| |
The Identification of Advanced Barley, Spring Triticale, Winter Triticale, and Winter Wheat Lines with Improved Levels of Dormancy
Inheritance of Seed Dormancy Complex Trait in Barley
Drought Stress Effects on Barley and Triticale
The Identification of Advanced Barley, Spring Triticale, Winter Triticale, and Winter Wheat Lines with Improved Levels of Dormancy
Purpose
To identify advanced lines in the breeding programs that have the potential to withstand extended periods of rain during harvest.
Procedure
All lines in the advanced stages of yield testing and all lines in the barley crossing block are subjected to several and various sprouting tests over a period of years to ensure that potential new cultivars are identified on the basis of their capability to tolerate sprouting conditions during harvest.
Reason for Project and Impact
In general, the adapted varieties of winter wheat, winter triticale, and spring triticale are quite susceptible to extended periods of rainfall in the fall. A similar problem occurs in both malting and feed barleys. Consequently this project was initiated in 1982. Two pertinent articles were published in the Agronomy Journal in 1985 (77: 649-652) and 1986 (78: 863-867). An attempt was made to transfer sprouting resistance into hulless barleys and evaluation is presently underway.
Summary of Results
A series of hulless lines with good pre-harvest sprouting resistance are being utilized as parents in the barley program. For example, some of the barley lines expected to have desirable levels of seed dormancy and sprouting resistance have been crossed into the Falcon and Phoenix background.
Other barley lines have been developed to determine if the sprouting resistance gene(s) are different from those in B. Harvey’s malt line TR118.
Significant improvements in dormancy have also been found in the triticale and winter wheat program
Beginning in 2004, barley, triticale, and winter wheat lines that are in the advanced yield tests will be evaluated each year. In 2004, approximately 100 barley, 25 triticale, and 20 winter wheat lines were tested for preharvest spike sprouting and seed germination to determine the level of seed dormancy.
[Top of Document]
Inheritance of Seed Dormancy Complex Trait in Barley
Purpose
To determine the heritability of, and selection efficiency for, sprouting resistance in hulless barley and develop dormancy indices in a wide range of Canadian barley varieties.
Procedure
To make crosses between lines selected for dormancy and sprouting resistance and the hulless cultivars Falcon and Phoenix. Crosses will be advanced using single seed descent to determine inheritance of dormancy in non-segregating F6 generations.
Reason for Project and Impact
Sprouting of grain in the swath in years when conditions are wet after swathing can result in loss of yield and quality. Sprouted barley grain can result in poor seed germination, low human nutrition and animal feed quality. Lines of hulless barley with good sprouting resistance have been developed from crosses of Samson with hulless genotypes (I79207N, Falcon, Condor and Phoenix). Samson, a six-row, semi-dwarf barley was found to have good sprouting resistance under wet-swath conditions. Incorporation of this trait was made into the hulless germplasm and selection made by using rain simulator tests.
Summary of Results
Long-term project started in 1997. We have characterized the population according to weighted germination index.
The start of this project was slow due to lack of funding to complete the growth room facilities. However, in 2002 the new phase of the growth room facilities was completed and a new rain simulator purchased from Conviron©. These additional facilities will increase the testing and handling capacity for the dormancy and sprouting resistance projects.
Despite the slow start of the dormancy and sprouting project the following milestones have been achieved:
2001
F2-derived F3 lines were planted in the field at Lacombe as 260 single seed/populations and each population was described (hulled/hulless, two-row/six-row, awn type, etc.) A single head was collected from each population. In the fall, these F3-derived F4 lines were planted (3 seeds/pot) in the growth chambers. Seeds that did not readily germinate were stimulated to break dormancy by using gibberellic acid (GA) pretreatment. A single head was collected from each population.
2002
F4-derived F5 lines were planted (3 seeds/pot) in growth rooms. Dormancy was overcome by using GA pre-treatment. At least 1 head from each population was harvested. F5-derived F6 lines were sown in headrows at Lacombe and notes taken on each population.
2003
F7 seed of 235 lines was tested for dormancy using the petri-dish method. The weighted germination index will be used in data analysis to determine the range of dormancy in the population.
2004
Canadian barley varieties were rated for dormancy using the developed phenotyping methods. Several molecular markers for seed dormancy derived from Samson have been identified through microsatellite marker screening. This population will be further screened by AFLPs in 2005.
Previously identified molecular markers correlating to dormancy in other genetic populations are currently being tested and validated. The highest 10% dormant populations will be pooled for genetic marker analysis as will the lowest 10% dormant populations. Biotechnology tools will be used to develop markers for sprouting resistance in the developed barley populations.
[Top of Document]
Drought Stress Effects on Barley and Triticale
Purpose
To determine the effects of drought stress during development on yield and agronomic traits of barley and triticale.
Procedure
To use a rain shelter system in the field as a means to artificially induce drought stress during the growing season so that the effects of drought stress on a number of barley and triticale cultivars can be compared. Screening of advanced yield trials for six-rowed, two-rowed and hulless barley. Screening of barley and triticale germplasm.
In 2005, a joint project with Alberta Research Council, and funded by the Alberta Funding Consortium, is being initiated to study the use of 13C as a screening tool for drought tolerance in barley. As part of this project we will see if drought tolerance can be genetically mapped and markers identified.
Reason for Project and Impact
The impact of drought on production can be mediated by growing cultivars with drought tolerance and using proper production practices. Selection and development of drought tolerant genotypes and production practices to alleviate the effects of drought stress requires an understanding of how stress affects the plant during development, what traits are affected and when, and how genotypes differ in their ability to withstand stress.
Summary of Results
Have developed drought tolerance criteria for new genotypes for breeding and registration purposes. We will continue to use these tests to assess drought tolerance of lines in the advanced yield trials. Lines identified with resistance are forwarded to the germplasm for further development.
The new variety Manny (BT 562), released in 2003, has shown excellent water use efficiency (WUE, the ability to create yield under water stress). We have several lines currently in the Cooperative Testing system that also are showing excellent WUE (the line TR 03661 was recommended for registration at the 2005 Prairie Registration Recommending Committee for Grain meeting). The advanced triticale lines evaluated in these tests have continued to show superior WUE. |
|