2018 ASHS Annual Conference

Onion is the second most important vegetable in Chile. Production for export or storage is based in a small number of long-day open-pollinated (OP) cultivars. During the last decade many hybrid cultivars asserting to have superior yield and bulb quality have been introduced. The lack of objective information regarding the performance of these new hybrid cultivars under Chilean conditions, posed the main objectives of these studies: to compare yield and storability of available onion cultivars in Chile. During the season 2014/15 two trials were conducted in different locations: Malloa (34°27’ S, 70°57’ W) and Chépica (34°44’ S, 70°15’ W). In each location, 16 cultivars were produced; 10 of them were hybrid and 6 of them were OP, including the most used OP cultivar, Cobra, as control. For each cultivar, harvest was performed when around 50% of the plants foliage lodged. After bulbs weight and diameter were registered, they were cured and stored in well ventilated rooms (12,5ºC average temperature; 77,5% average relative humidity). Bulb losses due to sprouting or rotting were determined every two weeks. In Malloa yield ranged between 9,9 and 1,7 kg/m², while in Chépica ranged between 9,0 and 3,2 kg/m². In Malloa, Cobra out performed most of cultivars but there were two hybrids that had higher yields (non-significant difference). In Chépica, two hybrids had higher yields than ‘Cobra’ (p<0.05). In addition to their good yield, some of the hybrids stood out for their high bulb quality (uniformity, size and high percentage of single centers). When stored, Cobra and three other OP cultivars had greater resistance to sprouting than most of hybrids. In bulbs produced in Malloa, after 245 days of storage ‘Cobra’ presented 14% of bulbs sprouted while most of hybrids had over 40% sprouting. In onions produced in Chépica, after 223 days of storage, ‘Cobra’ presented 30% sprouting and most of hybrids had over 50% sprouting. In summary, results highlight the importance of cultivar evaluation and selection in onion productivity. Some of the new hybrid cultivars that are been introduced in Chile presented competitive yields and quality, however it lower resistance to sprouting during storage should be considered.