Genetic analysis of grain yield and endosperm protein quality in the quality protein maize (QPM) lines

Abstract

To evaluate the performance of Quality Protein Maize (QPM) lines with respect to grain yield and endosperm protein quality, a set of 14 lines developed in India (DMRQPM series) and three exotic testers (from CIMMYT, Mexico) were involved in a Line x Tester mating design. The resultant experimental hybrids along with the parental lines were evaluated at two locations (Delhi and Pantnagar) during Kharif2003, and biochemical analysis for estimation of endosperm protein content and per cent tryptophan in endosperm protein was undertaken on the harvested material (control-pollinated). DMRQPM-65 and CML189 at Delhi and DMRQPM-28·5, CML166 and CML189 at Pantnagar were found to be the best general combiners for grain yield, while DMRQPM-401, DMRQPM·28-5 and DMRQPM·65 exhibited best GCA effects for most of the characters at both the locations. DMRQPM·45 x CML189 and DMRQPM-404 x CML189 displayed highest SCA effects for grain yield at Delhi and Pantnagar, respectively. The study revealed preponderance of variance due to dominance effects over that due to additive effects for most of the characters at both Delhi and Pantnagar. The present investigation identified DMRQPM·404 x CML189 as the best heterotic combination at both locations. DMRQPM·28·5 (0.99%) and CML189 (0.98%) among the inbred lines and DMRQPM·56 x CML189 (1.03%) among the crosses recorded the highest per cent tryptophan content in the endosperm protein. CML189 was found to be the best donor for endosperm quality traits. Taking into account the combining ability effects for grain yield and endosperm protein quality, besides heterosis, DMRQPM65 and CML189 among the inbreds and DMRQPM-45 x CML189 among the crosses were found to be the most promising for utilization in the QPM breeding programmes.