Before starting, it is important to understand what will be required from a variety. The farmer needs a crop which is easy to manage within whatever farming system he operates, and which reliably produces high yields of good quality grain. The miller, baker or other end user requires that grain to be of consistent quality for ease of processing and to ensure a high quality product which in turn meets the requirements of the consumer.
The first step is to select parent plants to cross, which between them have the required characteristics for yield, quality, disease resistance and other agronomic features such as lodging resistance. Many hundreds of crosses of different combinations are made each year. These may involve parents with unique genes for characteristics which are not available in current commercial varieties but which may become more important in the future.
From these crosses, millions of plants and then many thousands of short rows sown from selected ears are grown, harvested and resown for successive generations in what is know as the ‘pedigree breeding’ system. Here selection is made in the field for disease, height, lodging resistance etc and in the laboratory using DNA markers and quality tests.
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Initially each potential new variety is a single metre-long row but after multiplying for four generations enough seed is available to sow yield trials which are initially at one site, increasing to eight sites before they are ready to enter into National List trials.
To speed up the breeding process, a technique known as ‘Single Seed Descent’ (SSD) is used. Here, three generations may be grown in the glasshouse in one year by growing plants using artificial vernalisation (two months of cold treatment) to ensure the plants will flower and set seed. In the first two generations only a single seed is required from each plant to be re-sown for the next generation; the third generation is grown to produce a larger ear so that the seeds can be sown in the field as a single row. These rows are re-selected as in the pedigree system. This potentially saves two years development time. Consort, Gladiator, Ambrosia, Mascot, Battalion and Marksman are all examples of SSD-bred varieties.
The final part of the breeding programme before a variety is commercialised involves the multiplication of pure seed, a process which begins before the variety registration process commences, to ensure certified seed is available for the market.
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