Introgression of low phytic acid trait in selected inbred lines of maize

Abstract

Phytic acid (PA) is one of the important anti-nutritional factors which affect the bioavailability of micronutrients like iron, zinc. Maize being one of the important food and feed crop requires serious attentions to reduce its PA; majority of total phosphorous is stored in this form which makes it unavailable to monogastric animals. The phosphorus thus stored in the form of PA phosphate contributes to water pollution because it is excreted as such. PA being strong chelating agent also forms phytate salts with cation mineral elements like iron, zinc, calcium etc., thus affects the bioavailability of micronutrient mineral elements. Thus causes micronutrient mineral deficiency in humans and phosphorous deficiency in animals. In the present study efforts have been made to introgress gene (lpa2) determining low􀀐PA has been transferred from low-phytate mutant line lpa2 into an elite inbreds LM14 and LM17 through marker-assisted backcross breeding (MABB). The BC2F2 near-isogenic lines (NILs) have been developed through introgression of lpa2 gene. Out of 118 BC2F2 plants of LM 17 × LPA2 family, 26 were homozygous positive for lpa2 gene and 65 were heterozygous; the remaining plant were negative (27 plants). Similarly, in LM 19 × LPA2 cross, out of 127 BC2F2 plants 24 were homozygous for lpa2and 70 plants were heterozygous. The remaining plants were (33) were negative for the lpa2 gene. The molecular marker, umc2230 was used as linked marker to select lpa2 gene. Whereas the sequence-tagged molecular markers (STMS), were chosen to select segregants with the highest genome recovery. The recurrent parent genome (RPG) varies between 79-89 and 82-93 per cent in BC2F2 individuals derived from LM 17 × LPA2 and LM 19 × LPA2 respectively. The agronomic performance of selected NILs of BC2F3 and the respective recurrent parents has shown that the NILs are comparable with respective recurrent parents for days to flowering and almost all the yield component traits like number of ear length, ear girth, kernel rows, kernels per row, test weight etc. and also biochemical analysis for lowPA is underway. The NILs developed would be used to re􀀐constitute the original hybrids.