Colchicine Induced Variation in Sweet Orange (Citrus sinensis (L.) Osbeck) cv. Mosambi

Abstract

The sweet orange cultivar Mosambi, valued for its low acidity, high juice yield, and superior antioxidant properties, faces challenges due to its high seed count, which diminishes consumer appeal and complicates juice processing. Induced mutagenesis, particularly through colchicine treatment, offers a promising approach for trait improvement. This study characterized variations in two-year-old non-bearing Mosambi mutants induced by colchicine at concentrations of 0.05, 0.10, 0.15, and 0.20%. Colchi-mutants were evaluated against the wild type (WT) for leaf sclerophylly, gas exchange parameters, and stomatal traits. Dose-independent variations were observed, with the CS-9 mutant (0.05% colchicine) showing significant increases in leaf area, fresh mass, and dry mass (2.30–2.43 fold). Colchi-mutants CS-9 and CS-4 exhibited over 28% higher net photosynthesis (A), while colchi-mutants from 0.05 and 0.15% treatments enhanced stomatal conductance and transpiration. A general reduction in stomatal number was observed, accompanied by an increase in size. These findings provide criteria for selecting desirable mutants for sweet orange improvement programs.