Mixtures of wheat semolina, 5% glucose and 0-30% defatted soybean flour were used for the preparation of extruded samples using a pilot plant single screw extruder, maximum temperature being 140°C. The browning reactions were only moderate, the intensities of the trichromatic a* coordinate increased, and some changes were observed in chroma and the odour difference ΔE*. The sensory acceptability improved by increasing the content of soybean flour, the odour intensity increased, and some changes were observed in the sensory profile. Volatile substances were isolated using a SPME procedure, and the volatiles were separated using a Fisons GLC 8000 apparatus equipped with a mass spectrometer. Among the flavour active volatiles, pyrazines were the most prominent class of compounds, especially methyl and ethyl substituted derivatives. Pyrrole and furan substituted pyrazines were found only in small amounts because of the low extrusion temperature. Other furan and pyrrole derivatives had a lesser effect on flavour because of their relatively low amounts. Aldehydes, fatty acids, ketones, and other aliphatic derivatives contributed only a little to the resulting flavour. Compared to the mixtures of semolina and glucose only, the additions of defatted soybean flour moderately increased the number of substituted pyrazines detected in the extruded mixtures but increased substantially the pyrazine fraction in the total peak area. Among furan derivatives, 2-furancarboxaldehyde, 2-furanmethanol and 5-methyl-2-furyl alcohol belonged to the most prominent derivatives. Among other compounds, acetic acid, butyrolactone and maltol should be mentioned.

Earliness, morphological and agronomic characters and grain quality were studied in 123 European landraces and old cultivars of winter wheat in three-year field experiments. Simultaneously, HMW Glu-alleles were identified in these cultivars by means of SDS-PAGE. Within this set of cultivars 224 Glu-lines (with occurrence over 5% in the cultivar) were identified carrying 3 different allelic combinations at 1A, 10 combinations at 1B and 3 combinations at 1D chromosomes, respectively. Relatively rare were alleles 2* at 1A and 3+12 at 1D as well as alleles 8, 6, 9, 7, 13+16 and 17+ 18 at 1B. Allele 20 at 1B was identified only in cultivars from DNK, CHE and EST. Allele 2* at 1A locus was found mainly in cultivars from Eastern, South-Eastern and Central Europe. Allelic combination 17+18 at 1B was also characteristic of cultivars from Central Europe. However, the gluten patterns themselves were not a sufficient tool for geographic characterisation of cultivars. The composition of Glu-alleles influenced the earliness of cultivars (alleles 2* at 1A, 17+ 18 and 6 at 1B and 3+12 at 1D). Spike length was positively affected by allele 1 at 1A and number of spikelets per spike by alleles 2+12 et 1D chromosome. Allele 2* was also associated with lower grain weight per spike. Crude protein content was decreased in cultivars where GS at 1A locus was absent (0). The value of gluten index was considerably higher (59.2) in cultivars bearing allelic combination 5+10 at 1D. A number of alleles affected the values of SDS micro-sedimentation test.

The effect of crop height on the epidemics of Septoria tritici and Stagonospora nodorum was investigated using visual assessment and PCR-based assays. Based on the results of our study, the primary mechanism of disease escape in tall crops is through a reduction of spore arrival. Real-time PCR is an important tool to quantify spore arrival and can, in combination with visual assessment, identify factors involved in the onset and extent of disease development.

The need for vernalization of winter wheat varieties cultivated in the CzechRepublic in 2000 was studied in comparison with the need for vernalization in the past decades since 1950. In 2000, many foreign varieties were cultivated in the Czech Republic, mostly West European. Varieties with a vernalization of 40-50 days and 50-60 days show the highest representation in the assortment (47.3% and 31.6%, resp.). The share of varieties with a long vernalization over 60 days is 15.8%. In around 1990, when varieties of domestic breeding were mostly grown, there were, next to the largest group with a vernalization of 40-50 days, 21.7% of varieties with a vernalization of 30-40 days and the same amount with a vernalization of 50-60 days. During the last ten years, the share of varieties with a longer vernalization has risen, not only due to foreign varieties, but also due to new domestic varieties. It is apparent from a 50-year overview that what has predominated are varieties with a vernalization of 40-50 or 40-60 days, which is a range usual for winter varieties of wheat in Middle and West Europe. After 1950, a departure from original domestic varieties appeared; those were represented by original alternative varieties (in Czech přesívky, in German Wechselweizen, in Russian dvuručki) and half-winter varieties with a shorter vernalization, strictly speaking with a vernalization fixed to a short day, and a strong photoperiodic reaction. Representation of varieties as related to their length of vernalization has changed in the course of the decades following utilization of foreign varieties; this was affected above all by varieties from Russia (the former USSR), Germany, but also Yugoslavia. Varieties from these countries were utilized also as parent components in domestic breeding.

