Variability, heritability, and correlations of agronomic traits in an onion landrace and derived S1 lines

This study assessed variability, heritability and correlations of agronomic traits in an onion (Allium cepa L.) landrace and derived S-1 lines after a single selfing generation. Bulbs used to develop S-1 lines were selected for shape, colour and high number of skins. Fifty-one S-1 lines and the original population were evaluated using an incomplete random block design. The original population and S-1 lines were highly diverse for quantitative and qualitative traits. S-1 lines were significantly different, with transgressive segregation for number and maximum leaf length, bulbing index, bulb weight, diameter, and dry matter content. Variances within S-1 lines were greater than among S-1 lines for all traits. Bulb colour and number of skins responded to selection. Heritabilities for dry matter and soluble solids were 52.6% and 36.1% respectively. Both traits were highly correlated. The development of S-1 lines allowed the expression of genetic variation and the identification of better genotypes for agronomic traits of interest.