Disease resistant flue-cured tobacco breeding lines for north Queensland I. Resistance to blue mould, Peronospora tabacina

Abstract

Blue mould, Peronospora tabacina Adam., is the most serious disease of tobacco in north Oueensland. Two cultivars were released in 1969 and one in 1972 which were resistant to the north Queensland strain of blue mould, APTI. During 1972 and 1973, a new strain of mould, APT2, became established in the area. The APT1 resistant cultivars, which carried resistance from Nicotiana debneyi or N. goodspeedii, were susceptible to APT2. Breeding lines carrying blue mould resistance from these species and from N. exigua, N. velutina or N. excelsior were introduced for screening for resistance to the new strain of mould. Some of these lines had been developed by backcrossing and selection, some from crosses between lines carrying resistance from different sources and others by following backcrossing by production of doubled haploids through anther culture. Following the screening of these lines for blue mould resistance and for commercial attributes, three backcross lines, three double haploid lines and one line carrying resistance from two sources were selected for further screening as potential commercial cultivars.