Ks. Reddy et al., INHERITANCE OF POWDERY MILDEW (ERYSIPHE POLYGONI DC) RESISTANCE IN MUNGBEAN (VIGNA-RADIATA L WILCZEK), Theoretical and Applied Genetics, 88(8), 1994, pp. 945-948
Detached mungbean (Vigna radiata L. Wilczek) leaves were inoculated wi
th a conidial suspension of a local isolate (TI-1) of the powdery mild
ew pathogen (Ery-siphe polygoni DC) under controlled environment condi
tions. Based on the latent period and severity of the infection, a rat
ing scale of 0-5 was used to classify the host pathogen interactions.
Reactions O, 1 and 2 were considered resistant and referred to as R0,
R1 and R2 while 3, 4 and 5 were classified as susceptible (S). RUM lin
es (resistant to powdery mildew) and their derivatives are crossed wit
h several susceptible (reaction types 3-5) genotypes and the inheritan
ce of the resistance was studied in the F-1, F-2 and F-3 generations.
The results showed that powdery mildew resistance in mungbean is gover
ned by two dominant genes designated as Pm-1 and Pm-2. When both Pm-1
and Pm-2 were present, an R0 reaction was observed after inoculation w
ith TI-1. The resistant reaction was R1 when only Pm-1 was present and
R2 in the presence of Pm-2. In the absence of both Pm-1 and Pm-2, sus
ceptible reactions 3, 4 and 5 were observed.