Barley Vernalization Markers
Functional markers for the vernalization requirement in barley (VS0137)
Description
The primary aim of this research is to develop a SNP genotyping assay that will reliably predict the vernalization requirement of a given barley variety. This SNP assay will be based on the results of a survey of sequence variation across modern spring and winter barleys for two recently identified barley gene sequences, Vrn-H1 and Vrn-H2.
The research addresses a need to find efficient alternatives to the current cost- and labour-intensive vernalization test carried out in the first year of statutory DUS (Distinctness, Uniformity and Stability) testing of new varieties for National List and Plant Breeders’ Rights purposes. More generally however, if successful in its objectives, this will be the first example of a recognised botanical characteristic used in DUS testing which can be reliably predicted via a simple molecular test and will therefore provide a paradigm for the extension of the approach to other botanical/morphological characteristics, including those recognised by the international breeding community and included in current UK protocols and UPOV Guidelines.
Defra is responsible for operating the statutory systems required for the registration of new varieties of agricultural crops according to EC Directives. The technical work for these systems in cereals is carried out by NIAB. An important part of registration is the National Listing of new varieties and one element of NL testing requires new varieties to be distinct, uniform and stable (DUS). This DUS testing involves the observation and recording of a number of mostly morphological characteristics in replicated field trials. One of these characteristics in cereals is the winter/spring growth habit and vernalization requirement. In barley, the current UK protocol for evaluating seasonal growth habit (SGH) stipulates that –
“In the case of winter varieties an additional 50 ear-rows are sown in late April during the first year of tests to examine the uniformity of the vernalization response of the variety under test.”
The scoring of this character therefore entails a dedicated planting of 50 ear rows per candidate variety, as well as the inclusion of example varieties; these plots (50 ear rows per winter variety) require normal husbandry over the full growing season and manual observation and scoring is completed only when the latest flowering spring variety is fully mature (GS91/92). Recent advances in our understanding of the molecular basis for the vernalization requirement in cereals have given rise to the opportunity to develop a molecular test for vernalization response which can be accomplished quickly and cost effectively within hours of reception of a seed lot. There is thus an opportunity to explore the use of a molecular marker for DUS testing as a direct replacement for an existing field-based characteristic. In addition to cost-efficiencies, this might serve as a model for the use of molecular markers in other cereals and other crops.
Objectives
• Explore sequence diversity in the Vrn-H1 and Vrn-H2 genes.
• Develop a single reaction SNP assay which is predictive for seasonal growth habit.
• Make recommendations for implementation of vernalization markers in future testing.
Time-scale
From: 01/010/04
To: 30/05/05