Prospects of endosperm DNA in maize seed characterization

Abstract

DNA based characterisation of maize germplasm has become the easiest and fastest approach to identify genetic diversity as compared to phenotyping. The conventional DNA source for genotyping is the leaf which required at least 2 weeks waiting period from seed planting to leaves sampling. This work exploits the use of endosperm DNA (EDNA) for the genotyping of maize germplasm. Maize endosperm was excised from maize seeds using pli¬ers, ground and used for Genomic DNA extraction (gDNA). Leaves DNA (LDNA) was also extracted concurrently. The extracted LDNA and EDNA were quantified and subjected to SSR-PCR. The mean concentrations of DNA extracted were 1575 ng/ul for the leaves and 526 ng/ul for endosperm. Though the difference in quantity of EDNA and LDNA were highly significant, the quality (A260/A280) for both EDNA and LDNA fall within 1.6-1.8 range of pure DNA index. SSR-PCR products using phi032 were similar for both EDNA and LDNA, indicating the usability of EDNA in genotyping. This seed based method of gDNA extraction takes less than 24 hours from sampling to quantification and genotyping. It also allows germination of sampled seeds, selection before planting, avoids the delay of planting and waiting in leaf sampling and saves field space.