Root morphology, gas exchange and chlorophyll fluorescence of coffee cultivars and progenies are altered by Meloidogyne paranaensis infestation and water deficit

Abstract

Climate change greatly influences coffee production, especially in areas infested with plant‐parasitic nematodes. In this study, coffee genotypes showed differences in their morphological and physiological characteristics when subjected to a water deficit and parasitism by Meloidogyne paranaensis. The cultivar IPR 100 had the largest superficial and volumetric root system area, even when parasitized. The two progenies (MG 0179‐1 and MG 0179‐3) and the cultivar Catuaí IAC 62 had a similar surface area (p < .05) when parasitized. However, the root surface area and volume of MG 0179‐3 increased by 96% and 400%, respectively, when parasitized by M. paranaensis. On the other hand, Catuaí IAC 62 had a 31% reduction in root surface area. Catuai 62 and IPR 100 showed higher sensitivity to drought when parasitized because of the increased photochemical sensitivity and reduction in photochemical quenching. In MG 0179‐1 and MG 0179‐3, an increase in non‐photochemical quenching occurred in response to stress, indicating that these progenies use a photochemical response to protect photosystem II. In this work, MG 0179‐3, which is resistant to M. paranaensis, was remarkable because, interestingly, the infestation caused an increase in its root surface area. In addition, MG 0179‐3 had relatively good photochemical performance under water deficit and M. paranaensis parasitism.