Precocious floral initiation and identification of exact timing of embryo physiological maturity facilitate germination of immature seeds to truncate the lifecycle of pea
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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.
KeywordsEarly floral onset Embryo physiological maturity Pisum sativum L. Precocious seed germination Seed moisture content Seed sucrose content
This work was supported by the Grains Research and Development Corporation [UWA00159]. We thank Mr. R. Creasy, Mr B. Piasini and Mr. L. Hodgson for glasshouse expertise and Dr Tony Leonforte (pea breeder, Pulse Breeding Australia) for assisting in germplasm selection and seed supply.
- Cummings IG, Reid JB, Koutoulis A (2007) Red to far-red ratio correction in plant growth chambers—growth responses and influence of thermal load on garden pea. Physiol Plantarum 131:171–179Google Scholar
- Ellis RH, Hong TD, Roberts EH (1987) The development of desiccation-tolerance and maximum seed quality during seed maturation in six grain legumes. Ann Bot 59:23–29Google Scholar
- Goulden CH (1939) Problems in plant selection. In: Burnett RC (ed) Proceeding of the Seventh Genetic Congress. Cambridge University Press, England, pp 132–133Google Scholar
- Redden B, Leonforte T, Ford R, Croser J, Slattery J (2005) Pea (Pisum sativum L.). In: Singh RJ, Jauhar PP (eds) Genetic resources, chromosome engineering, and crop improvement, vol 1. Taylor & Francis, Boca Raton, pp 49–83Google Scholar
- Runkle ES, Heins RD (2001) Specific functions of red, far red, and blue light in flowering and stem extension of long-day plants. J Amer Soc Hort Sci 126:275–282Google Scholar
- Summerfield RJ, Roberts EH, Erskine W, Ellis RH (1985) Effects of temperature and photoperiod on flowering in lentils (Lens culinaris Medic.) Ann Bot 56:659–671Google Scholar
- Vince-Prue D (1981) Daylight and photoperiodism. In: Smith H (ed) Plants and the daylight spectrum. Academic Press Inc., London, pp 223–242Google Scholar