Program 3 Genetic Improvement For Sustainable Production
Program Leader:
Dr Liz Dennis
CSIRO Plant Industry
Canberra
Research in Program 3 uses traditional breeding and physiology combined with newer molecular techniques to improve the genetic base of the Australian rice crop. Australia's rice industry already produces a high yield. Our aims are to increase this yield further and to overcome specific problems such as reduction of yield through low temperatures and its effect on grain development.
Traditional breeding approaches include the evaluation of new lines from other countries with the characteristics of shorter duration life cycle or male sterility for possible use in hybrid rice development with the potential of increased yield. Advanced physiological approaches involve screening rice lines for improved yield potential using stomatal aperture traits, which may result in improved water use efficiency or other desirable attributes.
Molecular approaches include identification of the cellular and molecular characteristics responsible for cold-induced pollen sterility and introduction of genes for resistance to bloodworm attack. Advanced tissue culture approaches may assist breeding objectives.
Genes affecting quality attributes such as suncracking and starch content and structure are also being investigated. It is hoped that this combination of traditional and novel methodology will improve the sustainability of Australia's rice industry.
Sub-Program Leader:
Dr Laurie Lewin and Mr Russell Reinke
NSW Agriculture
Yanco
Improved yield efficiency can be achieved through increased grain yield, by maintaining yield but reducing duration or a combination of both. The RIRDC-funded rice improvement program has improved yield potential and reduced duration as objectives. The CRC Sub-Program aims at novel approaches for development of this objective.
Improved yield efficiency (3101)
Project Leaders:
Dr Laurie Lewin, Mr Russell Reinke and Mr Peter Snell
NSW Agriculture
Yanco
· Short duration rice
Rice cultivars introduced from Russia and Hungary were evaluated for yield and quality characteristics. They were of shorter duration than Jarrah, the quickest growing NSW commercial rice cultivar. Liman and Spalchik, two of the Russian cultivars, had relatively high yield potential but they were of poor grain quality and would not be acceptable, particularly for chalkiness. The other Russian and Hungarian cultivars had unacceptable yield and quality.
Sixty-two additional crosses were made with these cultivars during the year. These crosses were made in an effort to combine acceptable yield and quality with the rapid growth, seedling vigour and good cold tolerance of the varieties.
These sources of short duration are likely to be of significance for the development of more efficient cultivars if the linkage can be broken between duration and poor quality.
Table 3. Duration (days sowing to anthesis) and grain yield (tonnes/hectare at 14% moisture) of Pavlovsky, Liman and Spachik from Russia, HSC55 from Hungary and Jarrah (NSW commercial cultivar) in a trial at Leeton.
Cultivar |
Duration |
Grain yield |
(days to anthesis) |
te.ha-1 | |
Pavlovsky |
97 |
5.5 |
Liman |
97 |
9.5 |
Spalchik |
96 |
9.4 |
HSC55 |
88 |
3.3 |
Jarrah |
103 |
9.0 |
lsd (p<.05) |
3 |
1.5 |
Table 4. % whole grain (whole milled grain as a percentage of paddy entering the milling process) and % chalk (% chalky area expressed as a percentage of the total milled grain surface area) for the four cultivars in Table 3.
Cultivar |
Whole grain |
Chalk |
% |
% | |
Pavlovsky |
44.5 |
9.8 |
Liman |
33.2 |
15.7 |
Spalchik |
31.5 |
17.0 |
HSC55 |
38.6 |
34.0 |
Jarrah |
69.3 |
6.3 |
lsd (p<.05) |
4.0 |
4.5 |
· Hybrid rice
There is potential to improve yield through production of hybrid rice. Most production of hybrid rice is in "indica" producing areas rather than in those areas, like Australia, that produce "japonica" rice. There are no satisfactory sources for sterility in "japonica" types and this has been an important barrier to the production of hybrids in Australia.
The 11 cytoplasmic and seven thermo-sensitive male sterile lines, introduced from the International Rice Research Institute, were multiplied and some crosses made in an effort to create improved male sterile lines. The lines are of long duration when grown in Australia, however, and this has slowed the progress in this project. Further multiplication will be attempted in the glasshouse but field production will be delayed until new, shorter duration lines can be developed.
