Farmers' Newsletter No 171, Summer 2005
For other issues see here
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| AGRONOMY AND CROP PROTECTION |
Bloodworms - the search for the X factor (293 K)
- Bloodworms release a compound into the water of rice fields which deters adult rice bloodworm midges looking for suitable egg laying sites – adult midges respond by laying their eggs in other areas where there will be less competition
- Identifying the compound involved in deterring midges may help to provide an alternative approach for bloodworm management in establishing rice crops
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Travels with Stroppy (230 K)
- Small transmitters have been attached to 23 grey teal Anas gracilis in the rice-growing areas and in the Lake Eyre Basin to track bird movement by satellite
- One bird released in the Lake Eyre Basin has been tracked for nearly two years
- Individual birds have moved up to 978 km in a single flight and travelled more than 6400 km since being released
- Satellite imagery is being used to map wetland distribution and combined with transmitter information, these data will be used to model waterfowl movements
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Ecology and biology of nuisance algae in rice fields (407 K)
- Brown slime is due to sticky sugars (polysaccharides) on the surface of bacteria, which cause stubble and a variety of organisms to adhere to it, leading to the formation of mats of slime
- Brown slime is frequently associated with particular conditions on grey soils, which are rich in reduced iron; once nitrogen and water are added, iron-oxidizing bacteria, which lead to slime, multiply and the soil colour changes to orange-brown
- It is impossible to remove either bacteria or iron from rice growing soils but if slime inducing conditions are managed during rice establishment, yield loss can be avoided
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Cold damage leaves nitrogen questions unanswered in 2004-05 (230 K)
- It is difficult to make solid conclusions about 2004–05 trials on nitrogen fertiliser application timing, as the results may have been influenced by the extreme cold weather experienced during the first week of February 2005
- However, this season, treatments with split nitrogen application showed better yields than total pre-flood nitrogen applications
- In continuously flooded fields, a second nitrogen application at panicle initiation showed better yields than a nitrogen application at mid-season
- In fields drained at mid-season, a second application of nitrogen fertiliser just before re-flooding showed better responses than application at panicle initiation
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Remote sensing of nitogen in rice crops (160 K)
- This project is investigating the potential to combine the precision of the NIR Rice Tissue Test with the sampling ease and overall "picture" provided by remote sensing imagery
- Current remote sensing produces a map distinguishing areas of differing vegetative growth, which can aid in determining where to take samples for NIR analysis but it is not a direct measurement of plant nutrients
- Correlations between spectral information from satellite imagery and results from traditional NIR tissue testing suggest a strong relationship between the two, paving the way for remote nitrogen testing for rice crops
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| SUSTAINABLE FARMING SYSTEMS |
Effects of rice pesticides on soil and aquatic organisms (309 K)
- The effect of pesticides on overall soil microbial activity was not significant and no measurable effect on soil biological health could be established under field conditions
- Laboratory experiments were conducted to avoid the effects of field variability and in these conditions also, overall microbial activity was not adversely affected by pesticide applications, although some potential toxicity of pesticides to soil biological processes was observed
- Based on a suite of tests, the pesticides were ranked in decreasing order of toxicity: Chlorpyrifos > Fipronil > Thiobencarb > Molinate > Benzofenap > Clomazone. Pesticides when applied in mixtures or together with high salinity levels were found to show greater toxicity to organisms
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Continuous sampling of pesticides in waterways (224 K)
- Passive sampling devices offer a cheaper and more effective procedure for measuring pesticide concentrations in the aquatic environment over time than conventional manual sampling procedures
- Once the passive samplers are calibrated for each pesticide, their ability to determine time-integrated water concentrations will make it possible to link average water concentrations to water quality guideline values
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Permanent beds for sustainable cropping (337 K)
- High wheat and barley grain yields were achieved in 2004 on both lateral raised beds and flat layouts in a year with no rainfall-induced waterlogging in winter and spring
