Wild emmer wheat, Triticum dicoccoides, is the progenitor of modern tetraploid and hexaploid cultivated wheats. Our objective was to map domestication-related quantitative trait loci (QTL) in T. dicoccoides. The studied traits include brittle rachis, heading date, plant height, grain size, yield, and yield components. Our mapping population was derived from a cross between T. dicoccoides and Triticum durum. Approximately 70 domestication QTL effects were detected, nonrandomly distributed among and along chromosomes. Seven domestication syndrome factors were proposed, each affecting 5-11 traits. We showed: (i) clustering and strong effects of some QTLs; (ii) remarkable genomic association of strong domestication-related QTLs with gene-rich regions; and (iii) unexpected predominance of QTL effects in the A genome. The A genome of wheat may have played a more important role than the B genome during domestication evolution. The cryptic beneficial alleles at specific QTLs derived from T. dicoccoides may contribute to wheat and cereal improvement. F rom agriculture origins in the Near East 10,000 years ago, emmer was the principal wheat of the newly established farming settlements, subsequently spreading 7,000 years ago to Egypt, India, and Europe (1). Wild emmer wheat, Triticum dicoccoides, genome AABB, is a tetraploid, a predominantly self-pollinating wild progenitor of modern tetraploid and hexaploid cultivated wheats (2, 3). T. dicoccoides proved important in wheat breeding in the past, and it deserves in-depth study as a potential genetic resource for cereal improvement (1).Analysis of quantitative trait (QT) loci (QTL) of domestication-related traits was studied in rice (4), maize (5), sorghum (6, 7), and millet (8). In recent years, QTLs were mapped in hexaploid wheat for agronomic traits (9, 10). To date, QTLs have been reported for tetraploid wheat mainly for quality traits (11, 12) but not for domestication traits. Grass domestication evolution is the key to exploiting genome diversity for future cereal improvement (13). Therefore, the objective of this study was to map genetic loci underlying domestication-related traits, including brittle rachis (Br), heading date (HD), plant height (HT), grain size, yield, yield components, and the genomic distribution pattern of domestication QTLs in T. dicoccoides. Materials and MethodsMapping Population. A cross was made between a highly striperust-resistant T. dicoccoides accession, Hermon H52 (H52) (1), with typical wild traits, from Mt. Hermon, Israel, and a Triticum durum cultivar, Langdon (Ldn). The F 2 mapping population consisted of 150 genotypes. Leaf samples were collected in the greenhouse at the elongation stage, frozen in liquid nitrogen, and stored at -80°C until DNA isolation (14). The F 2 individuals were bagged to ensure selfing for producing F 3 families.Phenotyping of Domestication-Related Traits. A randomized block design field experiment was conducted in Neve Yaar, Israel, from 1997 to 1998. The trial totaled 162 single-row plots, 150 for the F 3 fa...

Trypanosomosis, or sleeping sickness, is a major disease constraint on livestock productivity in sub-Saharan Africa. To identify quantitative trait loci (QTL) controlling resistance to trypanosomosis in cattle, an experimental cross was made between trypanotolerant African N'Dama (Bos taurus) and trypanosusceptible improved Kenya Boran (Bos indicus) cattle. Sixteen phenotypic traits were defined describing anemia, body weight, and parasitemia. One hundred seventy-seven F2 animals and their parents and grandparents were genotyped at 477 molecular marker loci covering all 29 cattle autosomes. Total genome coverage was 82%. Putative QTL were mapped to 18 autosomes at a genomewise false discovery rate of <0.20. The results are consistent with a single QTL on 17 chromosomes and two QTL on BTA16. Individual QTL effects ranged from Ϸ6% to 20% of the phenotypic variance of the trait. Excluding chromosomes with ambiguous or nontrypanotolerance effects, the allele for resistance to trypanosomosis originated from the N'Dama parent at nine QTL and from the Kenya Boran at five QTL, and at four QTL there is evidence of an overdominant mode of inheritance. These results suggest that selection for trypanotolerance within an F2 cross between N'Dama and Boran cattle could produce a synthetic breed with higher trypanotolerance levels than currently exist in the parental breeds.