Project Number: 8042-21000-283-04-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Apr 15, 2016
End Date: Mar 20, 2020
To 1) identify genomic regions associated with stable high specific gravity, 2) study correlation between tuber texture, amylose and amylopectin ratio and pectin methyl esterase activity with specific gravity and identify associated genetic regions, and 3) introgress high specific gravity and quality texture traits into commercial processing potatoes.
A diploid hybrid population of S. phureja – S. stenotomum segregating for high specific gravity will be used to identify clones that are high in specific gravity and stable across environments. A total of 144 clones will be evaluated in replicated trials at 3 locations (Beltsville, MD; Hermiston, OR; Corvallis, OR) which are representative of short, middle and long growing seasons for two years. Twenty-four clones from each of two high, moderate, and low specific gravity families will be utilized in this study. 1. A combination of genotyping-by- sequencing based (GBS) single nucleotide polymorphism (SNP) marker approach and SolCap SNP array will be utilized to identify genomic regions linked to high specific gravity. The whole population (144 plants) will be SNP genotyped using both GBS and SNP array approaches. A linkage map will be constructed and quantitative trait loci (QTL) mapping will be carried out to identify QTLs linked to high specific gravity. The genotyping data will be further utilized to identify genomic regions associated with texture and starch profiles. 2. The best performance clones will be screened with the following methods to develop correlations with specific gravity. Mechanical methods have been developed for the quantitative assessment of textural properties. Texture profile analysis (TPA) of the raw and cooked potato cylinders from different lines will be performed in triplicate using a QTS 25 Texture Analyzer (Brookfield Engineering, Harlow, UK). Amylose: amylopectin ratios can be estimated from the ratio of the 620 and 550nm absorbance values of iodine complexes with both amylose and long chains within amylopectin and comparing them to a standard curve. The PME assay will be carried out as described by Phan et al. (2007). 3. High specific gravity and texture quality germplasm that are stable across all environments will be used as parents to introgress this trait in to commercial varieties. A large portion of this population produces 2n pollen and many of these clones can be readily crossed with tetraploid S. tuberosum. We will identify the best performing clones from this diploid population and will cross them with commercial chip (Beltsville, MD) and russet cultivars (Hermiston, OR) to introgress the high specific gravity trait.