Performance and Adaptability Evaluation of Improved Onion Varieties (Allium cepa L.) for Bulb Yield and Some Agronomic Traits

Onion is one of the most important vegetable crops in the world including Ethiopia. The field experiment was conducted in Arsi zone at Kulumsa Agriculture Research Center and Ziway Dugda districts under irrigation condition. A total of five improved onion varieties were evaluated in Randomized Complete Block Design with three replications with the objectives of studying the performance and adaptability of improved onion varieties for bulb yield and yield related traits in 2017 during off season. The combined Analysis of variance (variety by location) revealed that significant difference between improved onion varieties for maturity date, marketable and unmarketable bulb yield tons per hectare, bulb length in centimeter, and bulb weight in gram was observed. But non-significant difference for plant height in centimeter, total bulb yield tons per hectare and average bulb diameter in centimeter were observed between improved onion varieties. Except variety Adama Red all the tested improved onion varieties (Melkam, Nafis, Nasik Red and Bombay Red) was well performed and adapted. These varieties were gave more than 40 marketable bulb yield t ha-1. So those improved onion varieties were recommended for the study area and areas of similar agro- ecological zones under off season growing condition.