· Evaluation of tropical japonica germplasm (super rices)
The first generation "super rices", introduced from the International Rice Research Institute were poorly adapted to Australian rice growing conditions (1998/1999 Annual Report). They were late maturing and cold susceptible. The next generation of introductions were of similar maturity and could not be sensibly tested. They produced large panicles but were sterile and had poor grain quality. The lines have been crossed with more adapted cultivars and the progeny will be evaluated when developed.
New indirect selection techniques for improving rice yield potential (3102)
Project Leader:
Dr Tony Condon
CSIRO Plant Industry
Canberra
There is strong evidence, from previous work with rice and ongoing work with wheat, that physiological traits related to stomatal aperture may prove effective in screening rice breeding lines for yield potential.
This project aims to determine:-
Progress
During January 2000 variation in canopy temperature was assessed in replicated and unreplicated field trials at Yanco. Leaf samples were collected for analysis of stable isotope composition of oxygen and carbon. Near-infrared reflectance (NIR) is being assessed as a possible means of reducing the cost of these isotope analyses. Once these analyses are complete then relationships between canopy temperature, isotopic composition and grain yield will be determined.
Achievements/Highlights
Substantial genotypic variation in canopy temperature was found within the rice germplasm tested. Preliminary results from the use of NIR have been encouraging and strategies have been devised to improve the reliability of the technique as a surrogate for expensive isotope analyses.
Sub-Program Leader:
Dr Liz Dennis
CSIRO Plant Industry
Canberra
The chief abiotic stress investigated in this Sub-Program is the molecular and cellular basis of cold induced pollen sterility, which can decrease rice yields by as much as 50% in bad years, and by some percentage most years. The cellular and molecular approaches being investigated in Program 3 complement the physiological approaches in Program 2. Biotic stresses investigated include attack by bloodworm where a molecular approach is underway and weed competition where a number of rice lines are being screened for the ability to compete with weeds.
Molecular basis of cold tolerance (3201); Molecular mechanisms of cold stress (3204)
Project Leader:
Dr Liz Dennis
CSIRO Plant Industry
Canberra
Cold-induced pollen sterility in rice is a major problem in Australia and other temperate rice growing areas in the world. Attempts to select cold-tolerant rice varieties using breeding techniques have been relatively unsuccessful. This is mainly due to a poor understanding of the physiology and molecular basis of the problem. This project aims to use molecular biology techniques to identify which genes are affected by cold conditions. The outcomes of this study will lead to the design of strategies to engineer cold-tolerant rice varieties either by genetic engineering or molecular marker assisted breeding. This will be achieved by using the following approaches:-
Progress
Cellular biology of chilling-induced pollen damage in rice (3202 - incorporates former Projects 2203/2204)
Project Leader:
Dr Bruce Sutton
University of Sydney
Sydney
The aim of the project is to provide a description of the development and physiology of the anther up to the early microspore stage using light and electron microscopy.
It is becoming clear to us that the development of reproductive tissues in rice is very sensitive to a range of stresses which the plant may encounter, resulting in abortion of the male (pollen), female (ovary) tissues or both. Chilling damage is a result of the plant aborting pollen development after a short exposure to mild (12-15°C) chilling, with the female parts in this case remaining undamaged (Satake and Koike, 1983). The sensitive stage for this response appears to be late in meiosis, around the stage of tetrad release. Of all the possible mechanisms that may be responsible for this result, we are currently examining two broad areas. Is the chilling damage a direct effect on the meiotic cells or is it a response to changes that chilling causes in the integrated functioning of the anther?
Progress
· Culture of anthers and meiocytes for live cell studies
Many processes are not well described for anther development in any species. In rice, factors such as the duration of meiosis, cell energy levels, and substrate tracer studies have not been investigated and require the development of a viable culture method for isolated anthers or meiocytes so that they can be examined. Dr Laurence Cantrill has been conducting this work with the cooperation of Dr Norman Darvey's group at PBI Cobbitty (Sub-Program 3.3) with the aim of carrying the meiocytes from premeiosis through meiosis to tetrad and early microspore stages. Early problems encountered in culturing anthers had parallels with symptoms of cold damage, namely tapetal hypertrophy and meiocyte or microspore collapse while the surrounding tissues remained viable. Indeed, the tapetal hypertrophy and rapid meiocyte/microspore death observed in tissue culture might serve as a model for pollen abortion under chilling stress. The challenge has been to reduce stress-related damage to the anthers after they are isolated from the plant. A range of anti-stress and anti-cell-death compounds has been employed in an attempt to overcome this problem.
