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United States Department of Agriculture

Agricultural Research Service

Research Project: Genetic Controls of Apple Fruit-Specific Auxin
2012 Annual Report


1a.Objectives (from AD-416):
1. Phenotyping fruit maturation and ripening behaviors including fruit firmness, crispness, ripening season, fruit size, and storability for 6-8 cultivars and selected seedlings in Pink Lady x Honeycrisp progeny, in a developmental stage-specific fashion. 2. Characterizing expression patterns of 20-25 previously identified candidate genes, implicated in plant hormone biosynthesis, transport and response by qRT-PCR method and analyzing their association with the specific traits of apple fruit ripening pattern and quality attributes.


1b.Approach (from AD-416):
Apple fruit ripening behaviors and fruit quality attributes including ripening season, fruit firmness and fruit size will be characterized for selections in a "Pink Lady x Honeycrisp” progeny.

The expression patterns of 20-25 previously identified candidate genes, implicated in plant hormone biosynthesis, transport and response will be analyzed by qRT-PCR method. Association of expression with the specific traits of apple fruit ripening pattern and quality attributes will be assessed.


3.Progress Report:

This project relates to objective 1 of the associated in-house project which seeks to identify factors that influence postharvest fruit quality and development of market limiting physiological disorders. Plant hormones are the major regulators of apple fruit ripening and quality. Understanding how plant hormones regulate apple fruit quality and ripening patterns is a necessary step in developing tools to assist breeders to design new apple varieties with desired ripening characteristics. The expression patterns of a number of genes that control hormones during apple fruit maturation and ripening were characterized. Results indicate relationships between genes controlling different plant hormones is complex in apple fruit and that a cascade of hormone activity may lead to fruit ripening. The timing of the cascade may vary among apple varieties and lead to differences in ripening patterns that are characteristic for different apples.


Last Modified: 9/10/2014
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