ISTITUTO SPERIMENTALE PER LA CEREALICOLTURA - EXPERIMENTAL INSITUTUE FOR CEREAL RESEARCH
via R. Forlani, 3 26866 S. Angelo Lodigiano (LO), Italy.
M. Corbellini, P. Vaccino, A. Curioni, and L. Tavella.
Cereal bugs are one of the main wheat pests in southeastern Europe, western Asia, and northern Africa. Recently outbreaks of Eurygaster maura have been observed in northwestern Italy even if its populations are usually well controlled by egg parasitoids. The bugs feed on spikes, piercing the developing grains and injecting their saliva rich in proteolytic enzymes into the endosperm and affecting baking quality because of the detrimental effect of proteases on gluten structure.
In order to pinpoint the relationships between the timing of the bug attack and gluten degradation, a study was set up by caging plants of two bread wheat cultivars characterized by different seed texture and bread-making quality and introducing adults of E. maura in four different grain-filling stages. The timing of the bug attack was related to the amount of bug damage and to the qualitative decline shown by the decreasing of protein content and SDS-sedimentation volume. Results from SDS gel electrophoresis of storage proteins showed that bug damage was associated with the degradation of some gliadin or glutenin components; however, despite any evident technological damage, the degradation of protein components was not always observed. The latency of the proteases injected by the insects may be one explanation. In order to activate the proteases, a micromethod was set up by mixing small quantities of flour with water at 30 C. Extraction of glutenin components from these microdoughs followed by one-dimensional SDS-PAGE revealed progressive degradation of two components of the HMW glutenins in damaged samples, associated with the appearance of minor fragments with lower Mr that should represent the product of the proteolytic activity. The results were confirmed by HPLC analyses. The soluble fraction profiles of both damaged and undamaged samples do not show any variation. On the contrary, a breakdown of the first peak of the insoluble fraction, representing the high Mr typical of the gluten network, is evident in the damaged samples.
Under the experimental conditions, maximum degradation of gluten aggregates was observed with bug attacks at the late milk-ripe stage of grain filling, suggesting that chemical crop protection avoid general treatment throughout the plant life-cycle.
G. Boggini, M. Cattaneo, C. Basone, and P. Vaccino.
Waxy mutations in bread wheat are derived by the loss of functionality of the granule-bound starch synthase I (GBSSI), the enzyme involved in amylose synthesis, encoded by three different Wx genes at the single-copy homoeologous locus Waxy. The loss of one or more GBSS isoforms results in the reduction (partial-waxy) or absence (waxy) of amylose in the starch. Waxy wheats may find application in the production of modified food starch and their flour may be used to extend the shelf life of baked products; moreover, they strongly influence Asian noodle quality.
The breeding program at our institute to develop waxy wheat lines adapted to the Italian environment is in progress. F4 generations derived from nine crosses were selected for agronomic traits. Grains were analyzed by SDS-PAGE, and the flour of the double-null mutants were analyzed for starch-pasting properties using a Rapid Visco Analyzer.
G. Boggini, A. Brandolini, M. Perenzin, S. Empilli, P. Vaccino, R. Stefanini, and M. Cattaneo.
Nazareno Strampelli was one of the most important breeders in the world. His work preceded that of Norman Borlaug and the 'Green Revolution' by nearly 30 years. During his long career, he released more than 75 bread wheat cultivars, largely grown in Italy and all over the world, that also appear in the pedigree of significant recent cultivars. The agronomic and quality description of these cultivars, their comparison with modern cultivars, and their rescue from loss were the aim of this work.
The cultivars were clustered in different groups according to the coefficient of parentage, on the basis of the pedigrees described by Strampelli. The narrow genetic background of Strampelli germ plasm was confirmed by the limited variability observed in gliadin and glutenin composition. Molecular genetic diversity also was assessed by means of AFLP analysis.
The detailed results of this study were summarized on a CD, edited by the Institute for Cereal Research. The CD may be requested from cattaneo@iscsal.it.
N.E. Pogna, L. Gazza, G. Boggini, M. Corbellini, and P. Vaccino.
Kernel hardness, an important technological characteristic influencing milling and uses of bread wheat, is under the genetic control of Pina-D1 and Pinb-D1 loci coding for puroindoline a (pin A) and puroindoline b (pinB), respectively. We investigated both extra-soft and hard bread wheat cultivars lacking pin A. Extra-soft cultivars tend to have high amounts of pin on the surface of starch granules as compared to soft cultivars sharing the same pin composition. With the exception of five European extra-soft cultivars, which likely have a modified DNA conformation in a specific promoter region, the extra-soft cultivars analyzed showed no differences in their pin sequence with respect to soft cultivars. This result suggests the presence of factors other than pins that could modulate kernel texture as well, and investigations, in particular on starch conformation of extra soft cultivars, are in progress. In addition, we found that extra-soft cultivars have higher amounts of pin gene transcripts and a different temporal distribution of the above mentioned transcript. We now are investigating the promoter region of these extra-soft bread wheat cultivars.
