Productive performance of ‘Pera’ sweet orange grafted onto 37 rootstocks in tropical cohesive soils under rainfed condition

Abstract

• Cumulative fruit yield was decisive for identify promising rootstocks to ‘Pera’;. • Rangpur, Volkamer x Rangpur, Maravilha Sunki and Indio induced higher yield to ‘Pera’;. • Florida Sunki x citrange 13–012 and Sunki x Swingle-041 perform similar to Rangpur. • The citrus rootstocks induced no significant change on the fruit's quality. In tropical cohesive soils of Brazil, ‘Rangpur’ lime provide high fruit yield to ‘Pera’ sweet oranges. However, the predominance of a single rootstock puts the citrus industry in this region at risk. To identify promising rootstocks for diversification of ‘Pera’ sweet orange orchard's in the tropical cohesive soils of Brazil, a trial was established with 37 citrus rootstocks on the northeast coast of Brazil. The horticultural performance, fruit yield up to the tenth year, and physic-chemical fruit quality attributes were evaluated. The rootstocks induced changes in the tree size, cumulative fruit yield fresh mass and size of fruit, but had not significant influence on chemical fruit quality. The Hierarchical Cluster Analysis allowed group rootstocks into three classes, in which the accumulated fruit yield was the attribute that most contributed. A group with 15 rootstocks was chosen due to the best productive performance and fruits with 193.75–218.5 g, 57.36–62.65% of juice with 9.85–13.08° brix, which meets the requirement of the Brazilian market. Among these 15, the hybrid of ‘Volkamer’ lemon (VKL) with ‘Rangpur’ lime (RL), ‘Maravilha Sunki’ mandarin, ‘Indio’ citrandarin and the local selection of RL stood out by inducing the highest yield . VKL × RL – 030 produced fruits later, but favored the highest fruit yield at the tenth year. Trees grafted on these four rootstocks and also onto RLCNPMF, TSKC × CTQT1434 – 001, MXWL × LHA – 004, ‘Santa Cruz’ Rangpur, ‘San Diego’ citrandarin,– 004 and trifoliate TRH-208 had greater production regularity across the harvests, although the last three showed lower cumulative yield. The earliest fruit bearing was induced by TSKFL × CTC13 – 012, followed by the ‘Sunki' mandarin hybrids TSKC × CTQT1434 – 001, RL, TSKC x TRFD -007 and TSKC x CTSW-041. It is concluded that the most promising rootstocks for diversification of citrus orchards under rainfed condition on the northeast coast of Brazil are VKL x RL-030, ‘Maravilha Sunki’ , ‘Indio’, TSKFL × CTC13 – 012 and TSKC × CTQT1434 – 001, RLCNPMF – 004, TSKC x TRFD -007, TSKC x CTSW-041 and MXWL × LHA – 004.