm are tolerant.

Harvest season, productivity and physicochemical quality of peach fruits grown in Dois Vizinhos, Paraná State, Brazil

“…Other factors may have contributed to the low yields of some of the peach cultivars evaluated in this study, including the occurrence of frost recorded on 17 and 18 July 2016 and 18 and 19 July 2017 (data not shown). The occurrence and intensity of frost, depending on the phenological stage of the peach trees, can cause abscission of flowers and fruits, especially if it occurs during the initial stage of development (Assmann et al, 2008).…”

INJÚRIAS POR BAIXA TEMPERATURA EM FRUTOS: Um enfoque no uso de tecnologias para retardar as injúrias pós-colheita - Revisão

“…Os açúcares posseum importante papel na resposta ao frio em frutos de banana na aclimatação (AGOPIAN RG et al, 2011). Os efeitos da baixa temperatura podem ser atenuados por meio do desenvolvimento de cultivares resistentes às baixas temperaturas (ASSMAN AP et al, 2008).…”

Genotype-environment interaction on the density of peach buds cultivated in a humid subtropical climate

“…With the obtainment of peach tree cultivars with a low chilling requirement, there has been a reduction in flowering and sprouting heterogeneity. However, problems still persist, such as low fruit set, low fruitification and/ or production irregularity, which could be related to three environmental effects: 1) the occurrence of temperatures above 25 ºC during the pre-flowering period and flowering (in the winter), these cause a delay in the formation of the female gametophyte, causing anomalies in their formation (NAVA et al, 2009;COUTO et al, 2010); 2) The occurrence of elevated temperatures during November/ December, which coincides with the period of induction and floral differentiation in the southern hemisphere, this can cause the formation of blind buds due to the inhibition of floral differentiation, resulting in a reduction in flower bud density (MONET and BASTARD, 1971;BANGERTH, 2006); and 3) the occurrence of frost during the flowering period until the hardening of the endocarp of the fruit (ASSMANN et al, 2008).…”