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Abstract
This work was carried out to study salt tolerance of potato (Solanum tuberosum L.) at Vegetable Research Departments, Horticulture Research Institute, during the period from 2003 to 2008. The objectives of this study were to evaluate relative salinity tolerance of some potato genotypes using in vitro and in vivo studies to determine the impact of salinity on potato tuber yields and study the possibility of using potassium and calcium in ameliorating the adverse effects of salinity. Four in vitro experiments using Cara, Diamant and Spunta potato cultivars were conducted to study the effect of NaCl and potassium or calcium levels on growth of plantlets and microtuberization. Two pot trials were carried out during autumn seasons of 2006 and 2007 using Cara and Diamant cultivars. Obtained results indicated that increasing NaCl level caused a significant reduction in shoot length, number of leaves, number roots and plantlet fresh and dry weights. Microtuberization of the three studied cultivars was affected by increasing NaCl salinity. The cultivars gave significant differences in microtuberization rate and microtuber fresh and microtuber dry weights. Diamant gave the highest microtuberization ratio and microtuber fresh and dry weights. Spunta produced the lowest value of microtuberization rate and microtuber fresh and dry weights. Addition of 20 mM potassium ameliorated the adverse effects of salinity on microtuberization. Addition of 1 mM calcium mitigated the adverse effects of salinity on microtuberization
The pot experiments indicated obviously that Cara cultivar gave better results for the studied characteristics than Diamant cultivar. Salinity caused a reduction in vegetative characteristics and tuber yield. Also, it caused a decrease in nitrogen and phosphorus content in the leaves and the tubers. Moreover, increasing salinity level resulted in increased carbohydrate content in tubers. Addition of calcium or potassium did not show significant effects on mitigating the adverse effects of salinity.
It is concluded from the study that utilization of in vitro techniques in screening potato cultivars for salinity stress under controlled conditions may help in overcoming the problem of large environmental error encountered over years and locations in field evaluation. In addition, it can be assumed that potassium or calcium augmentation in the saline medium may ameliorate the adverse effects of salinity on plant growth.