Aspects of Kharif Onion Production and Improvement Through Molecular Markers: A Review

Abstract

Onion (Allium cepa L.) is a vital commercial vegetable crop cultivated worldwide for its culinary, nutritional, and medicinal properties. India ranks among the top producers, yet productivity remains low due to climatic constraints, pest and disease pressure, and limited adoption of improved cultivars. Understanding genetic variability is essential for effective selection and crop improvement. Numerous studies have demonstrated significant variation among onion genotypes in yield, bulb size, quality traits, and adaptability across regions and seasons. Traditional breeding approaches, when combined with modern molecular marker technologies, have accelerated the identification of superior genotypes and enhanced breeding precision. Molecular markers such as RAPD, SSR, AFLP, and SNPs are increasingly used to assess genetic diversity, map desirable traits, and support marker-assisted selection. These tools have proven valuable in identifying high-yielding, disease-resistant, and stress-tolerant onion varieties. Integration of molecular marker-based strategies with conventional breeding offers a promising pathway for developing improved onion cultivars suited to diverse agro-climatic conditions. This review consolidates current research on onion production, genetic diversity, and molecular marker applications, highlighting future prospects for sustainable onion improvement.