The inheritance of seed dormancy in Sinapis arvensis L

Selection for dormant and non-dormant seed in Sinapis arvensis was carried to the seventh and fourteenth generation, respectively. Crosses between the dormant and non-dormant lines clearly showed both a maternal and an embryonic component of seed dormancy. A model for the number of alleles controlling dormancy was constructed and tested. The maternal component of dormancy was shown to be controlled by a single locus with two alleles, the dormant allele being dominant to the non-dormant. No clear picture of the control of the embryonic component of dormancy was found

Does the Seed Sector Offer Meet the Needs of Organic Cropping Diversity? Challenges for Organic Crop Varieties

This chapter aims to study the current balance between the offer and demand of the organic seed sector and how the breeding system can be adapted to the diversity of needs. The offer is assessed by the evolution, over time, of the number and types of species and varieties registered in the French and European catalogues. This number has greatly increased, but some species remain or become orphans. There is an increasing number of varieties listed for the major crops, whereas the choice concerning organic seed varieties is severely limited. Moreover, the standardised varieties listed in the catalogue are currently in dispute because of the new diversification of cropping systems, outlets and social organisation. Do we need to change ideotypes, breeding methods, breeding criteria and evaluating methods? In other words, do we need to reform the seed system or to adapt it to this new diversity? The diversity of organic seed variety requirements is represented by four models: Label, Brand, Autonomy and Empowerment. Each model requires a specific breeding scheme and relevant breeding actors. These different ways to look at new varieties and plant breeding must not exclude each other but must be considered as complementary and capable of renewing ways to implement plant improvements for agriculture. In such a context, there is a need for new references to evaluate and register varieties (new criteria, new protocols, changes in legislation, etc.)