Fixing heterosis in Canola using apomixis

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Apomixis is a naturally occurring form of asexual reproduction through seeds in plants which differs from sexual seed formation in three essential developmental events that are genetically controlled: (i) formation of a chromosomally unreduced egg cell (apomeiosis), (ii) parthenogenetic (without fertilization) embryonic development of this egg cell, and (iii) fertilization of the polar nuclei with male gametes to produce chromosomally balanced endosperm (pseudogamy)1. Together these events produce apomictic seeds with embryos that are genetic clones of the mother plant. Importantly, the development of this technology in crops would enable the permanent fixation of any heterozygous genotype, regardless of its genomic heredity and phenotypic complexity, in a single generation1. The multiple uses of apomixis in agriculture have long been recognized as important future steps for sustainability and food security, as it could (i) significantly shorten and lower risk in the costs and time required to produce new crop varieties, (ii) it would enable the fixation of complex multi-genic traits which cannot be bred using present technologies, and (iii) it would enable hybrid breeding and seed production in crops for which this does not exist (e.g. pulse crops and tubers)2. The estimated market improvement value of having apomixis introduced to rice alone would be $2.5 billion per year1. Despite its importance, apomixis has not yet been successfully introduced into crops, although it is under intense study in the global research community (e.g. Gates Foundation, Max Planck Society, etc.) as well as in industry. The long-term goal of my research program is to introduce apomixis into Canola (Brassica napus), one of Canada's most important crops. In this light, my lab studies the genus Boechera, a wild relative of Canola, and we have recently completed sequencing of a sexual and apomictic genome to the chromosome level, and have demonstrated in an ongoing backcrossing experiment that we can transfer apomixis to a sexual plant in a single generation. Importantly, we have a core apomixis gene candidate list (see below), and thus the short-term proposed objectives of my program are: (i) screening Arabidopsis mutant lines for these candidate apomixis genes, and (ii) multiplex manipulation of these candidate apomixis genes in Canola (and other Brassica crops). Over the last 15 years, my lab has trained a significant number of international HQPs, and in the present Discovery Grant Application new HQPs will be trained to transfer our latest discoveries to Canola, which would place Canada at the forefront of global crop plant research. The impact of utilizing apomixis in breeding programs would be enormous, as the fixation of traits demonstrating heterosis in a single generation would permit the rapid development of superior crop varieties adapted to changing environmental conditions, diverse farming niches and systems, and evolving markets.