Screening of citrus scion-rootstock combinations for tolerance to water salinity during seedling formation

Marcos Eric Barbosa Brito,Janivan Fernandes Suassuna,Hans Raj Gheyi,Walter Dos Santos Soares Filho,Pedro Dantas Fernandes,Lauriane Almeida Dos Anjos Soares

doi:10.4025/actasciagron.v43i1.48163

Abstract

Arid and semiarid regions are vulnerable to water deficits and salinity. Citrus plants are sensitive to saline stress and require the use of tolerant scion-rootstock combinations. Thus, this study aimed to evaluate and classify citrus scion-rootstock combinations with respect to their tolerance to salinity during seedling formation in a protected environment. An experiment was conducted in a randomized block design with a 5 x 12 x 2 factorial scheme corresponding to five levels of water salinity (0.8, 1.6, 2.4, 3.2, and 4.0 dS m-1) applied in 12 citrus rootstocks grafted with two scion varieties: ‘Tahiti’ acid lime and ‘Star Ruby’ grapefruit. The scion-rootstock combinations were evaluated for accumulated dry matter and survival index at 330 days after sowing the rootstocks. Salinity exerted different effects on the dry matter formation of scion-rootstock combinations. ‘Star Ruby’ was less sensitive to salinity, particularly when the rootstocks were the hybrids from ‘Sunki of Florida’ mandarin (TSKFL) with ‘Troyer’ citrange (CTTR) – 013 (TSKFL x CTTR – 013), common ‘Sunki’ mandarin (TSKC) with ‘Argentina’ citrange (CTARG) – 019 (TSKC x CTARG – 019), TSKC with ‘Swingle’ citrumelo (CTSW) – 031 (TSKC x CTSW – 031), and the trifoliate hybrid (HTR) - 069, as well as the varieties Volkamer lemon and Santa Cruz Rangpur lime. When grafted with ‘Tahiti’ acid lime, the rootstocks displaying the less sensitive to salinity were TSKFL x CTTR - 013 and TSKC x CTARG - 019.

Highlights

Citrus are very important fruit crops worldwide, in Brazil, because of the creation of jobs and income
The water with different salinity (ECw) levels was applied on the citrus plants from 60 days after sowing (DAS) the rootstocks to 330 DAS, a period that covered the stages of rootstock formation and grafting of the scion varieties
According to the analysis of variance (Table 2), a significant triple interaction affected the formation of dry matter of roots (DMRoots) and scion (DMScion)

Summary

Introduction

Citrus are very important fruit crops worldwide, in Brazil, because of the creation of jobs and income. According to FAO, the global production of sweet oranges [Citrus sinensis (L.) Osbeck] exceeds 73 million tonnes and Brazil is responsible for more than 23% of this production, which guarantees its position as a main producer and exporter, notably for concentrated orange juice (Food and Agriculture Organization of the United Nations (FAO, 2017). In Northeast Brazil, orange production is distributed in all states, with a mean yield of 13 ton ha-1, which is less than the national mean yield of 25 Mg ha-1 (IBGE, 2019) This yield is inferior to the potential of the crop since the yield in some countries is more than 40 Mg ha-1 (Food and Agriculture Organization of the United Nations [FAO], 2017). The production of other citrus species, such as lemons and mandarins, which have a low yield, is approximately 25 Mg ha-1 in Brazil and may be related to the use of low-yielding scion-rootstock combinations, in addition to the low level of use of technologies such as irrigation and fertigation (Simões et al, 2017; Teixeira, Reis, Leivas, Silva, & Struinving, 2017)

Objectives

Methods

Results

Discussion

Conclusion