Effects of conventional and organic farming systems on bio-agronomic and quality traits of durum wheat under Mediterranean conditions

The effects of conventional and organic farming systems on 10 durum wheat (Triticum durum Desf.) cultivars were studied over a 3year period (2012)(2013)(2014) in Foggia (southern Italy).The aim was to compare their agronomic and qualitative characteristics, and to test their adaptability and stability to these different management practices in terms of seed yield.The experiment followed a splitplot design, with three replications in each year.Six traits were investigated: heading time, plant height, seed yield, test weight, 1000seed weight, and protein content.The data from the analysis of variance indicated that there were significant differences between years, cropping systems, and genotypes for all of these characteristics.The mean seed yield for the organic system was 40% lower than that of the conventional system.The wheat quality was affected by cultivation management, with protein content 19% higher under the conventional system.The highly significant differences found for the genotype  environment interaction of the seed yield indicated the possibility to choose the stable genotypes across environments.Three univariate (b, S 2 d, R 2 ) and two multivariate (additive main effect and multiplicative interaction stability value, yield stability index) stability statistics were used.Based on these analyses, the varieties 'Iride' and 'Saragolla' showed high-stability responses and good seed yield under both farming systems.Therefore, these can be recommended for less fertile environments, such as organic farming systems in Mediterranean areas.On the contrary, the genotype 'Anco Marzio' was well adapted for high seed yield in more fertile environments.