Dr Harsh Raman1, Dr Rosy Raman1, Mr Brett  McVittie1, Dr Ramethaa  Pirathiban2, Dr Niharika  Sharma3, Dr Yuanyuan  Zhang4, Prof Shengyi Liu4, Prof Graham  Farquhar5, Prof Brian Cullis2, Dr David Tabah6, Mr Andrew  Easton6

 1NSW Department Of Primary Industries, WAGGA WAGGA, Australia,
2Centre for Bioinformatics and Biometrics, National Institute for Applied Statistics Research Australia, University of Wollongong , Wollongong, Australia,
3NSW Department of Primary Industries, Orange Agricultural Institute, Orange, Australia,
4Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, China,
5Research School of Biology, Australian National University, Canberra, Australia,
6Advanta Seeds Pty Ltd, 268 Anzac Avenue, Toowoomba,  Australia

Drought stress (water deficit) is a major limitation of canola production in Australia and elsewhere.  In this study, we assessed genetic variation for key exemplar traits involved in adaptation strategies under water deficit conditions (drought escape, and drought avoidance) in a 11-5101 DH population. Genetic analyses identified multiple QTL that contribute to variation in flowering time (drought escape); Δ13C and fractional ground cover (drought avoidance) and agronomic WUE (seed yield). Both parental lines contributed favourable alleles for trait variation. Candidate genes that underlie QTL regions for drought resistance traits were identified. Our multi-environment data showed that early flowering is negatively related to seed yield, while high shoot biomass, early ground cover, plant height and high Δ13C are positively related to seed yield. To understand physiological basis of water use efficiency, we made gas exchange measurements and showed that leaf intrinsic water use efficiency is negatively related with Δ13C, but the latter had positive relationship with seed yield. To uncover functional genes and gene networks that contribute to effective water use, we performed mRNA sequencing of parental lines of 11-5101 population that showed significant variation in iWUE, Δ13C signatures and seed yield. Transcriptome analysis revealed that 906 genes are differentially expressed in response to water deficit, including those which were located within QTL regions associated with adaptive traits. In summary, our research identified the useful variation in drought related traits and molecular tools  that would accelerate the development of improved canola varieties for cultivation under water deficit conditions.


Dr Harsh Raman is a Senior Principal Research Scientist at the Wagga Wagga Agricultural Institute, NSW Department of Primary Industries, Wagga Wagga. He joined the NSW DPI in 1996 and led plant genetics and pre-breeding research in wheat, barley and canola. He has published over 120 peer-refereed papers in national and international journals.

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