Valuable New Leaf or Inflorescence Resistances Ensure Improved Management of White Rust ( Albugo candida) in Mustard ( Brassica juncea) Crops.

Field resistances/susceptibilities against Albugo candida race 2V were determined for 29 Indian Brassica juncea varieties and compared with resistant varieties from China (6) and Australia (7). 'Basanti' (AUDPC incidence 46.7; AUDPC severity 29.2) represents the first high-level resistance to race 2V in Indian varieties. Several others showed lower but still useful levels of resistance, including Narendra Ageti Rai-4 (AUDPC incidence 150.6; AUDPC severity 66.8) and JM1 (AUDPC incidence 167.1; AUDPC severity 83.7). Highly susceptible Indian varieties had AUDPC incidence values >200 and severity >100. 'Basanti' had least stagheads/plant (0.32), while Narendra Ageti Rai-4 had lowest % plants with stagheads (2.48). In contrast, almost half of Indian varieties had stagheads/plant >1 and % plants with stagheads >4, and >26 for 'Kranti'. The resistance in 'Basanti' paves the way forward towards significantly improved white rust management in mustard in India. JM06011, JM06021, JR049 from Australia and CJB-003 from China had zero leaf incidence. There were significant (P < 0.001) relationships between disease incidence with severity (R2 0.92), stagheads/plant (R2 0.69) and also % plants with stagheads (R2 0.60); between disease severity with stagheads/plant (R2 0.68) and also % plants with stagheads (R2 0.69); and between stagheads/plant with % plants with stagheads (R2 0.59). [ABSTRACT FROM AUTHOR]