· Structural and physiological studies at the cell level
Techniques for fluorescent labelling of whole anthers to examine callose distribution, cytoskeleton, and meiosis have been developed. Methods for live cell labelling to monitor cell viability, cell energy levels and mitochondrial function are also available but are dependent upon successful culturing of whole anthers or isolated meiocytes.
· Rice anther development under normal and chilled conditions
Development of the anther at these stages is not well described in the literature. Most information available is restricted to the meiocytes and the tapetum and there is little knowledge about the other tissues; the middle layer, endothecium, epidermis and anther filament. As part of his PhD work, Mr Mohammad Ezaz Al Mamun has been documenting the developmental sequence of the rice anther covering all the cell layers using light and electron microscopy. High quality images have been produced. A parallel study on chilled anthers has revealed differences in development such as tapetal hypertropy as well as some potential new symptoms of cold damage including granular locule contents, loss of exine formation around microspores, and the presence of vacuole-like bodies in the tapetal cell layer.
|
Transverse electron micrograph of rice anther grown under 12°C night temperature. Normal epidermis (ep) and endothecium (en) layers surround a middle layer (ml) with enlarged vacuoles, tapetum (t) with numerous vacuole like bodies (arrows) and microspores (mi) lacking development of the pollen wall. |
· The role of callose formation and dissolution in rice anther chilling damage
A particularly important part of structural development is the deposition and dissolution of callose in the anther. Callose is a _-1,3-D-glucan that is deposited in a thick layer between the plasmalemma and cellulose cell wall of meiocytes prior to meiosis. Isolation of the meiocytes by callose is thought to be necessary to confine meiosis within these special cells and the callose wall might also form a template for later deposition of the pollen exine. Work has been progressing in immunogold labelling of EM sections of rice anthers to examine the distribution of callose in the cell walls of anthers under normal and chilled conditions. We have also obtained an antibody against two forms of the _-1,3-D-glucanase enzyme involved in callose dissolution that will be used in immunolocalisation studies.
· Pathways of substrate supply
The process of anther development and pollen formation places heavy demands on substrate supply. The literature on the tapetum concentrates on its role in supplying metabolites to the microspores in the later stages of pollen development, particularly those associated with pollen wall (exine) development. However there is little information on the supply of substrates, particularly energy substrates, in the early chilling sensitive stages of pollen development. We are pursuing this to determine whether chilling may be causing a disruption in substrate supply.
Mapping of the pathways of substrate movement within anthers grown at normal temperatures has been carried out using two different techniques, namely microinjection and the passive loading of symplasmic tracers. This work done by Dr Laurence Cantrill and Ms Karen Herbert within Assoc Prof Robyn Overall's laboratory has revealed that the phloem within the filament of the anther is linked symplasmically with the epidermis and endothecium. However, the middle layer, tapetum and meiocytes are symplasmically isolated from the phloem fairly early in development. This indicates a role for plasmodesmal regulation followed by energy dependent apoplasmic transport of sugars from the source leaves to the developing pollen grains. The presence of an apoplasmic step has particular relevance for work being carried out on chilling sensitivity of invertases in the rice anther by Dr Liz Dennis's group at CSIRO Plant Industry, Canberra. In addition, microinjection experiments have shown that plasmodesmata within the epidermis of the rice anther have a large size exclusion limit that might indicate cell-to-cell movement of large volumes of substrate and/or developmentally important macromolecules.
Further work on substrate pathways using fluorescent and radiolabelled sugar analogues as well as 14CO2 incorporation will be used to more precisely follow the sugar pathways from source to sink in the rice anther. Fluorescent tracer studies will also be carried out to observe the symplasmic linkages between the inner cell layers of the anther.
|
Dr Laurence Cantrill and Mr Mohammad Ezaz Al Mamun in the confocal microscope room. |
References
Satake, T., and Koike, S. (1983). Sterility caused by cooling treatment at the flowering stage in rice plants. I. The stage and organ susceptible to cool temperature. Japanese Journal of Crop Sciences, 52: 207-214.
