Background

OLYMPUS DIGITAL CAMERAOrganic farming, despite its successes over the last decade, faces some major challenges.

A key problem is the lack of appropriate plant varieties which are adapted to the specific conditions of organic systems. In particular, plant varieties are needed that can cope with the characteristic biotic and abiotic stresses in organic systems. Because conventional plant breeding has concentrated on the development of varieties for high-input (non-organic) systems, there is currently not enough choice of varieties for organic producers. Despite the known demand for varieties bred for organic systems, however, organic plant breeding enterprises are still struggling.

Meanwhile agriculture is experiencing the continued loss of genetic diversity of cultivated plant species as landraces are being replaced by modern cultivars. However, agricultural productivity strongly depends on high genetic diversity of cultivated plants and on the availability and maintenance of suitable germplasm.

For two reasons, this is particularly relevant for organic agriculture. First, the loss of plant genetic diversity mainly affects germplasm that would be especially suitable for organic conditions, because it stems from agriculture that did not use synthetic inputs for plant protection or plant nutrition. Second, the comparatively large environmental variability in organic systems needs to be buffered with higher levels of in-field diversity.

Besides the need to breed specifically adapted pure line varieties for organic production, there is a complementary strategy, the use of plant material with High genetic Diversity (Hi-D) e.g. as in Composite Cross populations (CCPs). Apart from buffering against environmental fluctuations and providing insurance in stressful and risky environments, Hi-D-based approaches allow for evolutionary adaptation to organic farming conditions. However, although Hi-D-based systems have shown promising results under organic management and are currently subject to intensive research , their benefits can at present not be exploited, due to agronomic, technical, and regulatory hurdles. These constraints of Hi-D breeding approaches are shared with and linked to organic plant breeding in general.