the use of onion hybrids in brazil is still recent, with little information regarding the gains from heterosis. however, the first step to exploit the heterosis is the evaluation of available germplasm. due to the need for genotypes adapted to the climatic conditions of south-central region of paraná state, brazil, this study aimed to evaluate the agronomic performance of 19 hybrids and 50 inbred lines of onion, as well as the heterotic gain of six of these hybrids. the experimental design was randomized blocks with three replications. the evaluated traits were yield, average weight of the bulbs, commercial classification of bulbs, waxy of the leaves and cycle. in general the hybrids were superior to the lineages in yield and average bulb weight and had lower cycle. the heterotic gain in hybrids was evident, indicating the viability of hybrids for cultivation in the region. hybrids 2572, 2573 and 2578 are promising due their high yield, earliness cycle and better classification of the bulbs. the lineages 2507-1 and 2983 provided the highest heterotic gain for the yield of the hybrid 2857, which was classified in the group of earliest genotypes, showing an inverse correlation between these two characters.