Drought and root-knot nematode effect on cotton plant growth and detecting its health status using hyperspectral reflectance features

Authors: RAMAMOORTHY, PURUSHOTHAMAN - Mississippi State University; SAMIAPPAN, SATHISHKUMAR - Mississippi State University; Wubben, Martin; Brooks, John; SHRESTHA, AMRIT - Mississippi State University; RAJENDRA, PANDA - Mississippi State University; REDDY, RAJA - Mississippi State University; BHEEMANAHALLI, RAJU - Mississippi State University

Submitted to: Remote Sensing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/17/2022
Publication Date: 8/18/2022
Citation: Ramamoorthy, P., Samiappan, S., Wubben, M., Brooks, J.P., Shrestha, A., Rajendra, P., Reddy, R., Bheemanahalli, R. 2022. Drought and root-knot nematode effect on cotton plant growth and detecting its health status using hyperspectral reflectance features. Remote Sensing. 14(16). https://doi.org/10.3390/rs14164021.
DOI: https://doi.org/10.3390/rs14164021

Interpretive Summary: Crop production is affected by environmental factors (abiotic stress) and disease processes (biotic stress) that often occur at the same time in the same field. The effects of these stresses on plant growth and appearance are nearly indistinguishable to the naked eye. Remote sensing may serve as a means to diagnose abiotic vs. biotic stresses under field conditions. In cotton, water stress, i.e., drought, is perhaps the most prevalent abiotic stress, and root-knot nematode infection annually causes nearly 3% yield losses across the southeastern United States. Therefore, as a proof-of-concept, in this report, we describe the individual and combined effects of drought (abiotic) and root-knot nematode infection (biotic) on cotton leaf reflectance, growth, and physiology in a greenhouse setting. Our findings show that cotton leaf reflectance differed significantly between plants experiencing drought or root-knot nematode infection and that remote sensing bears promise as a means to identify these stresses in the field on a large scale.

Technical Abstract: Cotton encounters biotic and abiotic stresses during the growing season, which significantly affects the genetic potential of stress tolerance and productivity. The occurrence of abiotic stress (drought stress, DS) can alter the plant-disease (root-knot nematode, RKN) interactions by enhancing host plant sensitivity. An experiment was conducted for two years under greenhouse conditions to investigate the effect of RKN and DS and their combination using nematode-resistant (Rk-Rn-1) and nematode susceptible (M8) genotypes. These genotypes were subjected to four treatments: control (100% irrigation and nematode free), RKN (with nematodes and 100% irrigation), DS (50% irrigation with no nematodes), and DS+RKN. We measured treatments-induced changes in cotton (i) leaf reflectance between 350 and 2500 nm, (ii) pigments, physiology and biomass-related traits for diagnosing cotton plant health under combined biotic and abiotic stresses. The genotypes ‘Rk-Rn-1’and ‘M8’ showed differential responses to drought, root-knot nematode, and combined stress. With a few exceptions, all the three stressors reduced the pigments, physiology, shoot and root traits and the magnitude of reduction was relatively higher in ‘M8’ than ‘Rk-Rn-1’. RKN stress had a comparable effect on pigments as DS+RKN and had a lower negative impact than drought stress. Drought stress, on the other hand, had a comparable effect on gas exchange, shoot, and root characteristics as DS+ RKN stress, and the negative impact was greater than RKN stress. We observed the impact of stressors on plant growth followed DS+RKN