Study on Genetic of Chlorine Accumulation in Leaves of Oriental Tobacco (Nicotiana tabacum L.)

Chlorine as a micronutrient has a positive effect on the quality of tobacco leaves. However, the more chlorine has adverse effects on tobacco quality. To study the genetic accumulation of chlorine in leaves of oriental tobacco, each of the two lines ‘Basma 16-10’ and ‘SPT 406’ with the low accumulation of chlorine were crossed separately with Basma S. 31 with the high accumulation of chlorine. Parents of each cross together with F1, F2, BC1 and BC2 generations were evaluated for chlorine accumulation in a randomized complete block design with 3 replications under filed condition. Analysis of variance showed a significant difference between generations for accumulation of chlorine in leaves. Therefore, generation mean analysis was performed to estimate gene actions using Chi-square and scaling tests. The Chi-square of simple three-parametric model (additive- dominance model) was significant for studied crosses that indicate the presence of non-allelic interaction in the inheritance of property of accumulation of chlorine in leaves. In ‘Basma S. 31 × Basma 16-10’ cross, the best model to explain the inheritance of chlorine accumulation is 5-parameters model with [m], [h], [i], [j] and [l] components. High and significant value of [h] compared to [d] show the importance of dominance effect in controlling trait. In ‘SPT406 × Basma S. 31’ cross, 4-parameters model with [m], [d], [i], and [l] components is the best model. The presence of [d] and [i] in the absence of [h] suggest the importance of additive genetic effects in control of chlorine. So we can say that the mechanisms involved in the accumulation of chlorine are different in studied genotypes. So, different breeding strategies are necessary to selection and modification of genotypes with low chlorine accumulation in segrigation populations.