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Many wheat breeding programs in the world utilize semidwarf germplasm to improve productivity and lodging resistance. Four sources of the reduced height gene Rhtl, were crossed with a conventional height cultivar to determine the influence of this gene on yield, yield components, test weight, and grain protein in durum wheat (Triticum turgidum L. var durum). Seedlings having the Rhtl/Rhtl (semidwarf) or rhtl/rhtl (tall) genotype were selected in the F2 generation of each cross based on their sensitivity to gibberellic acid. The F2‐derived F4 families were evaluated during the 1981 and 1982 field seasons. The semidwarf and tall height classes differed significantly for yield, test weight, kernel weight, tiller number, height, kernels per spike, spike length and grain protein. Semidwarfs produced significantly greater yield, number of tillers, and kernels per spike than the tall height class. The difference in tillering was found in only two of the four crosses and thus was not a general trend. Tall lines had consistently higher test weight, kernel weight, and grain protein than semidwarf lines. A positive correlation was observed between plant height and grain protein concentration (r=0.80, p<0.01). Factors in addition to the dilution of the protein in the kernel due to high yield are responsible for the low grain protein concentration associated with semidwarfs because low yielding semidwarf lines had significantly lower grain protein concentration than the high yielding tall lines. The use of the Rhtl gene in durum wheat breeding programs may contribute to higher grain yield in the absence of lodging but reduced grain protein levels may become a serious quality problem.

Triticum sp., tetraploid wheats, semi-dwarfism, yield. SUMMARY A genetic study ofa range ofNORIN 10 based semi-dwarfdurum wheats showed that only Gai/Rht 1, located on chromosome 4A, was present. No varieties carrying a second Gai/Rht allele were identified and deliberate attempts to introduce Gai/Rht2 into tetraploid wheats have so far been unsuccessful.In a spaced plant trial of homozygous random F, lines from two tall x semi-dwarfcrosses, the semi-dwarfs had lower ear yields, due mainly to reduced kernel weight, but.had higher tiller numbers than the tall genotypes. Although there was no difference in overall plant yield between tails and semi-dwarfs, an analysis of character associations within the semi-dwarf F,'s shbwed positive height-yield and height-kernel weight correlations indicating that selection for 'tall dwarfs' may be a useful breeding strategy in tetraploid wheats.

We report a distinctive angiomyxofibromatous lesion arising from the falx cerebri of a 48-year-old woman. The tumor was composed of bland-appearing, spindle, and stellate cells in a myxoid matrix with prominent vascularity. The tumor cells were immunopositive diffusely for vimentin and focally for S-100 protein, but were immunonegative for epithelial membrane antigen, CD34, MIC2, Bcl-2, glial fibrillary acidic protein, cytokeratin CAM 5.2, desmin, and smooth muscle actin. This lesion could not be categorized according to the current World Health Organization classification of tumors of the nervous system, thus underscoring a need to enhance our understanding of myxoid mesenchymal neoplasms and reassess their nosology.

In seven field experiments conducted over 6 years with a wide range of disease severities, triticale was intermediate in resistance to Gaeumannomyces graminis between wheat (susceptible) and rye (resistant). Use of triticale is suggested as an immediately available means of introducing take‐all resistance into cereal cultivation. Octoploid triticale was slightly more susceptible than hexaploid triticale. There was little evidence of consistent variation in resistance among wheat or rye cultivars but a few hexaploid triticale cultivars varied in resistance. The resistance of triticale was not reliably expressed in the glasshouse tests used, so selection for resistance to take‐all in a breeding programme would need to be conducted in the field. Individual pairs of rye chromosomes added to wheat did not significantly reduce its susceptibility. The feasibility of transferring the resistance of rye to wheat is considered.

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SummaryA tetraploid wheat breeding programme was initiated at the Plant Breeding Institute in 1970. Hexaploid × tetraploid wheat crosses were expected to contribute to the improvement of the tetraploid wheats but severe hybrid necrosis caused the death of the pentaploid Fxhybrid plants in most crosses. The genotypes of tetraploid wheat selections derived from crosses involving Rampton Rivet, a non-carrier of Neu were determined by test crossing to hexaploid wheat varieties which were known to carry the Neim allele. Similarly, hexaploid wheat selections which did not carry Ne2 were identified from crosses involving Maris Ranger by test crossing to durum selections which carried the Nef allele. By the careful choice of one parent, hexaploid x tetraploid wheat crosses were then made which avoided the hybrid necrosis problem. Segregation of the Ne% gene was as expected but selection for agronomic characters appeared to favour the retention of the dominant allele of the Ne1gene. Nevertheless, test crossing on a relatively small scale still identified many non-carriers.