Base temperature for leaf appearance and phyllochron of selected strawberry cultivars in a subtropical environment

Abstract

Leaf development is characterized by the appearance of new leaves and is related to crop leaf area index, which affects the interception of solar radiation used for photosynthesis and biomass production and ultimately defines crop yield. The objectives of this paper were to estimate the base temperature for leaf appearance and to determine the phyllochron of two strawberry cultivars considering several planting dates. A two-year field experiment was conducted during 2008 and 2009 in Santa Maria (RS). The cultivars Arazá (early) and Yvapitá (late) were used at three planting dates in both years. Base temperature (Tb) was estimated using the Mean Square Error (MSE) approach of the regression between accumulated leaf number (LN) and accumulated thermal time (ATT). The phyllochron was calculated as the inverse of the slope of the regression of LN against ATT. Estimated Tb for leaf appearance in both cultivars was 0 °C. Variations in phyllochron were observed among the two cultivars, among planting dates and also during the plant developmental period of each cultivar. Before flowering, the phyllochron was similar in both cultivars and after flowering it was higher in cultivar Arazá. Phyllochron was greater for later planting dates and increased at short photoperiods in Fall and Winter. Results showed that both cultivars have a typical longday plant response because phyllochron decreased as photoperiod increased up to approximately 11.8 hours, and phyllochron was the lowest at longer photoperiod.Key words: Fragaria x ananassa, leaf development, plant development, temperature, thermal time.Temperatura-base de emissão de folhas e filocrono de algumas cultivares de morangueiro em ambiente subtropical Resumo O desenvolvimento foliar é caracterizado pelo aparecimento de novas folhas e relacionado com o índice de área foliar da cultura, que afeta a interceptação de radiação solar usada na fotossíntese e produção de biomassa e que, em ultima análise, define a produtividade da cultura. Os objetivos deste trabalho foram estimar a temperatura-base de aparecimento de folhas e determinar o filocrono em duas cultivares de morangueiro em diferentes datas de plantio. Um experimento de campo foi desenvolvido em 2008 e 2009 em Santa Maria (RS). Foram utilizadas as cultivares Arazá (precoce) e Yvapitá (tardia) em três datas de plantio em cada ano. A temperatura-base (Tb) foi estimada pela metodologia de menor Quadrado Médio do Erro (QME) da regressão linear entre o número de folhas acumuladas (NF) e a Soma Térmica acumulada (STa). O filocrono foi calculado pelo inverso do coeficiente angular da regressão linear entre NF e STa. A Tb estimada para o aparecimento de folhas das cultivares foi de 0 °C. O filocrono variou durante o ciclo de desenvolvimento, sendo maior após a floração. Até a floração, o filocrono foi similar nas duas cultivares e após o início do florescimento o filocrono foi maior na cultivar Arazá. O filocrono é maior em datas de plantio mais tardias, durante o outono e o inverno, quando o fotoperíodo é menor, uma ...

The growth and productivity of ‘Festival’ strawberry plants growing in a subtropical environment

“…It was not possible to calculate growingdegree days from the weather data because of the lack of information about the base temperature for the growth of short-day strawberry cultivars growing in subtropical environments. The base temperature of 0°C calculated for leaf appearance of strawberry cultivars in Brazil by Rosa et al (2011) appears too low for a subtropical plant.…”

Phyllochron and leaf appearance rate in oat

“…Phyllochron variability among cultivars was also verified by Clerget et al (2008) and Rosa et al (2009) in wheat and by Pržulj and Momčilović (2013) in barley. Furthermore, in assessing the phyllochron in strawberry, Rosa et al (2011) andMendonça et al (2012) observed differences among cultivars. According to these authors, different results among cultivars are due to genetic differences.…”

“…Studies to determine the phyllochron were performed for crops, such as sorghum (Clerget et al 2008), brachiaria (Santos et al 2009), maize Martins et al 2012), wheat (Rosa et al 2009;Mohamed et al 2013;Pržulj and Momčilović 2013), and strawberry (Rosa et al 2011;Mendonça et al 2012). Researches for determination of leaf appearance rate were carried out for the crops brachiaria (Santos et al 2009;Paciullo et al 2008), maize (Streck et al 2010), and wheat (Mohamed et al 2013).…”

Yield and Quality Performance of Italian and American Strawberry Genotypes in Brazil

“…The base temperature (Tb) is defined as the daily thermal time units above a lower base temperature, below which the plant does not grow or its development is so slow that it can be ignored (Rosa et al, 2011), for the strawberry evaluation a 7 °C as a base temperature (Mendonça et al, 2012).…”