Browsing by Author "Palta, Jiwan P."

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A Comparison of the Responses of Five Potato Cultivars To Chloride Stress From Either Sodium Chloride or Calcium Chloride
(Parlar Scientific Publications (p S P), 2019) Okut, Nese; Vega-Semorile, Sandra; Navarro, Felix; Palta, Jiwan P.
Field trials were performed using the five following cultivars; Dark Red Norland, Russet Burbank, Superior, and Snowden. Randomized complete design with four replication swere conducted. Chloride salt treatments were given to plants twice after 7 and I 1 weeks of planting. The rate applied was about 100 kg per hectare from NaCI, CaCl2 or a combination of 50% NaCl and CaCl2. About 70 A grade tubers from each replicationwere cut and examined for internal defects after harvesting. The tissue calcium concentration of periderm and nonperiderm were then measured. From each replication, a composite sample of 20 tubers were combined for Ca analysis. Our results showed: (i) NaCl stress reduced tuber yield in all of the cultivars. This reduction was not as dramatic in the cultivar Superior. (ii) NaCl also reduced specific gravity by about 5% as well as tuber tissue calcium concentrations of cultivars. (iii) Same amount of chloride supplied from calcium chloride as a source increased tuber tissue calcium concentrations in all cultivars. However, there was no negative impact on either specific gravity or tuber yield. Results support our previous studies indicating that the negative impact of chloride on potato cultivars is only presented when NaCl is used as the source of chloride.
Genetic Variation for the Tolerance To NaCl Stress in Relation To Cultivars: Rooted Vs Non-Rooted In Vitro Studies
(Hard, 2025) Okut, Nese; Palta, Jiwan P.
Micro-propagated plantlets were used to screen potatoes for salinity (NaCl) tolerance. Nodal cuttings were placed in media with NaCl. The ability of cuttings to induce roots, in part, determined the tolerance of a given clone. We compared the response of rooted versus non-rooted nodal cuttings to salinity stress. Rooted or non-rooted nodal cuttings of "Russet Burbank", "Dark Red Norland", "Snowden", "Atlantic", and "Superior" potato plants were propagated in vitro on a medium containing 60 mM NaCl with 3 mM CaCl2. Rooted cuttings were produced by growing cuttings in normal MS medium and MS medium + 60 mM NaCl for 11 days. These rooted cuttings were then transferred to media containing salinity treatments. Thirty replicates were used per treatment. Observations were made up to 32 days after transfer. Results show: (i) Rooted cuttings displayed more tolerance to normal MS medium + 60 mM NaCl stress than non-rooted cuttings; (ii) Injury by NaCl does not appear to be due to osmotic stress. The primary cause of injury is likely ionic toxicity rather than osmotic stress, as evidenced by the protective effect of added CaCl2, which mitigates the toxic effects of Na+ ions, and the observed symptoms of necrosis and chlorosis. We suggest that rooted cuttings better simulate the response to saline water irrigation.