The influence of storage temperature and length of time in storage on anthocyanin tuber concentration were investigated in seven potato genotypes. These genotypes were cultivars `All Blue' and `Yukon Gold' plus five selections that were various skin/flesh color types of red/red, purple/purple, white/yellow, and two red/yellow types. The red, blue, and purple colors are the result of various anthocyanin compounds. Tubers of the seven genotypes were stored at 4.4 or 10 °C for 0, 4, 6, 8, 10, 12, 16, 20, or 24 weeks. Both fresh and freeze-dried samples of the tubers were evaluated for each temperature and time treatment combination. Extractable anthocyanins were found in only the three pigmented genotypes red/red, purple/purple, and `All Blue'. Anthocyanin concentrations were estimated spectrophotometrically with a Molecular Devices Spectramax 384, based upon extinction coefficients reported in the literature for purple and red pigmented potatoes. Anthocyanin concentration increased in storage as time in storage increased for both fresh and freeze-dried samples. Tubers stored at the cooler temperature (4.4 °C) had higher levels of anthocyanin than those tubers stored at the higher temperature (10 °C). Increased levels of anthocyanins in cold-stored tubers may be linked to the conversion of starch to sugar (so called cold sweetening) known to occur at cold storage temperatures. Pigment extraction was more efficient from freeze-dried tuber samples compared to fresh tuber samples. There was, however, a similar increasing trend in both freeze-dried and fresh tuber sources with storage duration.
Mekhled M. Alenazi, Harrison G. Hughes, Cecil Stushnoff, and David G. Holm
Jennifer K. Hart and David J. Hannapel
Homeobox genes contain sequences coding for DNA-binding motifs. These sequences are highly conserved across both the animal and plant kingdoms. Members of this gene family code for transcription factors that are key regulators of developmental organization. In an attempt to further elucidate the developmental process of tuberization in the potato plant, a full-length homeobox cDNA has been isolated via sequence homology from an early tuberization stage cDNA library constructed from 4-day axillary bud tubers. This cDNA, POTH1, has been sequenced and characterized by Southern blotting, northern analysis, sequence comparison, and in situ hybridization. POTH1 is shown to be a class I homeobox gene with 45% overall similarity to Kn-1 of maize and 73% match in the homeobox region. Messenger RNA accumulation studies indicate that POTH1 mRNA, unlike most homeobox transcripts, is not limited to a particular organ or developmental stage. Instead, POTH1 mRNA accumulates in rapidly growing cells of the potato plant: the apical meristems, the vascular cambium, the edges of young leaves, axillary buds, and root tips. In situ studies indicate accumulation of POTH1 mRNA in the tunica and corpus layers of the apical dome of the shoot apex and the stolon apex. In the stolon, growth and proliferation of the parenchymal cells associated with the vascular cambium contribute to swelling during early stages of tuberization, and this tissue accumulates POTH1 mRNA. It is possible that POTH1 may be posttranscriptionally regulated in a particular organ or stage of growth, or that it is involved in a wider range of growth processes than most plant homeobox genes.
Leila Farhadi*, Cyrus Abdmishani, Shahram Ahmadian, and Majid Foolad
The aim of this study was to assess the suitable hormonal balance on potato microtuberization from the plantlets which had been in heat therapy condition before culturing the meristem. The effects of different levels of BAP and sucrose concentration were studied 16 weeks after the last culture in two genotypes. Explants from meristem were propagated in vitro in several stages and then subcultured with MS medium containing the combination of BAP (three levels) and sucrose (three levels). Then they were transferred to a completely dark incubation room at 22 °C. In vitro tuber formation was analyzed 16 weeks later. Traits which studied were: length, diameter, fresh weight and number of micro tubers. There was no significant difference among the genotypes for all the traits. The micro tuber number was significantly different among the levels of BAP concentration and the BAP and sucrose interaction was significant for the diameter. The micro tuber fresh weight and diameter were highly significant for the sucrose levels. The sucrose and genotype interaction for micro tuber length; sucrose and BAP interaction for micro tuber length and diameter were significant. Also the genotype, BAP and sucrose interaction was significant for the micro tuber fresh weight.
Tyann Blessington, Douglas C. Scheuring, and J. Creighton Miller Jr.
