Progress in breeding for nematode (Meloidogyne spp.) resistance in tobacco
Resistance to Meloidogyne incognita races 2 and 4 and M. javanica has been transferred from the original cross R23/NC95 to a TL33 background. The material known as NOD's in general did not cure well. They produced green tobacco of low value. Crossed to a series of flue-cured lines curing in the lemon range rather than orange or mahogany quality improvements were significant. This material will be evaluated on a commercial scale in the coming season. Nicotine and sugars were closer to that of TL33. Air-cured cultivars like CDL28, DL11 and DL17 were crossed to certain of the NOD's. Root growth of these combination and their progenies was better than those of the flue-cured combinations and nicotine and sugar concentrations were near to that of CDL28. Further improvements through backcrossing are anticipated. Oriental tobacco backcrosses are in progress again with NOD' as donor parents and Elsoma, OT 17 and OT 1 as recurrent parent.