Earlyseason morphological and physiological responses of resistant and susceptible cotton genotypes to reniform nematode and soil nitrogen

Authors: SINGH, BHUPINDER - Mississippi State University; CHASTAIN, DARYL - Mississippi State University; REDDY, K. RAJA - Mississippi State University; SNIDER, JOHN - University Of Georgia; KRUTZ, LARRY - Mississippi State University; Stetina, Salliana - Sally; SEGHAL, AKANKSHA - Mississippi State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2020
Publication Date: 12/15/2020
Publication URL: https://handle.nal.usda.gov/10113/7215325
Citation: Singh, B., Chastain, D.R., Reddy, K., Snider, J.L., Krutz, L.J., Stetina, S.R., Seghal, A. 2020. Earlyseason morphological and physiological responses of resistant and susceptible cotton genotypes to reniform nematode and soil nitrogen. Agronomy. 10(12):1974. https://doi.org/10.3390/agronomy10121974.
DOI: https://doi.org/10.3390/agronomy10121974

Interpretive Summary: Soil nitrogen fertility and infection by reniform nematode are two stresses that directly affect cotton development and yield, but their combined effects on early-season growth and physiology of cotton have not been characterized. A 60-day greenhouse study evaluated the response of four cotton lines susceptible (Deltapine 16 or PHY 490 W3FE) or resistant (08SS100 or 08SS110-NE06.OP) to reniform nematode to nitrogen fertilization (four levels ranging from 0 to 150% of recommended rate) in the presence or absence of the nematode. All cotton lines tested had similar rates of change in growth and physiological responses at all nitrogen levels. Higher levels of nitrogen fertility resulted in increases in plant growth. Although fewer reniform nematodes were associated with resistant cotton lines than with susceptible cotton lines at harvest, there was no interaction between nitrogen and nematode levels for any of the growth traits. Physiological traits such as net photosynthesis, anthocyanin content, and chlorophyll content were influenced by reniform nematode pressure. The resistant cotton line 08SS110-NE06.OP was more resilient under reniform nematode stress when compared to other cotton lines. These findings provide a basis for researchers to expand upon this work to include a broader range of reniform nematode pressure, different populations of the nematode, and a broader range of resistant cotton lines in future studies. Our expanded knowledge of early-season responses of cotton and can be used to improve grower recommendations to optimize early season growth of cotton.

Technical Abstract: Soil fertility and reniform nematode (RN) directly affect early-season 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. The two RN-resistant upland cotton lines (Gossypium barbadense introgressions; 08SS110-NE06.OP and 08SS100) along with two susceptible cultivars (Deltapine 16 and PHY 490 W3FE) were subjected to four different levels of N [100% of recommended rates, 150% of recommended, 50% of recommended, and base level] from sowing until harvesting, 60 days after sowing (DAS), in the presence and absence of RN. The linear and quadratic functions (r2 = 0.72 to 0.99) best-described growth and physiological responses of cotton genotypes to soil N. The rate of change in growth and physiological parameters to soil N were not different among genotypes, except for plant height at 30 DAS. Overall, the study revealed significant increases in plant height, mainstem node number, leaf area, dry weights, taproot length, and leaf temperature with increasing rates of N. No interaction between N and RN was found for morphological parameters. Further, RN population in the pots grown with resistant lines was less than pots grown with susceptible cultivars at the final harvest. Physiological parameters such as net photosynthesis, anthocyanin content, and chlorophyll content indicated genotypic susceptibility to RN pressure. Such physiological responses showed 08SS110-NE06.OP was resilient under RN stress when compared to other genotypes. The information on genotypic growth and physiological responses across a range of N or RN environments could be useful in the management of early season growth of cotton.