Effect of opaque-2 allele on accumulation of tryptophan among backcross-derived introgressed progenies of maize

Abstract

The tryptophan concentration of the 85 BC2F2:3 progenies derived from a cross between normal maize inbred line, Pant 10k1375 and o2 donor line, CML 161 were determined. The genic marker phi057 positive progenies showed significant variation for tryptophan concentration in BC2F2:3 progenies with tryptophan as low as 0.046 per cent in BC2F2:3-80, whereas BC2F2:3-78 possessed maximum tryptophan concentration of 0.082 per cent. Normal maize line Pant10k1375 possessed tryptophan concentration of 0.040 per cent whereas o2 donor line CML161 had tryptophan concentration of 0.089 per cent. All the BC2F2:3 progenies had tryptophan concentration higher than the normal maize inbred, whereas none of the progenies had tryptophan concentration higher than the donor line CML161. Twelve lines of BC2F2:3 populations had tryptophan concentration 0.075 per cent or more, the level used to determine quality protein maize. Variability in amino acid modifier genes in the background and/or the insertion of transposable element at the regulatory sites indicated by unusual segregation pattern of phi057 and umc1066 in backcross progenies could be the possible reasons for such high level of variation in tryptophan concentration. The progenies with tryptophan concentration > 0.075 per cent may serve as potential germplasm in development of quality protein maize hybrids.