Ground Cover North : GroundCover 137 November-December 2018
REGIONAL EXTENSION REPORT PAGES 41 TO 43 ISSUE 137 | November – December 2018 By Gio Braidotti The rapid development of gene- editing technologies is providing plant breeders and researchers with important tools that complement existing plant breeding techniques. They provide a faster and far more specific way to alter target genes compared to traditional techniques. This is providing a faster route to improved traits for use in developing advanced grain varieties. Gene editing is a generic ter m for a set of molecular biology tools capable of making targeted sequence changes in the DNA of living cells. Most discussion, however, has centred on the CRISPR-Cas9 system, the most popular version of gene editing among medical and agricultural scientists. The practical applications of gene editing in crop improvement are many and varied. Internationally, examples from cereals include the editing of the MLO gene in wheat by Chinese researchers to confer resistance to powdery mildew and the replacement of the NRT1.1B gene in rice by Chinese and US researchers to improve nitrogen-use efficiency. Australian researchers are similarly CONSISTENCY KEY TO CAPTURING GENE-EDITING OPPORTUNITIES employing gene editing to address grain grower production constraints. GRDC has invested in CSIRO researchers working within the Australian Cereal Rust Control Program to use the technology to identify new rust resistance genes. While gene editing has been applied to many plants and animals, there are different views regarding the perceived risks posed by new gene-editing technologies. These have included considerations of the potential for unintended changes occurring to the genome beyond the targeted gene. A recent study of CRISPR-Cas9 has also prompted researchers to consider the potential Continued: Page 3 WITH THIS ISSUE 20-PAGE SUPPLEMENT Summer weeds Farm manager John Stevenson, from Lockhart, NSW, tested chickpeas for their suitability for cropping across Warakirri’s ‘Orange Park’ farm. However, dry conditions meant he did not harvest the crop. By Nicole Baxter n Farm manager John Stevenson planted kabuli chickpeas for the first time this year in a bid to investigate the pulse’s suitability as a profitable break crop on Warakirri Cropping’s ‘Orange Park’ aggregation near Lockhart, NSW. With return on investment the biggest challenge facing ‘Orange Park’, John had hoped chickpeas, planted in May this year, would add much-needed profit to the company’s bottom line. The decision to plant chickpeas came when John was looking for a profitable alternative to faba beans, which he says have been a great agronomic addition to the rotation at ‘Orange Park’. When John was completing a financial analysis to decide whether to plant the pulse crop, kabuli chickpeas were fetching about $1000 per tonne. Since then, the chickpea price has dropped, but at the time John felt there was money to be made. “It was easy to compare one tonne of chickpeas with one tonne of canola and decide we should be giving this a try because we’re obviously missing out on some potential income,” he says. “We worked out 1.5 tonnes per hectare of canola can only be as profitable as 0.75t/ha of chickpeas, so we only need half the yield to be equally as profitable at a lower growing cost.” To test the viability of growing chickpeas, John planted the ascochyta-resistant, small chickpea GenesisTM 090 into a 550ha block that had been sown to canola the previous year. The block was favoured because it was relatively free of weeds and contained the entire mix of soil types found across ‘Orange Park’, from acidic gravels to sodic vertosol clays. To assist nodulation, John used a double rate of peat inoculant before sowing. After using a Kelly chain to level the paddock, the GenesisTM 090 seed was sown at 3.5 centimetres deep targeting a plant density of 35 to 45 plants per square metre. Ideally, John says he would have preferred to have planted the seed 5cm deep, but the disc seeder he had recently purchased did not have enough ballast at the time to enable deeper penetration into hard, dry soils. Fortunately, 25 chickpea plants per square metre emerged, which John hoped would have been enough to produce a reasonable crop. He was hoping for a wet September and October to provide enough moisture for the chickpeas to produce pods with seeds. However, with extremely dry conditions and a growing season rainfall of just 67 millimetres, John decided not to harvest the crop. He says chickpeas will be tried again next year in the hope that they will prove to be a profitable crop in more favourable seasonal conditions. o Feature: Page 10 Chickpea trial beaten by the dry PHOTO:NICOLEBAXTER “IT WAS EASY TO COMPARE ONE TONNE OF CHICKPEAS WITH ONE TONNE OF CANOLA AND DECIDE WE SHOULD BE GIVING THIS A TRY.” – JOHN STEVENSON for unintended edits to occur in the target gene. CRISPR functions use a ‘guide RNA’ that can interact directly with DNA at the targeted gene. When these match up, the Cas9 protein is triggered to act as a scalpel, making a fine incision in the genome. The sequence of the gene is then modified when the cell acts to repair the cut in the DNA. From the technology’s inception, it was known that CRISPR-Cas9 could occasionally produce incisions at non-targeted regions of the genome (see GroundCoverTM issue 123).
GroundCover 136 September-October 2018