Effects of Irradiation on Certain Characteristics of Shallots (Allium ascalonicum)

Although shallots (A. ascalonicum) has been grown for a long time and used as a seasoning in many West African diets very little effort has been made to improve on yield and bulb size. The bulbs are so small that handling during food preparation is tedious and time consuming. It would, therefore, be desirable to improve the bulb size to that found in common onions. The variability in bulb size of shallots has not been found sufficient to warrant a programme for selection. It has therefore, been necessary to explore the possibility of inducing mutations with irradiation, with the hope of recovering mutants which show increase in bulb size. Irradiation studies using gamma rays of 10 to 500 rads indicated that shallots are very sensitive to irradiation. Beyond 500 rads the bulbs of Ml plants failed to sprout. There were increases in seedling death when dosage of gamma rays was increased. The number of bulbs per cluster, mean weight per cluster, weight per bulb, plant height and number of leaves per plant were all reduced by increase in dosage rate. It is concluded that irradiation of shallots produced mainly deleterious effects. (author)