Engineering rice for resistance to bloodworm (3203)
Project Leader:
Dr Liz Dennis
CSIRO Plant Industry
Canberra
The aim of the project is to develop rice varieties resistant to bloodworm (Chironomus tepperi). This should lead to decreased use of pesticides during rice establishment.
Specifically, the project aims to:-
Progress
The growth conditions required to culture Bti have been determined and the toxicity of the culture and purified crystals to C. tepperi indicates that the level of expression required to control the larvae is within levels achievable in transgenic plants. To determine the most effective combination of genes, all of the known Cry toxin genes in Bti have been cloned and are being used to express them as single gene product strains in sufficient quantity to conduct toxicity bioassays.
Identification of the most toxic gene/combination will be followed by preparation of constructs for expression in rice.
Current knowledge of C. tepperi feeding on rice seedlings suggests that rice roots are the primary target of their feeding. However if the roots are made toxic, then it is likely that the feeding pattern would change to include the shoots. Constructs are being made to determine if double stranded RNA can achieve tissue specific transgene suppression. If tissue specific suppression is feasible then it would be possible to severely reduce the expression of the toxin genes in the parts of the plant meant for human consumption.
|
Trial site at Yanco Agricultural Institute sampled to determine patterns of chironomid colonisation. |
Allelopathy and weed competition (3205)
Project Leader:
Prof Jim Pratley
Charles Sturt University
Wagga Wagga
Research conducted in the United States and the Philippines has demonstrated that a number of rice varieties have the ability to suppress the growth of certain weeds. The current project aims to:-
Progress
In an attempt to locate a rice variety that has retained its allelopathic ability despite selection pressures for higher yield and competitive ability, 46 rice varieties originating from 17 different countries were selected and obtained.
After discussions with prominent allelopathy researchers at the Second World Congress on Allelopathy in Thunder Bay, Canada, work commenced on the development of a suitable bioassay which would effectively separate allelopathy from competition in an aquatic system. A reliable screening procedure has yet to be established for each of the four major weeds of Australian rice crops, namely Echinochloa crus galli, Sagittaria montevidensis, Cyperus difformis and Damasonium minus. Once established, allelopathic potential of the various rice cultivars can be assessed and chemical analysis can be undertaken.
Salt tolerance
Project Leader:
Mr David Troldahl
NSW Agriculture
Yanco
Whilst there is ongoing research into salinity control on-farm, no salt-tolerant rice varieties have been developed in Australia. Salt-tolerant varieties would be useful where rice is to be used to reclaim salt-affected areas, where water is used from saline underground water or where salt accumulates temporarily in bays.
The aim of the project is to measure the response of NSW commercial rice cultivars to salinity and to devise selection strategies to ensure that cultivars of the future have adequate tolerance.
Progress
Glasshouse trials have continued to screen commercial and advanced breeding lines using different salt treatments. The screen is being modified to enable testing of more lines of rice per screen to increase throughput.
Concurrent trials have been carried out in the glasshouse (Yanco) and in the field (Deniliquin) to assess the effects of salt on commercial varieties through to maturity. These trials look at the impact of salt on plant biomass, yield, grain size, grain quality and time of salt applications and its effects on the plant.
Medium grain cultivars Amaroo, Namaga and Millin were most tolerant, where long grain cultivars Langi and Pelde were least tolerant. The reactions of Jarrah, Doongara and Kyeema were variable and will be re-tested.
Seven salt-tolerant genotypes were recommended by International Rice Research Institute scientist Dr Corinta Quijano after discussion at the 2nd Temperate Rice Conference in Sacramento. These were chosen for their likely adaptation to Australian conditions. These genotypes have been introduced and will now be included in the crossing and research program.
Sub-Program Leader:
Dr Norm Darvey
University of Sydney
Cobbitty
Use of anther culture is now a recognised tool for speeding up rice breeding. Its application is limited, however, by low regeneration rates. This could be improved by development of an appropriate microspore culture method.
Related to the development of microspore culture is the development of a standard system for isolated organ culture. This would provide a standard system for controlled experiments on cold tolerance.
A third objective is to develop a hydroponic system to provide more panicles for cold tolerance and reproductive experiments.
