Base temperature, thermal time and phyllochron of escarole cultivation

Abstract

The objective of this study was to determine the base temperature of escarole and to apply in the phenological analysis of crop during four growing periods. The study was carried out with escarole (Chicorium endivia) ‘Escarola Lisa’ cultivar, at the Federal University of Santa Maria, campus Frederico Westphalen-RS. The experiment was performed in a randomized block design with four sowing periods (P1: 2/15/2015; P2: 04/29/2015, P3: 07/22/2015, P4: 10/16/2015) and 10 replicates, each replicate being one plant. The evaluations consisted of counting the number of leaves, performed three times a week after transplanting date until the harvesting point. To determine the base temperature, the following methods were used: standard deviation in degree-days (SDgd), standard deviation in days (SDd), coefficient of variation in degree-days (CVgd), coefficient of variation in days (CVd), regression coefficient (RC) and X-intercept. The base temperature for emission of two successive leaves in the escarole is 4.7°C, obtained by values of 4.0 and 5.5°C, observed in the SDgd and RC methods. For two leaves emission, the temperature between 16.6 and 27.8°C day leaf-1 is necessary.

Cardinal temperatures and thermal requirements for the initial development of two Brazilian native species

“…Because the methods used for estimating base temperatures are statistical, it is usual to have small differences between statistically estimated temperatures and the physiological temperature of each species (Lago et al, 2009;Freitas et al, 2017). Therefore, it is important to verify if the estimated base temperatures are within the temperature ranges observed in the field (Schmidt et al, 2018), and coherent with phenological observations. Given this fact, some methods have been shown to register low and unrealistic base temperature, much lower than those registered in the field (Souza & Martins, 2014); hence, it is customary to exclude values less than or equal to 6.5ºC for tropical climate species (Lago et al, 2009).…”

“…Studies on cardinal temperatures are frequently carried out for annual and biannual cultures due to agricultural interest (Lucas et al, 2012;Luz et al, 2012;Gonçalves et al, 2015;Muttoni et al, 2017;Schmidt et al, 2018), but are practically nonexistent for perennial cultures (Souza & Martins, 2014;Freitas et al, 2017), mainly for tree species native to Brazil. Information on the capacity of a species to adapt to a wide range of environments is of great interest to producers and researchers, since knowledge of cardinal temperatures and thermal requirements values are important for developing and refining optimization strategies to manage and improve both production and its quality, as well as to integrate species that are more adapted to the climactic conditions of cultivation Freitas et al, 2017;Schmidt et al, 2018). Furthermore, this information constitutes important input data for forest management models applied to native forest trees, like gap models and mechanistic ones.…”

Temperatura base e plastocrono de uma variedade de lúpulo

“…Entretanto, os autores obtiveram o maior valor de Tb pelo método do coeficiente de variação (CV gd =15,4°C; SD d = 14,8°C). Segundo Schmidt et al, (2018), a baixa variabilidade da Tb determinada por diferentes métodos demonstra que os mesmos são viáveis para a determinação da Tb das culturas.…”

Climate variables effect on fruiting pattern of Kinnow mandarin (Citrus nobilis Lour × C. deliciosa Tenora) grown at different agro-climatic regions

“…Climate variables like relative temperature disparity (RTD), phototemperature (T p ), nyctotemperature (T n ), relative humidity disparity (RHD), photo relative humidity (RH p ), nycto relative humidity (RH n ), vapor pressure deficit (VPD), photo vapor pressure deficit (VPD p ) and nycto vapor pressure deficit (VPD n ) were calculated from weather data using computation of 30 – 32 , 59 . Relatively humidity recorded at midnight (0000 UTC) and midday (1200 UTC) was used while computing climate variables.…”

“…Similarly, asymmetry in fruiting habits is shown in extreme climate variables 28 by displaying more differences in its magnitude in different regions 29 with more irregularity in warm areas 13 . Climate variables depict phototemperature (Tp), nyctotemperature (Tn), relative temperature and humidity disparities, photo & nycto humidity levels as well as vapor pressure deficit (VPD) by using temperature and relative humidity for these variables computation 30 – 32 are further utilized in plant adoptive behavior, growth and development and survival against erratic weather 33 to predict weather conditions 34 suitability for certain crop in a particular area 35 and finally reproductive span and behavior 36 .…”