Developing fall-sown pea cultivars as an answer to the challenges of climatic changes

Chapitre 4

International audience

إنجليزي. Pea is considered rather well adapted to wide temperature ranges, with seedlings able to survive even -20 °C. From a physiological viewpoint, pea becomes tolerant to frost if first exposed to low non-freezing temperatures, causing the so-called cold acclimation. Delayed floral initiation helps some forage pea genotypes to escape the main winter freezing periods, as susceptibility to frost increases during the transition to the reproductive state. The oldest winter pea cultivars carry the dominant allele, Hr, although some bear hr. They are generally characterized by prominent winter hardiness and a long growing season, from sowing in early October until either cutting for forage production in late May or harvesting seeds in mid-July. The average forage yields in the winter forage pea cultivars often exceed 45 t ha-1 of green forage, 9 t ha-1 of forage dry matter and 1700 kg ha-1 of forage crude protein. Modern dry pea cultivars have advanced winter hardiness and enhanced dry grain production. They are already in use in other temperate regions in both Europe, especially France, and the USA. One of the strategic advantages of fall-sown dry pea cultivars of recent release is their significantly improved earliness.These cultivars are regularly at least one week earlier than winter barley, providing many farmers with the novel opportunity of not having to choose between pea and cereals, since many have only one combine harvester available and give priority to their cereals. Furthermore, fall-sown dry pea cultivars may have increased grain dry matter crude protein content and it is possible to merge winter hardiness and low content of antinutritional factors. Low thousand seed weight, not exceeding 200 g, and a population density of 75-80 plants m-2 provide inexpensive sowing. All these outcomes should result in an increased area and production of dry pea in many temperate regions. In the end, growing winter-hardy pea cultivars also mean a significant shift into the wetter half of the year and thus mitigating more and more prominent and unpredictable effects of spring droughts, demonstrating an efficient answer to the challenges of climatic changes.