New onion (Allium cepa L.) cultivars for long- and short-day periods

Turkey has suitable climatic conditions for short- and long-day onion (Allium cepa L.) cultivation causing onion to be one of the main vegetables in Turkey with 1,904,846 t of production. Since long-day onion cultivars generally propagated by sets and production is based on open pollinated cultivars, demand for short-day onions has been constantly increasing for the last three decades. Therefore, this research was performed in Ataturk Horticultural Central Research Institute to determine the best long- and short-day onion cultivars for production in the Marmara Region of Turkey. Each experiment was arranged in a randomized complete block design with 4 cultivars and 4 replications. Short-day onion cultivars (K1, K2, K3 and K4) were seeded in autumn and long-day onions cultivars (U1, U2, U3 and U4) were seeded in spring. During the growth period, morphological parameters including number of leaves per pseudostem, leaves attitude, waxiness, intensity of green color, cranking, leaf length, leaf diameter and pseudostem length; and after harvest, bulb size, diameter, height, ratio of height to diameter, shape, width of neck, scale thickness, base color, number of centers per bulb and dry matter content properties of bulbs were determined. Data were subject to analysis of variance using the JUMP (version 7.0) pc program, where means were separated by Tukey's multiple range test. Among the short-day onions, K4 cultivar having the highest yield (67,200 kg ha(-1)) produced the heaviest bulb with a weight of 240 g. Among the long-day onions, U-1 cultivar had a bulb weight of 161.5 g and yield of 54,380 kg ha(-1); U-4 cultivar had a bulb weight of 155.9 g and yield of 52,470 kg ha(-1). Consequently, according to the results of yield and yield parameters, K-1, U-1 and U-4 cultivars distinguished as the most promising for production in the Marmara region among the other onion cultivars.