Is Nor region variability in wheat invariably caused by tissue culture?

In a previous study we observed extensive Nor region variability in tissue-culture derived plants of only one out of three tested wheat cultivars. This finding prompted us to further question whether or not this variability was invariably caused by in vitro culture. In the present study, the upper halves of spikes from four source plants of the inbred cultivar 'ND7532' were removed 12 days after anthesis.

Aneuploid and alloplasmic lines as tools for the study of nuclear and cytoplasmic control of culture ability and regeneration of scutellar calli from common wheat.

Twenty four B genome aneuploid lines (di-telosomics, nullisomic-tetrasomics and tetrasomics) of Triticum aestivum cv 'Chinese Spring' were used in an analysis of the culture ability and regeneration capability of scutellar calli. Several correlations were found between the presence or absence of specific chromosomes and chromosomal arms of the B genome of common wheat and the growth and differentiation capabilities of these calli. The rate of callus growth decreased only when the long arm of chromosome 6B was not present.

Nor loci analysis in progenies of plants regenerated from the scutellar callus of bread-wheat : A molecular approach to evaluate somaclonal variation.

Progenies of plants regenerated from scutellar callus of bread wheat (Triticum aestivum L.) were analysed for the organization of the intergenic spacer of the rRNA genes, located at the sites of the nucleolar organizer region (Nor loci). Sexual progenies derived from the regenerated plants of three wheat cultivars were subjected to this analysis.

Genetic counselling for trisomy 20 mosaicism in amniotic fluid cell cultures.

Trisomy 20 mosaicism in amniotic fluid cell cultures has an obscure origin and significance. In only a few cases has the mosaicism been confirmed in fetal tissues, but never in neonatal tissues. There is some indication that the trisomic cells might originate from epithelial cells deriving from the urinary tract.