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

The long period of time required for fruit ripening is a main drawback to t he adoption of mishqui (Solanum muricatum) as a new crop. Variation in the fruit ripening period was studied in 18 mishqui clones in response to ethep hon sprays (0.500 or 2000 mg l(-1)). Significant differences in the length of the fruit ripening period were detected between clones, ethephon doses a nd their interactions. Some clones did not respond to ethephon sprays, whil e 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 pe riod. Furthermore, differences between clones of up to 20 days were found i n the fruit growth period, Lengths of both periods (fruit growth and ripeni ng) were not correlated, indicating that independent selection can be perfo rmed for both traits. The effects of ethephon on fruit quality characters w ere not significant in the majority of clones, although in five clones ethe phon produced a skin degreening. Fruits from these clones had a higher firm ness and lower soluble solid content (SSC) after ethephon treatment, On the other hand, ethephon sprays did not affect either the postharvest behaviou r or the sensitivity to bruising. The results obtained here point to the ex istence of genotypic variation in the fruit ripening physiology of this spe cies and they give relevant information for the improvement of mishqui earl iness. (C) 2001 Elsevier Science B.V. All rights reserved.