Plant breeding for organic and sustainable, low-input agriculture

Appropriate breeding approach and type of cultivar in breeding faba bean for organic
farming
Lamiae Ghaouti, Wolfgang Link
Department of Crop Sciences, Georg-August University, Göttingen, Germany
As organic farming refrains from the use of agrochemical inputs, the organic environments are
characterized by a large environmental heterogeneity. Therefore, genotype × location interaction
is expected to be larger across organic cropping areas than across conventional ones. So far,
formal plant breeding generally has concentrated on increasing yield and quality in environments
that were modified by application of agro-chemicals. The importance of adaptation to variable
and even risky low-input conditions often found in organic farming received little or no
attention. A strong asset of local breeding is the possibility to select in the target environment
and to exploit genotype × location interactions, being repeatable over time. Therefore, the
objective was to compare for faba bean the effectiveness of local breeding and formal breeding
for grain yield in organic farming and to compare the performance of inbred lines and
corresponding synthetics using the two breeding approaches.
The material involved included a set of 18 inbred lines, their polycross progenies and 13 checks.
The entries were tested in four organic locations and one conventional station in Germany in
2004, 2005 and 2006. Three organic farmers were involved in a participatory breeding approach
and gave a score of a personal appreciation to the material tested in their farm.
Results showed that the correlations between the personal appreciation scores attributed to the
studied locations were very low and sometimes even negative. Personal appreciation score was
strongly influenced by biotic and abiotic constraints faced by the crop in each location. For grain
yield, genotype × location interactions were the highest component of the genotype ×
environment interactions and contributed more than three quarter as much as the genotypes to the
yield variation. The genetic correlations between the locations for grain yield were generally
low indicating that the performances in the studied locations were controlled by substantially
different sets of genes. To increase gain from selection in an organic location, local breeding
proved to be markedly more efficient than formal breeding. Based on the genotypic performance
and variance of inbred lines and synthetics at the first generation Syn-1, and on intensity of
selection, the best Syn-1(4) and the best inbred lines were predicted. Despite the large variance
of inbred lines available in local breeding, due to the partial realization of heterosis in the
synthetics, these were the best performing in both breeding approaches. Unlike pure lines, they
are providing the option of further local evolution and adaptation over time.
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