David Cann1, James Hunt1, Felicity Harris2, Kenton Porker3
1Department of Animal, Plant and Soil Sciences, La Trobe University, VIC 3083, email@example.com,
2Department of Primary Industries, Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650,
3South Australian Research and Development Institute, Hartley Grove, Urrbrae SA 5064
The development of winter wheats suitable for early sowing in the semi-arid Mediterranean environments of southern Australia can potentially increase water-limited potential yield despite decreasing autumn rainfall. Early-sown winter wheats generally have higher biomass than later-sown spring wheats. However, this increased biomass does not always translate to greater yield in comparison to spring wheats, as winter wheats often have lower harvest index. This study aimed to determine whether yield physiology differs in winter and spring wheats with concurrent flowering times. We hypothesised that the partitioning traits harvest index and fruiting efficiency would be more closely related to yield in winter wheats than in spring wheats. Inbred lines derived from a Mace/Gauntlet cross, incorporating 42 winter- and 24 spring- types were sown in a partially-replicated field experiment at Narraport, VIC in 2018. Vegetative and reproductive growth rate, heading date, harvest dry matter, yield, yield components, harvest index and fruiting efficiency were measured. There was a wide range of heading dates, particularly for the winter lines, suggesting that minor development genes or genetic variation not captured by molecular markers have a significant role in development rate. There was no difference in the relationship between phenotypic traits and yield for winter wheat lines compared to spring wheat lines. Harvest dry matter and grain number explained the largest amount of variation in grain yield, whilst harvest index and fruiting efficiency were both weakly associated with yield. This study will be repeated with lines matched for flowering time and with a greater level of replication in 2019.