Zahra Abasi - Horticulture Crops Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, (AREEO), Isfahan, Iran
Abdosattar Darabi - Horticulture Crops Research Department, Khuzestan Agricultural and Natural Resources Research and Education Center, (AREEO), Khuzestan, Iran
Emad Shahmansouri - ۱Horticulture Crops Research Department, Isfahan Agricultural and Natural Resources Research and Education Center, (AREEO), Isfahan, Iran

Purpose: In the first stage to produce open pollinated and hybrid onion cultivars, identification of compatible genotypes as breeding base populations with the climatic conditions is of special importance. Thus, this research was performed to evaluate short day onion hybrids and achieve a breeding base population by identifying the best genotypes in terms of quantity and quality traits and also for studying the reaction of genotypes to the climatic conditions of Isfahan and Khuzestan. Research method: Fifteen onion genotypes were evaluated as complete block design with three replications in two locations (Isfahan and Khuzestan) under field condition during the ۲۰۱۷-۲۰۱۸ growing season. The traits evaluated included: bulb yield, average bulb weight, dry matter content, total soluble solids, and weight loss. Findings: According to the results of Isfahan location, Savannah Sweet and Saba hybrids had the highest bulb yield (۴۲.۷۲ t/ha and ۴۱.۰۵ t/ha, respectively) and Vania hybrid with high significant different (p< ۰.۰۵) was showed the lowest bulb yield (۱۹.۷۷ t/ha). In Khuzestan location, SV۶۳۲۶, Saba and Savannah Sweet for bulb yield (۹۲.۳۸, ۸۹.۷۱ and ۸۹.۱۴ t/ha, respectively) were recognized as super hybrids, in contrast, hybrids: Early Super Select, Behbahan improved population, Super Perfect, Sahar and Vania, were considered as weak hybrids (bulb yields<۶۰ t/ha). In terms of quality traits, Behbahan improved population with ۱۸.۸۴% and ۱۴.۷۵% of total soluble solids as well as ۱۹.۵۲% and ۱۵.۷۷% of dry matter content in Isfahan and Khuzestan locations had significant difference from the other hybrids. Saba hybrid was identified as high bulb yield with low weight loss hybrid, Vania hybrid recognized as low bulb yield and the Savannah Sweet was identified as high yield with high weight loss in two experiments. Research limitations: Further work could be done with other commercial short day onion hybrids. Originality/Value: These genotypes can be used as parental material in the quantity and quality improvement of bulb onion. In future breeding programmes, emphasis should be given to Saba hybrid for producing high bulb yield and best quality onion variety.

Bulbs, dry matter content, Storability, Yield