A third objective aimed at clonal propagation of rice plants in vivo using a locally constructed hydroponic system is proving to be highly successful, and large number of panicles have been generated for experimental purposes. Information on the system and media components is available from Dr Xiaochun Zhao. This system requires a significant input of artificial lighting during the winter months, and new HQI (halogen quartz iodide) lights are currently being installed in one of the quarantine greenhouses, which is the main location of the clonal propagation of rice. This program also generates a significant number of panicles for the research group on the main (Camperdown) campus.
Microspore and spikelet culture in rice (3301)/ Microspore culture of rice for rapid breeding and enhanced levels of interspecific recombination (3303)
Project Leader:
Dr Norm Darvey
University of Sydney
Cobbitty
· Microspore culture
The aims of the project are to:-
Progress
The original objective of this Sub-Program was to develop an isolated microspore culture system for rice. This project was initiated by Dr Xiaochun Zhao with the assistance of a masters coursework student in Plant Breeding, Ms Xiao Bo Lu. The work on "anther culture" identified moderate levels of embryoid induction in a number of Australian cultivars, with good responses being obtained with cultivars Doongara, Calrose, Jarrah and Kyeema. A positive response to the use of the anti-mitotic herbicide APM (amiprophos-methyl) was obtained for all but one of the tested cultivars during the pre-treatment phase. Likewise the cultivars Millin and Doongara responded positively to the presence of the anti-apoptopic compound ATA (aurintricarboxylic acid) in the induction medium. From June 2000, this work will be continued by a postgraduate student, Mr Manoj Gupta. In the meantime, the project technical assistant, Ms Feiyan Chen, has initiated some isolated microspores on liquid medium, and obtained a good level of embryoid induction using the excellent wheat and triticale medium, CHB (Chu et al., 1990) on the cold tolerant Japanese rice cultivar Hitomebore (Figure 11). This was the first positive result with isolated microspore culture of rice in Australia. Some of this success is in part due to modifications to the procedure for the isolation of the microspores.
Figure 11. Rice isolated microspore culture.
Left: 12 days in induction medium (Hoffman interference microscopy). Solid arrows indicate dividing microspores, line arrow indicates a microspore which is about to commence division. Right: 20 days in induction medium (bright field microscopy). Numerous embryoids present (some marked with arrows). |
|
· In vivo and in vitro culture of rice for controlled experimentation into cold tolerance
Large numbers of spikes continue to be generated in the hydroponic systems (Figure 12). The alternative approach at propagating plants with roots in vitro was not followed up in 1999/2000 but remains of interest as a means of speeding up the turnover of generations.
Figure 12
|
Hydroponic culture of rice |
Another approach to studying the critical stage of cold damage in rice is to culture the spikes or the floral organs in vitro for a sufficient period of time to allow normal cell processes to take place during the critical stage of damage by cold. In 1998/1999, it was noted that: (i) different panicle development stages give different culture responses; (ii) growth regulators affect culture response and hormones are necessary for panicle and anther development; (iii) the composition of the culture medium has a significant effect on the culture response. The most successful medium that has been identified since 1998/1999 has been a modified wheat spike culture medium, which consists of high concentrations of amino acids, vitamins and other organic chemicals. In this medium, which contains reduced nitrogen, individual spikes containing anthers at various developmental stages from meiosis to the uninucleate stage, showed normal physiological development of the anthers and associated tissues, and after five to seven days shed pollen grains into the medium (Figure 13). These pollen grains appeared normal in that they stained black with iodine. Further attempts to increase the precision of the culture system indicated that the earliest stage for the successful culture of the anthers was post-meiotic, commencing at the tetrad stage. Attempts to culture microsporocytes prior to the tetrad stage in rice have so far been unsuccessful.
Figure 13
|
Rice anthers in culture media |
· Molecular genetics research
During the ongoing research work it became evident that there was an increasing interface between molecular biology and cellular biology. Mr. Zhao has focused on seeking molecular markers for cold tolerance and has worked as part of Dr Liz Dennis' group in Canberra. His most recent work involves the identification of genes involved in low temperature male sterility in rice by using a differential subtraction chain technique.
