Heterosis for yield and quality traits and resistance to purple blotch in onion

The study was carried out to estimate magnitude of heterosis for bulb yield and its attributing traits in 28 crosses resulting from a Line × Tester mating design of 4 male sterile lines and 7 testers in onion. Among the 28 crosses, L₂ × T₄ was highly heterotic for purple blotch disease resistant (−42.62), plant height (7.25), neck thickness (−6.67), ten bulb weight (6.75), polar diameter (6.77), equatorial diameter (7.28), marketable bulb yield (25.95), number of rings per bulb (22.16) and per cent of sprout bulbs (−30.85) over commercial check. While the cross L₃ × T₅ exhibited significant heterosis over standard check for days to maturity (−6.67), neck thickness (−15.56), polar diameter (3.84), equatorial diameter (3.99), marketable bulb yield (28.65), rotten bulb (−25.22), number of centers per bulb (−4.55) and number of rings per bulb (6.23). Hence, these two crosses, viz., L₂× T₄ and L₃ × T₅ can be exploited commercial cultivation.