A method for obtaining flexible broccoli varieties for sustainable agriculture

Abstract

BackgroundThe use of high inputs in agriculture has resulted in few varieties (hybrids and pure lines) used in all agricultural systems. Also varieties of vegetables, including broccoli (Brassica oleracea L.), for organic and low-input agriculture, are almost exclusively hybrids, due to lack of specific breeding programs and varieties for sustainable agriculture.A strategy to overcome this issue is the adoption of specific breeding programs for developing heterogeneous varieties (i.e. synthetics, open pollinated varieties, composite cross populations and mixtures). The heterogeneous varieties, in fact, are able to evolve and adapt to specific agro-climatic conditions.Aim of this study was to develop a method (an Evolutionary Breeding Program, EBP) for obtaining heterogeneous varieties and test its efficiency in giving rise to highly diverse varieties, as needed in sustainable agriculture.A synthetic variety originated from a landrace was multiplied in different environments for 3 cycles and morpho-phenological and genetic diversity of the derived populations was assessed. ResultsThe resulted presented are the first and unique indication about the efficiency of a short-time EBP for an allogamous species like broccoli.Few morphological changes were observed among varieties multiplied in different environments with different agro-climatic conditions. This could be probably due to the initial genetic diversity of the landrace from which the populations were selected and to the great plasticity of the crop. However, SSR data highlighted a genetic differentiation among populations multiplied for two/three years across Europe and in Central Italy, that was not so evident with morphological data. ConclusionsFew years of multiplication in different environments resulted in genetically differentiated broccoli populations that none the less preserved the original genetic diversity and productivity level and appear to evolve in relationship to different environments: the applied EBP is useful for developing