- Good growth and grain yield of double-cropped soybean and barley were achieved on lateral beds in bays over two consecutive years (four crops)
- Rice yields on raised beds were low due to severe cold damage at the young microspore stage in 2005, and several management issues which will be addressed in the 2005–06 summer cropping season
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| VARIETAL IMPROVEMENT AND PURE SEED MAINTENANCE |
Drought puts new focus on rice improvement program (441 K)
- Low levels of rice production have led to changes in the objectives of the breeding program, with an increased emphasis on improving the cold tolerance of varieties in all grain quality classes
- A greater proportion of breeding program resources will be directed at improving medium grains in all maturity groups, and soft-cooking long grains similar to Langi
- A series of selections from a long-grain line will continue in testing as possible Langi replacements
- On-farm testing of two new fragrant lines will continue in advanced trials, as possible Kyeema replacements
- Two advanced medium-grain lines will be maintained in advanced trials as possible new varieties in the Amaroo and Millin maturity classes
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New tools for precise and efficient grain evaluation (205 K)
- A partnership has been formed between the irrigation associations and the Australian government to develop a national certification and training framework and an information network for the irrigation industry
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Perfect molecular markers for fragrance and gelatinisation temperature (153 K)
- Molecular markers have been identified that will help Australian rice breeders identify 'difficult to measure' traits, early in the rice breeding program
- Markers for fragrance and gelatinisation temperature have been identified, meaning that quick DNA analysis methods on tissue from young rice plants can replace labour intensive, time consuming analysis on harvested rice grain
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Diversity array technology (DArT) for the rice breeding program (230 K)
- Diversity array technology (DArT) provides a powerful tool for measuring genetic diversity among breeding lines and cultivars at the molecular level – the technology provides a means for "fingerprinting" rice varieties
- DArT can be used in breeding programs to compare the DNA of parent lines and their progeny
- Diversity panels (the means of setting out all the genetic information) have been generated and analysed using DArT for 243 diverse rice varieties from around the world, including 50 varieties used extensively in the breeding program at Yanco
- A sub-set of 69 semi-dwarf lines were phenotyped for seedling vigour from a specific cross, and DArT analysis of the highest and lowest vigour lines showed a total of 61 DArT markers that varied – raising the prospect of using DArT analysis to select for specific DNA fragments associated with traits needing improvement, such as seedling vigour
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Rice microspore culture - a fast track to new varieties (215 K)
- Immature pollen grains or microspores (with one set of chromosomes, haploid) can be made to divide and grow into a complete haploid plant on a specialised culture medium
- The microspore-derived plants can then be induced to double their chromosome number to obtain doubledhaploid plants (with two identical set of chromosomes, thus homozygous), which is an attractive alternative to repeated cycles of in-breeding in self-pollinating crops like rice
- Establishment of a microspore culture system for rice at Yanco would mean breeders will have direct access to doubled-haploid plants, thus development of better varieties faster
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| EXTENDING RICE TECHNOLOGY |
Accolades and advancement for irrigators (185 K)
- A combo-seeder, designed for working in heavy stubble has been purchased by IREC, for use by farmers and groups in local trials
- The 2005 Irrigated Farm Competition (Horticulture) highlighted irrigators who enjoy success through novel partnership agreements, innovative technology and risk management strategies
- IREC is encouraging and working with other groups and organisations to identify key areas of R&D, so coordinated proposals for funding can be tendered to appropriate organisations
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Better extension programs improving rice yields (230 K)
- The rice extension program facilitates the transfer of the best techniques and new technologies to rice growers
- The benefits of the extension program over the last seven years are not immediately evident due to the impact of three years with cold damage and two years affected by drought
- Economic evaluation of Ricecheck has demonstrated a benefit of $18.50 to the rice industry for each dollar invested in the Ricecheck program, over and above normal research, breeding and extension activities
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| Rice book almost finished.pdf (206 K) |
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