Phenotypic evaluation of a hybrid diploid blueberry population for plant development and fruit quality traits

Authors: Rowland, Lisa; Ogden, Elizabeth; Vinyard, Bryan

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/23/2020
Publication Date: 7/24/2020
Citation: Rowland, L.J., Ogden, E.L., Vinyard, B.T. 2020. Phenotypic evaluation of a hybrid diploid blueberry population for plant development and fruit quality traits. Agronomy. 10(8), 1067. https://doi.org/10.3390/agronomy10081067.
DOI: https://doi.org/10.3390/agronomy10081067

Interpretive Summary: A blueberry population of about 120 plants that was developed for identification of genes that influence economically important traits in blueberry was evaluated for growth and fruit quality traits. Growth traits that are important for expanding the harvest season by developing earlier and later fruiting varieties included timing of flower budbreak, full bloom, early fruit set, ripe fruit, and related morphological traits. Fruit quality traits are a high priority in blueberry breeding programs and included berry firmness, size, weight, color, and flavor. Results indicated that plants in this population varied considerably for growth and fruit traits that we evaluated. Most of the traits also appeared to be heritable. These findings suggest that the population should be very useful for mapping these traits in blueberry. Identifying the regions of the blueberry map, and eventually the genes themselves, that control these traits will be useful to blueberry scientists and breeders to efficiently track these traits when developing new early and late season varieties with high fruit quality.

Technical Abstract: A diploid blueberry mapping population, used previously to map QTL for chilling requirement and cold hardiness, was evaluated for several plant development and fruit quality traits. Specifically, the population was phenotyped for timing of various stages of flower bud, leaf bud and fruit development and for various fruit quality traits including weight, diameter, color, scar, firmness, flavor and soluble solids. The phenotypic data was analyzed statistically by analysis of variance, correlation tests to examine associations of traits, and heritability. Results indicated that the traits were segregating and distributed normally in the population. Many of the growth traits were correlated, and timing of shoot expansion, early bloom and full bloom were also correlated with the previously evaluated trait of chilling requirement. Several correlations were found among the fruit quality traits as well. For example, weight was highly correlated with diameter, and the subjectively measured trait of firmness was moderately correlated with the objectively measured firmness trait defined as the force required to puncture the skin. In addition, most of the traits showed significant variation across genotypes and across years, and most had moderate to high heritability. Therefore, we conclude that the diploid population should be useful for identifying QTL for many of these traits.