Varietal Response of Cotton to Diseases in the Texas High Plains

Planting decisions should be based on various factors including agronomic properties, fiber quality factors as well as insecticide and herbicide traits. In addition, information on the response of varieties to various diseases is important. Small and large plot field studies were conducted in 2012 throughout the High Plains of Texas to evaluate the performance of commercially available varieties and advanced breeding line in fields with a history of Fusarium wilt and/or root-knot nematode. While harsh growing conditions were experienced throughout much of the season, differences in varietal performance were observed at all locations. In large plot trials, the partially resistant root-knot nematode varieties Phytogen 367WRF, Stoneville 4288B2F and Stoneville 5458B2F consistently outperformed the susceptible varieties; however, yield differences were not as obvious as in other years. Disease pressure in the small plot Fusarium wilt screening trial was moderate. Appreciable levels of plant mortality were observed in some of the more susceptible varieties. Final yields ranged from 630 to 1458 lb acre^-1 and were negatively correlated with mid-season stand counts. Plots were assayed towards the end of the growing season to compare nematode reproduction on the 20 varieties evaluated in this trial. Significant differences in reproduction were observed among varieties and genotypes. Egg plus nematode counts were greatest for All Tex 10WR585RF followed by Deltapine 1032B2RF, NexGen 3010B2RF, Phytogen 499WRF and Fibermax 9160B2F. Reproduction was lowest on Stoneville 5458B2F, Deltapine 1044B2RF and Fibermax 2011GT. Although Deltapine 1044B2RF is not known to contain any rot-knot resistance genes, circumstantial evidence exists indicating that Fibermax 2011GT may possess partial resistance. These data support such findings, thus increasing the total number of varieties commercially available for producers on the High Plains.