Inheritance of Resistance to Bacterial Wilt in Chinese Domestic Tobacco Cultivar GDSY-1

In order to clarify the mode of inheritance of resistance to bacterial wilt disease, genetic analysis was performed under major gene+polygene mixed inheritance model using the P1, P2, F1 and F2 populations of three crosses among GDSY-1, DB101 and Changbohuang. GDSY-1, a Chinese domestic sun-cured cultivar, was newly identified to have high resistance to bacterial wilt caused by Ralstonia solanacearum. DB101 is a USA cultivar, carrying the polygenic resistance derived from T.I.448A. Changbohuang, a Chinese domestic flue-cured cultivar, was susceptible to bacterial wilt. The results indicated that GDSY-1 was considerably more resistant than DB101. The inheritance of DB101 resistance showed mainly additive effects, conforming to the two adding major genes plus additive-dominance polygene model (E-4). The inheritance of GDSY-1 was partially dominant, conforming to the two additive-dominance-epistatic major gene plus additive -dominance-epistatic polygene model (E-0). The additive and dominant effect values of the first major gene were -2.6909 and -2.6909, with the resistance being completely dominant. The additive and dominance effect values of the second major gene were -1.2194 and -0.2307, with the resistance being partially dominant. The heritability of major genes was 85.02%.