MORPHOLOGICAL VARIATION OF BIPOLARIS ISOLATE FROM THE WHEAT GERMPLASMS

Abstract

Wheat is cultivated worldwide, especially at the eastern plains of south Asia,
constitutes a very important source of food to a vast population. In India, it contributes nearly
31.50% of the total food grain basket. The investigation included the screening of 600 genotypes
with a broad genetic base. A symptom of the different variant was collected. The pathogen was
isolated from different genotypes from different plant parts; variations in the isolates were
documented along with in-vitro pathogenicity testing. The morphological study of both culture
and conidia was made on half-strength PDA and water agar, respectively. Singles spore cultures
were made from all those isolates for the studies for pathogenicity. The results of the
morphological study comes with the findings that the UBS-1 (Septation: 9.1±1.3, Length: 92.2 ±
25.7, Width:49.3± 37.8) and UBS-2 (Septation: 7.6±1.7,Length:85.3±19.1,Width:33.6±19.2 )
has higher in average septation.UBS-7,UBS-9,UBS-11,UBS-12 has triangular shape conidia.
USB -9 and USB-14 has two different types of septation euseptate and distoseptate. The result of
the pathogenicity shows that out of 14 isolates, UBS -1 and UBS-2 is the most virulent isolates in
in-vitro condition and the remaining are moderately virulent and a virulent isolates. The finding
comes with the variability of the pathogen depends on the host factor and environmental factor.
Different degrees of host resistance lead to evolving new characters in the pathogen to adjust
with the respective genotype and environment. From the cluster of different isolates, it was found
that the potential virulent pathogen remains consistent in-vivo. In contrast, a virulent or
moderately virulent isolate shows different degrees of virulence based on morphological and
physiological characters in a different environment.