Potatoes are stored to ensure a continuous supply; however, losses due to shrinkage and sprouting can be large. It is believed that ionizing irradiation will become more prominent for sprout inhibition due to the increasingly higher operating costs of low-temperature storage and possible phase-out of chemical sprout inhibitors. The effects of storage and ionizing irradiation (gamma and electron beam) on antioxidant activity (AOA), phenolic content, and carotenoid content were analyzed using the potato cultivar Atlantic. Tubers were subjected to 0, 75, and 200 Gy γ-irradiation doses, stored at 20 °C, and analyzed after 0, 10, 20, 75, and 110 days. Tubers from another harvest were subjected to a surface dose of 0 or 200 Gy e-beam irradiation, stored at 20 °C, and analyzed after 0, 10, 20, 75, and 110 days. AOA was measured via the DPPH method; phenolic content via the Folin-Ciocalteau method and individual phenolics via HPLC; and carotenoid content via absorbance at 445 nm and individual carotenoids via HPLC. During early storage, higher doses resulted in higher AOA, while, during longer storage, lower doses produced greater AOA. Phenolic content increased in storage during the γ-irradiation study, but decreased in the e-beam study, partly due to increases in chlorogenic acid in the former and decreases in caffeic acid in the latter. The e-beam dose of 200 Gy resulted in significantly greater total phenolics than 0 Gy. Total carotenoids and lutein decreased with storage, but were not affected by irradiation. Storage exerted a much greater influence on AOA, phenolic content, and carotenoid content than either irradiation treatment.
Y.D. Park, A.A. Boe, and M.K. Ehlenfeldt
Leaf disks of potato cv. Kennebec and ND 860-2 (North Dakota potato breeding clone) were cultured on Murashige Skoog (MS) medium supplemented with 6 levels of indole acetic acid (IAA) and 7 levels of zeatin riboside (ZR). Shoots were induced at various combinations of hormone levels. The medium containing 3.5 mg/l IAA and 4.0 mg/l ZR produced the most shoots. Rooted plantlets were grown in the greenhouse. The growth of regenerated plants obtained from the MS medium supplemented with 7.0 mg/l IAA and 3.0 mg/l ZR was significantly greater than those grown from nodal explants. In ND 8602, a leaf chimera with chlorophyll deficient (light yellow) sectors was found in plants regenerated from leaf disks (grown on MS medium supplemented with 3.5 mg/l IAA and 3.0 mg/l ZR) but not in plants grown from nodal explants. Phenotypic variability was also observed for tuber number, size and weight.
Yu-Kuang Chen, John B. Bamberg, and Jiwan P. Palta
Tetraploid somatic hybrids between S. tuberosum (tbr) and S. commersonii (cmm) have been produced to incorporate desirable traits such as cold hardiness from cmm into cultivated potatoes. While nonacclimated freezing tolerance (NA) of these somatic hybrids were as low as tbr fusion parent, their acclimation capacity (ACC) approximated that of the parental mean. In order to further explore the potential of using these somatic hybrids in breeding programs and to examine the segregation of genes conferring NA and ACC in somatic hybrids, progenies have been developed from either selfing somatic hybrids or crossing them with a tuberosum breeding line, Wis 231. In total, 48 selfed and 6 backcross progenies were characterized for the expression of NA and ACC. The NA derived from cmm was still poorly recovered in both sets of progenies. However, ACC did show some variation ranging from the level of sensitive fusion parent to that of the selfed parent, HA 26-5. None of the progeny had ACC as high as their cmm parent. Our results suggest that the expression of NA was suppressed by the cold sensitive genome of tbr. Thus, ACC is the form of cold tolerance from cmm, which appears to be most easily accessed though these somatic hybrids.
Lumariz Hernandez Rosario, Juan O. Rodríguez Padilla, Desiree Ramos Martínez, Alejandra Morales Grajales, Joel A. Mercado Reyes, Gabriel J. Veintidós Feliu, Benjamin Van Ee, and Dimuth Siritunga
The Solanaceae family is one of the major groups of angiosperms with ≈2500 species and 100 genera ( Filipowicz and Renner, 2012 ). The family contains species with agricultural and economical importance worldwide such as Solanum tuberosum
Hisayuki Kudo and Takeo Harada
, because most fruit trees and many vegetables are grafted ( Lee, 1994 ). So we grafted potato ( Solanum tuberosum L.) scions onto Me tomato rootstock to test whether the RNA molecule can move from Me tomato and whether it alters the potato leaf
Joseph C. Kuhl, Kelly Zarka, Joseph Coombs, William W. Kirk, and David S. Douches
incorporate such resistance into cultivated lines. The cultivated potato, S. tuberosum , is tetraploid (4 x ) with an endosperm balance number (EBN) of 4, resulting in crossing barriers with wild Solanum species that differ in ploidy or EBN ( Hanneman, 1999
Christian T. Christensen, Lincoln Zotarelli, Kathleen G. Haynes, and Charles Ethan Kelly
, gibberellic acid and CCC on sprout growth and mobilization of tuber reserves in the potato ( Solanum tuberosum L.) Planta 77 224 232 Mustefa, G. Mohammed, W. Dechassa, N. Gelmesa, D. 2017 Effects of different dormancy-breaking and storage methods on seed