Biochemical estimation of phytic acid and inorganic phosphate in diverse maize germplasm to identify potential donor for low phytic acid (LPA) trait in tropical genetic background

Phytic acid (PA), an anti-nutritional factor in maize (Zea mays L.) grains form various salts by chelating essential vital mineral elements namely, Fe3+; Zn2+, Mg2+, etc. affecting their bioavailability. Low phytic acid (LPA) maize can play a vital role as an important food and feed crop to diversify the existing food basket to address micronutrient malnutrition. Globally efforts to identify LPA maize genotypes in the existing germplasm are limited. Keeping this in view, the present experiment was designed using the diverse set of maize germplasm including landraces, composites, inbred lines and hybrids of field corn and also some genotypes of quality protein maize and sweet corn to explore the extent of variability for PA in the existing germplasm and to identify the LPA maize genotypes. The mean PA content across 104 genotypes excluding LPA mutants varied from 1.7 mg/g (CM L150) to 4.5 mg/g (VMH45) whereas inorganic phosphate (P-i) varied from 0.07 mg/g (LM16) to 0.95 mg/g (PMH9). The correlation coefficient between PA and Pi across genotypes was negative but moderate (-0.35) (P = 0.00024). The present study has identified two inbred lines namely, CM L150 (1.7 mg/g) and CML176 (1.8 mg/g) which do not differ significantly with either of the two LPA mutants namely, LPA1 (1.3 mg/g) and LPA2 (1.7 mg/g). The study further indicated that PA content is generally low in white kernel colour germplasm as compared to other kernel colours. The identified genotypes could be potential donor for developing LPA maize genotypes and also their utilization in the breeding for development of LPA maize cultivars.