Early selection of drought-tolerant Coffea arabica genotypes at the seedling stage using functional divergence

• Published in: Pesquisa agropecuária tropical 2022, Vol.52, p.e72412
• Main Authors: Reis, André Moraes, Mendes, Antônio Nazareno Guimarães, Abrahão, Juliana Costa de Rezende, Santos, Meline de Oliveira, Silva, Vânia Aparecida
• Format: Article
• Language: English
• Subjects: AGRICULTURE, MULTIDISCIPLINARY; AGRONOMY; coffee; leaf water potential; water-use efficiency
• ISSN: 1517-6398; 1983-4063; 1983-4063
• DOI: 10.1590/1983-40632022v5272412

ABSTRACT The development of more drought-tolerant cultivars is essential for the maintenance of global agricultural production. This study aimed to perform an early selection of drought-tolerant Coffea arabica genotypes by evaluating their functional divergence using morphological, anatomical and physiological analyses. Seedlings of 14 genotypes were subjected to the drought stress imposed by irrigation for 18 days. Growth and anatomical parameters, leaf water potential and gas exchanges were measured. Under irrigated conditions and prolonged drought (18 days), the divergence among the genotypes was determined mainly by morphological traits, such as leaf area, stem diameter and, consequently, shoot dry mass. Under moderate drought (14 days), parameters such as water potential, cuticle thickness, stomatal density, number of xylem vessels and water-use efficiency were important for the divergence of the group with the highest ability to maintain its water status. The genotypes 1, 2, 4, 11 and 12 have characteristics that contributed to the maintenance of water status, such as greater cuticle thickness, stomatal density, smaller number of xylem vessels and phloem thickness, bigger root length and greater water-use efficiency. The functional divergence combining morphological, anatomical and physiological analyses in response to the moderate drought indicated the early selection of the genotypes 1, 2,4, 11 and 12 as more drought tolerant during the seedling stage. RESUMO O desenvolvimento de cultivares mais tolerantes à seca é essencial para a manutenção da produção agrícola mundial. Objetivou-se realizar uma seleção precoce de genótipos de Coffea arabica tolerantes à seca, avaliando-se sua divergência funcional por meio de análises morfológicas, anatômicas e fisiológicas. Mudas de 14 genótipos foram submetidas ao estresse hídrico imposto pela irrigação por 18 dias. Foram medidos parâmetros de crescimento e anatômicos, potencial hídrico foliar e trocas gasosas. Em condições irrigadas e seca prolongada (18 dias), a divergência entre os genótipos foi determinada principalmente por características morfológicas, como área foliar, diâmetro do caule e, consequentemente, massa seca da parte aérea. Sob seca moderada (14 dias), parâmetros como potencial hídrico, espessura da cutícula, densidade estomática, número de vasos do xilema e eficiência do uso da água foram importantes para a divergência do grupo com maior capacidade de manter seu estado hídrico. Os genótipos 1