Submitted to: American Society of Sugar Cane Technologists
Publication Type: Abstract Only
Publication Acceptance Date: April 23, 2010
Publication Date: June 20, 2010
Citation: Grisham, M.P., Comstock, J.C., Flynn, J.L. 2010. Comparing the natural spread of Sugarcane yellow leaf virus in Florida to its natural spread in Louisiana [abstract]. Journal of the American Society of Sugar Cane Technologists. 30:151. Available: http://www.assct.org/ Technical Abstract: Among reports sugarcane infected with Sugarcane yellow leaf virus (SCYLV), the incidence of infections has been higher in Florida than in Louisiana. An experiment was planted in 2003 at two USDA, ARS sugarcane research locations, the Sugarcane Field Station, Canal Point, Florida and the Sugarcane Research Laboratory, Houma, Louisiana to compare the spread of SCYLV at one location to the other utilizing the same cultivars from a common source of seed cane. The experimental design was a complete block design with 13 treatments (cultivars) and three replications. Each experimental plot was planted with 33 plantlets produced in tissue-culture (Kleentek®, Certis U.S.A., Baton Rouge, LA). Six Florida commercial cultivars (CP 72-1210, CP 72-2086, CP 78-1628, CP 80-1743, CP 88-1762, and CP 89-2143) and seven Louisiana commercial cultivars (CP 70-321, LCP 85-384, HoCP 85-845, HoCP 91-555, Ho 95-988, HoCP 96-540, and L 97-128) were included. Leaf samples were collected for laboratory diagnosis with reverse transcriptase-polymerase chain reaction (RT-PCR) in the plant-cane, first-ratoon, and second-ratoon crops in Florida and in plant-cane and first-ratoon crops in Louisiana. The experiment was replanted at the Louisiana location in 2004 with virus-free stalks from the initial experiment. Leaf samples were collected in the plant-cane and in the first-, second-, and third-ratoon crops. At the Florida location, the incidence (% of total samples analyzed) of SCYLV-infected plants among the Florida cultivars was similar to the incidence among the Louisiana cultivars (13.4% in Florida cultivars compared to 12.9% in Louisiana cultivars). At the Louisiana location, the incidence of SCYLV-infected plants was greater in the Florida cultivars than in the Louisiana cultivars (6.6% in Florida cultivars compared to 1.8% in Louisiana cultivars). Comparing the incidence of SCYLV-infected among all cultivars in the plant-cane and first-ratoon crops at the Florida and Louisiana locations, the incidence of SCYLV-infected plants was greater at the Florida location than at the Louisiana location (14.1% at Florida compared to 4.0% at Louisiana). In the repeated experiment in Louisiana, the incidence of SCYLV-infected plants was very low (<2.0 % overall), even though samples were collected through the third-ratoon crop. Under Florida conditions, the overall susceptibility of the Louisiana set of cultivars does not appear to differ from that of the Florida set of cultivars suggesting that the Louisiana set is no less susceptible than the Florida set. Although the incidence of SCYLV was greater among Florida cultivars at the Louisiana location, the overall incidence was low for both sets of cultivars. Other possible explanations for why the incidence of SCYLV infections is greater in Florida than in Louisiana need to be explored including differences in environmental conditions and virus-vector efficiency.