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United States Department of Agriculture

Agricultural Research Service

Title: A Genetic Study of Unilateral Incompatibility Between Diploid (1ebn) Mexican Species Solanum Pinnatisectum and S. Cardiophyllum Subsp Cardiophyllum

Authors
item Kuhl, Joseph - DEPT OF HORT UW MADISON
item Havey, Michael
item Hanneman Jr, Robert

Submitted to: Sexual Plant Reproduction
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 3, 2002
Publication Date: N/A

Interpretive Summary: Wild species possess many desirable traits, such as disease resistances, useful in the genetic improvement of cultivated plants. Crossing barriers exist between wild species and cultivated types, limiting the introduction of useful genetic traits. In the potato family, successful crosses often occur in only one direction; the reciprocal cross usually fails. This phenomenon is called unilateral incompatibility. We observed unilateral incompatibility in crosses between two wild potato species, Solanum pinnatisectum and S. cardiophyllum. Progenies were generated only when S. pinnatisectum was the male parent. We generated a backcross family and identified two independent putative genetic loci controlling unilateral incompatibility. Both putative loci were inherited independently of the S-locus, which controls self fertility within potato. However, segregations in the reciprocal backcross family did not agree with those observed in the first family. Segregation disparity between the two families may be due to unequal transfer of specific alleles or the presence of different mechanisms controlling pistil and pollen recognition systems in these two species. These results will be useful to potato breeders in order to understand incompatibilities among wild potato species and predict crossabilities in order to transfer benefical traits to the cultivated potato.

Technical Abstract: Many angiosperms have developed mechanisms to prevent self pollination and inbreeding. The most wide spread system of self incompatibility (SI) is gametophytic, where pollen tube growth is inhibited in the style by the action of a single locus (S-locus). Similar inhibition of pollen tube growth can also be observed in interspecific crosses, where successful pollinations occur in only one direction, termed unilateral incompatibility. We observed unilateral incompatibility in crosses between Solanum pinnatisectum and S. cardiophyllum and progenies were generated only when S. pinnatisectum was the staminate parent. Segregations in the BC1 family to S. cardiophyllum revealed two independent putative loci controlling unilateral incompatibility, with both putative loci inherited independently of the S-locus. However, segregation ratios in the second backcross family to S. pinnatisectum did not agree with those observed in the first family. Segregation disparity between the two families may be due to distorted transfer of specific alleles or the presence of different mechanisms controlling pistil and pollen recognition systems in these two species.

Last Modified: 9/2/2014
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