Improving plant breeding with exotic genetic libraries


Naturally occurring variation among wild relatives of cultivated crops is an under-exploited resource in plant breeding. Here, I argue that exotic libraries, which consist of marker-defined genomic regions taken from wild species and introgressed onto the background of elite crop lines, provide plant breeders with an important opportunity to improve the agricultural performance of modern crop varieties. These libraries can also act as reagents for the discovery and characterization of genes that underlie traits of agricultural value.

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Figure 1: The central dogma of plant breeding.
Figure 2: Wild, hybrid and cultivated watermelons.
Figure 3: The Lycopersicon pennellii library.


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I thank E. Fridman, Y. Eshed and S. Abbo for helpful discussions. This work was supported by the United States–Israel Binational Research and Development Fund (BARD).

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Maize Database 



C. M. Rick Tomato Genetics Resource Center (TGRC)

Consultative group on international agricultural research

Encyclopedia of Life Sciences: Plant breeding and crop improvement

L. pennellii tomato introgression lines

Maize genome database

Map of L. pennellii introgression lines

Rice genome research program

The Solanaceae Genome Network



A sample of plant material that is collected at a specific location and maintained in a seed bank.


A variety that excels under conditions of modern intensive agriculture.


An interaction between non-allelic genes, such that one gene masks, interferes with or enhances the expression of the other gene.


Hybrid vigour that leads to superior crop varieties.


The incorporation of selected traits from an unadapted exotic resource through a succession of crosses (backcrosses) to a commercially elite variety.


A locally adapted, cultivated variety that is selected by farmers.


The collapse of top-heavy plants, particularly grain crops.


The accumulation of several independent traits in the same genotype through introgression breeding.


(QTL). Genetic loci that are identified through the statistical analysis of complex traits (such as plant height or body weight). Quantitative traits are typically affected by more than one gene and by the environment.

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Zamir, D. Improving plant breeding with exotic genetic libraries. Nat Rev Genet 2, 983–989 (2001).

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