Development of stage-specific onion hybrids through heterosis analysis at four main growth stages

Abstract Allium cepa, commonly known as onion, is a valuable crop worldwide for its medicinal and culinary uses. However, its growth is highly sensitive to temperature changes during the early stages, limiting its yield and profitability. While hybrid onion varieties offer higher productivity, disease resistance, and stress tolerance, they are expensive and lack stage-specific characteristics. To address these challenges, our study aimed to evaluate heterosis for stage-specific hybrids in onion farming. Over three years, we conducted experiments with three lines and four testers, observing growth at four stages (73, 83, 123, and 138 days after transplanting) and analyzing trait variance critical to yield and profitability. Our results showed highly significant improvements across all growth stages for both parent and cross interactions. Specifically, ANOVA of parents, parents versus crosses, and line x tester interactions were highly significant. Notably, MKS-8823GO × Super-Sarhad and MKS-8823GO × MKS-TPSWP hybrids were the best performers at the first stage for traits such as leaf weight and diameter, while 28,540 × VRIO-2 was optimal for the second stage for traits such as bulb weight and yield. For the third and fourth stages, 28,540 × MKS-TPSWP was optimal for traits such as bulb weight, yield, and dry matter content. These findings offer a promising solution to cost and productivity challenges in hybrid onion farming, providing farmers with stage-specific hybrids for profitable, high-yielding onion production.