Precocious floral initiation and identification of exact timing of embryo physiological maturity facilitate germination of immature seeds to truncate the lifecycle of pea

Abstract

We propose herein a novel single seed descent protocol that has application across a broad phenotypic range of pea genotypes. Manipulation of key in vivo growing conditions, including light, photoperiod and temperature, combined with precocious in vitro germination of the embryo at full physiological maturity substantially shortened the pea lifecycle. We define full embryo physiological maturity as the earliest point in seed development when precocious in vitro germination and robust seedling growth can be reliably achieved without supply of exogenous hormones. Under our optimised conditions for accelerated plant growth, embryo physiological maturity was attained at c. 18 days after pollination, when seed moisture content was below 60 % and sucrose level under 100 mg g−1 DW. No delay penalty in terms of time to flowering and plant development was caused by the culture of immature seeds 18 days after pollination compared to the used of mature ones. Determining the role embryo maturity plays in the fitness of the germinated plant has facilitated the truncation of the lifecycle across pea genotypes. The accelerated single seed descent system proposed within this research will benefit complex genetic studies via the rapid development of recombinant inbred lines (RIL) and multi-parental advanced generation intercrosses (MAGIC) populations.