Resistance to black root rot (Chalara elegans Nag. Raj and Kendrick) and some growth characteristics in doubled haploid derivatives of the F1 hybrid of tobacco (Nicotiana tabacum L.)

Black root rot (BRR), caused by Chalara elegans, is a widespread and severe disease of tobacco ( Nicotiana tabacum L.). Anther culture and stem culture techniques were used to produce the haploids and doubled haploids (DHR 0 ) lines of F 1 hybrids of N. tabacum cv. 'K 326' susceptible to BRR and cv . 'Wentu- ra', a male parent of the widely cultivated BRR-resistant hybrid 'VRG 2'. Twenty four mature DHR 0 plants were self-pollinated and their derivatives (DHR 1 ) were screened for BRR resistance in greenhouse tests. From a total of 24 DHR 1 lines, seven (29.2%)