Min-Chien (Coco) Tsai | ALES Graduate Seminar

Event details: A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Min-Chien (Coco) Tsai. This seminar is open to the general public to attend.

MSc with Dr. Habibur Rahman.

Thesis Topic: Introgression of clubroot resistance from B. oleracea into B. napus and study the inheritance of the resistance

Abstract:

Clubroot disease, caused by Plasmodiophora brassicae, is one of the most devastating threats to Brassica napus canola production worldwide. Growing clubroot-resistant cultivars is considered the most efficient way of managing this disease. All available clubroot-resistant canola cultivars carry resistance in their A-genome. Some of the qualitative resistances located in the A genome of canola became ineffective after growing only for a few years due to the evolution of new P. brassicae pathotypes. This highlighted the need of introducing the quantitative resistance from Brassica oleracea into the C genome of B. napus canola. The objective of this thesis research was to investigate the prospect of developing clubroot-resistant canola quality spring growth habit B. napus plants carrying resistance in the C genome through B. napus × B. oleracea interspecific cross. In addition to this, genetic analysis of clubroot resistance was carried out using canola lines from the canola breeding program to investigate the prospect of developing non-GM (non-genetically modified) clubroot resistant canola.

This thesis research demonstrated that clubroot resistant euploid B. napus (2n = 38) lines carrying resistance in the C genome can be achieved in advanced generation population of the B. napus × B. oleracea interspecific cross. Mapping of this resistance identified four QTL located on the C genome chromosomes C04 (two loci), C05 and C08. Agronomic and seed quality analysis of the population showed that clubroot resistant B. napus lines that flower a day earlier than the B. napus parent and contain low erucic acid in seed oil and low glucosinolate in seed meal can be achieved from this population. The average oil and protein contents of the advanced generation population was low; however, these traits can be improved through breeding.  Segregation for clubroot resistance in the F₂ and backcross (B₁ = F₁ × Resistant parent; B₂ = F₁ × Susceptible parent) populations derived from clubroot resistant × susceptible canola crosses showed that a major locus involved in the control of resistance in these populations. This simpler genetic control of clubroot resistance suggested that clubroot resistant non-GM canola lines can be developed from these populations without facing much difficulty. Thus, the results from this thesis research demonstrated the feasibility of the development of clubroot-resistant spring growth habit B. napus lines carrying clubroot resistance in the C genome, and disclosed the inheritance of clubroot resistance in three canola populations. The knowledge and materials developed from this thesis research can be used in breeding clubroot resistant canola germplasm/cultivars.