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Recent epidemics of fusarium head blight (FHB), caused by Fusarium graminearum Schwabe (telomorph: Gibberella zeae), in the USA and Canada have caused severe yield and quality losses in wheat (Triticum aestivum L.). Development of resistant cultivars has been difficult because of the complex inheritance of resistance and confounding environmental effects. This study was conducted to identify and map DNA markers linked to genes associated with FHB resistance. A population of 112 F5‐derived recombinant inbred (RI) wheat lines from the cross ‘Sumai 3’ (resistant)/‘Stoa’ (moderately susceptible) was evaluated in two greenhouse experiments for Type II resistance (spread within the spike). On the basis of restriction fragment length polymorphism (RFLP) marker analyses, five genomic regions were significantly (P < 0.01) associated with FHB resistance, three derived from Sumai 3 and two from Stoa. Regions on Chromosomes 3BS (from Sumai 3) and 2AL (from Stoa) were identified by interval analysis using a LOD threshold of 3.0. These two quantitative trait loci (QTL) have been assigned the gene designations QFhs.ndsu‐3B and QFhs.ndsu‐2A, respectively. Recombinant inbred lines with these two QTL had a median severity of 20.9%, compared with 36.2% for all RI lines. The best RFLP marker in the 3BS region explained 15.4% of the variation and a multiple regression model consisting of three QTL explained 29.5% of the variation. These results indicate that resistance to FHB is inherited in a quantitative manner and that marker‐assisted selection may aid the development of FHB‐resistant cultivars.

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crested wheatgrass [Agropyron cristatum (L.) Gaertn.] (Dewey, 1960(Dewey, , 1962. A lack of salt-tolerant cultivars may be due in part to inadequateEven though the literature contains numerous reports evaluation protocols used for selection. Our objective was to develop indicating variability for tolerance to salinity in many a greenhouse protocol that is simple and consistently separates genocrops, few salt-tolerant cultivars have been released (Flowtypes for their relative ability to survive under saline conditions. In 2000 and 2001, 12 alfalfa (Medicago sativa L.) cultivars were seeded ers and Yeo, 1995). Sruvastave and Jana (1984) and Shanin 3.8-by 21-cm cone-shaped containers plugged with capillary matting non (1984) attribute the lack of salt-tolerant cultivars and filled with silica sand. Six-week-old seedlings were submersed in to multiple factors, including inadequate means of dea NaCl-nutrient solution starting at an electrical conductivity (EC) tecting and measuring plant response to salinity and of 3.0 dS m Ϫ1 and increased 3.0 dS m Ϫ1 every 1 to 2 wk for 10 to 13 ineffective selection methods. Selection of salt-tolerant wk. Probit analysis was used to estimate the time and salt dose to plants from saline fields or plots seems a logical step reach 50 (LD 50 ) and 75% (LD 75 ) mortality. Probit results were comfor most plant breeders; however, this procedure has pared with cultivar ranking for mean percentage plant mortality when not produced consistent results (Shannon, 1984). Selecoverall trial mortality reached approximately 50 and 75%. Pearson's tion in the field is not efficient because soil salinity rank correlations between 2000 and 2001 at the LD 50 and LD 75 levels varies substantially with time, location, soil type, and were r ϭ 0.90 (P Ͻ 0.001) and r ϭ 0.88 (P Ͻ 0.001), respectively. Rank correlations between 2000 and 2001 based on means whendepth. Furthermore, it has been reported that little relaoverall trial mortality levels were approximately 50 and 75% were

The yield stability of cool‐season pasture grasses at different irrigation levels has not been well documented. Objectives were to evaluate selection of pasture grass species in environments where irrigation may be limited or unreliable. Dry matter yield was determined for eight grass species during 1996 through 1998 at five irrigation levels. Shukla's stability statistics were calculated and species selection based on mean‐yield versus Kang's yield‐stability indices were compared. Tall fescue (Festuca arundinacea Schreb.), meadow brome (Bromus riparius Rehm.), and orchardgrass (Dactylis glomerata L.) had higher than average dry matter yield and were selected on a mean‐yield basis. On the basis of Shukla's statistics, meadow brome and orchardgrass did not contribute to the genotype × irrigation level interaction or the genotype × irrigation level × year interaction, respectively. Perennial ryegrass (Lolium perenne L.) also did not contribute to these genotype × environment interactions; however, Shukla's statistics suggested that the linear effect of irrigation was the underlying determinant of perennial ryegrass's apparent stability. Species selection based on yield‐stability indices were generally in close agreement to selection of species on a mean‐yield basis. One exception, Kang's Modified Rank Sum method, placed too much emphasis on stability resulting in selection of species with low forage yields. Tall fescue had superior forage yield at all irrigation levels and was always selected by yield‐stability indices. Orchardgrass and meadow brome were also selected by all yield‐stability indices. These results indicate that tall fescue, orchardgrass, and meadow brome are the species of choice where irrigation may be limited.