Reliability of Measurement and Genotype × Environment Interaction for Potato Specific Gravity

Abstract

Specific gravity (SpGr) is often used to measure the processing quality of potato (Solanum tuberosum L.) tubers for French fries or potato chips because of its strong correlation with dry matter content and ease of measurement. For French fry processing genotypes, the desirable range for mean SpGr is typically 1.080 to 1.095, and a small variance around the mean is essential for product uniformity. Two multi‐year, multi‐location trials were conducted to investigate the genetics of SpGr in elite russet germplasm. Consistent with earlier studies, the mean SpGr was measured with high repeatability within each environment: the median plot‐basis value was 0.83 for a national trial with six locations and 3 yr. In contrast, the median repeatability of the SD between tubers was only 0.21. Thus, multi‐environment trials are needed to identify genotypes with a narrow SpGr distribution. Finlay–Wilkinson stability analysis of the mean SpGr established one genotype as an outlier: when best linear unbiased predictions were regressed on the environment means, this genotype had a regression coefficient of 2.1, compared with 0.4 to 1.4 for the others. The genetic correlation between environments showed a consistent regional pattern in mean SpGr over the years. There was a higher mean correlation between environments within the Pacific Northwest (0.97), Upper Midwest (0.91), and Northeast (0.85) than between environments from the different regions (0.35–0.78). Although breeding for national adaptation is an attractive idea, our results suggest that genetic gain may be easier to achieve at the regional level.

Genetic Covariance of Environments in the Potato National Chip Processing Trial

“…The analysis used linear mixed models with factor-analytic (FA) covariance structures to parsimoniously model the genetic correlation between many environments (Piepho, 1998;Smith et al, 2001). Factor-analytic models have been used before to analyze multienvironment trials of potato, including Paget et al (2015) for yield in New Zealand and Wang et al (2017) for specific gravity of russet potatoes in the United States. Both studies used the "uniplot" technique of Cullis et al (2010) to visualize genetic correlation with a second-order FA model.…”

Stability of potato clones resistant to potato virus Y under subtropical conditions

“…The G×E is commonly detected for SG and has already been described in other studies (Teixeira et al 2015, Wang et al 2017. Teixeira et al (2015) discussed the effect temperature has on the SG, where environments that had higher temperatures can cause a decrease in SG compared to environments with mild temperatures.…”

Genomic selection and genome‐wide association studies in tetraploid chipping potatoes

“…Lynch et al (1992) found high GCA effects and nonsignificant SCA effects for specific gravity and suggested that mainly additive genetic factors account for the genetic variation. Wang et al (2017) also showed relatively little genotype × environment interaction for specific gravity. Specific gravity as a proxy for dry matter content can be used for selecting chipping potatoes.…”