Association of phytic acid content with biotic stress tolerance in mungbean (Vigna radiata L. Wilczek)

Phytic acid (PA), though an antinutritional factor that causes mineral deficiency in monogastric animals but also reported to be associated with expression of stress tolerance genes. The present study was conducted to find out association of seed PA with tolerance to yellow mosaic disease (YMD), powdery mildew disease (PMD) and storage pest bruchid in mungbean. Ninety four genotypes were screened for YMD by using infector rows technique in summer 2011 and 2012 and PMD screening was done in rabi 2012 in the field conditions and using excised leaf technique in growth chamber. Screening for bruchid (Callosobruchus chinensis L.) was carried out by following standard procedure. PA and inorganic phosphorous (IP) were estimated from seeds by colorimetric method and Chen's modified method respectively. Among 94 genotypes, 47 were found susceptible while out of 47 resistant genotypes, 37, 9 and 1 were found resistant to YMD, PMD and bruchid respectively. PA was found to be highest in bruchid resistant genotype followed by PMD and YMD. Along with the resistance genes, high seed PA (>8 mgg(-1)) was required for resistant reaction to YMD and PMD, while for bruchid resistance very high PA (similar to 18 mgg(-1)) should be present in seeds. If the concentration of PA is reduced below this level my leads to decrease in tolerance to biotic stresses, even though the resistance gene is present in the plant.