Screening of clubroot-resistant varieties and transfer of clubroot resistance genes to <i>Brassica napus</i> using distant hybridization

Abstract

Clubroot is an economically important disease affecting plants in the family Cruciferae worldwide. In this study, a collection of 50 Cruciferae accessions was screened using Plasmodiophora brassicae pathotype 4 in China. Eight of these demonstrated resistance, including three Chinese cabbages, two cabbages, one radish, one kale, and one Brassica juncea. The three clubroot-resistant Chinese cabbages (1003, 1007 and 1008) were then used to transfer the clubroot resistance genes to B. napus by distant hybridization combined with embryo rescue. Three methods including morphological identification, cytology identification, and molecular marker-assisted selection were used to determine hybrid authenticity, and 0, 2, and 4 false hybrids were identified by these three methods, respectively. In total, 297 true hybrids were identified. Clubroot resistance markers and artificial inoculation were utilized to determine the source of clubroot resistance in the true hybrids. As a result, two simple sequence repeat (SSR) and two intron polymorphic (IP) markers linked to clubroot resistance genes were identified, the clubroot resistance genes of 1007 and 1008 were mapped to A03. At last, 159 clubroot-resistant hybrids were obtained by clubroot resistance markers and artificial inoculation. These intermediate varieties will be used as the ‘bridge material’ of clubroot resistance for further B. napus breeding.

A Modified Meiotic Recombination in Brassica napus Largely Improves Its Breeding Efficiency

“…The frequent use of B. rapa in Asian B. napus breeding programs may partially explain why Asian oilseed rape varieties appear as a specific group of oilseed rape varieties and why it is still possible to detect B. rapa introgression in this material [71]. Similarly, direct crosses between B. napus and B. rapa have been performed to introduce in B. napus major resistance genes to clubroot [72] or blackleg [73].…”

Multi-omics-based prediction of hybrid performance in canola

“…These varieties perform better than open-pollinated varieties, especially under stressful environmental conditions. Hybrid oilseed rape plants can be sown later, due to their early vigour, show higher disease resistance, and have increased vitality and compensation ability, securing high, stable and consistent yields (Qian et al 2007 ; Zhang et al 2017 ; Liu et al 2018c ). A very important element in implementing hybrid breeding is the recognition of a heterotic pattern that supports high-yielding lines (Zhao et al 2015 ).…”

An update on the arsenal: mining resistance genes for disease management of Brassica crops in the genomic era

“…The closely linked markers and resistance genes have been widely used in Brassica CR resistance breeding, generating a series of resistant cultivars that successfully control CR in many areas. For example, considering that high resistance is found mostly in B. rapa, researchers have frequently applied interspecies crossing to facilitate R gene transfer combined with MAS and phenotype evaluation 165,166 .…”