Evaluation of morphological traits, genetic diversity and major resistance genes in barley subpopulations cultivated under organic and conventional farming systems

Most crop varieties currently grown in organic conditions have been bred for conventional farming, and are not adapted to increased environmental variability under organic farming conditions and unpredictable environmental fluctuations due to climate change. This can be mitigated by the use of heterogeneous material, increasing genetic diversity and enabling adaptation to local conditions. The objective of this study was to determine the effects of several generations of cultivation in parallel under organic and conventional farming systems on the genetic diversity, morphological traits and frequency of major disease resistance genes as indicators of adaptation to the farming system in heterogeneous spring barley populations with differing levels of diversity. Populations in differing generations originating from crosses between two, three, 10 and 15 parental genotypes were cultivated in organic and conventional farming systems for three, four or 10 generations, thus forming subpopulations in each environment. These subpopulations were genotyped, and tested for morphological traits in both farming systems. A significant effect of cultivation environment on tillering capacity (p < 0.05) was found for all tested populations and in several cases for plant height, ear length and grain number per spike, indicating some adaptation trends. In the short term, genetic diversity parameters were not decreased in the later generation populations in comparison to the initial populations with the exception of observed heterozygosity, as expected for a self-pollinating species. No clear differences in genetic diversity parameters between populations cultivated under either organic or conventional condition for several generations were identified.