Cereal variety and population selection

Kurzfassung

This research review notes that cereal variety breeding in the last 50 years has been based on pedigree line bred varieties as part of the development of a production system dependent on oil-based inputs. The characteristics desirable for an organic system are frequently at odds with those designed for non-organic systems. Despite this, varietal choice for organic farmers remains largely from the pool of varieties developed for non-organic production. The challenges to address are on what basis can farmers and advisers select varieties, and how to develop varieties suitable for organic production. Plant characteristics are discussed and main desirable features outlined under the headings of:
• Nutrient use efficiency
• Disease resistance
• Weed competitive ability
• Quality
Breeding selection parameters are then considered. The wide variation that occurs in organic systems and the aim to improve the consistency of performance (yield stability) means that the adaptability of a single variety is not sufficient to buffer these variables. The place for variety mixes is considered, and then the case for composite cross populations. The development of these alternative approaches is hindered by market acceptability and for composite populations by the legislative framework. The conclusions note there are many and different combinations of characteristics that may be of advantage. The suitability of a variety can be affected by the management of the whole organic system, not just one crop in isolation. The situation is complex and selection of genotypes is best undertaken under organic management. Low input line breeding programmes have achieved some success, but the review argues that better environmental adaptation is achieved by genotype diversity, either as variety mixes or as composite populations. For the future there is potential in the (relatively) short term for line breeding under organic conditions. For the longer term there is opportunity in mixtures, and especially of populations. For these to be successfully developed there is a need to address cultural attitudes, inertia in the market and production infrastructure and legislative framework.