‘Single-Seed-SpeedBulks:’ a protocol that combines ‘speed breeding’ with a cost-efficient modified single-seed descent method for rapid-generation-advancement in oat (Avena sativa L.)

Abstract

Abstract Background In plant breeding, one of the most cost-effective and efficient ways to increase genetic gain is to reduce the breeding cycle time. In general, modern breeding methods for self-pollinated crops should strive to develop fixed lines at the lowest possible cost and in the minimum possible amount of time. Previous studies on spring oat (Avena sativa L.) showed that combining high plant density with limited soil fertility and moisture levels in a media like sand effectively decreases the time and cost of generating fixed single-seed descent lines. More recently, ‘speed breeding’, or the exposure of prolonged photoperiod regimes of 22 hours, has been shown to decrease flowering time in oat significantly. The goal of this study was to combine ‘speed breeding’ with high-density planting in a limited soil fertility media to reduce further the costs and time required to develop oat single-seed-descent lines. Results We grew oat plants at low density in potting-mix (control), high density in potting-mix (HD-soil), and high density in sand (HD-sand) under 16 and 22 hours of day length. We observed that oat plants grown in HD-sand and exposed to 22 hours day length reduced their flowering time by around 20 and 5 days on average compared to those grown in control conditions at 16 and 22 hours, respectively. We also observed that 85% of plants grown at high density in sandproduced a single seed when grown in bulk conditions. In contrast, only 40% of plants grown at high density in potting-mix produced a single seed. Conclusions Our novel protocol showed that oat plants grown in high-density bulks, using sand media and 22-hour day length reduced their flowering time by 20 days compared to control conditions and produced plants with single seeds, following closely single-seed descent assumptions while significantly reducing labor costs and greenhouse space. This methodology can be deployed in oat breeding programs to help them accelerate their rate of genetic grain for multiple traits.