Flowering plants exhibit a variety of different life cycles. This variation contributes in nature to adaptation to diverse environments and in agriculture to optimising crop yield. Annual monocarpic species flower once during their life, produce seeds and then undergo generalized senescence leading to death of the plant. By contrast polycarpic perennials survive seed production and live for many years flowering repeatedly. Most of our major crops are monocarpic annuals but perennials predominate in many ecological niches. Perennials exhibit phenotypic traits that would be advantageous for crops, such as an extended growing season, long duration of flowering and seed set as well as longer roots that more efficiently utilize nutrients and water supply. The high productivity of perennials explains their current use as sources of biomass. I propose here to use the progeny of hybrids between annual and perennial species in the Brassicaceae to isolate genes that confer key differences between these life histories. The utility of such genes in improving annual crops will then be tested. Arabis alpina and Arabis montbretiana are sister species that are respectively perennial and annual. We produced hybrids between these species and from them derived segregating populations by backcrossing. Here I propose to extensively genotype and phenotype these populations to identify genes promoting or suppressing senescence after flowering as well as those controlling the duration and extent of flowering. Orthologues of these genes will be identified in closely related Brassica species and alleles conferring perennial traits introduced into annual oil seed rape using genetic as well as transgenic strategies. Particularly those genes suppressing senescence and extending the duration of flowering will be tested for their effects on yield. This knowledge-based approach to introducing perennial traits into annual crops is expected to generate novel phenotypic variation that enhances yield.