Harnessing Male Sterility Systems in Marigold (Tagetes erecta L.) for Hybrid Breeding Focused on Carotenoid Enrichment and Flower Yield

Marigold ( Tagetes erecta L.) is a commercially important flower crop, valued both for its ornamental use and as a natural source of carotenoids. With the rising global demand for carotenoids in the food, feed, and nutraceutical industries, there is a growing need for marigold hybrids that combine high carotenoid content with superior yield. Male sterility systems are essential for hybrid seed production, but their specific contributions to carotenoid enrichment and yield related traits remain underexplored. This study evaluated the performance of different male sterile systems cytoplasmic male sterility (CMS) and genic male sterility (GMS; apetaloid and petaloid) along with their hybrids derived from a common pollen parent ( Pusa Narangi Gainda ). Seventeen agronomic and floral traits, including carotenoid content, were assessed in parental lines and hybrids. The CMS petaloid sterile hybrids showed superior performance for plant height, number of branches, flower yield per plant, flowering duration, and carotenoid content (1.52 g/100 g dry petal weight), whereas the GMS apetaloid hybrids exhibited earliness and shorter crop duration. GMS petaloid hybrids excelled in flower diameter, number of flowers per plant, shelf life, and number of harvests. Correlation and path coefficient analyses revealed that dry petal weight, flower diameter, and fresh flower weight had strong positive direct effects on carotenoid content, while plant height, shelf life, and dry flower weight had negative direct effects. Despite the higher heterosis for carotenoid content observed in GMS apetaloid hybrids, CMS petaloid hybrids recorded the highest mean carotenoid content and overall yield. These findings underscore the potential of CMS petaloid sterile lines in developing dual-purpose marigold hybrids for both floral and industrial carotenoid extraction markets with enhanced flower yield. The results provide actionable insights for breeding programs targeting industrial pigment production through optimised marigold hybridisation strategies