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

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.