The occurrence of low night temperatures during reproductive development is one of the
factors most limiting rice yields in southern Australia. Yield losses due to cold temperature
are the result of incomplete pollen formation and subsequent floret sterility. Researchers have
found that in 75% of years, rice farmers suffer losses between 0.5 and 2.5 t/ha. Research is
being undertaken to identify overseas rice varieties, that are cold tolerant under the local
weather conditions and by using those genotypes as parent material, develop cold tolerance
varieties of rice. A yield simulation model was used to measure reduction in losses due to
cold at different minimum threshold temperatures, while the SAMBOY Rice model was used
to measure the costs and returns of a breeding program for cold tolerance. The results of the
economic analysis reveal that new cold tolerant varieties would lead to significant increase in
financial benefits through reduction in losses due to cold, and an increase in yield from the
better use on nitrogen by the cold tolerant varieties. The returns to investment on the research
project are estimated to be high
