Environmental and genetic influences on phenology and plant size in a perennial herb, Senecio integrifolius

Abstract

Individual plants of the perennial herb Senecio integrifolius showed a highly significant correlation between rank order of the dates of first flowering and of first fruiting in a natural population and in cultivation. Plants exposed to full sunshine were smaller and flowered earlier than shaded plants both in a natural population and in cultivation. Within the two groups, plants with large inflorescences started to flower first. Duration of flowering was regulated by the size of the inflorescence; plants with many heads flowered longer than plants with few heads. There was a significant correlation between phenological rank order of mother plants in natural populations and their progenies in cultivation, but no consistent relationship between mother size and progeny size was found. Cultivated plants were consistent in rank order of flowering and in size over the years. Key words: flowering phenology, plant size, genetic variation, Senecio.