Genetic diversity of tropical early-maturing maize inbreds and theirperformance in hybrid combinations under drought and optimum growing conditions
Published in: Field Crops Research 2014, vol. 170, p. 55-65.
Hybrid development is enhanced by the assessment and understanding of genetic diversity and dis-tance within inbreds. One hundred and fifty hybrids derived from 30 early-maturing inbreds plus sixchecks were evaluated at three locations in Nigeria for 2 years to assess their performance under droughtand well-watered conditions. In addition, twenty three microsatellite markers were employed to assessgenetic diversity of selected 42 inbreds. Significant differences were observed among inbreds and hybridsfor most traits under both research conditions. A total of 130 alleles were detected ranging from two fornc133 to nine for phi299852 with an average of 5.7 alleles per locus. Polymorphic information contentranged from 0.17 for phi308707 to 0.77 for phi084 with an average of 0.54. Thirty-one unique alleleswere detected in 21 inbreds. Microsatellite markers classified the inbred lines into five groups. Geneticdistance estimates among pairs of inbreds ranged from 0.42 (TZEI 26 vs TZEI 108) to 0.85 (TZEI 24 vs TZEI4) with an average of 0.67. Correlation between microsatellite-based GD estimates of the parental linesand their F1hybrids were not significant for grain yield and other traits under drought and well-wateredconditions. However, significant correlations existed between F1hybrid grain yield and heterosis underdrought and well-watered conditions. TZEI 31 × TZEI 18 was identified as the highest-yielding and stablehybrid across environments and should be promoted for adoption by farmers in West and Central Africa.