Changes of some physiological parameters of different wheat genotypes in ontogenesis depending on infection of leave level
Rust diseases are considered the main stress factors that limit wheat productivity in the Azerbaijan. The studies on the impact of rust diseases on physiological processes at reproductive vegetation period is of very importance with view of evaluating size of yield and quality of the studied genotypes. For this purpose the studies focused on bread wheat genotypes (Triticum aestivum L.), which differ sharply by architectonics, biological peculiarities and resistance to rust diseases. Comparative evaluation of the studied genotypes by physiological and quality parameters has been undertaken in two options: over plants infected with diseases in natural background, and over healthy plants (fungicide sprayed plants). Area of photosynthesis apparatus of leaf story (18,3-50,2 sm2) of the studied wheat genotypes changes in wide interval. Infestation level of leaves with yellow rust (Puccinia striiformis West.) in wheat genotypes grown in natural infection background fluctuates between 5MS-40S in ontogenesis, but between 10MS-90S with brown rust (Puccinia recondita Desm.).
High level of infection with rust diseases leads to reduced size of leaf assimilation area and defoliation. Reduction of these dimensions makes up 10-90% in lower story leaves of genotypes infected with rust diseases, but 20-30% in upper story leaves. Genotypes with large and bending leaves subject to this disease more frequently. Value of photosynthesis intensity in ontogenesis at upper story leaves of the genotypes infected with rust diseases at natural background fluctuates between 6-18 ?mol CO2 .m-2.s-1 depending on level of infection, but in healthy plants between 16-29 ?molCO2 .m-2.s-1. Negative impact of these diseases on normal course of plant physiological process ultimately causes is reflected in yield and quality parameters.