Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 7665 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 cold (‘blowing up’) on in vivo germination on pollen collected from field trials. How does this research benefit rice growers? Developing cold tolerant rice varieties will not only reduce yield loss and year-to-year yield variability caused by cold damage, it also will increase water productivity by eliminating the need for deep water. Eventually this work will lead to the development of new aerobic rice varieties that can be grown without flooded field conditions for the entire season. These varieties will be specifically adapted for performance in well-drained, non-ponded and unsaturated soils. Aerobic rice will require irrigation to bring the soil in the root zone to field capacity but ponding will not be needed, resulting in significant water savings. It is possible that a new cropping system with intermittent irrigation will reveal a whole new dynamic of nitrogen nutrition and water productivity that will affect successful fertilisation of rice due to both cold temperatures at early microspore and high temperatures at flowering. Such concerns have driven this and the associated RIRDC project, Cold tolerant traits and QTLs for improved efficiency of rice breeding program (page 61) to understand what components of the reproductive process influence successful seed set under extreme thermal weather conditions. RIRDC Project PRJ-009950 Australian Rice Partnership II This project involves the following members of the Australian Rice Partnership II: l  Kim Philpot, Senior Techical Officer l  Dr Mark Talbot, Plant Cell Biologist and Microscopist l  Dr Peter Snell, Senior Plant Breeder Acknowledgements Thanks to technical staff Greg Napier and Minna Russell for assistance with glasshouse work and to Aleesha Turner for assistance with fluorescence microscopy and imaging, except Figure 2 (whole rice flower), which was provided by Dr Mark Talbot. More information Kim Philpot T: 02 6951 2610 E: [email protected] l Figure 4. Pollen germination, 24 hours after anthesis, of Reiziq plants not exposed to cold treatment at pollen microspore. A: Germinated pollen on rice flower stigma showing pollen tube growth down the style. B: Pollen tubes have entered the ovary area and continued down to the micropyle opening at the base of the ovary. C: Pollen tubes entering the micropyle opening where they will release sperm cells completing the fertilisation process A B C Pollen tubes down the style Stigma Ovary Pollen tubes in ovary area Pollen tubes entering micropyle opening Pollen grain Pollen tube l Figure 5. Pollen germination, 24 hours after anthesis, of Reiziq plants exposed to cold treatment at pollen microspore. Images A and B are from one rice flower and C and D are from a different flower. A: Very little pollen is on the stigma and no pollen tubes can be seen down the style. B: The exposed embryo sac with no visible pollen tubes in the ovary area or at the micropyle opening. C: Germinated pollen with good pollen tube growth down the style. D: Pollen tube growth has halted at the top of the ovary area with no pollen tubes reaching the micropyle opening. No pollen tubes down the style No pollen tubes around the embryo sac or micropyle opening Pollen tubes are present down the style Halted pollen tube growth A B C D