Eyespot is an important disease of wheat in the United States Pacific Northwest. Genes Pch1, located on chromosome 7D, and Pch2, located on chromosome 7A, are the only known sources of eyespot resistance in hexaploid wheat. A core collection of Triticum monococcum, a close relative of the A-genome donor of bread wheat, consisting of 118 accessions from 26 countries was screened for resistance using a β-glucuronidase-transformed strain of the pathogen. Fifty-two (44%) accessions from 15 different countries were resistant. More than half of the accessions collected in Turkey (26 of 42) were resistant. Two accessions were more resistant than resistant cultivars Cappelle Desprez (Pch2) and Madsen (Pch1). Screening these accessions for the isozyme marker Ep-A1b, which is linked with Pch2 in hexaploid wheat, revealed variation but no association with resistance. These results indicate T. monococcum is a new source of resistance to Pseudocercosporella herpotrichoides that potentially contains more effective resistance to P. herpotrichoides than that conferred by either Pch1 or Pch2.

Club wheats {Triticum aestivum L.), having the allele at the C locus conferring short spike rachis internodes and giving compact appearance of spikes, which have unique and highly desirable soft white wheat enduse quality characteristics are a vital submarket class of soft white wheat in the US Pacific Northwest. Two important varieties, 'Tyee' and 'Albit', are heterogeneous for high molecular weight glutenin subunits 2+12 and 5 + 10 encoded by the Glu-Dl locus. Replicated nearisogenic lines (NILs) of club wheats 'Tyee' and 'Albit' were grown in four field environments and used to determine the effect of Glu-Dl coded high molecular weight glutenin subunits (HMWGS) 5 + 10 and 2 + 12 on various end-use quality traits. The greatest effect of variation at this locus was observed for mixing time to peak, where there was significant variation (P < 0.01) between each 5 + 10 and 2 + 12 NIL group in each environment. Mixing time values for the 2+12 NILs for both 'Albit' and 'Tyee' ranged from 0.60 to 1.23 min lower than the 5 + 10 NILs. Mean values for traits mixing time to peak, cake volume, and viscosity were more favourable for the 2 + 12 NIL groups for all genotypes in all environments. No effects of these HMWGS were detected for test weight, kernel hardness, whole wheat protein, flour yield, ash, flour protein or cookie diameter. Selection for HMWGS 2 + 12 in club wheat breeding programmes should have positive effects on end-use quality.

The plant hormone abscisic acid (ABA) affects developmental and physiological processes that can impact crop production. These processes include germination, environmental stress responses in vegetative tissue, embryo maturation, and dormancy. Identification and molecular tagging of ABA-responsive genes, as well as the vp1 gene, required for ABA sensitivity, may be valuable in developing breeding strategies designed for manipulating ABA-regulated traits. Using aneuploid genetic stocks and alien substitution lines the chromosomal location of vp1 and seven abscisic acid (ABA) responsive genes was determined in wheat and Lophopyrum elongatum (Host) Löve. Clones (gene homology, if known, in parentheses) isolated from wheat hybridized to wheat and L. elongatum homoeologous chromosome groups as follows: pMA80 (dhn), chromosome 4; pMA1949 (group 3 LEA (1I)), chromosome 3S; pMA1951, chromosome 5S; pMA1959 (Em), chromosome 1L; pMA2005 (group 3 LEA), chromosome 1S; and PKABA1, chromosome 2L. Clone pBS128, corresponding to an ABA-responsive gene from Bromus secalinus, hybridized to wheat chromosome 2S. The cDNA clone pcvp23 that is homologous to vp1, a gene required for ABA responsiveness and the prevention of precocious germination in maize embryos, did not hybridize well with wheat but hybridized to chromosomes 3L and 7β in L. elongatum. Three of the clones mapped previously in barley by other researchers, pMA1949, pMA1951, pMA1959, were found here to be on the corresponding homoeologous chromosomes in wheat.