Fertilisation increases plant biomass and seed production but does not influence seed heteromorphism in Aegilops

Aegilops species are important crop wild relatives (CWR) characterised by seed heteromorphism. Within each spikelet seeds differ in terms of size, colour, phenology, abiotic stress tolerance among others. although the seed heteromorphism in Aegilops has a genetic component, the level of plasticity of this character has been poorly investigated. To fill this gap, we measured the effect of fertilization on seed heteromorphism in nine Aegilops species, to understand if nutrient availability can affect the reproductive ecology in this important CWR genus. We measured the number of stems per plant, number spikelets per stem, total dry plant biomass, seed weight and germination percentage in fertilized and control (non-fertilized) plants. Fertilization did not affect heteromorphism but increased the biomass and the number of flowering stems (hence spikelets and seeds) in fertilized plants. However, seeds produced by fertilized plants showed significantly lower germination than control plants, in a sort of trade-off between seed quantity and seed quality.