Fortuna and Glenman are two null pin A, hard common wheats that show a cytosine deletion in position 265 in the coding region of pin A gene, which resulted in a TGA stop codon at position 361. The novel gene is the first null a allele due to a point mutation revealed in the pina-D1 locus. We now are characterizing the other hard bread wheat cultivars lacking Pin A.
CD-ROM.
"Le varietà di frumento tenero costituite da Nazareno
Strampelli" by R. Stefanini, M. Cattaneo, and G. Boggini.
ISTITUTO SPERIMENTALE PER LA CEREALICOLTURA - EXPERIMENTAL INSITUTUE FOR CEREAL RESEARCH
Via Cassia 176, 00191 Roma, Italy.
V. Vallega and C. Rubies-Autonell, and C. Ratti (Dipartimento di Scienze e Tecnologie Agroalimentari, Area di Patologia Vegetale, Università di Bologna, Via Fanin 44, 40127 Bologna, Italy).
Wheat soilborne mosaic virus is widespread in northern and central Italy where it causes severe losses on both common and durum wheat crops. Yield losses of up to 50 % and 70 % have been recorded on susceptible cultivars of common wheat and durum wheat, respectively. WSBMV also is present in a number of farms in southern Italy and in Sicily. During the 2003-04 season, 31 durum wheat cultivars were assayed in a severely WSBMV-infested field situated near Minerbio (Bologna) to study their reaction to this virus. The cultivars were grown in 10-m^2^ plots distributed in the field according to a randomized block design with three replicates. As in previous years, resistance to WSBMV was evaluated on the basis of DAS-ELISA readings (on two dates), symptom severity (on four dates, using a 0-4 scale), and agronomic performance. Although symptom severity (mean score = 1.6; range = 0.3-3.4) was moderately high, disease pressure was insufficient to adequately discern all susceptible entries. Cultivars Duilio, Quadrato, and Torrebianca, for instance, had low ELISA values despite their reknown susceptibility to WSBMV. Cultivars Prometeo and Concadoro, assayed for the first time, proved susceptible in terms of symptom severity, ELISA values, and agronomic performance. Simple correlation coefficients between agronomic data, ELISA values, and symptom scores (Table 1) were relatively high and mostly statistically significant. Regression analysis indicated that the cultivars with the highest disease scores suffered grain losses attributable to WSBMV of about 50 %. Among the durum wheat cultivars marketed in Italy, only seven (Colorado, Dupri, Dylan, Ionio, Neodur, Provenzal, and Tiziana) of the 91 we have tested so far have shown high levels of resistance to WSBMV.
| Disease severity | ELISA value | |
|---|---|---|
| Grain yield | -0.859** | -0.874** |
| Test weight | -0.340 | -0.325 |
| Plant height | -0.766** | -0.797** |
| 1,000-kernel weight | -0.537** | -0.497** |
| Heading date | 0.330 | 0.266 |
| ELISA value | 0.928** | --- |
V. Vallega, and C. Rubies-Autonell, and C. Ratti (Dipartimento di Scienze e Tecnologie Agroalimentari, Area di Patologia Vegetale, Università di Bologna, Via Fanin 44, 40127 Bologna, Italy).
Thirty-six cultivars of common wheat were grown in a severely WSBMV-infested field near Minerbio (Bologna) during the 2003-04 season. Entries were grown in 10-m^2^ plots distributed in the field according to a randomized block design with three replicates. Resistance to WSBMV was evaluated on the basis of DAS-ELISA readings (on two dates), symptom severity (on four dates, using a 0-4 scale), and agronomic performance. Symptoms (mean score = 0.4; range = 0.1-0.8) were extremely mild and, as in all our previous trials, milder than those observed on the durum wheat cultivars assayed in an adjacent field. Common wheat cultivars Nomade and Paderno, assayed for the first time, were classed as susceptible based on their relatively high ELISA values. ELISA values, symptom scores, and agronomic data were not significantly correlated with each other (Table 2).
| Disease severity | ELISA value | |
|---|---|---|
| Grain yield | -0.318 | 0.179 |
| Test weight | 0.008 | 0.143 |
| Plant height | 0.267 | 0.059 |
| 1,000-kernel weight | -0.232 | -0.024 |
| Heading date | -0.109 | -0.383* |
| ELISA value | 0.044 | --- |