No abstract

The potential of near infra-red spectroscopy (NIRS) for predicting the sprouting capacity of potato (Solanum tuberosum L.) tubers was investigated. The experiment was conducted for 2 years using 'Superior' and 'Atlantic' potatoes. A total of 380 potato tubers (200, Superior; 180, Atlantic) weighing 100-200 g were scanned by NIRS, and the sample sets were divided into four groups; three groups were classified based on the cultivars or years as follows: 'Superior', 2004; 'Superior', 2005; 'Atlantic', 2005; the fourth group contained the total number of samples. The reference value for the sprouting capacities was measured by determining the sprout weight after 30 days of incubation at 20°C. The first derivative transformation equation for raw optical data was standardized by applying standard normal variate (SNV) and detrending (DT) algorithms, and calibration equations between them were developed by modified partial least square (MPLS) regression. The coefficient of determination (r 2 ) ranged from 0.868 to 0.965 with a standard error of calibration (SEC) from 0.31 to 0.40 for the calibration sets; r 2 ranged from 0.724 to 0.904 with a standard error of prediction (SEP) from 0.532 to 0.602 for the four validation sets. These results indicate that the calibration model obtained from this experiment is applicable to all the different cultivars for different years, and the NIRS method is a powerful tool for the predictive assessment of the sprouting capacity of potato tubers.

No abstract

Potato (Solanum tuberosum L. `Russet Burbank' and `Shepody') tubers were exposed to continuous 4 μL·L-1 (166 μmol·m-3) ethylene in air. Treatment started after 8 weeks in storage and continued up to 33 weeks of storage at 9 °C over one (`Russet Burbank') or two (`Shepody') storage seasons. Tubers were sampled at 3 week (`Shepody') or 5 week (`Russet Burbank') intervals for polyamine content [putrescine, (PUT); spermidine, (SPD); and spermine, (SPM)] and sprout number and fresh weight per tuber. During the storage period, `Shepody' had higher concentrations of all three polyamines and a higher PUT/(SPD + SPM) ratio, compared with `Russet Burbank'. All three polyamines in both cultivars increased during storage, and the increase was more rapid in `Shepody' than in `Russet Burbank'. Regardless of cultivar and year, exposure to ethylene induced higher spermidine (SPD) content and a lower PUT/(SPD + SPM) ratio, compared with the air treatment. Sprouts appeared later and were smaller on ethylene-treated tubers and were more numerous in `Russet Burbank'. These long-term ethylene effects may be due, in part, to enhanced transformation of PUT to SPD.

This study was carried out to determine environmental factors affecting the anthocyanin content of colorfleshed potato (Solanum tuberosum L.) tubers. After planting of two color-fleshed potato cultivars of 'Hongyoung' and 'Jayoung' in different 14 locations, their soil chemical properties and meteorological data were evaluated, and anthocyanin contents of tubers were analyzed after harvest, additionally their relationship among them was analyzed through correlation analysis. In comparison with two cultivars, purple-fleshed 'Jayoung' potatoes showed higher anthocyanin content than red-fleshed 'Hongyoung' in almost locations. When locations were divided to three categories (highland, sub-highland and lowland) according to altitude, in general, highland-grown tubers had the higher content of anthocyanin compared to those grown in lowland. An analysis of the results of chemical components of soil showed that anthocyanin content of color-fleshed potato tubers was negatively correlated with the pH of soil. In addition, mean temperature and minimum temperature from 80 to 100 days after planting most significantly affected on the accumulation of anthocyanin in color-fleshed potato tubers, that is, higher content of anthocyanin was observed in tubers produced in locations with lower mean temperature and minimum temperature from 80 to 100 days after planting. This information can be useful to producers and industries in selection of proper fields for the production of color-fleshed potato tubers having high quality in Korea.