Biochemical changes in genetic and induced systemic resistance due to infection of Albugo candida (Pers. ex. Lev) in Indian mustard
Loading...
Date
2020-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
CCSHAU, Hisar
Abstract
White rust disease incited by Albugo candida is an important disease of Indian mustard (Brassica juncea) in
India particularly in northern and North eastern states. Keeping in view the enormous losses caused by the pathogen,
the present investigation has been devised on biochemical changes due to infection of Albugo candida in different
Indian mustard genotypes, induction of systemic resistance by non conventional chemicals, identification of slow
white rusting genotypes and role of micronutrients in defence against white rust under laboratory, screen house and
field conditions at Chaudhary Charan Singh Haryana Agricultural University, Hisar. The results of biochemical
analysis revealed that total phenolic content, PO, PPO, PAL and chitinase activity were found higher in healthy
leaves of resistant genotypes (BIOYSR, EC399299) as compared to moderately resistant genotypes (EC399301,
DRMRIJ-31) and susceptible genotypes (RH 30, RH 8812) at 35-40 DAS. There was steep increase in all the
biochemical constituents at the time of disease initiation ie. at 45-50 DAS. However, increase was more in inoculated
environment as compared to uninoculated environment. At maximum disease severity i.e.70-75 DAS, there was
decline in all the biochemical constituents in all genotypes under both the environments. Decrease was more in
susceptible genotypes indicating the exhaustion of these biochemical constituents which otherwise consider
necessary to trigger genetic resistance through pathways. Efficacy of six non conventional chemicals were tested
with different concentrations for induction of resistance against white rust. None of the non conventional chemical
completely controlled the white rust disease even at higher concentration of 100 μg/ml. However, a maximum
control was also recorded by BTH at 100 μg/ml concentration after six weeks of challenge inoculation by the
pathogen followed by SA in both the variety (RH 30 and RH 0749) under screen house conditions. BTH has shown
maximum induction of phenolic content, PO, PPO, PAL and chitinase activity at three days after inoculation (DAI)
in both the varieties at 100 μg/ml concentration followed by SA. However, MgSO4 has shown minimum induction
of these activities at three DAI in both the varieties.Out of 22 Indian mustard genotypes screened for identification of
slow white rusting component, 9 genotypes exhibited longer incubation and latent periods, minimum number of
pustules per leaf, minimum size of pustule, minimum sporulation, minimum disease severity and minimum AUDPC
indicating slow white rusting behaviour. Among the different treatments of mcronutrients alone and in combinations,
soil application of Gypsum + Borax + CuSO4 + Na2MoO4 at 30 DAS as basal dose recorded minimum white rust
severity of 31.1% and staghead incidence of 4.44% and highest seed yield of 2228.55 kg ha-1 as compared to the
45.83% white rust severity and 6.09% staghead incidence and seed yield of 1779.79 kg ha-1 in control. Maximum
number of primary branches per plant (5.83), secondary branches per plant (12.33), main shoot length (90.93 cm),
siliquae on main shoot (62.60) and seeds per siliquae (12.53) were also observed with above treatment. Plant height,
siliqua length, oil content and 1000 seed weight did not vary significantly among all the treatments.