Seleção de genótipos de limão com tolerância ao HLB para produção de óleo essencial

Abstract

Brazilian citriculture is one of the pillars of the national trade balance, being one of the largest in the world, however huanglongbing (HLB) has been causing significant losses in the sector. There are no reports in the literature on citrus varieties and species resistant or tolerant to HLB. In BAG Citros IAC there are 105 accessions of lemon (Citrus limon), a species that can be exploited in the fresh fruit and juice market, and also presents by-products with high added value, the most important of which being the essential oil of the peel. The objective of this work was to select lemon genotypes with tolerance to HLB and with high production of essential oil. Six lemon genotypes (Saisons variegated IAC 290, Eureka IAC 644, Woglum IAC 271, Mayer IAC 630, São Matheus IAC 265 and Laranjado IAC 281) were evaluated for incidence and severity of HLB, physicochemical characteristics of fruits, productivity and essential oil yield. The evaluations were carried out in the second semester of 2018 and the first semester of 2019. All genotypes presented 100% incidence of HLB in the evaluation carried out in the first semester of 2019. The genotype Woglum presented, in the studied edaphoclimatic conditions, less severity to the HLB in the evaluation in 2018 and 2019, in relation to the São Matheus, Eureka, Laranjado and Saisons Variegado genotypes. As for the physical-chemical characteristics, there was a decrease in the mass of fruits harvested in 2018, for fruits harvested in 2019 for the cultivars Mayer and São Matheus. Fruits harvested in 2018 and 2019 did not differ between genotypes in parameters of height and width of fruit, juice yield, acidity, vitamin C and ratio. The genotypes Woglum, Mayer, Laranjado and Saison variegado, showed a decrease in total soluble solids from fruits harvested in 2018, for fruits harvested in 2019. The cultivar Eureka showed higher production per plant in the 2019 evaluation, while the cultivar São Matheus showed greater efficiency productive in the same evaluation in relation to the others. The essential oil yield of the peel was higher in the fruits harvested in the first half of 2019 compared to 2018 for all genotypes. Of the six genotypes studied, the Woglum and Mayer genotypes have a higher tolerance to HLB and the Eureka genotype has high oil productivity per hectare.