Progress
Differential subtraction chain is a PCR-based sequential subtractive hybridisation method that rapidly isolates unique DNA sequences present between two tissue or cell types. In the first experiment, the rice cultivars of "Doongara" and "Langi" (both of them were classified as cold susceptible) were grown at both a normal temperature and low temperature (13ºC for three days) during the booting stage. The cDNAs were synthesised from mRNA extracted from anthers which were between meiosis and the tetrad stage. Restriction enzyme fragmented cDNAs were ligated to an adaptor. Two populations of PCR amplified cDNA fragments from the plants grown in the different temperatures were hybridised reciprocally to remove common DNA sequences. After three rounds of hybridisation, some unique expressed DNA sequences were isolated from both varieties of normal temperature vs. low temperature hybridisation as shown in the Figure 14. This suggested that some genes have been switched off at the low temperature in these two varieties.
Figure 14. 1st subtractive hybridisation testing.
|
|
Sub-Program Leader:
Mr Tony Blakeney
BRI Australia Ltd
Sydney
The quality attributes of rice include physical descriptors of the milled white grains and characteristics of the cooking quality of rice. In this Sub-Program research is addressing three quality attributes that are difficult to measure and to breed for:-
· suncracking;
· amylose structure; and
· heritability and expression of isoforms of the genes of starch synthesis.
The problem of cracked grain reduces both yield and quality. Cracked grains tend to break during milling, which decreases milling yield and those that do not break detract from the physical appearance of the rice. It is difficult to breed for because environmental conditions greatly influence cracking.
Cooking quality is difficult to breed for as the factors that influence it are not fully understood. The findings of the projects on amylose structure and on the isoforms of the genes of starch synthesis will contribute to our understanding of cooking quality and our capacity to breed rices that contain the quality attributes that markets desire.
Suncracking in rice (3401)
Project Leader:
Dr Melissa Fitzgerald
NSW Agriculture
Yanco
Following the resignation of the student for this project a review occurred to see whether the objectives needed to be revised as a result of progress to date and the time available for the remainder of the project. As a result the aim of this project is to determine the susceptibility of each of our varieties to suncracking, and to understand the physical basis for susceptibility to suncracking and the difference in eating quality between cracked and whole grains.
Progress
It was previously thought that grains cracked along cell walls, but we now have data that shows grains crack through cells and through starch granules. The cooking quality of cracked grains differs from the cooking quality of whole grains, and since starch granules are broken, this is no surprise. One of the factors that influence cooking quality is the fragility of the granules. Fragility is a parameter that is influenced by cracks. The cooking quality of rice of varieties with fragile starch granules seems to be affected to a greater extent with cracking than for varieties that have more robust granules.
At a particular temperature during the process of cooking, starch granules absorb water and swell within the starch granules: several enzymes exist that can break down starch. One of these,__-amylase, cuts starch randomly, and therefore changes the ability of the starch granules to bind water and swell. For rice, starch granules begin to absorb water and swell at about 65 -70°C; at this temperature, _-amylase is not viable. However, a broken starch granule exposed to water and _-amylase is viable; the enzyme can break the starch and change the cooking quality. The addition of silver nitrate to cooking quality (RVA) tests in wheat renders _-amylase non-viable. This provided a way to test whether _-amylase was affecting the starch. When silver nitrate was added to RVA tests of whole and broken grain, in all cases but one, the difference between whole and broken grain was removed, indicating that the ability of _-amylase to act on starch in broken grains contributes to the difference in cooking quality between whole and cracked grain.
Progress was being made on screening the different varieties for their tolerance to suncracking. A technical problem has slowed progress but this will be overcome in the near future. The varieties screened so far show differences in their susceptibility to suncracking.
Understanding amylose structure: what it controls and what controls it (3402)
Project Leader:
Dr Melissa Fitzgerald
NSW Agriculture
Yanco
This project aims to:-
Progress
A technical officer has been appointed, plants with different alleles of the GBSS gene have been grown and material collected from them. The method for separating amylose from amylopectin has been incorporated into the research project. Two varieties, Koshihikari and Amaroo have the same amylose content (~19%) but different eating qualities. They also differ in the GBSS allele they contain. The amylose of Koshihikari appears to contain more branches and more high molecular weight chains than the amylose in Amaroo. Progress in understanding the relationship between amylose structure and eating quality is underway.
