ABSTRACT
Tetraploid hybrid tea roses (Rosa hybrida) represent most of the commercial cultivars of cut roses and form the basis for breeding programmes. Due to intensive interspecific hybridizations, modern cut roses are complex tetraploids for which the mode of inheritance is not exactly known. The segregation patterns of molecular markers in a tetraploid mapping population of 184 genotypes, an F(1) progeny from a cross of two heterozygous parents, were investigated for disomic and tetrasomic inheritance. The possible occurrence of double reduction was studied as well. We can exclude disomic inheritance, but while our observations are more in line with a tetrasomic inheritance, we cannot exclude that there is a mixture of both inheritance modes. Two novel parental tetraploid linkage maps were constructed using markers known from literature, combined with newly generated markers. Comparison with the integrated consensus diploid map (ICM) of Spiller et al. (Theor Appl Genet 122:489-500, 2010) allowed assigning numbers to each of the linkage groups of both maps and including small linkage groups. So far, the possibility of using marker-assisted selection in breeding of tetraploid cut roses and of other species with a tetrasomic or partly tetrasomic inheritance, is still limited due to the difficulties in establishing marker-trait associations. We used these tetraploid linkage maps to determine associations between markers, two morphological traits and powdery mildew resistance. The knowledge on inheritance and marker-trait associations in tetraploid cut roses will be of direct use to cut rose breeding.
Subject(s)
Chromosomes, Plant/genetics , Genome, Plant , Inheritance Patterns/genetics , Rosa/genetics , Tetraploidy , Amplified Fragment Length Polymorphism Analysis , Ascomycota/pathogenicity , Breeding , Chromosome Mapping/methods , Chromosome Segregation/genetics , Crosses, Genetic , DNA, Plant/genetics , Diploidy , Disease Resistance , Gene Expression Profiling , Genetic Linkage , Genotype , Hybridization, Genetic , Microsatellite Repeats , Phenotype , Quantitative Trait LociABSTRACT
Studies that investigate possible developmental changes in gastrointestinal hormones in the pig are sparse and contradictory. Therefore, a quantitative morphological study using stereologic methods on paraffin sections of the different small intestinal regions (cranial and caudal duodenum, jejunum and ileum) of the developing pig (second half of the gestation, neonatal and weaning period) has been conducted. The sections were processed for GLP-1-immunohistochemistry. During the investigated time span, the volume of GLP-1-IR cells increased approximately 40-fold in both the jejunum and ileum, notwithstanding a decrease of their volume density. The ileal small intestinal segment contained the highest volume density of GLP-1-IR cells. In contrast, GLP-1-IR cells were only occasionally encountered in the duodenum. The development-related changes of the investigated parameters coincide with dietary changes and the regional differences are in accordance with functional reports that point to GLP-1 as a gastrointestinal hormone that ediates the 'ileal brake' and stimulates glucose-dependent pancreatic insulin secretion.