'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 EARLY EMERGENCE OF TASSEL IN MAIZE - A POTENTIALLY NEW TRAIT WORTH BREEDING I. PEJIC, M. QUINT, H. SARAVIC, M. PECINA, T. LUBBERSTEDT Faculty of Agriculture, University of Zagreb, Svetosimunska 25, 1000 Zagreb, Croatia

Two inbred lines (EET1 and EET") have very early emergence of tassel with regard to start of pollination (10-13 days vs 2-5 days). Performance of the early emergence of tassel (EET) would reduce the amount of labour for manual detasseling in hybrid seed production because all female tassels could be removed at once with low risk of self-pollination. EET1 and EET2 were crossed with commercial inbreds of short time interval between tassel appearance and pollen shed (T-P interval). Biomodal distributions were observed in segregating populations with respect to T-P interval suggesting presence of one recessive major gene increasing T-P interval. Within the F₂ population (n=508) derived from cross EET x B73 the date of tasseling and the date of pollination was recorded for each individual plant to compute T-P interval. Bulked segregant analysis (BSA) based on ISSR markers was employed to detect a DNA fragment discriminating F₂ plants with large and small T-P interval. This fragment co-segregated with EET was used as a RFLP probe in a F_2:3 mapping population (Xia et al. 1999) and mapping to chromosome 6. Since EET is a recessively inherited trait, this genetic marker significantly simplifies and accelerates its introgression into commercial germplasm.