Variability in leaf mineral content of colchicine-treated Corchorus olitorius.

Corchorus olitorius is an underutilized, but nutrient-rich leafy vegetable. However, the nutritive value and micronutrient bioavailability of this vegetable has not been wellresearched in South Africa. Therefore, this study aimed at using a novel breeding technique, that is, utilization of colchicine treatment on mineral content of C. olitorius leaves. C. olitorius seeds were treated with 0, 0.025, 0.05, 0.075 and 0.1 g/l of colchicine for 2, 4, 6, 8 and 10 h. Treated seeds were sown in pots and laid out in a completely randomized design with three replications. Tender leaves were harvested at 49 days after planting for mineral content analysis using atomic absorption spectrophotometry. Data were subjected to ANOVA, principal component analysis and cluster analysis. Treatment with 0.025 g/l of colchicine for 2 h resulted in the highest nitrogen, phosphorus, potassium, calcium, magnesium, aluminium and iron content in C. olitorius leaves. Other studied leaf minerals decreased with an increase in colchicine concentration and prolonged treatment duration. All minerals were correlated positively with each other, but sodium, manganese and copper had an exclusive association with one another. Again, all minerals were positively associated with first principal component, while Na, Mn and Cu were associated with the second principal component. Biplot and dendrogram grouped treatments mainly according to treatment duration. The study also demonstrated high levels of variation among the colchicine treatments in the nutritional traits evaluated. This implies that colchicine has the potential to induce genetic variability which can be used for future C. olitorius crop improvement. [ABSTRACT FROM AUTHOR]