Growth and development of onions in a subtropical environment

Australia currently produces 210 000 tonnes of onions annually. The major production areas are in southern Australia where the predominant onion type is adapted to an intermediate long daylength. Queensland's annual production is stable at 10% (20 000 to 25 000 tonnes) of the national production. Ninety percent of the Queensland crop is grown in southern Queensland (Lockyer Valley and the Darling Downs). Small production areas can be found in central and tropical north Queensland. Consequently, onions in Queensland are grown under a predominantly subtropical environment. Crops are sown from late February to late June. An extensive range of cultivars is required to meet the changing environmental conditions that occur during this time period in order to achieve maximum economic crop yield. In the past, incorrect cultivar selection has resulted in high levels of doubling and bolting with a corresponding reduction in economic yield. This study conducted at Gallon Research Station in the Lockyer Valley investigated the growth and development of several cultivars currently available to growers in Queensland.