Horticultural production in Australia is widespread occurring in many diverse climatic zones ranging from cool temperate to tropical. Between and within these zones, there have been attempts to diversify production through either the introduction of crops from similar regions of the world or by evaluating cultivars normally adapted to other climatic zones. In both cases there is often a need to identify and develop improved locally adaped genotypes through genetic improvement programs.
In developing cultivars of deciduous fruiting tree crops, research programs have involved introduction, breeding, selection and subsequently evaluation of horticultural performance under local conditions. Clearly winter chilling requirements are important considerations in these programs. Better adapted cultivars are needed to maintain or extend production in regions where winter chilling is either marginal or clearly insufficient for currently available cultivars.
This paper presents an overview of genetic improvement research current in Australia which is aimed at the development of temperate fruiting tree crops in regions where climate in terms of winter chilling minimizes their performance.