Hilling of Transplanted Seedlings from Novel Hybrid True Potato Seeds Does Not Enhance Tuber Yield but Can Affect Tuber Size Distribution

Abstract

A novel cropping system for potato was tested for two consecutive years under normal Dutch agronomic conditions. Seedlings from two experimental genotypes of hybrid true potato seeds were produced in a greenhouse nursery and transplanted into the field 5 weeks after sowing to assess tuber yield levels and to study effects of hilling on tuber yield and number, tuber size distribution and tuber greening. Field experiments had a split-plot design with hilling treatments as the main plots and genotypes as the sub-plots. Final harvest was at 122 and 132 days after transplanting in 2017 and 2018, respectively. Hybrid seedlings were transplanted into small initial ridges and irrigated straight after planting. Three hilling treatments were applied between transplanting and 100% canopy cover. Treatment ‘zero hilling’ did not receive any additional hilling after transplanting. Treatments ‘double hilling’ and ‘triple hilling’ received two and three additional hilling treatments, respectively. Total tuber yields at final harvest in both years were not affected by the hilling treatments. Yields for the respective genotypes were 26 and 30 Mg/ha in 2017 and 25 and 32 Mg/ha in 2018. Total tuber numbers were only affected by hilling treatments in 2017, where under hilled conditions, plants produced more tubers compared with plants under zero hilling. Plants under zero hilling yielded more tubers in size class > 40 mm compared with triple hilling in 2017. In 2018, no significant effects of hilling on tuber numbers were found, but the trend was similar to that in 2017.

Transplanting Hybrid Potato Seedlings at Increased Densities Enhances Tuber Yield and Shifts Tuber-Size Distributions

“…It is suggested that more cultivar-specific trials are conducted when improved hybrid potato cultivars become available to growers. These studies will contribute with the current study, and those carried out by Kacheyo et al (2021), Stockem et al (2020) and van Dijk et al (2021), useful information on the novel cultivation systems for hybrid potato, including crop management recommendations. More information will also be required on the optimal field conditions at the moment of transplanting and the subsequent seedling establishing period to enhance quick plant development.…”

“…Both experimental hybrids originated from the breeding programme described by Lindhout et al (2018) and were derived from similar research lines as the hybrids studied by Stockem et al (2020). Hybrid true seeds were sown by hand in 104-plug nursery trays on 13 April in 2017 and on 3 April in 2018 and cultivated as described by van Dijk et al (2021). Five weeks after sowing, 1 day prior to transplanting, a selection of transplantable seedlings (measuring 7-12 cm above-ground, containing 5-8 true leaves, BBCH stage 105-108; Kacheyo et al 2021) was made consistent with the protocol of van , after which seedlings were irrigated and loaded for transport to the field locations.…”

“…First, samples were cleaned from remaining soil and dirt; this step removed also tubers < 20 mm. Then, the samples passed by a 3D-camera to assess individual tuber size and tuber volume, needed to calculate tuber number and fresh weight (FW) per size class of all tubers in a net plot based on the total net-plot tuber FW, which was measured at the end of the phenotyping line (van Dijk et al 2021;Stockem et al 2020). Six basic tuber-size classes (sc) were used: 20 < sc ≤ 28 mm, 28 < sc ≤ 35 mm, 35 < sc ≤ 50 mm, 50 < sc ≤ 60 mm, 60 < sc ≤ 70 mm and sc > 70 mm.…”

“…Depending on variety, region and crop management, field-sown hybrid TPS and transplanted hybrid seedlings could potentially be used in these new cultivation systems. These may then produce either seed tubers or ware tubers (Almekinders et al 1996;Lindhout et al 2018;van Dijk et al 2021).…”

Optimal Plot Dimensions for Performance Testing of Hybrid Potato in the Field

“…One of the factors that leads to variation in potato plants is the quality of the seed tubers (Struik and Wiersema 2012). When testing hybrids, an alternative to using seed tubers as starting material is to use seedlings from true seed to prevent variation due to seed tuber quality, also from seedlings from true seeds relatively high yields up to 32 Mg/ha can be reached (Van Dijk et al 2021).…”