Acrylamide-Forming Potential and Agronomic Properties of Elite US Potato Germplasm from the National Fry Processing Trial

Processed potato (Solanum tuberosum L.) products, such as chips and French fries, contribute to the dietary intake of acrylamide, a suspected human carcinogen. One of the most promising approaches for reducing its consumption is to develop and commercialize new potato varieties with low acrylamide-forming potential. To facilitate this effort, a National Fry Processing Trial (NFPT) was conducted from 2011 to 2013 in five states. More than 140 advanced breeding lines were evaluated for tuber agronomic traits and biochemical properties from harvest through 8 mo of storage. Thirty-eight and 29 entries had significantly less acrylamide in French fries than standard varieties Russet Burbank and Ranger Russet, with reductions in excess of 50%, after one and 8 mo of storage, respectively. As in previous studies, the glucose content of raw tubers was predictive of acrylamide in finished French fries (R² = 0.64–0.77). Despite its role in acrylamide formation, tuber free asparagine was not significant, potentially because it showed relatively little variation in the NFPT population. Even when glucose was included in the model as a covariate, genotype was highly significant (p = 0.001) for predicting acrylamide, indicating there may be yet-unidentified genetic loci to target in breeding. The NFPT has demonstrated that there exist many elite US breeding lines with low acrylamide-forming potential. Our ongoing challenge is to combine this trait with complex quality attributes required by the fry processing industry.This is the publisher’s final pdf. The published article is copyrighted by the Crop Science Society of America and can be found at: https://dl.sciencesocieties.org/publications/c

Modeling Long-Term Trends in Russet Burbank Potato Growth and Development in Wisconsin

Improving understanding and prediction of the potato (Solanum tuberosum) tuber size over the growing season is important due to its effects on crop price and marketing. Several models have been proposed to describe potato growth and development, but are based on short-term data and have little use for predicting yields or in-season management decisions. This analysis uses long-term data collected from 1979 to 1993 in central Wisconsin to describe growth and development of the Russet Burbank potato variety. This paper describes average number of potato tubers per plant and tuber length as influenced by thermal time and stem number per plant over 14 years. For each plant variable, data analysis uses multivariate techniques to fit a hierarchical logistic model with parameters potentially depending on stem number per plant. Analysis finds that the average number of potato tubers and average tuber length were affected by thermal time and stem number per plant. Estimated models are biologically relevant, provide an understanding of seasonal thermal variability and stem number per plant effects on average tuber set and growth, and can be used to describe yearly variation in average potato growth and development. Increased understanding of potato growth in response to thermal time and stem number per plant can improve management recommendations and predictions of crop economic value

Vacuolar Invertase Gene Silencing in Potato (<i>Solanum tuberosum</i> L.) Improves Processing Quality by Decreasing the Frequency of Sugar-End Defects

<div><p>Sugar-end defect is a tuber quality disorder and persistent problem for the French fry processing industry that causes unacceptable darkening of one end of French fries. This defect appears when environmental stress during tuber growth increases post-harvest vacuolar acid invertase activity at one end of the tuber. Reducing sugars produced by invertase form dark-colored Maillard reaction products during frying. Acrylamide is another Maillard reaction product formed from reducing sugars and acrylamide consumption has raised health concerns worldwide. Vacuolar invertase gene (<i>VInv</i>) expression was suppressed in cultivars Russet Burbank and Ranger Russet using RNA interference to determine if this approach could control sugar-end defect formation. Acid invertase activity and reducing sugar content decreased at both ends of tubers. Sugar-end defects and acrylamide in fried potato strips were strongly reduced in multiple transgenic potato lines. Thus vacuolar invertase silencing can minimize a long-standing French fry quality problem while providing consumers with attractive products that reduce health concerns related to dietary acrylamide.</p></div

Sucrose content in both ends of Russet Burbank potato tubers and in tubers from <i>VInv</i>-silencing lines (RBKx) of Russet Burbank at harvest and after one, three and five months of storage.

<p>Note: Data are means ± standard deviation of five independent tuber samples. Sucrose contents are shown as mg g⁻¹ fresh tuber weight.</p

Sugar-end defect frequency was reduced in French fries prepared from <i>VInv</i>-silencing lines of Ranger Russet.

<p>Sugar-end defects are apparent on nearly half of the fries from Ranger Russet (A) and empty vector (B) control tubers. No sugar-end defect fries where observed in fries from lines 1632-1 (C) and 1632-4 (D) in which the <i>VInv</i> had been silenced using RNA interference. In (A) and (B), fries with sugar-end defects are on the right and fries without sugar-end defects are on the left.</p

Expression of <i>VInv</i> in the bud end and stem end of tubers from <i>VInv</i>-silencing lines of Russet Burbank (RBKx) relative to expression of <i>VInv</i> in untransformed Russet Burbank at harvest and after one, three and five months of storage.

<p>Note: ^§Asterisks indicate overall differences of least squares means between RBKx and Russet Burbank controls at the same tuber end across sampling times of harvest and one, three and five months of storage.</p><p>*, p<0.05;</p><p>**, p<0.01;</p><p>***, p<0.001.</p><p><i>VInv</i> expression was determined using <i>actin97</i> as a reference gene and results are presented as a percentage of the level in Russet Burbank controls.</p

Time and position dependent <i>VInv</i> expression and acid invertase activity in Russet Burbank silencing lines differed from that in Russet Burbank controls.

<p><i>VInv</i> expression (A, C) and acid invertase activity (B, D) in the stem (A, B) and bud (C, D) end of five <i>VInv</i>-silencing lines and controls of Russet Burbank potato tubers at harvest and after 1, 3 and 5 months of storage. <i>VInv</i> expression in stem and bud end samples was expressed relative to expression of the reference gene <i>actin97</i>. Bars represent mean ± standard error of five independent tuber samples.</p