Consequences de la manipulation des plants et de la variation des conditions de croissance sur le comportement d'une culture de pomme de terre, en zone mediterraneenne

Abstract

In the Mediterranean area the growth vigour of seed tubers of potato can be kept at a high level by combining different storage techniques, even without or with only short cold storage. The effects of the different techniques investigated depended on the cultivar used and on the duration of the storage.Crops grown in the main season (planting in January - February) , yielded more than crops grown in the autumn season (planting in August or September). In the autumn season, soil cover reached higher values than in the main season. In the main season, however, the amounts of light intercepted and the harvest index were more favourable than in the autumn season. In both seasons, each delay of planting caused a reduction in yield, even though it increased the light-conversion efficiency and the rate of canopy development. Yields were highly correlated with the duration of the soil cover, especially for the early plantings in the main season.A late planting date during the main season was associated with a severe heat stress at the end of the growing season. In the autumn season, mainly the low temperatures and the short photoperiod were limiting the canopy development.Tubers produced during the main season had higher dry-matter contents than tubers produced during the autumn season. Autumn crops produced fewer tubers per unit area, but the size distribution was shifted towards the larger sizes.</TT