Biochemicals Associated With Callosobruchus Chinensis Resistance in Soybean.

Abstract

Soybean is a very important crop worldwide because of its 40% protein and 20% oil content. However, soybean suffers damage from bruchid (Callosobruchus chinensis) during storage. Understanding of factor(s) contributing to bruchid resistance is useful for development of soybean cultivars with genetic resistance to bruchid damage. Biochemicals associated with resistance to Callosobruchus chinensis were investigated on eight soybean genotypes with varying levels of resistance. Significant differences (P<0.05) were observed amongst genotypes with regards to antinutritional factors particularly total antioxidants (TAOX), tannins, peroxidase (POD), and flavonoids. There were no significant differences among genotypes with regards to nutritional factors particularly proteins, starch, lipid peroxidation, and reducing sugars. A resistant genotype AVRDC G8527 had the highest concentration of total antioxidants (1.98 AU min -1 mg -1 ) and tannins (1.85mg TAE 100g -1 ) followed by Maksoy 3N while the least was in a very susceptible genotype AGS 292 (TAOX=0.39 AU min -1 mg -1 , Tannin=0.296 mg TAE 100g -1 ). AGS 292 had the highest concentration of flavonoids (31.22 mg QE 100g -1 ) while AVRDC G8527 had the least (5.13 mg QE 100g -1 ). Peroxidase activity was highest in AVRDC G89 (0.27AU min -1 mg -1 ) while AGS 292 had the least (0.07AU min -1 mg -1 ). From the correlation analysis, a significant strong negative relationship between flavonoids and tannin (r=-0.73 ** ) and TAOX (r=-0.71 ** ) but a positive non significant relationship with phenolic (r=0.22) and alkaloids (r=0.37) was recorded. Peroxidase activity had a significant relationships with median development period (r=0.69 * ) indicating that increased peroxidase activity resulted into increased seed resistance through prolonged insect development period. There was a strong relationship between tannins and total antioxidants (r=0.99 ** ). These results indicate that secondary metabolites; peroxidase, tannin, and TAOX were biochemicals associated with higher resistance to C. chinensis in soybean while flavonoids were associated with higher susceptibility.Copy Right, IJAR, 2018,. All rights reserved. Corresponding Author:-Msiska U. M. ISSN: 2320-5407Int. J. Adv. Res. 6(5), 292-305is an annual legume that belongs to the legume family Fabaceae and is classed as an oil crop (Singh et al., 2007). Soybean is one of the five oldest cultivated crops and was utilized by the Chinese as a source of food before 2500 BC (Gibson et al., 2005). Nigeria is the largest producer of soybean in sub-Saharan Africa (SSA), followed by South Africa (Tefera, 2015). Commercial soybean production on large farms takes place in Zambia, Zimbabwe and South Africa (Tefera, 2015). However, it is mostly cultivated by small-scale farmers in other parts of Africa where it is planted as a minor food crop among sorghum, maize, or cassava. In Africa, Uganda is the second largest consumer of soybean following Nigeria (Murithi et al., 2016). Soybean is among the major industrial, feed and food crops gro...

Seed storage proteins and seed coat compounds additively influence Callosobruchus maculatus Fab. tolerance in selected cowpea (Vigna unguiculata L. Walp.) varieties

“…Consequently, this may have led to the development of a more complex defense mechanism system against phytophagous insects such as the C. maculatus . As a result, seeds contain a diverse range of compounds that act either additively or synergistically against C. maculatus infestation (Msiska et al, 2018).…”