EarlySeason Morphological and Physiological Responses of Resistant and Susceptible Cotton Genotypes to Reniform Nematode and Soil Nitrogen

Abstract

Soil fertility and reniform nematode (RN) directly affect earlyseason growth and physiology of cotton. The growth responses to soil fertility and RN may, however, vary across germplasm. A greenhouse study was conducted to gain information on the role that host plant resistance plays in influencing RN populations, and cotton growth and physiological response to a range of soil nitrogen (N) levels in the presence and absence of RN. RN-resistant cotton lines (08SS110-NE06.OP and 08SS100) along with susceptible cultivars (Deltapine 16 and PHY 490 W3FE) were subjected to four levels of N from planting until biomass harvesting, 60 days after planting(DAP), under the presence orabsence of RN. The linear and quadratic functions (r2 = 0.72 to 0.99) bestdescribed measured responses of cotton genotypes to soil N. However, the responses were not different among genotypes, except for plant height at 30 DAP. This study revealed significant increases in several morphological parameters with increasing rates of N. RN population in the pots grown with resistant lines was lower whencompared to susceptible cultivars at biomassharvest. Physiological responses indicated that 08SS110-NE06.OP was more resilient to RN stress than other genotypes. The information from this study could be useful in managing the early season growth of cotton.

Reniform nematode impact on cotton growth and management strategies: A review

“…In addition to aboveground growth, greenhouse studies have focused on belowground growth and reported a higher root-to-shoot biomass ratio of cotton seedlings as a typical symptom of reniform nematode damage (Moore & Lawrence, 2013, Singh et al, 2020. Singh et al (2020) observed reniform nematode damage on both morphological and physiological plant growth at 30 and 60 days after reniform nematode inoculation under greenhouse conditions.…”

“…In addition to aboveground growth, greenhouse studies have focused on belowground growth and reported a higher root-to-shoot biomass ratio of cotton seedlings as a typical symptom of reniform nematode damage (Moore & Lawrence, 2013, Singh et al, 2020. Singh et al (2020) observed reniform nematode damage on both morphological and physiological plant growth at 30 and 60 days after reniform nematode inoculation under greenhouse conditions. The main stem length, leaf thickness, shoot biomass, and root biomass were reduced under the presence of reniform nematode compared to no reniform nematode pressure at 30 and 60 days from reniform nematode inoculation.…”

“…In addition to aboveground growth, greenhouse studies have focused on belowground growth and reported a higher root‐to‐shoot biomass ratio of cotton seedlings as a typical symptom of reniform nematode damage (Moore & Lawrence, 2013, Singh et al., 2020). Singh et al.…”

“…Singh et al. (2020) observed reniform nematode damage on both morphological and physiological plant growth at 30 and 60 days after reniform nematode inoculation under greenhouse conditions. The main stem length, leaf thickness, shoot biomass, and root biomass were reduced under the presence of reniform nematode compared to no reniform nematode pressure at 30 and 60 days from reniform nematode inoculation.…”

“…Moreover, the tap root length of cotton plant was reduced by 14% in the presence of reniform nematode 60 days after inoculation. Similarly, leaf carboxylation rate, temperature, chlorophyll content, the efficiency of photosystem II (φPSII), and maximum quantum yield of photosystem II (Fv/Fm) were reduced in cotton seedlings under the presence of reniform nematode, whereas leaf anthocyanin content increased when compared to the absence of reniform nematode (Singh et al., 2020). Unlike field studies, pot‐based greenhouse studies allow for the determination of nematode damage on a single plant rather than a plant canopy.…”