Intra- and Interspecific Incompatibility in Brachiaria ruziziensis Germain et Evrard (Panicoideae)
An introgression program aiming at transfering apomixis from tetraploid species Brachiaria decumbens (B.d) and Brachiaria brizantha (B.b) into the genome of the sexuate diploid Brachiaria ruziziensis (B.r), an interesting forage crop, started in our laboratory (Gobbe and al., 1983). Its first step was the obtention of autotetraploid plants of B.r. The second step was to cross them with the apomictic tetraploid species. As self-seed-set is generally very low in B.r, about 1–7 % in both diploids and tetraploids, these interspecific crosses were not preceded by emasculation (a very uneasy operation in Brachiaria). A few seeds were obtained, but most of these were self-seeds (Ndikumana, 1985). To investigate the reason of this and to localize precisely the interspecific barrier in Brachiaria, self-incompatibility and interspecific incompatibility in the progamic phase were studied and compared. For this purpose, we observed pollentube growth after self- and cross-intraspecific pollinations and interspecific pollinations of emasculated flowers of diploid and tetraploid B.r.
KeywordsPollen Tube Pollen Tube Growth Pollen Germination Callose Plug Interspecific Pollination
Unable to display preview. Download preview PDF.
- Gobbe J, Longly B, Louant B-P (1983) Apomixie, sexualite et amelioration des graminees tropicales. Tropicultura 1(1): 5–9.Google Scholar
- Heslop-Harrison J, Heslop-Harrison Y (1982) The pollen-stigma interaction in the grasses. 4. An interpretation of the self-incompatibility response. Acta Bot Neerl 31(5/6): 429–439.Google Scholar
- Heslop-Harrison Y, Reger BJ, Heslop-Harrison J (1984) The pollenstigma interaction in the grasses. 6. The stigma (’silk’) of Zea mays L. as host to the pollens of Sorghum bicolor (L.) Moench and Pennisetum americanum (L.) Leeke. Acta Bot Neerl 33(2): 205–227.Google Scholar
- Ndikumana J (1985) Transfert du caractère “Reproduction apomictique” d’une esp~ce apomictique, naturellement tétraploïde, a une espèce sexuée, nature11ement diploïde, dans le genre Brachiaria. Doctorate thesis, Universite Catho1ique de Louvain.Google Scholar
- Shivanna KR, Heslop-Harrison Y, Heslop-Harrison J (1982) The pollen-stigma interaction in the grasses. 3. Features of the self-incompatibility response. Acta Bot Neerl 31: 307–319.Google Scholar
- Thomas SM, Murray BG (1975) A new site for the self-incompatibility reaction in the Gramineae. Incomp Newslett 6: 22–23.Google Scholar
- Wilms HJ (1974) Branching of pollen tubes in Spinach. In: Linskens HF (ed) Fertilization in Higher Plants. North Holland, American Elsevier. pp 155–160.Google Scholar