Pre-emptive breeding to combine superior eating quality in tropical super sweet corn with resistance to major diseases
Australia’s sweet corn industry has huge potential to expand as long as it remains competitive in the international market. Tropical and subtropical environments are major areas of expansion. However, germplasm grown in such environments have poor eating quality compared to temperate types. Moreover, there are a number of diseases that can cause significant loses both in terms of yield and quality. Selection for improved tenderness and flavor in tropically-adapted super sweet corn germplasm in the Kairi (North Queensland) breeding program has resulted in improvements in eating quality. Significant progress has also been made in terms of developing resistance to the most prevalent diseases of super sweet corn. Some of these diseases can cause as much as 75% yield losses in sweet corn. In some Asian countries downy mildew is reported to cause as much as 100% loss. Considering the increased difficulty to control by fungicide, breeding resistance remains to be the most feasible option. Downy mildew is a quarantinable disease presently not in Australia. If it finds its way into this country, it will be very damaging to the industry. Therefore, pre-emptive breeding is required to protect the local industry from any potential threats. To ensure the competitiveness of Australian sweet corn industry, it’s necessary to develop hybrids that are not just productive but must also be profitable to grow. Horticulture Australia Ltd in partnership with Queensland Department of Agriculture Fisheries and Forestry, supported a five year project aimed at the development of effective sources of resistance to the most important tropical diseases, and to develop hybrids that are superior to the current major tropical hybrid, Hybrix 5 in terms of productivity, quality and disease resistance. In this project downy mildew resistance has been transferred from imported maize germplasm to local sweet corn using conventional breeding supported by use of molecular markers. Resistances to other le