Flowering Time Studies in Canadian Cultivars and 5-Azacytidine Mutants of Oilseed Flax (Linum usitatissimum L.)

• Other Authors: Booker, Helen
• Language: English
• Published: 2015
• Subjects: Flax flowering time; early flowering; 5-azacytidine mutants; photoperiod sensitivity
• Online Access: http://hdl.handle.net/10388/ETD-2015-01-1985

Canada is a global leader in flax production, but flax acreage in Canada remains limited since flax is not well adapted to the northern Prairies. Therefore, breeding early-flowering and early maturing flax cultivars that are adapted to the climate of the northern Prairies is one of the major strategies to expand flax acreage in Canada. The objective of this project is to understand flowering time in flax and generate early flowering genotypes that are adapted to the continental climate of the Canadian Prairies. This project examined photoperiod sensitivity in five Canadian flax cultivars (CDC Sorrel, CDC Bethune, Flanders, Prairie Thunder and Royal) and three M9 genotypes derived from 5-azacytidine (5-azaC) treatment (RE1, RE2 and RE3). To investigate how each cultivar or genotype responds to photoperiod changes, a reciprocal transfer experiment between long day and short day conditions was conducted. All cultivars and genotypes were photoperiod sensitive. However, the level of sensitivity and length of the sensitive phase varied among cultivars and genotypes. The five cultivars were more sensitive to photoperiod changes compared with the three mutant genotypes, while RE2, which was the earliest flowering genotype, was the least sensitive genotype. This project, in addition, examined the expression pattern of ELF4 (EARLY FLOWERING 4), a specific flowering-related gene. This experiment was conducted with three Canadian flax cultivars (CDC Sorrel, CDC Bethune and Royal) and one 5-azaC mutant genotype (RE2). GAPDH (Glyceraldehyde 3-phosphate dehydrogenase) was used as a reference gene in RT-qPCR. Results of RT-qPCR demonstrated that CDC Sorrel and CDC Bethune had a similar expression pattern, while Royal and RE2 had a similar expression pattern. This project also sought to generate early-flowering genotypes by treating CDC Sorrel with 5-azaC as well as to introgress the early-flowering trait from RE genotypes into CDC Sorrel via hybridization. Mutant populations (M2, M3, bulk M3) and hybrid populations (F2, F3, and bulk F3) were grown and evaluated for time to flowering, maturity and height under latitude (53° N) field conditions in 2012 and 2013. 5-azaC treatment did not induce significant differences in flowering or maturity in the CDC Sorrel background. However, the early flowering trait was successfully introgressed into CDC Sorrel background since selected progeny lines flowered significantly earlier than the later flowering CDC Sorrel parental line.