Submitted to: Society of Nematology Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 6/7/2015
Publication Date: 9/30/2015
Citation: Davis, R.F., Knoll, J.E., Anderson, W.F., Harris-Shultz, K.R. 2015. Tolerance of sweet sorghum to Meloidogyne incognita and crop effect on nematode population density. Society of Nematology Abstracts. 47:232.
Technical Abstract: Sweet sorghum (Sorghum bicolor) is a sugar-producing crop that can be used for biofuel and plastics production, and the crop could be incorporated into annual cropping systems in the southern US. The effect of Meloidogyne incognita on sweet sorghum yield and sugar content has not been reported. Because sweet sorghum genotypes exhibit a wide range of susceptibility to M. incognita, there is the potential for the nematode to affect the yield and sugar content of some genotypes more than others. Field studies were conducted in 2012 and 2013 to determine whether M. incognita reduces the yield or sugar content of sweet sorghum. A secondary objective was to evaluate the effect of sweet sorghum on M. incognita population levels. Twelve genotypes representing a range of susceptibility to M. incognita were grown in a split-plot design where whole-plots were sweet sorghum genotype and sub-plots were either non-treated or fumigated with 1,3-dichloropropene to minimize nematode population levels. Nematode population levels were assessed in early and late season, above-ground biomass (yield) and sugar content (degrees Brix) were measured at harvest, and the percentage yield loss between fumigated and non-fumigated plots of each genotype was calculated. Although there were significant differences among genotypes for both yield and sugar content, there was no effect of fumigation on either variable, nor did fumigation influence the effect of genotype (no genotype × fumigation interaction) on either variable. Because fumigation had no effect on yield for any genotype, the percentage loss did not differ among genotypes. Population levels of M. incognita at harvest differed among genotypes and fumigated plots had significantly lower population levels than non-fumigated plots; fumigation influenced the effect of genotype on nematode levels (a significant genotype × fumigation interaction) in 2013 but not in 2012. These results indicate that sweet sorghum is highly tolerant and not significantly damaged by M. incognita. However, because some genotypes supported greater population densities of M. incognita, which likely increases the risk of damage to subsequent crops, selecting more resistant genotypes for infested fields is recommended.