Aphid population on wheat crop was studied during the growing season of crop at New Campus, Lahore. Two species of aphids were recorded on wheat crop. These were Schizaphis graminum and Rhopalosiphum padi. The aphid density per leaf varied from January 9, 1998 to April 14, 1998 and was maximum on February 26, 1998. At the end of February, aphids started shifting to the ears. Maximum aphid population per ear (48.0) was recorded on March 27, 1998.

The processing and quality of wheat flour tortillas prepared with partial waxy and normal flour were evaluated. Control procedures and formula were utilized with water absorption varied to obtain machineable doughs. Amylose content was lower in most partial waxy compared with normal wheats. The type of wheat starch did not affect most dough properties or tortilla diameter. Tortilla height and opacity were adversely affected by the decreased amount of amylose in partial waxy wheats. Sufficient leavening reactions occurred early in baking (after 10 sec) to yield an opaque disk, but some baked tortillas lost opacity and become partially transparent after baking. Starch gelatinizes, disperses, and retrogrades concurrently with the leavening reaction during the short (<30 sec) baking time. Amylose functionality during baking and cooling appears to be involved in the retention of air bubbles in tortillas.

A pot experiment was conducted in a lath house at the Kulumsa research station in Ethiopia using soil and wheat straw collected from research fields at the Kulumsa and Asasa stations. The experiment comprised 13 treatments, consisting of a control (i.e., no straw added) plus the full factorial combination of three levels of straw management (i.e, burning incorporation and surface retention), two types of straw (i.e., naturally degraded and fresh straw), and two rates of straw application (i.e., 0.8 and 2.5 t ha-1). The trial was replicated over time in three separate runs during 1999 and 2000. In general, straw application exhibited a negative effect upon most of the measured seedling parameters, and in some cases this may have been due to an allelopathic effect. Burning of the straw at least partially alleviated the negative effects of straw application. Conversely, soil incorporation of straw resulted in pronounced reductions in most of the measured seedling parameters. Similarly, the highest rate of straw application consistently reduced seedling parameters, while the application of fresh straw tended to reduce the measured parameters more than naturally degraded straw. The deleterious effects of the high rate of straw application were consistently exacerbated by soil incorporation, while straw burning _ and occasionally surface retention _ tended to negate the effects of the highest rate of straw application.

The effects of addition of purified total gliadin and its subgroups (α-, β-, γ- and ω-gliadins) on the dynamic rheology of gluten were investigated. The frequency sweeps of gluten with added α-, β-, γ- and ω2-gliadins showed unexpected increases in the magnitude of G′ and G′′, suggesting stiffening of the native gluten. Conversely, a reduction in the magnitude of G′ and G′′ occurred upon addition of the total gliadin fraction and the ω1-gliadin, implying softening of the gluten. Addition of individual gliadin fractions increased the values of slope log G′ vs log frequency, suggesting increased concentrations of uncrossed-linked material compared with the native gluten. There were significant differences in the slope values for individual gliadin fractions. The increasing order of slopes for different gliadins was: β- >γ- >α- =ω1>ω2, indicating that glutens containing ω- and α- gliadins are relatively less crossed-linked than those containing β- and γ-gliadins. The dynamic moduli, G′ and G′′, of cv. Hereward gluten showed significant positive relationships with Mixograph parameter peak dough resistance (PDR), and loaf volume for gliadin subgroups added to cv. Hereward flour.