Rootstocks Influence Yield Precocity, Productivity, and Pre-Harvest Fruit Drop of Mandared Pigmented Mandarin

Marco Caruso,Claudia Pannitteri,Giuseppe Russo,Alessandra Gentile,Giulia Modica,Riccardo Russo,Carmen Arlotta,Alberto Continella,Fabrizio Salonia

doi:10.3390/agronomy10091305

Abstract

Citrus fruit quality and scion productivity are influenced by the choice of rootstock. We aimed to evaluate the effect of rootstocks on yield and fruit quality of Mandared, a triploid pigmented mandarin. To do so, we established a rootstock field trial on a high pH soil (8.6) in which Mandared was grafted onto 11 rootstocks. These included some standard rootstocks, such as trifoliate orange ((Poncirus trifoliata (L.) Raf.), Troyer citrange (Citrus sinensis (L.) Osb. × P. trifoliata), Swingle citrumelo (Citrus paradisi Macf. × P. trifoliata), and C35 citrange (C. sinensis × P. trifoliata), as well as new releases from the Council for Agricultural Research and Economics (CREA, Acireale, Italy) and the University of California Riverside (UCR). The cumulative yield was measured over five consecutive years, while fruit quality was analyzed for two years. The trees on C35, C57 (Citrus sunki Hort. ex. Tan. × P. trifoliata), and C22 (C. sunki × P. trifoliata), started to set fruits one year earlier than the others. The trees on C57 provided some of the highest cumulative yields and canopy volumes. The production of Mandared grafted onto C57 was double that of Mandared grafted onto Troyer, while Mandared grafted onto C35 and C22 resulted in the best yield efficiency. The trees on Swingle and C57 significantly reduced the pre-harvest fruit drop, to which Mandared is particularly sensitive. However, grafting Mandared onto Swingle resulted in the highest variation among replicates, probably due to its high sensitivity to iron chlorosis. Most of the fruit quality parameters, such as fruit size, total soluble solids (TSS), and acidity were not significantly different among the rootstock treatments. However, fruits produced by Mandared grafted onto C22 had one of the highest rates of anthocyanin accumulation. The results indicate that C57, C35, and C22 were the most suitable rootstocks for Mandared in South-Eastern Sicily.

Highlights

Rootstocks are known to affect the performance of many traits of different citrus varieties, including tolerance to biotic and abiotic stresses, fruit quality and size, productivity, ripening period, and yield precocity [1,2]
Most of the citrus fruits in Italy are intended for fresh sale at markets, and fruit quality is of great importance for the produced in Italy are intended for fresh sale at markets, and fruit quality is of great
Six Mandared plants grafted onto F. dragon, five plants grafted onto S. buxifolia, and one plant grafted onto F6P13 died during the first 3–4 years after planting

Summary

Introduction

Rootstocks are known to affect the performance of many traits of different citrus varieties, including tolerance to biotic and abiotic stresses, fruit quality and size, productivity, ripening period, and yield precocity [1,2]. An effect of rootstocks on anthocyanin pigmentation of blood oranges was observed [3]. In the case of pigmented citrus cultivars, an appropriate rootstock choice is essential to produce high quality fruits. Is the second largest European producer of citrus fruits [4]. Most of the citrus fruits in Italy are intended for fresh sale at markets, and fruit quality is of great importance for the produced in Italy are intended for fresh sale at markets, and fruit quality is of great

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