Genetic and molecular characterisation of subtropically adapted low-phytate genotypes for utilisation in mineral biofortification of maize (

Abstract

Phytic acid (PA) is a major anti-nutritional factor in maize grains and significantly reduces the bioavailability of minerals such as iron and zinc in humans. Reduction of PA in maize (Zea mays L.) thus assumes great significance. Despite the availability of low phytic-acid (lpa) mutants in maize, their utilisation in breeding has been limited because of non-availability of well adapted lpa-based inbreds. A set of 24 subtropically adapted lpa1-1-based maize inbreds derived through molecular breeding was evaluated along with seven wild-type inbreds at multilocation. The lpa1-1 inbreds possessed 35.8% lower PA (1.68 mg/g) than the wild-type inbreds (2.61 mg/g). Mean proportion of PA was lower in the lpa1-1-based inbreds (62.8%) than in the wild-type inbreds (91.6%). The lpa1-1 inbreds showed similar performance for plant- and ear-height besides flowering behaviour as did wild types. Average grain yield among lpa1-1 inbreds (2735.9 kg/ha) was at par with the original versions (2907.3 kg/ha). Molecular profiling of these lpa1-1 inbreds using 60 genome-wide single-sequence repeats generated 172 alleles, with a mean of 2.87 alleles per locus. Mean polymorphism information content and mean gene diversity were 0.41 and 0.48 respectively. Genetic dissimilarity ranged from 0.23 to 0.81, with an average of 0.64. Cluster analyses grouped 24 lpa1-1 genotypes into three major clusters, and principal-coordinate analysis depicted the diverse nature of genotypes. The study also identified a set of potential hybrid combinations with low PA for their direct utilisation in biofortification program. This is the first study on comprehensive characterisation of lpa1-1-based inbreds adapted to subtropical conditions.