Studies on selected physiological and biochemical parameters responsible for resistance to spot blotch of barley (Hordeum vulgare L.)

Abstract

The spot blotch caused by Helminthosporium sativum Pam., King and Bakke is attaining importance in Karnataka and
Northern and Eastern parts of India, Hence, an attempt was made for a systematic study of the various physiological
and biochemical factors which contribue to the resistance of the barley genotypes, The resistant genotypes recorded
less number of stomata, lesser length and breadth of the stomata when compared to susceptible genotypes. The
histological studies indicated that the cuticular thickness, epidermal thickness were more in resistant genotypes than
in susceptible ones. The resistant genotypes recorded less number of epidermal cells per millimeter (mm) compared
to susceptible ones. From the biochemical studies, it has indicated that resistant genotypes had more amount of total
sugar, reducing sugar protein, total phenols, amino acid and wax content than susceptible genotypes. These were
decreased after infection and the decrease was more in susceptible genotypes than in resistant ones. In contrast to
this non-reducing sugars were more in susceptible genotypes than in resistant ones.