Evaluation of Chloride Accumulation and yield Stability of Oriental Tobacco Promising lines (Nicotiana tabacum L.)

Tobacco (Nicotiana tabacum L.) is one of the unique industrial and commercial crops from Solanaceae family. Chlorine as a micronutrient has positive effects on tobacco leaf quality, but its higher amounts (more than 2 percent of dry weight) reduce the quality of tobacco leaves. A breeding project was designed and implemented to achieve new lines with low chloride accumulation in leaves.

Based on the results of diallel and generation mean analyses, the Basma Seres 31 × SPT 406 combination was selected and the management of segregant populations was continued with pedigree method until reaching to promising lines with low chlorine accumulation. Four lines with the least Cl accumulation were selected from F7 of above mentioned cross combination. The four promising lines (including 11, 37, 38 and 45) together with two commercial tobacco cultivars as controls, Basma Seres 31 and Urmia 205; famous for accumulating high level of Cl in leaf, were evaluated in completely randomized block design with three replications at two locations (Marangalou-e-Bozorgh village /Urmia and Bastam village/Qarezyadin with high soil and irrigation water chloride levels) during 2018 and 2019 growing seasons.

Analysis of variance revealed significant difference among the tobacco lines for Cl accumulation in leaves and dry leaf yield. Based on the first and second years of experiments results, the Cl accumulation ranged from 1.89 -3.20 and 1.79 -3.29 percent and leaf yield ranged from 1388-3574 and 1320-3108 kg/hectare, respectively. Based on the means comparisons, line 45 and line 11 presented least accumulation rate of Cl; 1.79 and 1.99 percent. This rate was 3.30 and 3.20 percent for check cultivars; Basma Seres 31 and Urmia 205. Means comparison of yield revealed that cultivar Urmia 205 and line 11 with 2840 and 2775 kg/hectare dry leaf yield had maximum and line 45 with 1508 kg/hectare had minimum dry leaf yield.

Line 11 with low Cl uptake and high and stable dry leaf yield is the best line among the studied lines and cultivars. Therefore, in the areas under tobacco cultivation in West Azerbaijan where there is high chlorine in soil and irrigation water (more than 1.5 milliequivalents per liter of saturated extract) and the obtained product contains more than 3% chlorine per dry weight and that's why tobacco cultivation is banned; line 11 can be cultivated and thus oriental tobacco cultivation can be maintained and revived in this region.