An investigation on soybean (Glycine max L.) commenced at the experimental field of the Institute of Genetics and Plant Experimental Biology, Academy of Sciences, Republic of Uzbekistan. The purposive study aimed to determine the effects of Fusarium solani phytopathogenic micromycetes on the physiological and biochemical composition of five soybean cultivars, viz., Sochilmas, Genetic-1, Nafis, Tomaris, and Baraka. The results revealed in the budding and flowering stages, the soybean cultivar leaves infected with F. solani showed decreased amounts of chlorophyll a and b compared with the healthy plants (control). In the control comparison against the soybean variants with phytopathogenic micromycetes, some soybean cultivars showed enhanced contents of carotenoids in the leaves, and others revealed a decline in carotenoids to varying degrees. The peroxidase enzyme activity was higher in soybean cultivars Tomaris and Nafis artificially infected with F. solani than the other cultivars. It was evident that the peroxidase enzyme activity under the influence of F. solani in the leaves of studied soybean cultivars increased by 20.76%, 43.6%, and 35.4%, respectively, in Baraka, Tomaris and Nafis cultivars. Results further indicated that under the influence and stressful conditions of F. solani, the activity of the polyphenol oxidase enzyme enhanced by 84.1% and 117.1%, respectively, in soybean cultivars Tomaris and Nafis. The phenylalanine-ammonia-lyase enzyme activity was also higher in the said cultivars with F. solani infection compared with the control. The earlier situation confirmed that the soybean plant leaves’ physiological and biochemical parameters are closely associated with the phytopathogenic micromycetes.

Keywords: Soybean (Glycine max L. Merr.), genotypes, chlorophyll, carotenoids, budding, flowering, pigment, enzyme, peroxidase, catalase

Key findings: The physio-biochemical defense system of the soybean exhibited the protective enzymes’ sharp increase in resistant genotypes, showing a significant resistance to the fungus F. solani. Therefore, the local soybean cultivars Tomaris and Nafis became the choices as resistant cultivars to F. solani that can serve as a base material to develop the soybean-resistant cultivars to fusariosis in future breeding programs.