Evaluation of Brassica Germplasm for Resistance sources against White Rust

A series of Brassica germplasm NDN (National disease nursery) and UDN (Uniform disease nursery) were evaluated in field under natural epiphytotic condition followed by in glasshouse at cotyledonary and true leaf stage under controlled artificial epiphytotic condition for the confirmation of resistance against Albugo candida (white rust disease). In field, out of 30 (NDN) germplasm (03 no.) DRMRIJ 12-37, RH 1234 and NDRE-08-14-01 were found immune and 03, DRMRIJ 12-41, DRMRJA 35 and DRMRIJ 12-03 were found resistant. However, among UDN germplasm (34 no.), 03, DLSC-1, DRMR-312, RMM-09-04 were found immune and 02, RMWR 09-5-1, DRMR 2035, were found resistant while remaining germplasm in both the series most of them showed moderately resistant reaction and some showed moderately susceptible to susceptible reaction against white rust disease at 90 days after sowing (DAS). All these (NDN) and (UDN) germplasm were further tested in glasshouse at cotyledonary and true leaf stage for the confirmation of resistance. The (NDN) germplasm (03 no.) which were immune and 03, (total no. 6) which were moderately resistant in field at cotyledonary and true leaf stage only 02 showed immune reaction and 04 showed susceptible reaction. Similarly in (UDN), germplasm 03, showed immune reactions and 02, (total no.5) showed resistant reaction in field at cotyledonary and true leaf stage only 02 showed immune reaction and 03 showed susceptible to highly susceptible reaction. And remaining germplasm which were found moderately resistant in field in both the series most of them converted into susceptible germplasm in glasshouse. Present investigation explained that the glass house study is appropriate method for evaluation of resistance against white rust as actual resistance is obtained. However, the present findings revealed that in glasshouse (controlled artificial epiphytotic condition) at cotyledonary and true leaf stage is most important in my opinion for the confirmation rather than field study at leaf stage as some times disease escaped in field condition.