Basal temperature and thermal sum in phenological phases of nectarine and peach cultivars

Abstract

-The objective of this work was to evaluate basal temperature, thermal sum at different phenological stages, phenological phase duration, yield and seasonality of one nectarine and 14 peach cultivars, between 2006 and 2009. The considered phenological phases were: pruning-sprouting; sprouting-flowering, from swollen bud to open flower; flowering-fruiting, from petal fall to medium-sized fruit; and ripening. Minimum basal temperatures (Tb) obtained were: pruning-sprouting, 8°C, irrespective of the cultivars; sproutingflowering, 10°C, except for 'Cascata 968', which required 8°C Tb; flowering-fruiting, 12°C, except for 'Oro Azteca', which required 14°C Tb; ripening, 14°C, except for 'Sunblaze', 'Diamante Mejorado' and 'Precocinho' with 12°C Tb. For most cultivars, the maximum basal temperatures were 30, 34, 34 and 28ºC for phases pruning-sprouting, sprouting-flowering, flowering-fruiting and ripening, respectively. 'Turmalina', 'Marli' and 'Tropic Beauty' showed average yields of 3,945.0, 3,969.3 and 3,954.0 kg ha -1 , respectively, in 2009, while the nectarine 'Sunblaze' showed around 3,900 kg ha -1 in 2008 and 2009. The cultivars differed for their total cycle and for the accumulated thermal sums which varied, respectively, from 245 days and 1,881.4 degree-days for 'Oro Azteca', to144 days and 1,455.7 degree-days for 'Precocinho'.Index terms: Prunus persica, degree day, thermal unit. Temperatura basal e soma térmica em fases fenológicas de cultivares de nectarineira e pessegueiroResumo -O objetivo deste trabalho foi avaliar a temperatura basal, a soma térmica acumulada em diferentes fases fenológicas, a duração das fenofases, a produtividade e a sazonalidade do ciclo de uma cultivar de nectarina e de 14 cultivares de pêssego, entre 2006 e 2009. As fases fenológicas consideradas foram: podabrotação; brotação-florescimento, da gema inchada até a flor aberta; florescimento-frutificação, da queda das pétalas até o fruto médio; e maturação. As temperaturas basais mínimas obtidas foram: poda-brotação, 8°C, independentemente das cultivares avaliadas; brotação-florescimento, 10°C, com exceção de 'Cascata 968', que necessitou de Tb de 8°C; florescimento-frutificação, 12°C, exceto 'Oro Azteca', que necessitou de Tb de 14°C; maturação, 14°C, com exceção de 'Sunblaze', 'Diamante Mejorado' e 'Precocinho', com Tb de 12°C. Para a maioria das cultivares, as temperaturas basais máximas foram de 30, 34, 34 e 28ºC, nas fases poda-brotação, brotação-florescimento, florescimento-frutificação e maturação, respectivamente. 'Turmalina', 'Marli' e 'Tropic Beauty' apresentaram produtividade média de 3.945,0, 3.969,3 e 3.954,0 kg ha -1 , em 2009, respectivamente, enquanto a nectarineira 'Sunblaze' produziu em torno de 3.900 kg ha -1 em 2008 e 2009. As cultivares diferiram quanto ao ciclo total e quanto às somas térmicas acumuladas que variaram, respectivamente, de 245 dias e 1.881,4 graus-dia em 'Oro Azteca', a 144 dias e 1.455,7 graus-dia em 'Precocinho'.

Base temperature as a function of genotype: a foundation for modeling phenology of temperate fruit species

“…By taking data from a biological test conducted under controlled conditions, we were able to obtain the results presented in Figures 1 to 5, which faithfully represent the responses of the plants to the air temperature variable, isolated from other factors. The results contrast those described by Richardson et al (1975) Souza et al (2011b), who determined Tb by simulation only using the statistical modeling proposed by Arnold (1959).…”

“…This parameter should be determined experimentally, considering the plants' biological status, rather than referring exclusively to statistical modeling, as in past research by Richardson et al (1975), Spiegel-Roy and Alston (1979), Hidalgo (1980), Morley-Bunker andSalinger (1987), Pedro Junior et al (1994), Rodríguez (1995), Nagata et al (2000), Marra et al (2002), Green (2007), and Souza et al (2011b). In those studies, Tb was based on an estimate, not an actual observation obtained experimentally; i.e., Tb was defined by evaluating the least standard deviation that a temperature, selected a priori, confers to the thermal time of a collection of data from past years/experiments (ARNOLD, 1959).…”

Base Temperature Comparisons for Leafing Date, Pistillate Flower Receptivity, and Pollen Shedding in Persian Walnut

“…This study confirms the findings of other researchers (Baker et al, 1986;Gallagher 1979;Sayed 1995;Stinner et al 1974) that changes in the phenological stages are the best markers for the fruit species for forecasting their behaviour with the increasing outside air temperature; however, there are differences in the base temperature values among the species, cultivars, and phenological states (Borges et al 2017;Kerr et al 1981;Rafael and Biasi 2016;Ribeiro et al 2009;Salinger and Kenny 1995;Souza et al 2011;Taghavi et al 2017). The strongest correlation of the observed phenological data was always on the same threshold values in both countries; in the case of leafing, the best correlation was at Tb5.5.…”

“…Previous studies in pome fruits, stone fruits, and berries showed that the minimum base temperature varied not only by fruit tree species but also by cultivars among species. Studies for determining the base temperatures for growth, sprouting, or leafing of peach and nectarine showed that, for Prunus persica sprouting, the base temperature (Tb) varied from 2.2 °C in 'Tropic Beauty' to 8 °C in 'Sunblaze' nectarine cultivar (Rafael and Biasi 2016;Souza et al 2011). Table 1 contains data for the Tb of phenological stages for several fruit tree species.…”

Comparative in vivo and in vitro study on Monilia fructicola causing brown rot of stone fruit in Brazil and California

“…Therefore, apothecia formation is tied closely to optimum conditions at the time of stone fruit bloom (Ogawa and English 1991). In Brazil, stone fruit is grown in a subtropical climate with mild winters, and transitional subtropical-temperate climate (Herter et al 2002;Caramori et al 2008;Souza et al 2011). The M. fructicola perfect stage is rare in Brazil, and the primary inoculum source is mainly conidia produced on overwintered mummified fruit (Bleicher 1997).…”