Linda Legzdina, Ieva Mezaka, Indra Beinarovica, Aina Kokare, Guna Usele, Dace Piliksere, Nils Rostoks

State Priekuli Plant Breeding Institute, Zinatnes street 1a, Priekuli, LV-4126, Latvia.

Abstract

Association mapping population consisting of 154 Latvian and foreign spring barley genotypes contrasting for traits that are important for organic agriculture was established with the aim to develop molecular markers useful in breeding for organic farming. The mapping population was genotyped at 3072 single-nucleotide polymorphism loci using Illumina GoldenGate platform to provide marker data for association mapping. Field trials in two organically and two conventionally managed locations are being carried out during three seasons. The following traits essential for organic farming were phenotyped: plant morphological traits ensuring competitive ability against weeds, grain yield in organic farming, yield stability/adaptability to organic conditions, nutrient use efficiency (measured as ability to form acceptable grain yield and accumulate protein in grain under conditions of organic farming) and prevalence of diseases. This chapter gives an overview on preliminary phenotyping results. ANOVA showed that genotype and location significantly influenced most of analysed traits (p < 0.01). The average yield reduction in organic trials, when compared to conventional, was 1.2 t ha⁻¹, and it ranged from 4.2 t ha⁻¹ reduction to 1.2 t ha⁻¹ increase. In respect to morphological traits related to competitive ability against weeds (canopy height in beginning of plant elongation, plant ground cover in tillering, length and width of flag leaves, tillering capacity, plant height before harvest), there was a tendency that average trait values were higher in conventional farming locations, but the coefficients of variation were higher in organic locations in most of the cases. The differences in protein content between conventional and organic trials correlated significantly (r = 0.732), and its variation was significantly effected by genotype. The average reduction of protein content in organic fields, if compared to conventional, was 2%, and it ranged 0–6.5%.