FIELD EXPERIMENT TO EVALUATE THE RESPONSE OF SUGARCANE VARIETIES TO WATERLOGGING

RECENT PRODUCTIVITY REVIEWS in the Herbert and Central regions identified strong negative correlations between excessive rainfall and productivity. Waterlogging has a significant effect on sugarcane productivity. It was estimated that yield is reduced by 0.5 t/ha for every day the water-table is within 50 cm of the soil surface. Waterlogging tolerance of sugarcane varieties is not assessed in the current variety selection program. Identification of varieties that perform better under waterlogged conditions is based on anecdotal observations from the field, after a variety is released. If a variety?s tolerance to waterlogging was known closer to the time of release, growers could make informed decisions on whether particular varieties are best suited to their farm or blocks within their farm. A field experiment was conducted near Ingham where the waterlogging tolerance of eight sugarcane varieties was assessed. Waterlogging treatments were established at two crop stages (early and late) in both the plant and first ratoon crops, and were compared with an untreated control. Waterlogging plots were surrounded by a bund wall and flooded for a period of 1?1.5 months. Cumulative cane and sugar yield was significantly reduced by the early (36% loss over the two crops) and late (12% loss over the two crops) waterlogging treatments. All varieties showed a significant decline in cumulative cane and sugar yield in the early treatment, but this decline was more severe for Q208A and Q200A, and to a lesser extent Q247A. For the late treatment, MQ239A, Q219A and Q247A, showed no loss of cumulative cane or sugar yield whereas all other varieties showed a significant decline. The cumulative cane and sugar yield of Q232A declined significantly in both waterlogging treatments, but it was one of the better performers across all treatments. Given that the site was poorly drained and control plots most likely experienced periods of saturation, Q232A also appeared to have better waterlogging tolerance. This work has implications for tolerance ratings in QCANESelectTM.