Comparison of Soybean Breeding and Variety Performance Between Conventional and Organic Production Systems in Ontario.

Organic production systems rely on manure, organic soil amendments, mechanical tillage and complex rotations for effective crop production whereas conventional systems use synthetic fertilizers and pesticides to modify the environment to maximize crop production. The European Technology Platform for Organic Food and Farming Research acknowledges the need to close the productivity gap between Organic and Conventional systems by 2025. The objectives of this study were to: 1) determine if current Ontario soybean cultivars performed differently in organic and conventional environments and if so, to examine what plant characteristics caused these differences; 2) to determine if selection of soybean lines for organic production systems needed to be performed on organically managed land. Rank correlation between the yield rankings for 30 cultivars in the organic and conventional sites was significant at 0.55, however, almost half the time the cultivars ranked differently. The soybean cultivars S03-W4 and DH530 were ranked as 1st and 2nd highest yielding cultivars in the organic location but only 9th and 19th in the conventional environment. Phosphorus Use Efficiency (PUE) was significantly correlated with yield in both the organic and conventional environments at -0.84 and -0.79, respectively. Significant difference was found between the cultivars in terms of root length in the organic environment only. Root length in the organic location was significantly correlated with plant height, yield and PUE (0.51, 0.46 and -0.362, respectively). Twenty-five percent of F4:5 lines from two breeding populations (OAC Calypso x DH618 and OAC Sunny x S05-T6) were selected in both conventional and organic environments. Of those, 21% and 57.5% of selections were in common between the two production environments in the OAC Calypso x DH618 and the OAC Sunny x S05-T6 populations, respectively. Differences in cultivar and breeding lines' performance were found between organic and conventional systems, which may be explained by the different response to the environmental challenges posed by the two production systems.