Phenotypic Differences Among and Within Extant Populations of Chrysanthemum Arcticum L. and C. a. Subsp. Arcticum

Abstract

Background. Chrysanthemum arcticum, Arctic daisy and its two subspecies (C. arcticum subsp. arcticum, C. arcticum subsp. polaré) are the only chrysanthemum species native to North America. A study on species’ variation in morphological and diagnostic traits is important to link morphological traits with previously described single nucleotide polymorphism (SNP) markers, particularly when the genomes are sequenced. The purpose of this study was to establish phenotypic differences and soil conditions among wild C. arcticum and C. a. subsp. arcticum populations, when grown in a uniform environment, for potential linkages with our SNP library. Sixteen quantitative morphological traits and five qualitative morphological traits were investigated for 255 individuals from nine C. arcticum populations and 326 individuals from 21 C. a. subsp. arcticum populations.Results. While 100% of the C. a. subsp. arcticum individuals flowered under long days, 0% of the C. arcticum individuals flowered in 2018 while only 2.7% flowered in 2019. Two distinct clusters, distributed by taxonomic classification, were detected by Principal component analysis (PCoA) for 551 individuals from C. arcticum and C. a. subsp. arcticum. Pearson’s correlation coefficient analysis indicated a positive and significant correlation between plant height, flower fresh and dry weights. Flower fresh weights were correlated with Δflower weight, while inflorescence length had showed a negative correlation with leaf number. Soil samples had high Na levels along with heavy metals. Thus, the species are salt-tolerant.Conclusion. A high level of salt tolerance (Na) is tolerated by these maritime species which is a unique trait in Chrysanthemum. A new diagnostic trait of inflorescence length was discovered to distinguish among C. arcticum and C. a. subsp. arcticum. Significant flowering differences occurred among the species wherein C. a. subsp. arcticum had 100% flowering in long days whereas C. arcticum had 0% to 3.1%. The mean number of weeks to visible bud date in C. a. subsp. arcticum is the fastest (2.2 wks.) ever reported in Chrysanthemum, in contrast with C. arcticum which is the longest (65.3-69.4 wks.). This study on the species’ variation in morphological and diagnostic traits is of importance to link morphological traits with single nucleotide polymorphism (SNP) markers.

De novowhole-genome assembly ofChrysanthemum makinoi, a key wild chrysanthemum

“…The Chrysanthemum genus consists of species with a basic number of nine chromosomes but with variable ploidy level, from diploid to decaploid ( Wang et al 2014 ). Native across Eurasia and the northern parts of North America, the genus consists of 40 different species ( Liu et al 2012 ; Liu 2020 ). More than 10 were originally identified as a potential source material for the domesticated C. morifolium Ramat.…”

De novo whole-genome assembly ofChrysanthemum makinoi, a key wild ancestor to hexaploid Chrysanthemum

“…It is The copyright holder for this preprint this version posted July 10, 2021. ; https://doi.org/10.1101/2021.07.09.451814 doi: bioRxiv preprint diploid to decaploid (Wang et al 2014). Native across Eurasia and the northern parts of North America, the genus consists of 40 different species (Liu et al 2012;Liu 2020). More than ten were originally identified as potential source material for the domesticated C. x morifolium (Dowrick 1952;Ackerson 1967), including C. makinoi (syn.…”