Combining ability and heterosis of tobacco (Nicotiana tabacum) resistance to bacterial wilt

Abstract

Bacterial wilt is one of the main diseases of tobacco, caused by Ralstonia solanacearum. One of the best approaches to control this pathogen is developing tobacco-resistant varieties. Combining ability analysis can be used to preliminarily identify the advantages and disadvantages of cross combinations and parents in earlier generations. The study aimed to estimate combining ability and heterosis of tobacco lines to bacterial wilt. Six tobacco genotypes were crossed in diallelic mating design to produce 15 F1‘s. These F1‘s and their parents were inoculated with the pathogen in the glasshouse condition based on Huang and Allen’s method. The experiment used Random Block Design with three replications. The analysis of combining ability was estimated following Griffing’s method-II and model-I, which is as described by Singh and Chaudhary. The analysis revealed that both additive and dominant genes controlled the resistance to R. solanacearum. The cross between NtJU and NtSP1 genotypes could generate F1 hybrid varieties that have more resistance to bacterial wilt. Tobacco genotype Nt_U2 showed a significant and negative value of general combining ability. Therefore, it can be used as a donor parent in the tobacco breeding program to generate resistant wilt tobacco varieties.