Exploration of novel opaque16 mutation as a source for high lysine and tryptophan in maize endosperm

Abstract

In the present study, two F2 populations derived by crossing
wild type- (CML533 and CML537) and o16-donor line
(QCL3024) were raised and genotyped. The recessive
o16o16 possessed nearly two-fold more lysine (0.247%)
and tryptophan (0.072%) in mutants, than wild type (0.125%
lysine and 0.035% tryptophan) across populations.
However, o16o16 showed wide variation for both lysine
(0.111-0.376%) and tryptophan (0.027-0.117%) across
populations, suggesting the role of modifier loci. The study
did not show any significant correlation (r=0.14) between
lysine and tryptophan, however some segregants with highlysine (>0.300%) and -tryptophan (>0.090%) were identified.
Some of the segregants with o16o16 possessed comparable
lysine and tryptophan with o2o2 genotypes. These o16o16
segregants may serve as novel genetic resource in the QPM
breeding programme, and some of them can be used for
enhancement of both lysine and tryptophan in place of o2
mutant. This is the first ever report of influence of o16 on
accumulation of tryptophan in maize.