Variation in metabolites constituent in leaves of downy mildew resistant and susceptible genotypes of pearl millet

In the present investigation biochemical characterization of pearl millet genotypes was carried at pre (45 DAS) and post-infection (57 DAS i.e. 7 days after infection) stage. Total soluble sugar was greater at pre infection than post infection in downy mildew resistant and susceptible genotypes of pearl millet. Total soluble sugar decreased in all genotypes at 7 days after infection (d.a.i.) except in 7042 S in which it increased 4.6 %. However, total soluble sugar was 2–3 folds more in highly susceptible genotypes (J-2296 and 7042 S) compared to resistant genotypes at 7 d.a.i. but it was decreased as compared to pre infection. The total amino acid content of all genotypes whether resistant or susceptible, finally increased as a result of infection. Moreover, susceptible genotypes registered 2–2.5 % higher amino acid, whereas resistant genotypes possessed 6.2–76 % higher amino acid than their constitutive level. Total chlorophyll and carotenoids content did not show any clear cut difference in resistant and susceptible genotypes at pre-infection stage. However, at post-infection stage a significant decrease in chlorophyll and carotenoids content occurred in susceptible genotypes from pre-infection. Amino acid profiling through HPTLC showed sulphur containing amino acids were higher in resistant genotypes.