Effect of climate on the seed dormancy state of Amaranthus retroflexus L.

DMaternal environment, beside genetic and developmental characters of a plant, has a significant influence over seed dormancy and germination. The impact of environmental conditions on seedling emergence, phenology, seed dormancy and germination was investigated in Amaranthus retroflexus L., an invasive weed species in agricultural fields in Turkey. Mature seeds were collected from naturally occuring 8 populations, originating from the localities where the annual temperature ranges between 9.3-20.6 °C. The production of F1 progeny were conducted in 2016-2017 under natural conditions at Kütahya. Seeds were buried in the soil at November 2016 and the experimental design was arranged as randomized complete block. Seedling emergence and plant development were recorded, and at harvest the dry weight of vegetative and reproductive tissues were determined. Dormancy and germination potential of mother and F1 seeds were tested on H2O and GA at 25 and 35 °C. Seedling emergence in the field started over a cold season in the first week of April and reached maximum at the end of May. Seedling emergence rate differed among populations and this was related with the initial dormancy status of these seed populations, regardless of the environment in which they were buried. Populations with higher seedling emergence showed higher germination and shorter time to reach 50% germination in laboratuvary experiment. Populations also showed phenotypic plasticity in morphological characters. F1 seeds, like mothers, showed similar response to temperature in the light although they were more dormant than the mothers. Results show that the seed behaviour of these populations is related to the environment to which they were adapted. Considering the wide genetic diversity of weed species, A. retroflexus may well adapt more rapidly to climate change than the crop species with narrow genetic diversity with which it competes. This has potentialy serious economic consequences for crop production in Turkey. aha sonra doldurulacaktır.