Effetto della tecnica agronomica e dell’ambiente pedo-climatico su accrescimento e resa quali-quantitativa di varietà di frumento duro

Aim of this PhD project was to evaluate the effect of both management practice and cropping environment on development and quali-quantitative yield of Italian durum wheat cultivars, testing in the same time their adaptability to organic farming. Organic and conventional varietal trials were performed at Rome and Campobasso, whereas in another location, namely Tarquinia, only organic trials were carried out. Eight cultivars were used (Claudio, Creso, Dylan, Iride, Meridiano, Normanno, Saragolla, Svevo) with two different seeding rates, 350 e 500 germinating seeds/m2. Moreover, in Rome a fertilization trial was performed, with a reduced nitrogen fertilizer supply, prior to sowing. Some quail-quantitative traits were determined (thousand kernel weight, heading date, number of spikes/ m2, plant height, grain yield, grain protein content, test weight). The results were submitted to analysis of variance (ANOVA). Moreover, a variety trial was carried out in Ridgetown – Ontario, Canada, aiming at evaluate the suitability of Italian durum wheat genotypes to such a pedoclimatic environment. Fifteen cultivars were tested. Grain yield regularly exceeding 5 t/ha were achieved at Rome and Campobasso, both in organic and conventional, whereas grain yields at Tarquinia where quite far from those obtained in the other locations (average grain production lower than 3 t/ha). It is worth to highlight the yields of Meridiano and Iride, not far from the value of 7 t/ha, while Claudio showed an interesting to be high yielding and well adaptable to any environment. Grain protein content revealed to be high both in organic and conventional trial in Rome, where mean values exceeded 13%; Svevo, Claudio and Dylan achieved the highest values. At Campobasso, protein contents were particularly high in conventional trial (mean value over 15%), and even in this case Svevo, Dylan and Claudio resulted to be the best cultivars. Conversely, in this location all the cultivars were clearly penalized by organic management, seen as values lower than 10% were detected. At Tarquinia, kernel protein content ranged from 10% to 12%, and even in this case Svevo revealed to be the best cultivar. Fertilization trial carried out in Rome showed an overall reduction of grain yield and protein content in less fertilized plots. Genotype x Management interaction was not significant for yield, while it was for protein content. Influence of seeding rate was poor, but a statistically significant effect emerged in 3 out to 5 fields on heading date and thousand kernel weight. In conclusion, data analysis revealed how an increase in the seeding rate didn’t allow to improve the performance of all the cultivars. Rome resulted to be a suitable environment for both organic and conventional management, regarding grain yield and protein content; at Campobasso, grain yields in organic farming were comparable to those obtained in conventional trial, while protein contents were clearly lower in the field managed organically. The environment of Tarquinia didn’t allow to reach satisfactory values of grain yield and protein content in organic management. Regarding the trial carried out in Canada, 4 cultivars (Claudio, Arnacoris, Dylan, Duilio) reached yield values not statistically different fro that achieved by OAC Amber, the only winter durum wheat cultivar currently registered in Canada.