MOLECULAR MARKERS FOR QTK DETECTION IN SEGREGATING MAIZE POPULATIONS DERIVED FROM EXOTIC GERMPLASM

The major objectives of this study included: 1) detect QTLs for grain yield (YLD), plant height (PH), and days to pollen shed (DPS) in maize exotic germplasm, and 2) to determine the relationship between the de gree of heterozygosity of marker alleles and the level of yield. Lines selected from Croatian open-pollinated varieties were used to generat e two half-sib populations for the study. In each population, 163 F-3 families were tested in field experiments at two locations. The 20 hig hest and the 20 lowest yielding families of each population were used for QTL detection. Isozymes, RFLPs and Simple Sequence Repeats (SSRs) were used as molecular markers. Marker-trait associations were assesse d by single factor and interval analyses. The population designated P- 1 had lower average yield but had more polymorphic loci and revealed m ore QTLs than the population designated P-2. In the two populations, Q TLs for YLD were found on chromosomes 1, 6, and 10; for PH on chromoso mes 1, 3, 5, and 6; and for DPS on chromosomes 1, 3, 6, 8 and 9. The p opulations had no QTLs in common. Higher yielding subpopulations showe d a higher degree of heterozygosity than the lower yielding subpopulat ions.