Abstract

Clubroot disease caused by Plasmodiophora brassicae Woronin is one of the most devastating diseases of canola (Brassica napus L.). Pathotype 3H has been the most prevalent and virulent pathotype in western Canada. Many resistant cultivars have been developed in Canada in recent years. However, large-scale cultivation of these cultivars resulted in the identification of several new virulent pathotypes including 3A and 5X that overcame this resistance. We studied two doubled haploid (DH) populations, developed by crossing a canola line carrying resistance to 3H, 3A, and 5X to two canola lines carrying resistance to 3H, for resistance to these three pathotypes. Furthermore, two clubroot-resistant populations derived from the first and second cycles of breeding were also investigated for resistance to 10 pathotypes to understand their inheritance. A 3R:1S segregation for resistance to 3H confirmed the involvement of two independent major gene loci in these DH populations. In contrast, a 1R:7S and 1R:15S segregation, respectively, for resistance to 3A and 5X indicated that more than two gene loci are involved in the control of resistance to these pathotypes. A significant positive correlation for resistance to 3A and 5X indicated that some common genes are involved in the control of resistance to both pathotypes. About 4% of the DH lines were resistant to all three pathotypes, suggesting that pyramiding of multiple resistance genes in canola is possible. Overall, the resistance observed in the population derived from the first cycle of breeding remained effective in the population derived from the second cycle of breeding.

摘要

芸苔疟原虫引起的马蹄根病沃罗宁是油菜中最具破坏性的疾病之一（甘蓝型油菜）L.）。3H型是加拿大西部最流行和最致命的型。近年来，加拿大已开发出许多抗性品种。然而，这些品种的大规模栽培导致鉴定了克服这种抗性的几种新的毒力型，包括3A和5X。我们研究了通过将对3H，3A和5X具有抗性的双低油菜谱系与对3H具有抗性的两株双低油菜谱系交叉发育而形成的两个双倍单倍体（DH）种群。此外，还研究了从第一和第二个繁殖周期衍生的两个具根茎抗性的种群对10种病态型的抗性，以了解它们的遗传。对3H抗性的3R：1S分离证实了这些DH群体中两个独立的主要基因位点的参与。相反，分别针对3A和5X的抗性进行1R：7S和1R：15S分离表明，有两个以上的基因位点参与了对这些致病型的抗性控制。对3A和5X的抗性显着正相关，表明某些常见基因参与了对两种病态型的抗性控制。大约4％的DH品系对所有这三种病态型均具有抗性，这表明双低油菜籽中多个抗性基因的金字塔化是可能的。总体而言，在第一个育种周期的种群中观察到的抗性在第二个育种周期的种群中仍然有效。对3A和5X的抗性显着正相关，表明某些常见基因参与了对两种病态型的抗性控制。大约4％的DH品系对所有这三种病态型均具有抗性，这表明双低油菜籽中多个抗性基因的金字塔化是可能的。总体而言，在第一个育种周期的种群中观察到的抗性在第二个育种周期的种群中仍然有效。对3A和5X的抗性显着正相关，表明某些常见基因参与了对两种病态型的抗性控制。大约4％的DH品系对所有这三种病态型均具有抗性，这表明双低油菜籽中多个抗性基因的金字塔化是可能的。总体而言，在第一个育种周期的种群中观察到的抗性在第二个育种周期的种群中仍然有效。