Genetic diversity and heterotic grouping of selected Philippine corn germplasm
2018
Saludares, R.A.G.
Genetic diversity is very essential in developing hybrid maize varieties. Two studies were done to assess genetic diversity and heterotic grouping among selected Philippine cor germplasm. Genetic diversity study consisted of 143 varieties showed significant variation for most traits. Correlation analysis showed 37 significant associations. Days to anthesis and silking had highest correlation (r=0.878). Cluster analysis based on 11 morpho-agronomic grouped varieties into two clusters. Heterotic grouping study was conducted using 12 unknown inbred lines and four testers in line x tester approach. All traits showed significant differences. EWL1 had highest significant positive GCA estimates for yield while four crosses (L5 x T2, L7 x T3, L11 x T4 and L12 x T4) had significant positive SCA estimates, L11 x T4 had highest heterosis. Cluster analyses using morpho-agronomic traits, SNP data, and combination of phenotypic and molecular data were performed on parental lines. Based on preliminary information, phenotypic evaluation is not reliable. Grouping of lines using SNP data and combination of phenotypic and molecular data showed similar results, since SNP markers used outnumbered the 10 morpho-agronomic traits measured. Waxy corn types (T3 and T4, and L8 to L12) were grouped in one cluster, while sweet corn types (T3 and T4, and L8 and L1 to L7 belonged to another cluster. Most parents crosses with high positive heterosis and SCA estimates for yield were grouped within the same cluster and vice versa. SCA estimates for yield were used for heterotic grouping. However, environmental effects can alter relationship between genetic distance and heterosis, hence further testing is recommended.
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