QTL identified that influence tuber length-width ratio and degree of flatness, tuber size, and specific gravity in a russet-skinned, tetraploid mapping population

Authors: PARK, JAEBUM - Oak Ridge Institute For Science And Education (ORISE); Whitworth, Jonathan; Novy, Richard - Rich

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2024
Publication Date: 3/22/2024
Citation: Park, J., Whitworth, J.L., Novy, R.G. 2024. QTL identified that influence tuber length-width ratio and degree of flatness, tuber size, and specific gravity in a russet-skinned, tetraploid mapping population. Frontiers in Plant Science. 15:1343632. https://doi.org/10.3389/fpls.2024.1343632.
DOI: https://doi.org/10.3389/fpls.2024.1343632

Interpretive Summary: Potato tuber shape, size, and dry matter content (the solids minus the water content) are important agronomic traits in the russet market class of potatoes, impacting the quality, consistency, and final processed products such as French fries. Understanding and identifying the genes controlling tuber shape, size, and dry matter is crucial for the development of laboratory-based tools for use in potato breeding programs. A cross was made for the purpose of genetic analysis between two russet-skinned parents ‘Palisade Russet’ and the breeding clone ND028673B-2Russ, producing a total of 190 individuals. Potatoes from this population were evaluated over a period of two years, which included taking measurements on tuber length-width and width-depth ratios using a digital caliper. The width-depth ratio provided an assessment of the “flatness” of a tuber, which is important because flat tubers are not desirable in potato processing. To cross-validate the accuracy and differences among tuber shape measurement methods, a trained evaluator also assessed identical tubers based on a 1-5 scale (compressed to long) visual assessment. Furthermore, the dry matter content rate and weights of the tested tubers were also collected. The genetic positions affecting each trait and their estimated impact were unveiled in this study. The outcomes of this study provide useful genetic information for making potato breeding programs more efficient.

Technical Abstract: Potato tuber shape, size, and specific gravity are important agronomic traits in the russet market class of potatoes with an impact on quality, consistency, and product recovery of processed foods such as French fries. Therefore, identifying genetic regions associated with the three traits through Quantitative Trait Locus/Loci (QTL) analysis is a crucial process in the subsequent development of marker-assisted selection for use in potato breeding programs. QTL analysis was conducted on a tetraploid mapping population consisting of 190 individuals derived from the cross between two russet-skinned parents, Palisade Russet and the breeding clone ND028673B-2Russ. Field data collected over a two-year period and used in the QTL analyses included tuber length-width and width-depth ratios that were obtained using a digital caliper. The width-depth ratio provided an assessment of the “flatness” of a tuber, which is of importance in potato processing. To cross-validate the accuracy and differences among tuber shape measurement methods, a trained evaluator also assessed the identical tubers based on 1-5 scale (compressed to long) visual assessment method. Furthermore, the weights of analyzed tubers and specific gravities were also collected during the phenotyping process for each mapping clone. A major tuber shape QTL was consistently observed on chromosome 10 with both the length-width ratio and visual assessments. On chromosome 4, a significant QTL for tuber shape from the visual assessment phenotypic data was also detected. Additionally, a tuber shape-related QTL on chromosome 6 was also detected from the length-width ratio data from 2020. Chromosome 2 was also identified as having a significant QTL for the width-depth ratio, which is of importance in influencing the flatness of a tuber. One significant QTL for tuber weight (i.e., tuber size) was observed on chromosome 5, and a significant QTL for specific gravity was found on chromosome 3. These significant and major QTL should be useful for developing marker-assisted selection for more efficient potato breeding.