Genetic variability for valuable fruit quality traits in Cucumis melo.

摘要

Melon (Cucumis melo L.) is highly polymorphic for fruit traits, providing seemingly endless possibilities for genetic improvement through introgression and recombination. By expanding our knowledge of genetic variation for various fruit-quality components and relationships among them, we have attempted to create novel combinations of desirable fruit characteristics. Our goal is to present a brief review of our activities and efforts to identify melon germplasm that is outstanding for one or more fruit-quality components, and we will discuss examples of new combinations and relationships. Fruit quality is determined primarily by taste and a major component of taste is content of sugar, particularly sucrose. Unlike most fruits eaten fresh, commercially available melons lack acidity. Using exotic melon germplasm, we have introgressed acidity into sweet melon, creating a new melon flavor, sweet-sour. Another component of fruit quality is nutritive value, particularly carotenoids and ascorbic acid (vitamin C). We surveyed approximately 350 melon accessions for fruit-quality components and identified several accessions that had consistently high sucrose content as well as high carotenoid and ascorbic acid contents. Aroma is yet another component of fruit quality and we have investigated the volatiles that affect the unique aromas of different melon cultivars, as well as some of the biochemical and molecular events that lead to their formation. Genomic resources have been developed, including a number of cDNA libraries representing the great polymorphism of the species, a collection of fruit-specific EST databases, and genetic maps..