Using cytological techniques to uncover the introgression potential of constituent genomes into the economically important crop brassica juncea

Download Statistics

Downloads

Downloads per month over past year

Shamim, Zeeshan (2019). Using cytological techniques to uncover the introgression potential of constituent genomes into the economically important crop brassica juncea. University of Birmingham. Ph.D.

Preview

Shamim2019PhD.pdf
Text - Accepted Version
Available under License All rights reserved.
Download (2MB) | Preview

Abstract

Polyploid crops (containing more than one genome) have been included in our daily-life food since ages and are used as raw and processed products (wheat, coffee, banana, cotton etc.). Owing to a range of options for meiotic pairing, allopolyploids have evolved a strictly regulated mechanism which inhibits intergenomic pairing and enhances intragenomic interactions equally. Brassica is one of the multigenomic genera where diploid and polyploid are linked to each other in the well-known U’s triangle which presents a rich source for genetic exploitation.
Meiosis holds the key in sustaining the ploidy intact during reproduction and it produces novel allelic combinations through its conserved mechanisms. To address the requirement for food because of an ever-increasing population, attempts are underway to understand the genetic basis of this system in order to explore and manipulate the unlocked genetic potential in crops.
Using the molecular cytogenetic tools developed for A. thaliana, I have been able to develop a partial karyotype of one of the research-neglected species in Brassica, i.e., Brassica nigra. The Genome In Situ Hybridization (GISH) technique performed has enabled me to trace the constituent genomes in a complex polyploid background. The recombination frequencies and their pattern in diploid were quite different from those in the allopolyploid species. For example, this has revealed the contrasting feature in the polyploid with crossovers (COs) localised at the termini of the chromosomes as compared to a non-terminal distribution in B. nigra. In addition, I have also been able to study heterologue (homoeologue) pairing between distinct genomes in a hybrid allodiploid plant (AB).

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):