Ground Cover North : Ground Cover 052 October-November 2004 - North
RESEARCH UPDATE 5 OCTOBER 2004 AutoSPRAY Smart guidance ... ... made simple 1800 174 639 www.rinex.com.au FREE CALL Large colour touch screen Easy to see & simple to use with intuitive menu, big menu buttons finger tip control on Smart guidance Visual guidance for contours, racetrack & parallel swaths using virtual road display & external light-bar Moving map display See exactly where you have been in the paddock, then store and print your maps at will AutoSPRAY ready Get ready for the revolution, minimize your spraying cost with automatic boom section control, suits most spray controllers AutoSTEER ready Let the wheel go for the ultimate in steering control, steer kits to suit most machines, sub-metre to centimetre solutions available Rinex Technology PO Box 945 S. Perth WA 6151, Tel : (08) 9474 4771, Fax : (08) 9474 4772 AutoSTEER Every graingrower knows that sinking feeling. The crop is mature, the harvester ready and the weather forecast says rain! In every season, somewhere in Australia, growers lose money when their wheat is downgraded at delivery to the silo because of weather damage. Pre-harvest sprouting (PHS) is the most common cause, but Black Point and late-maturity alpha amylase (LMA) are other related grain-quality defects that regularly take the gloss off an otherwise profitable crop. Now, after a decade of GRDC-supported research, progress is being made in understanding the causes of the defects, in being able to properly measure their effects and, most important, in finding lasting solutions that should eliminate all three defects from the varieties of the future. In this first report we define the quality defects related to weather damage and explain their impact. In the December issue of Ground Cover, we will explore the research that is uncovering the causes of the defects and the new insights that biotechnology is bringing to the problems -- and their solution. For growers, the reports will categorise the susceptibility of common varieties to each of the defects. Research on weather damage has been a GRDC research priority for more than a decade, and in its 2002-2003 Research Prospectus the GRDC set as a goal the elimination of PHS, LMA and Black Point as sources of loss to the grains industry within 10 years. The challenge the GRDC set for researchers and breeders was to have within a decade: "Varieties with appropriate quality and agronomic characteristics (for their region) free of the underlying genetic defects causing the predisposition to pre-harvesting sprouting, LMA and Black Point". Two years on, the GRDC has just reviewed its investment. In December Ground Cover, we will explore the progress that has been made in understanding the causes of the defects and in identifying the sources of resistance that wheat breeders can now use to reduce, and ultimately eliminate, the defects from their breeding populations. GRDC RESEARCH CODE UA 00039, program 1 For more information: Professor Daryl Mares, University of Adelaide, 08 8303 7480, email@example.com PRE-HARVEST SPROUTING LATE-MATURITY ALPHA- AMYLASE BLACK POINT Pre-harvest sprouting is caused by exposure of the grain to prolonged wet conditions at the later stages of ripening or when the grain is mature but still in the head. The wet conditions trigger the initial steps in germination and amylases and other hydrolytic enzymes are released in the germ and aleurone layer of the grain. These enzymes move into the endosperm of the grain and begin to break down the starch. In extreme cases the grains germinate in the head, but even if the crop dries after a few days the damage, in susceptible varieties, has been done and the presence of the enzymes in the grain renders it unsuitable for bread making or for Asian noodles. In the worst year for weather damage on record, 1982-83, widespread rain at harvest in eastern Australia led to a loss estimated at $500 million. Loss from PHS occurs every year, but historically seasons with extreme damage (in excess of $100 million) are interspersed with seasons where damage is more localised -- but no less real to the growers affected. Late-maturity alpha-amylase is a defect similar to pre-harvest sprouting in that amylase enzymes capable of degrading starch are produced in the aleurone layer of the grain during mid-to-late grain filling. The difference is that for LMA, it is not rainfall, but exposure to low temperatures at a critical stage of grain filling that triggers the release of the enzymes. As for PHS, presence of the enzymes renders the grain unsuitable for bread making or for Asian noodles due to degradation of starch during processing. Both PHS and LMA are detected at receival by the 'Falling Number' test. This test measures the time for a plunger to fall through a viscous paste made by mixing ground grain with water and heating to gelatinise the starch. Sound grain has a falling number greater than 300 seconds, but if amylase enzymes are present due to PHS or LMA, the starch is degraded, the paste less viscous and the falling number lower. A Falling Number below 300 means that the grain is downgraded to GP or Feed. Black Point is a darkening of the seed coat over the germ and adjacent areas of the grain and sometimes also extends along the crease. It is caused by exposure to high humidity during the later stages in grain filling and in some areas, for example Queensland and northern NSW, and the coastal portions of the northern wheat belt in WA, susceptible varieties are affected every year. Grain containing greater than five percent Black Point, or three percent Black Point in durum, is downgraded at receival and in extreme seasons the loss to the grains industry has been estimated to exceed $50 million. Unlike pre-harvest sprouting and LMA, Black Point affects the seed coat rather than the starchy endosperm. Buyers discount Black Point- affected grain because of the greater risk of black specks in flour and discolouration of end products, but if the darkened seed coat can be removed by careful milling, flour yield and quality may be unaffected. No silver lining: every year, some growers lose money through weather damage. Winning the war on weather damage In the first of two reports, MIKE PERRY looks at the challenge facing research to eliminate quality defects at delivery.
Ground Cover 053 December-January 2005 - North
Ground Cover 051 August-September 2004 - North