Investigation into natural variation and adaptation of arabidopsis thaliana in Edinburgh and the Lothians

The use of Arabidopsis thaliana populations to understand the genetic basis for natural variation has been highlighted in recent years. The role of adaptation in natural variation remains of key interest. Here, natural variation in growth rate, flowering time and seed production were examined in local populations of A. thaliana from the Edinburgh area using a common garden approach. Growth rate and seed production were found to be highly genetically determined and sometimes correlated, and some genotypes were found to perform consistently better as winter annuals and others as summer annuals, suggesting that adaptation to different seasons might maintain natural variation locally. In order to dissect the environmental factors that could affect growth, these genotypes were also grown under controlled conditions. Photoperiod and temperature were identified as two of the seasonal variables to which different genotypes may be adapted. The relationship between growth rate and competition was also examined. In general, competition exaggerated the differences in performance between genotypes, although the identity of neighbours was observed to have an effect on both growth rate and fitness of A. thaliana in competition. To understand the genetic basis of growth rate variation, the genetic relationships between local populations was examined. Local accessions were usually found to be more closely related to each other than to world-wide accessions, suggesting that their variation did not reflect recent immigration. To examine the genetic architecture of growth rate variation, hybrids between local genotypes with different growth rates were used in QTL analysis. Four chromosomal regions were detected; these regions represent potential growth-rate associated QTL