Preliminary assessment: Colchicine-induced mutants of wild Rubus rosifolius var. rosifolius for dryland adaptation

Abstract

Rubus rosifolius produces fruit with various beneficial bioactive compounds, but the fruit tastes sour and not tasty, thus making it unattractive and not cultivated. This study evaluated the effects of colchicine-induced on survival rate, polyploidy induction, and dryland adaptability of Rubus rosifolius. The results demonstrated that colchicine concentration significantly influenced both survival rate and mutation success. Increasing concentration reduced survival, with the highest mortality (60%) observed at 7.5 mM, but enhanced mutation frequency. Polyploid mutants, including two tetraploid (2n = 4x = 28) that stem cuttings originating from the mountains Sumbing and Sindoro, as well as one aneuploid (2n = 2x − 1 = 13), were successfully obtained. Under controlled drought stress conditions, polyploid mutants consistently outperformed the control in growth parameters, showing higher plant height, fresh weight, leaf number, and root length, indicating improved vigor and adaptability. In terms of yield, tetraploid mutants especially from Sindoro, produced significantly higher fruit weight, larger fruit size, and increased °Brix content compared to 2n plants, while aneuploid plants exhibited inferior performance. Overall, the results indicate that colchicine-induced polyploidy effectively improves both growth performance and fruit quality, highlighting its potential as a rapid strategy for developing superior and adaptive genotypes.