An Investigation in Cotton Square Size and Effects on Cotton Fleahopper Resistance.

Cotton fleahoppers(CFH) (Pseudatomoscelis seriatus) are an early season pest of upland cotton. Feeding damage results in loss and abscission of young floral buds (squares), and consequently a delay in maturation and potential yield losses. Traditional efforts to breed for CFH have focused on the role that pubescence has played in preferential feeding by CFH. The physical square morphology was investigated as a characteristic of resistance. Germplasm obtained from a previous cotton fleahopper breeding effort at Texas A&M and from the Texas A&M AgriLife Research Cotton Improvement Lab at College Station has been identified as having resistance, with the cultivar Pilose as the source of the resistance. 14 lines derived from the fleahopper breeding and 6 elite Texas A&M AgriLife Research Cotton Improvement Lab lines were grown in a split-plot spray non spray design to ascertain fleahopper resistance. The squares were measured throughout the growing season to obtain growth patterns for the 20 lines. Differences in square sizes and square growth rates as well as differing levels of resistance were found between lines.