Improvement of mishqui ( Solanum muricatum) earliness by selection and ethephon applications

Abstract

The long period of time required for fruit ripening is a main drawback to the adoption of mishqui ( Solanum muricatum) as a new crop. Variation in the fruit ripening period was studied in 18 mishqui clones in response to ethephon sprays (0, 500 or 2000 mg l −1). Significant differences in the length of the fruit ripening period were detected between clones, ethephon doses and their interactions. Some clones did not respond to ethephon sprays, while in others the ripening period was shortened by more than 60%. In general, the effect of ethephon was greater in the clones with a longer ripening period. Furthermore, differences between clones of up to 20 days were found in the fruit growth period. Lengths of both periods (fruit growth and ripening) were not correlated, indicating that independent selection can be performed for both traits. The effects of ethephon on fruit quality characters were not significant in the majority of clones, although in five clones ethephon produced a skin degreening. Fruits from these clones had a higher firmness and lower soluble solid content (SSC) after ethephon treatment. On the other hand, ethephon sprays did not affect either the postharvest behaviour or the sensitivity to bruising. The results obtained here point to the existence of genotypic variation in the fruit ripening physiology of this species and they give relevant information for the improvement of mishqui earliness.