Acknowledgements

1. Comparison of interconnections between barley breeding material traits under organic and conventional growing conditions 1L. Legzdina,1A. Kokare , 1I.Beinarovica and 2E.T. Lammerts van Bueren 1 State Priekuli Plant Breeding Institute, Latvia lindaleg@navigator.lv 2Wageningen UR Plantbreeding, Wageningen University, The Netherlands Material and methods Spring barley breeding lines selected from two cross combinations (Primus/Idumeja and Anni/Dziugiai) at two distinctive organic and two conventional locations (Table 1) were used in the study. ‘Primus’ is late maturing, old Swedish variety with very tall plants. It was crossed with recently released, early maturing Latvian variety ‘Idumeja’ with medium tall plants. In the second cross the short straw Estonian variety ‘Anni’ (developed in 1990-ties) with good yields under various growing conditions was crossed with the Lithuanian variety ‘Dziugiai’ from the middle of last century, with quite tall plants, poor lodging resistance, but with a rapid early development. Selection of the breeding lines was done under the respective growing conditions starting from F3 generation. Most appropriate lines for growing in organic farming were selected at all 4 environments. Selected breeding lines were evaluated for traits essential for organic farming in F5 and F6 generations and in F7 comparison of selected lines was done in all four environments (fig. 1). Phenotypic correlations between barley traits were calculated. Figure 1. Scheme of the breeding experiment, Priekuli 2006-2010. Table1. Description of crop management systems at two organic and two conventional trial locations in Priekuli, 2006 – 2010. Introduction While breeding for organic farming it is necessary to identify the most appropriate growing conditions in which to perform the selection process. Soil fertility, crop management, yield level and other factors may vary very much between each organic farm, and between organic farms and research institutions where the selection is usually performed. Since plant breeding requires considerable input of resources and the market for organic varieties is limited, it is essential to find the most appropriate selection conditions that will provide acceptable varieties for organic farms. Defining the most suitable selection environments was pointed out among the key questions for development of breeding strategies for organic farming (Wolfe et al., 2008). The aim of this study was to find out if there are different tendencies in correlations between the traits under different organic and conventional conditions. Results The analysis of the correlation between grain yieldand observed plant traits indicated that tendencies for the linesobtained from both cross combinations as well as between the locations and testing years were dissimilar in most of the cases. Soil shading correlated positively with grain yield in most of the cases (fig.2), but the correlation was significant in all years only for lines selected from cross Primus/Idumeja in O1 location. On the whole higher correlation coefficients were found for Primus/Idumeja lines and in organic locations, which can be explained by higher competitive ability with weeds. Plant development speed (scored in tillering) correlated with yield significantly positive for Primus/Idumeja lines in most of the cases in both organic and also C1 locations. For lines selected from cross Anni/Dziugiai this correlation was positive only in O2 location, but also negative tendencies were found. On the whole, higher positive correlations between plant height (measured in stem elongation and before harvest) and yield were stated in organic locations and for lines derived from cross Primus/Idumeja. Plant height in stem elongation for Anni/Dziugiai lines in 2010 correlated significantly positive in O2 location, however, in the same year it was significantly negative in C2 location. Unusual tendencies were found for correlations between grain protein content and yield under organic conditions: for Anni/Dziugiai lines there were no negative correlations (2009-2010) and for Primus/Idumeja lines the correlation was even significantly positive in 2010. On the contrary, correlation coefficients between yield and grain starch content were positive and on the whole higher in conventional locations. TGW correlated positively with yield in 2010 only and in all locations except O2. Soil shading correlated positively with leaf position and plant development speed in majority of the cases in organic and in conventional locations (data not shown). Regarding plant height, significant positive correlations with soil shading were found in more cases if it was measured in stem elongation if compared to measurement in maturity. The results of this study does not approve the usefulness of leaf length and width measurements for selection purposes: no significant positive correlations with soil shading ability were found for both measurements under organic conditions. However, in two cases leaf length correlated positively with grain yield. Correlations between soil shading and lodging were mostly negative indicating that genotypes with better soil shading ability are less resistant to lodging. This fact might cause a problem under organic conditions with higher fertilization level. Dissimilar tendencies in correlations between soil shading and plant growth habit for lines from both cross combinations are shown in Figure 3. For Anni/Dziugiai lines most of correlations are negative indicating that soil shading was better for lines with erect growth habit, while for other cross combination lines with more planophyle growth habit provided better shading. It can be explained by strong and significantly negative correlation between planophyle growth habit and plantdevelopment speed which was found for Anni/Dziugiai lines in majority of the cases. Figure 2. Coefficients of correlation between grain yieldand traits of lines selected from two cross combinations in two organic and two conventional locations in the years 2008-2010 (*, ** significant at the 0.05 and 0.01 level, respectively). Figure 3. Coefficients of correlation between soil shading and plant growth habit of lines selected from two cross combinations in two organic and two conventional locations in the years 2008-2010 (*, ** significant at the 0.05 and 0.01 level, respectively). • Conclusions • In the selection process it has to be considered, that the tendencies of correlative connections may differ between the cross combinations. Differences between the years suggest that meteorological conditions can influence correlative connections between the traits. • Positive correlations between grain yield and soil shading ability gives a possibility to select lines with good yield and good competitive ability with weeds at the same time; higher correlation coefficients under organic conditions approve the positive effect of better ability to compete with weeds. • Plant development speed can be positively related with grain yield, especially under organic and lower input conditions, but not under high input conventional conditions. • The interconnection between grain yield and protein content might be not negative under organic conditionsin contrary to conventional conditions. • Essential traits for assessment of competitive ability with weeds according to correlations with soil shading are plant development speed, leaf position and plant height in beginning of stem elongation stage. Reference Wolfe MS, Baresel JP, Desclaux D, Goldringer I, Hoad S, Kovacs G, Löschenberger F, Miedaner T, Østergård H, Lammerts van Bueren ET (2008) Developments in breeding cereals for organic agriculture. Euphytica, 163: 323-346. Acknowledgements This study was performed with financial support of EEA grant EEZ08AP-27 and European Social Fund co-financed project 2009/0218/1DP/1.1.1.2.0/09/APIA/VIAA/099.