Investigation of the molecular mechanisms of starch quality (3403)
Project Leader:
Dr Christopher Blanchard
Charles Sturt University
Wagga Wagga
The aim of this project is to characterise known rice genes and isolate new rice gene promoters that may be important for rice quality. A component of this project is the postraduate project of Mr Andrew Eamens. He has completed part of his study at Charles Sturt University, Wagga Wagga and relocated to Canberra to carry out additional components on functional genomics.
Progress
Sixty-two rice varieties were screened for the presence of a mutation which affects amylose content.
Two fragments, derived from a PCR amplification using primers complementary to exon 1 of the rice granule bound starch synthase (GBSS) gene, have been cloned and sequenced. One fragment was a non-specific amplification product. The other fragment was derived from the GBSS gene and contained a number of regions where the DNA sequence differed from the published sequence.
The focus of the work has now shifted to functional genomics with an emphasis on quality attributes.
|
Mr Andrew Eamens amplifying rice gene |
Milestones
Milestone |
Year 1 |
Year 2 |
Year 3 1999/2000 |
Year 4 |
Year 5 |
Year 6 |
Year 7 | |
3.1 |
Improved yield efficiency |
|||||||
Appointment of assistant |
X Deferred |
Deferred |
||||||
Introduction of male sterile lines |
X _ |
X _ |
X _ |
|||||
Evaluation of hybrid lines |
X Commenced |
X no lines developed |
X |
|||||
Evaluation of tropical japonica lines |
X _ |
X _ |
X discontinued |
|||||
Development and evaluation of inducible male sterility |
X RIRDC project |
X RIRDC project |
||||||
Evaluation of available apomictic systems |
X RIRDC project |
X RIRDC project |
X |
X |
X |
X | ||
Incorporation of improved yield traits |
X Commenced |
X _ |
X |
X |
X |
X | ||
3.2 |
Stress tolerance |
|||||||
Cold scientist appointed |
X _ |
|||||||
- develop assay methods for pollen sterility |
X _ |
|||||||
- ABA assay |
X Developed |
|||||||
- potential genes isolated |
X _ |
X _ |
||||||
- insert and test useful constructs |
X Commenced |
X _ |
X |
|||||
- student project commenced |
X _ |
X _ |
X _ |
X |
||||
- genes incorporated from Zinania |
X RIRDC project |
X RIRDC project |
||||||
Bloodworm resistance |
||||||||
- Feasibility investigated |
X Commenced |
X Partially achieved (see report for 3.2) |
_ |
|||||
- Insertion of genes |
X _ |
X |
X |
|||||
Allelopathy |
||||||||
- student appointed |
X Deferred |
_ |
||||||
- varieties introduced |
X Commenced |
X Partly achieved |
||||||
- mechanics studied |
X Deferred |
X Deferred |
X _ |
X |
||||
- characters incorporated |
X |
X |
X |
X | ||||
Salt tolerance |
||||||||
- commercial varieties evaluated |
X _ |
X_ |
||||||
- resistance incorporated |
X Commenced |
X continuing |
X |
X |
X |
X | ||
3.3 |
Breeding methods |
|||||||
Isolated microspore culture |
||||||||
- conditions optimised |
X Partially achieved |
|||||||
- optimise response |
X Partially achieved |
X Commenced |
X _ |
|||||
- evaluate cultivar response |
X Commenced |
X _ |
X |
|||||
- doubled haploid production |
X Not Achieved |
X commenced |
X |
X |
X |
X | ||
- extension of technique |
X |
X |
X | |||||
Development of markers for semi-dwarf and fragrance |
X RIRDC project |
X RIRDC project |
X |
|||||
Extension of markers to other traits |
cold |
X |
X |
X | ||||
Development of male sterility |
X |
X |
X |
X | ||||
3.4 |
Breeding for quality attributes |
|||||||
Appointment of research officer, PhD student |
X _ |
|||||||
Appointment of a technical officer |
X _ |
|||||||
Evaluate factors promoting chalkiness |
Promoted from year 2 to year 1 |
X Transferred to RIRDC |
X RIRDC project |
X |
||||
Evaluate factors promoting suncracking |
X Commenced |
X _ |
X |
|||||
Evaluate novel quality characteristics |
X Waxy gene evaluated |
X Commenced |
X _ |
X |
X |
X |
X |
X = Year due for completion (in some cases this exercise is spread over several years).
_= Achieved (if not achieved, status provided)
