Genetic Variations in CIMMYT and Ethiopian Maize(Zea mays L.) Inbred Lines as Determined by Microsatellite Markers

AbstractMolecular markers are more useful in identifying parental inbred lines crosses ofwhich create genetic variation among progenies in the advanced generation morerealistically than selection based on phenotypic data. In this study, 37 maize inbredlines including 14 of Ethiopian and 23 of CIMMYT origin were studied using 28microsatellite markers. Among the 23 CIMMYT inbred lines, 13 were soil aciditytolerant lines and were recently introduced. The main objective was to identifydistantly related Ethiopian maize inbred lines and soil acidity tolerant inbred linesof CIMMYT origin that could be used in broadening the genetic basis of maize fortolerance to soil acidity. Analysis of molecular variance indicated higher geneticvariability (77%) among the inbred lines indicating ability of the SSR markers indiscriminating the inbred lines. One-hundred and seven alleles were identified inthe inbred lines with average of 3.71 alleles per locus. Expected hetrozygosity (He)and major allele frequency ranged from 0.09 to 0.61 and from 0.34 to 0.95,respectively, indicating higher genetic variability among the inbred lines, whichcould be exploited in breeding program. Polymorphic information content (PIC)generated by each marker ranged from 0.10 (Bnlg 1063) to 0.74 (Umc 2205) with amean of 0.50 indicating their power in discriminating the inbred lines. Nei’s geneticdistance among pairs of the 37 maize inbred lines varied from 0.16 to 0.98. Pairs ofinbred lines of Ethiopian origin had genetic distance that ranged from 0.26 to 0.98and the highest genetic distance was in this population. Pairs of inbred lines ofEthiopian and CIMMYT inbred lines developed for tolerance to soil acidity hadgenetic distance that varied from 0.42 to 0.95 and 41.6 % of the pairs had geneticdistance of more than 0.8 indicating their potential in broadening the genetic basisof maize for developing varieties tolerant to soil acidity. Specifically, 124-b(109)was distantly related with five inbred lines, viz., CML359, CML360, CML361,CML436 and CML438, and F-7215 was also distantly related with CML361 withNei’s genetic distance of more than 0.9. These pairs of inbred lines could beexploited in pedigree breeding through which segregating populations can beselected for desirable traits in combination with tolerance to soil acidity. However,the soil acidity tolerant inbred lines have to be evaluated for adaptation toEthiopian environment before embarking on exploiting their potential in breedingfor tolerance to soil acidity.