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Synthesis of hybrid cultivars of ryegrass (Lolium) and white clover (Trifolium repens) incorporating research on cytoplasmic male sterelity, self in compatibility, in vitro fertilisation and DNA restriction analyses

Objective

To establish a reliable methodology for the production of hybrid varieties in ryegrass (Lolium perenne) and white clover (Trifolium repens) by applying cytoplasmic male sterility and self-incompatibility respectively.

To investigate the nature of mtDNA in male fertile and male sterile stock and study the origin of this induced male sterility by molecular techniques.

To investigate the use of in-vitro pollination and seed set as a means of by-passing the self-incompatibility mechanism of white clover and also to determine if in-vitro methods could be used effectively to produce intergeneric crosses between T. repens and other forage legumes.
A study was made of the synthesis of hybrid cultivars of ryegrass (Lolium perenne) and white clover (Trifolium repens). In ryegrass the hybrid methodology is based on cytoplasmic male sterility. Some 14 maintainer lines have been produced from over 1000 genotypes and the programme is prepared to move forward with reciprocal crosses using nuclear gene restoration. In white clover a wide range of partially inbred lines homozygous for the self incompatibility locus have been obtained and test crossed. In vitro procedures for improved self pollination and seed set were developed; these methods can also be applied to interspecific hybridization. Methods for direct ovarian pollination of ovules were also developed.

The methods give promise for successful application is breeding programmes of ryegrass and white clover. Their applicability to other crops deserves increased attention.
- Glasshouse : Pair crossing, screening of progenies, reciprocal test crosses, pollen staining.
- Field : Field plot evaluation and progeny testing, isolation of breeding populations.
- Lab : Pollen examination, fluorescent microscopy, tissue culture, in-vitro pollination. DNA extraction, purification and analysis of restriction enzyme products.

Coordinator

AN FORAS TALUNTAIS
Address
19, Sandymount Avenue
4 Dublin
Ireland