Genetic variability affecting duration of primary dormancy is demonstrated in natural populations of wild oats. Marked differences were found among local populations in germination behavior. The evidence suggests that these differences result in part from genetic adaptation to agronomic practices.

Limited information is available on the trace element contents of soils and crops in Saskatchewan. Trace elements, to a large extent, are derived from soil parent materials and partially from anthropogenic activities, such as agricultural application of fertilizers. The objective of this study was to establish levels of trace element concentrations of the surface horizons and parent materials of selected soils, fertilizers, and durum wheat (Triticum durum Desf.). Inductively coupled plasma mass spectrometry (ICP‐MS) having the capacity to determine 60 elements simultaneously at very low detection levels was used. Trace elements for this work are among the most frequently reported in the recent literature. We found a positive relationship between the total contents of trace elements and percent of clays in the soils, except Se. This suggests that the major part of the elements studied are associated with the clay minerals in soils. In two Regina heavy clay soils, total Cu, Zn, Se, and Pb were higher in the surface soil than the subsoil, but this increase was statistically not significant. All the elements, except Zn, Cd, and Pb, were depleted in soils that have lower clay content in the surface horizon than the parent material. Soils having similar clay contents in the surface horizon and subsoil, total V, Cr, Co, Ni, Zn, Cd, Sn, Sb, Tl, and Pb concentrations were higher in the surface horizon, relative to parent material. Only Zn and Cd increases were significant. Enrichment of elements in the surface horizons was, in part, attributed to anthropogenic additions. Experiments with EDTA and DTPA extraction techniques showed that almost half of Co, As and Cd, and other elements in fertilizers were between 4 and 50% in somewhat available form for plants indicating their potential for soil pollution.

Genetic improvement of crop plants for drought resistance is hindered by lack of information on variability and associations of drought‐response characters in breeding materials. We evaluated 3430 accessions in a world collection of durum wheat (Triticum turgidum L. var. durum) for 19 characters under severe moisture‐limiting field conditions at Swift Current, SK, Canada in 1984. Phenotypic diversity (H) and multicharacter associations were investigated in germplasm from nine durum wheat growing regions. The Middle East was one of the regions with a high level of diversity (H = 1.132). The rate of excised‐leaf water loss (RWL) was used as a possible indicator of drought resistance. Glaucousness, plant height, chlorotic leaf spots, days to flowering, and days to maturity were significantly associated with RWL in six to seven regions. The discrete multivariate log‐linear analysis involving these six characters revealed the first order (two‐character) and some second‐order (three‐character) associations. These five characters were chosen along with RWL as drought‐response characters that may be useful for establishing selection criteria for drought resistance. These results have important implications for developing durum wheat ideo‐types for high and stable production in drought‐prone environments.

Seven crosses, involving either nondormant × dormant or dormant × dormant pure lines of wild oats (Avena fatua L.), were made. Selfing of the hybrid and further hybridization were carried out to produce the F2 and reciprocal backcross generations. The seed germination time-course curves of the parents, their F1, and segregating generations over a 20-week period were studied. Differences in time course of germination in these generations were interpreted in terms of a minimum of three interacting loci. Two pure lines, AN51 and MO73, differed in their response to sodium azide, a respiratory inhibitor, with the former being more responsive. In crosses between these lines, the F1 seeds were also more responsive when AN51 was used as the maternal parent. This differential response of two dormant pure lines and their reciprocal F1s suggests maternal influence in germination response to sodium azide.

Breeding experiments were performed with pure lines of Avena fatua differing characteristically in duration of primary seed dormancy. The results indicate that the parental lines differ for at least three genes controlling rate of afterripening. It is evident that at least two of these genes influence the rate of afterripening at different periods after seed maturation.