Little attention has been given to the study of genotypic variation in the composition and digestibility of oat (Avena sativa L.) hulls. The aim of this study was to examine the variability in levels of acid detergent fiber (ADF), its components—cellulose, acid detergent lignin (ADL), and insoluble ash (mainly silica)— and pepsin cellulase digestibility (PCD) in hulls separated from current Western Australian genotypes. Analyses were conducted on six genotypes grown in trials at up to seven locations in Western Australia in 1981. In 1983, the same genotypes, and one other, were tested at five locations. In both years, considerable genotypic variance was observed in levels of PCD, ADF, and ADL. Location affected all traits, particularly insoluble ash, in both years. Genotype ✕ location interaction was not measured in 1981, but in 1983 was found to be significant for all traits. Interaction effects were of sufficient magnitude to mask the small genotypic variations in cellulose, but clear differentiation between genotypes with high or low PCD, ADF, and ADL was observed at each location. While PCD was highly correlated with ADF (r = −0.97** (significant at the 0.01 probability level), based on means for each of seven genotypes over five locations), differences between genotypes in both PCD and ADF were associated mainly with ADL (r = −0.98** and 0.95**, respectively). Among the genotypes tested, Swan (PCD, 293 g kg−1 ; ADL, 8 g kg−1) and 'Mortlock' (PCD, 108 g kg−1; ADL, 76 g kg−1) had the highest and lowest quality hulls, respectively. This study has shown considerable variation to exist in the highly correlated factors PCD and ADL among current Western Australian genotypes, and indicates potential for improvement in the feeding quality of oat grain through plant breeding.

A 0–4 scoring system to quantify scald (Rhynchosporium secalis) infection is suggested. Scores 1, 2, 3 and 4 allocated to represent 1/4, 1/2, 3/4 and 4/4 of the crop canopy scalded are easy to comprehend and intermediate scores e.g. 0.5, 1.5, 2.5 and 3.5 give it the breadth of a quantitative scale. Scores on a large number of lines showed a high degree of repeatability and were found to be highly correlated with the log transformed values of the actual leaf area damage. Although it was suggested that predictions of leaf area damage at scores 3–4 should be applied with caution, broad generalization of the scores in discriminating the amount of disease were shown to be soundly based and offered plant breeders a tool to standardize the evaluation of scald resistance in field plots on a large scale with this quick and reliable scoring system.

Simulated segregating barley populations were screened for resistance to scald (Rhynchosporium secalis) in the field at commercial seeding rates. A reduction in infection on the susceptible component occurred with increasing proportions of resistant genotypes. Similar trends were seen in space planted experiments but the use of susceptible buffer rows counteracted the effect, enhanced the infection in susceptible plants and greatly improved discrimination between resistant and susceptible. These results have been applied to the routine testing of F2 populations in the barley breeding programme.

A pneumatic grain transport system has been fitted to small plot combine harvesters to enable efficient one person operation. The system has three main components: fan, rotary valve, and cyclone. The machines are operated at the same rate as the previous two man operation. The samples are stacked directly into bins which provide a rapid and efficient means of collecting samples from the field. The system does not increase cross-contamination but can help to reduce it. The modification has greatly improved working conditions by eliminating the need for one operator to walk alongside the machine.