School of Plant Biology

Annaliese Mason (2011)

Thesis

Meiotic behaviour and chromosome inheritance in interspecific hybrids of allotetraploid Brassica species

Summary

I am investigating abnormal meiosis and the production of unreduced (2n) gametes in Brassica multi-genome hybrids, and am attempting to answer a number of questions, including these two below.

1. Are unreduced gametes (pollen and ovules with the somatic chromosome number) produced at higher frequencies as a response to the genome stress of interspecific hybridisation?

2. How does plant genotype and environment influence production of unreduced gametes and meiotic control of chromosome pairing?

I plan to use tetrad counts (unreduced gametes will be represented as dyads at this stage of development), pollen grain size and microspore flow cytometry to estimate frequencies of unreduced gamete production in the hybrids and natural parent species.

I am also trying to create stable, three-genome Brassica hybrids through two generations of hand-crossing, relying on production of unreduced gametes by the first-generation hybrids.

Why my research is important

Production of unreduced gametes is thought to be the primary driving force behind the high frequencies of polyploid species in the angiosperms, with implications for evolutionary diversification.

In addition, unreduced gametes have previously been utilised to create new polyploid crops, and the development of a new hexaploid Brassica crop may be an outcome of understanding control of this process.

Funding

• I am in receipt of an Australian Postgraduate Award (Industry), funded by the Australian Research Council Linkage Project LP0667805, with industry partners COGGO (Council of Grain Grower Organisations Ltd.) and NPZ (Norddeutsche Planfanzenzucht Hans-Georg Lembke Kg).