Genetic Assessment of the Role of Breeding Wheat for Organic Systems

Abstract

Organic farming as an agricultural system includes substantially different growing methods and guidelines than conventional farming systems. Plant breeding programs typically breed and select varieties under a farming system that includes the use of agronomic practices not permitted under organic fanning standards. One objective of our research is to quantify the overall differences in yield of winter wheat when grown under two contrasting systems, organic and conventional. Thirty-five advanced breeding lines were evaluated in five locations in Washington State in both organic and conventional plant breeding nurseries. These breeding lines showed a statistically significant difference in change of rank for yield and genotype by system interactions between the two systems at four of five locations. Another objective of our research is to evaluate historical and modern wheat varieties under organic conditions to identify traits that confer adaptation and optimal yields in organic conditions. Analysis of variance shows no significant difference in the top yielding historical varieties and the modem varieties when grown in organic conditions, indicating that traits important to yield in organic systems can be found in historical wheat varieties that were selected under low input conditions. These results support the argument for the need to select varieties for organic agriculture in an organic production system in order to optimize yield potential