The Grain Mold Pathogen, Fusarium thapsinum, Reduces Caryopsis Formation in Sorghum bicolor

• Published in: Journal of phytopathology 2009-08, Vol.157 (7-8), p.518-519
• Main Authors: Little, Christopher R., Magill, Clint W.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; caryopsis formation; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Gibberella fujikuroi; grain mold; Phytopathology. Animal pests. Plant and forest protection; resistance screening
• ISSN: 0931-1785; 1439-0434
• DOI: 10.1111/j.1439-0434.2008.01530.x

Grain mold is a globally important panicle disease of sorghum [Sorghum bicolor (L.) Moench] that occurs between floral anthesis and physiological maturity of the caryopsis. Many fungi, including Fusarium thapsinum, cause grain mold. In this study, sorghum florets of grain mold resistant (Sureno and Tx2911), moderately resistant (SC170), and susceptible (Tx430) cultivars were spray‐inoculated with a high density (1 × 106 microconidia/ml) of F. thapsinum at anthesis. Mean caryopsis formation frequencies [CFF = (total caryopses/total spikelets per panicle) × 100] for F. thapsinum‐inoculated Sureno and Tx2911 panicles did not significantly differ from their respective controls, however F. thapsinum‐inoculated SC170 and Tx430 panicles were significantly less than controls. In addition, CFF was significantly reduced in F. thapsinum‐inoculated Tx430 panicles when compared to the F. thapsinum‐inoculated grain mold resistant genotypes (P = 0.011). This study suggests that screening of sorghum varieties for caryopsis formation using high‐density inoculations at anthesis would provide an additional assay to measure F. thapsinum resistance in the greenhouse.