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Evaluation of reproductive barriers contributes to the development of novel interspecific hybrids in the Kalanchoë genus.

Kuligowska K, Lütken H, Christensen B, Skovgaard I, Linde M, Winkelmann T, Müller R - BMC Plant Biol. (2015)

Bottom Line: Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis of hybridization partners with cross-compatibility of Kalanchoë species.At the same time, differences in ploidy did not influence the success of interspecific crosses.This new knowledge will contribute to further understanding of reproductive isolation of Kalanchoë species and facilitate breeding of new cultivars.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegård Allé 9-13, DK-2630, Taastrup, Denmark. kku@plen.ku.dk.

ABSTRACT

Background: Interspecific hybridization is a useful tool in ornamental breeding to increase genetic variability and introduce new valuable traits into existing cultivars. The successful formation of interspecific hybrids is frequently limited by the presence of pre- and post-fertilization barriers. In the present study, we investigated the nature of hybridization barriers occurring in crosses between Kalanchoë species and evaluated possibilities of obtaining interspecific hybrids.

Results: The qualitative and quantitative analyses of pollen tube growth in situ were performed following intra- and interspecific pollinations. They revealed occurrence of pre-fertilization barriers associated with inhibition of pollen germination on the stigma and abnormal growth of pollen tubes. Unilateral incongruity related to differences in pistil length was also observed. The pollen quality was identified as a strong factor influencing the number of pollen tubes germinating in the stigma. In relation to post-fertilization barriers, endosperm degeneration was a probable barrier hampering production of interspecific hybrids. Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis of hybridization partners with cross-compatibility of Kalanchoë species. At the same time, differences in ploidy did not influence the success of interspecific crosses.

Conclusions: Our study presents the first comprehensive analysis of hybridization barriers occurring within Kalanchoë genus. Reproductive barriers were detected on both, pre- and post-fertilization levels. This new knowledge will contribute to further understanding of reproductive isolation of Kalanchoë species and facilitate breeding of new cultivars. For the first time, interspecific hybrids between K. nyikae as maternal plant and K. blossfeldiana as well as K. blossfeldiana and K. marnieriana were generated.

No MeSH data available.


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Comparison of pollen tube numbers following interspecific crosses ofK. blossfeldianacultivars and self-pollinations. (A, B, C) Number of pollen tubes after pollinations of two K. blossfeldiana cultivars with pollen of different Kalanchoë species and self-pollinations of paternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same maternal genotype according to t-test. (D, E, F) Number of pollen tubes after pollinations of Kalanchoë species with two K. blossfeldiana cultivars and self-pollinations of maternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same paternal genotype according to t test. The analyses were performed 48 h after pollination.
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Fig4: Comparison of pollen tube numbers following interspecific crosses ofK. blossfeldianacultivars and self-pollinations. (A, B, C) Number of pollen tubes after pollinations of two K. blossfeldiana cultivars with pollen of different Kalanchoë species and self-pollinations of paternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same maternal genotype according to t-test. (D, E, F) Number of pollen tubes after pollinations of Kalanchoë species with two K. blossfeldiana cultivars and self-pollinations of maternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same paternal genotype according to t test. The analyses were performed 48 h after pollination.

Mentions: The analysis of the numbers of pollen tubes presented similar patterns for 24 h and 48 h. Only in self-pollinations of K. pubescens a significant increase in the number of pollen tubes was detected in the ovaries 48 h after pollination compared with 24 h (Additional file 2, Figure 4).Figure 4


Evaluation of reproductive barriers contributes to the development of novel interspecific hybrids in the Kalanchoë genus.

Kuligowska K, Lütken H, Christensen B, Skovgaard I, Linde M, Winkelmann T, Müller R - BMC Plant Biol. (2015)

Comparison of pollen tube numbers following interspecific crosses ofK. blossfeldianacultivars and self-pollinations. (A, B, C) Number of pollen tubes after pollinations of two K. blossfeldiana cultivars with pollen of different Kalanchoë species and self-pollinations of paternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same maternal genotype according to t-test. (D, E, F) Number of pollen tubes after pollinations of Kalanchoë species with two K. blossfeldiana cultivars and self-pollinations of maternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same paternal genotype according to t test. The analyses were performed 48 h after pollination.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4352236&req=5

Fig4: Comparison of pollen tube numbers following interspecific crosses ofK. blossfeldianacultivars and self-pollinations. (A, B, C) Number of pollen tubes after pollinations of two K. blossfeldiana cultivars with pollen of different Kalanchoë species and self-pollinations of paternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same maternal genotype according to t-test. (D, E, F) Number of pollen tubes after pollinations of Kalanchoë species with two K. blossfeldiana cultivars and self-pollinations of maternal plants as controls observed on stigma, in the style and ovary. Values presented are means (±S.E.), n = 10. Values followed by different letters are significantly different (P ≤0.05) within the same paternal genotype according to t test. The analyses were performed 48 h after pollination.
Mentions: The analysis of the numbers of pollen tubes presented similar patterns for 24 h and 48 h. Only in self-pollinations of K. pubescens a significant increase in the number of pollen tubes was detected in the ovaries 48 h after pollination compared with 24 h (Additional file 2, Figure 4).Figure 4

Bottom Line: Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis of hybridization partners with cross-compatibility of Kalanchoë species.At the same time, differences in ploidy did not influence the success of interspecific crosses.This new knowledge will contribute to further understanding of reproductive isolation of Kalanchoë species and facilitate breeding of new cultivars.

View Article: PubMed Central - PubMed

Affiliation: Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Højbakkegård Allé 9-13, DK-2630, Taastrup, Denmark. kku@plen.ku.dk.

ABSTRACT

Background: Interspecific hybridization is a useful tool in ornamental breeding to increase genetic variability and introduce new valuable traits into existing cultivars. The successful formation of interspecific hybrids is frequently limited by the presence of pre- and post-fertilization barriers. In the present study, we investigated the nature of hybridization barriers occurring in crosses between Kalanchoë species and evaluated possibilities of obtaining interspecific hybrids.

Results: The qualitative and quantitative analyses of pollen tube growth in situ were performed following intra- and interspecific pollinations. They revealed occurrence of pre-fertilization barriers associated with inhibition of pollen germination on the stigma and abnormal growth of pollen tubes. Unilateral incongruity related to differences in pistil length was also observed. The pollen quality was identified as a strong factor influencing the number of pollen tubes germinating in the stigma. In relation to post-fertilization barriers, endosperm degeneration was a probable barrier hampering production of interspecific hybrids. Moreover, our results demonstrate the relation of genetic distance estimated by AFLP marker analysis of hybridization partners with cross-compatibility of Kalanchoë species. At the same time, differences in ploidy did not influence the success of interspecific crosses.

Conclusions: Our study presents the first comprehensive analysis of hybridization barriers occurring within Kalanchoë genus. Reproductive barriers were detected on both, pre- and post-fertilization levels. This new knowledge will contribute to further understanding of reproductive isolation of Kalanchoë species and facilitate breeding of new cultivars. For the first time, interspecific hybrids between K. nyikae as maternal plant and K. blossfeldiana as well as K. blossfeldiana and K. marnieriana were generated.

No MeSH data available.


Related in: MedlinePlus