THERMAL REQUIREMENTS OF CITRUS FRUITS GRAFTED ONTO ROOTSTOCKS IN THE LOW-MIDDLE REGION OF THE SÃO FRANCISCO RIVER BASIN

Fádia Samara Santos Nascimento,Jucieny Ferreira De Sá,Pedro Henrique Dias Nascimento,Débora Costa Bastos,Valtemir Gonçalves Ribeiro

doi:10.1590/1983-21252018v31n209rc

Fádia Samara Santos Nascimento, Jucieny Ferreira De Sá + Show 3 more

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https://doi.org/10.1590/1983-21252018v31n209rc

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Abstract

ABSTRACT To understand the production cycle of a particular cultivar in a given region, it is necessary to obtain information related to its phenology and the accumulated degree days. The purpose of this study was to evaluate the phenological cycle of citrus species grafted onto two rootstocks and grown in the Low-Middle Region of the São Francisco River Basin, in particular with respect to accumulated degree days. The experiment was conducted using ‘Rubi’ and ‘Pera D-12’ oranges and ‘Page’ mandarins. Two rootstocks were used, namely ‘Cravo’ and ‘Volkameriano’ lemon species that were drip irrigated in the Campo Experimental de Bebedouro, an experimental field owned by Embrapa Semiárido. ‘Page’ mandarins with ‘Cravo’ or ‘Volkameriano’ rootstocks exhibited a subperiod (0-10) of 183.32 and 181.24 days, respectively. Meanwhile, ‘Pera D-12’ and ‘Rubi’ oranges with ‘Cravo’ rootstocks had values of 249.57 and 178.58 days, respectively, while those with ‘Volkameriano’ rootstocks had values of 226.35 and 200.41 days, respectively. The accumulated degree days were measured from the initial sprouting to harvesting, which took place when the fruits presented a soluble solids/titratable acidity ratio equal to or greater than 12. ‘Page’ mandarins required 2,720 degree days, whereas ‘Pera D-12’ and ‘Rubi’ oranges required approximately 3,390 and 2,280 degree days, respectively. Finally, ‘Pera D-12’ and ‘Rubi’ oranges with either rootstock presented cycles characterized as mid-season and precocious, respectively, while ‘Page’ mandarins had precocious cycles.

Highlights

Brazil ranks first in the worldwide production of both oranges and orange juice, generating approximately 17 million tons in 2017 (IBGE, 2017)
Koller (2006) reported that species cultivated under high temperature conditions exhibit a decreased growth cycle and inferior production with respect to samples grown under lower temperature conditions
The purpose of this study was to evaluate the phenological cycle of citrus species that were grafted onto two rootstocks and grown in the Low-Middle Region of the São Francisco River Basin, with particular focus on accumulated degree days

Summary

Introduction

Brazil ranks first in the worldwide production of both oranges and orange juice, generating approximately 17 million tons in 2017 (IBGE, 2017). The largest subnational producer of oranges is the State of São Paulo, with an estimated production of 12.290 million tons. The Northeast Region of Brazil is the second-largest producer in the country, with a total yield of approximately 1.026 million tons (ANUÁRIO, 2016). Brazil is the third largest producer of mandarin oranges and hybrids, with an estimated yield of 937,819 tons in 2014 (AGRIANUAL, 2016). The São Francisco River Valley region has one of the most favorable climatic and soil conditions for the growth of citrus fruit. This valley provides high-quality products with respect to the local market and is notable for its low occurrence of pests and diseases (PASSOS et al, 2010; ALMEIDA; PASSOS, 2011). This valley provides high-quality products with respect to the local market and is notable for its low occurrence of pests and diseases (PASSOS et al, 2010; ALMEIDA; PASSOS, 2011). Koller (2006) reported that species cultivated under high temperature conditions exhibit a decreased growth cycle and inferior production with respect to samples grown under lower temperature conditions

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