Application of association mapping and genomic sequencing to starch and glycaemic index in potato

Summary

This PhD studentship project used an association genetics approach to identify genes that are important in traits related to glycaemic index (GI). 

Key Findings

The starch digestibility characteristics of samples from the 300 genotypes used in the study were determined. Trials were conducted over two growing seasons, using a replicated block design. Consistent variation in starch properties between the genotypes was observed in the year 1 trial. The starch digestibility characteristics were used in an association mapping approach using the SolCAP SNP marker data available for the association panel (ca. 8300 SNPs) and 44700 SNP markers available from a genotype-by-sequencing approach. Significant associations with starch digestibility were detected using the first trial. For the second trial the data were not well correlated between the two blocks used in the trial or with the first trial.

A reproducible and reliable starch digestibility assay has been developed. The assay requires 100 mg of starch and measures glucose release over 60 minutes. Compared with previous methods, this is a high throughput assay that can be used to assess many samples simultaneously.

Sector:
Potatoes
Project code:
11140010
Date:
01 October 2013 - 30 September 2016
Project leader:
Mark Taylor

Downloads

11140010 Mapping GI and Starch FINAL_0 11140010_Appendix_1 11140010_Appendix_2 11140010_Appendix_3

About this project

Aims and objectives

Aim:  To determine the degree of variation that exists in GI-related traits across a diverse range of potato germplasm. There are a number of factors that may affect the GI of potatoes, including starch structure, ratio of amylose and amylopectin, the level of processing, cooking technique, and the presence of other nutrients such as fat, protein, and dietary fibre.

Objectives:

a) To phenotype varieties over 2 years for factors contributing to glycaemic index: including dry matter, sugars and levels of resistant starch.
b) To understand the associations of phenotype and genotype data which will provide new insights into factors that influence GI in potatoes.
c) To identify key genes as well as development of diagnostic markers for starch qualities and ultimately new varieties with improved GI characteristics.
 
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