Heterotic grouping and patterning of quality protein maize inbreds based on genetic and molecular marker studies

Authors: AMBIKA RAJENDRAN, ARUNACHALAM MUTHIAH, JOHN JOEL, PONNUSAMY SHANMUGASUNDARAM, DHANDAPANI RAJU

Abstract: An investigation was done to study the heterotic grouping and patterning in quality protein maize inbreds. Biochemical screening resulted in the choice of 3 inbreds each with high (UQPM 2, UQPM 4, and UQPM 21) and low (UQPM 18, UQPM 19, and UQPM 20) lysine and tryptophan contents respectively for genetic studies using diallel analysis. UQPM 20 × UQPM 18 was notable as it possessed high standard heterosis and specific combining (sca) effect for grain yield, protein, tryptophan, and lysine. Based on yield sca, the 6 parental inbreds were classified into 3 heterotic groups. Intergroup cross UQPM 20 × UQPM 18 was the best in yield and quality. The superior heterotic pattern was flint × dent. In genetic diversity analysis using simple sequence repeat markers, the inbreds of the best hybrid, UQPM 20 × UQPM 18, lay in same cluster but different subclusters. Correlations between genetic distance and sca effects were low for grain yield, which hampers the prediction of heterosis from molecular data alone.

Keywords: Heterotic group, heterotic pattern, quality protein maize, genetic diversity

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