Nondestructive evaluation of cotton genotypes for resistance to reniform nematode

Authors: Stetina, Salliana - Sally; Erpelding, John

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/4/2023
Publication Date: 7/1/2023
Citation: Stetina, S.R., Erpelding, J.E. 2023. Nondestructive evaluation of cotton genotypes for resistance to reniform nematode. Journal of Cotton Science. 27:102-109. https://doi.org/10.56454/TDDZ4193.
DOI: https://doi.org/10.56454/TDDZ4193

Interpretive Summary: The reniform nematode, a microscopic worm that feeds on plant roots, is damaging to cotton. A rapid, nondestructive method was developed to assess cotton plants for resistance to the reniform nematode based on the number of females infecting the roots. In one set of experiments, the root system was cut off at either 0, 1, 2.5, or 5 cm below the soil line, and used to count the number of females infecting this portion of the root system. Resistant plants could be accurately identified while leaving up to 5 cm of roots with the shoot. In a second set of experiments, the rate of plant recovery and development of bolls and seeds was evaluated using a combination of root retention and shoot retention treatments. Plants rapidly recovered using a treatment combination in which the top leaves and 2.5 cm roots were kept. This combination saved more than 20 days to harvest compared to some other treatment combinations. This method will be useful for cotton breeders to screen their plants more effectively for resistance to reniform nematode.

Technical Abstract: Identification of new sources of reniform nematode resistance in cotton is critical to expanding host plant resistance to manage this important pathogen. Phenotyping plants in early breeding generations without destructive sampling would be highly useful for introgression of nematode resistance from exotic germplasm resources; therefore, a rapid, nondestructive method was developed to assess host plant resistance to the reniform nematode based on the number of females infecting the roots. In one set of experiments, the root system was cut off at either 0, 1, 2.5, or 5 cm below the soil line, and used to assess the number of females infecting this portion of the root system. Resistance could be accurately identified while leaving up to 5 cm of roots with the shoot. In a second set of experiments, the rate of plant recovery and reproductive development was evaluated using a combination of root retention (0 cm, 1 cm, 2.5 cm, or all root) and shoot retention (leaves at top two nodes, leaves at bottom two nodes, no leaves, all leaves) treatments. Plants more rapidly recovered using a treatment combination in which the top leaves and 2.5 cm roots were kept. This combination performed similarly to plants with neither shoots nor roots modified and saved more than 20 days to harvest compared to some other treatment combinations.