Reduction of saturated fats by mutagenesis and heat selection in Brassica napus L

Abstract

The reduction of saturated fats in canola oil has recently been promoted as a goal for breeders for commercial and human health benefits. Currently, saturated fatty acids in Canadian produced canola oil are above the 7% level, and the objective of this study was to generate canola lines with reduced major saturates (palmitic and stearic), by several percent. Mutant embryos generated from direct ultraviolet radiation mutagenesis of microspores in vitro were subjected to heat during the maturation stage. Heat artificially elevated the saturate levels in developing mutant embryos, allowing efficient identification of those with reduced saturates within the expanded range using HPLC fatty acid analysis of the embryo cotyledons. Mutagenesis produced embryos with fatty acids altered in both directions. Major saturate levels in the cotyledons of heat-treated mutant embryos ranged from 3.3 to 16.4% (heated control ca. 6-9%) and 1.3-10% (heated control ca. 2-4%) for palmitic and stearic fatty acids, respectively. Doubled haploid seed derived from embryos grown at normal temperatures confirmed the reduction of major saturates. HPLC fatty acid analysis of DH seed identified saturate levels ranging from 3.9 to 6.5% (control ca. 5.5%) and 0.9-2.7% (control ca.

Harnessing mutant donor plants for microspore culture in Indian mustard [Brassica juncea (L.) Czern and Coss]

“…Bars represent SE(m) Euphytica (2012) 184:207-222 219 similar to control genotypes agronomically, however, the FA profile for mutants was similar to the control genotypes. This is contrary to our report, however, FA profile modifications, similar to our report, have been reported by haploid mutagenesis in other Brassicas (Barro et al 2001;Beaith et al 2005;Velasco et al 1998). Low glucosinolate accumulation is unanimously considered to be a recessive quantitative trait controlled by the maternal genotype, with considerable environmental influence in Brassica species (Downey and Rimmer 1993;Agnihotri et al 2007).…”

Production of mutants with high cold tolerance in spring canola (Brassica napus)

“…Various economically important traits such as herbicide tolerance, enhanced quality and disease resistance have been achieved through induced microspore mutagenesis and chemical selection in B. napus (e.g. Swanson et al 1989;Kott et al 2002;Beaith et al 2005). This study produced many mutants without noticeable phenotypic changes, but with measurable enhanced cold tolerance.…”

“…An effective in vitro microspore culture, UV mutagenesis system, and chemical selection exists for the production of mutants of Brassica napus with improved quality and disease resistance traits (Kott 1995;Kott et al 2002;Beaith et al 2005). Haploid and doubled haploid tissues and plants express all traits, including native or induced mutations.…”

Application of doubled haploid technology in breeding of Brassica napus

“…Since this procedure preserved the embryo root/shoot axis, selected embryos were germinated and doubled, thus fi xing the selected genotype. Canadian canola breeders used mutagenesis and an in vitro heat selection system for development of DH lines with major saturates (palmitic and stearic) reduced by several per cent (Beaith et al, 2005). Mutant embryos generated from direct ultraviolet radiation mutagenesis of microspores in vitro were subjected to heat during the maturation stage.…”