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Improvement of rice breeding using biotechnology approaches
mm
by Norman Darvey and Xiaochun Zhao March 2007
RIRDC Publication No 07/044 RIRDC Project No US-143A
This report outlines our research which is aimed at improving the microspore culture technology, which can produce genetically uniform double haploid (DH) plants in one generation from crosses between selected parent lines. Application of this technology in breeding programs can cut off several generations for fixation of genetic segregation and save several years with respect to the release of new varieties. We also report here on progress in incorporation of cold tolerance from Chinese germplasm into Australian rice. This research provides techniques and materials for significant improvements in rice breeding efficiency, and result in new cold-tolerant rice cultivars. This should lead to greater stability and improved yield for rice production under adverse weather conditions, improved water-use efficiency and overall improved sustainability.
Background
This is a one-year project
continuing research carried over from a previous Cooperative Research Centre
for Sustainable Rice Production (Rice-CRC) program. Within the Rice-CRC
funded project, we developed a rice isolated microspore culture system
for production of DH plants. A broad culture response in induction of callus
from isolated microspores was achieved from most of the tested Australian
and international rice varieties and hybrids. However the frequency of
converting callus into plantlets (regeneration) is low. Improvements in
callus regeneration are required to transform the Microspore culture (MC)
technique into a workable system.
Some Chinese cold tolerant rice germplasm has been introduced into Australia under the previous Rice CRC project. Some crosses have been made with Australian rice varieties in order to transfer cold tolerance into Australian rice. This is on-going research aimed at establishing advanced breeding populations for breeding, selection, and the development of molecular markers for cold tolerance, as well as using the best progenies for further cycles of crossing and backcrossing.
Aims/Objectives
The objectives of this research
are to improve rice breeding efficiency as well as improve cold tolerance
of Australian rice through microspore culture enabled DH plant production
technology, which is incorporating cold tolerance from Chinese germplasm.
The rice industry will benefit from this research through cold tolerant
cultivars with improved stability for production under adverse weather
conditions, and also save water which is normally used for deep irrigation
to protect young panicles from cold damage.
Methods used
All rice experimental materials
used in this project were grown in hydroponics in a glasshouse.
Improvements in plants regeneration from MC derived callus was mainly achieved via modifications to the callus induction and regeneration media which led to improvements in callus quality and the frequency of regeneration.
Rice germplasm and segregating populations derived from different crosses were subjected to a low temperature treatment at 12 – 14°C for 4 days at panicle initiation stage to investigate cold tolerance.
Cold tolerant germplasm and individual plants were selected for crossing and backcrossing.
A two-step induction culture medium has improved callus quality and plant regeneration. Some DH plants have been produced.
Results/Key findings
Four Chinese varieties demonstrated
strong cold tolerance under our testing conditions. These varieties have
been crossed with Australian varieties. Some cold tolerant F2 plants have
been selected for backcrossing to ‘Doongara’. The hybrids of the crosses
have being processed for DH plant production.
Implications for relevant
stakeholders
Improvement of cold tolerance
will ensure stable rice production and save water. This will make the rice
industry more sustainable, and also minimise the conflicts between the
rice industry and other industries with respect to water use.
Recommendations
This research has demonstrated
that a two-step callus induction medium improves callus quality and plant
regeneration. Further optimisation of this technology should transform
isolated microspore culture into a workable technology for medium to large
scale DH production.
Further work should be carried out using existing and additional sources of Chinese cold tolerant germplasm for the improvement of cold tolerance in Australian rice, and for the development of molecular markers for cold tolerance selection.
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