Seed Chilling Enhances Head Earliness and Yield of Artichoke (Cynara scolymus L.) under Assiut Conditions.

Subjection of seeds to a chilling pretreatment has been reported to enhance crop yield particularly earliness in number of vegetable crops including seedgrown (annual) globe artichoke. Therefore, the current study was carried out to assess the impact of seed chilling pretreatment on the production of seedpropagated globe artichoke in two cultivars (EL-Balady and Chinese) under Assiut conditions. Four seed pretreatments were utilized. These were seeds imbibed in water for 24 h and subjected to chilling at 4-5 °C for 0 (positive control), 10 and 15 d, in addition to untreated seeds (negative control). These seed pretreatments were scheduled so as to be simultaneously ready at the time of sowing. A field experiment was carried out to test these treatments during 2014/2015 and 2015/2016 winter seasons at the Experimental Farm of Faculty of Agriculture, Assiut University, Assiut, Egypt. Data revealed an influential effect for seed chilling on growth, earliness and yield of artichoke. Comparing to plants of both control treatments, imbibed seeds which were subjected to chilling at 4-5˚C for 15 d gave the greatest reduction in number of days to form heads and highest early head yield. Average head weight, number of heads/plant and head diameter and height were increased while total yield was elevated. This pre-sowing seed chilling treatments increased yield by 22.5% and 40.3% relative to positive and negative controls, respectively, on average. The reduction in the number of days to develop harvestable inflorescences ranged from 21 d to 23 d comparing with the positive and negative controls, respectively, on average. Apparently, seed chilling pretreatment may be usefully applied to overcome the delay in head formation, due to insufficient natural chilling under Assiut conditions, while elevating total head yield and expanding production season. [ABSTRACT FROM AUTHOR]