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Plastome-genome incompatibility (PGI) is prevalent in several plants including the Zantedeschia species, a worldwide commercial flower crop native to South Africa. Generally, hybrids suffering from PGI appear less vigorous and more susceptible than normal plants. Previous reports revealed that the PGI level in interspecific hybrids is correlated with the relatedness of the parental species in the genus Zantedeschia. To provide a basis for utilizing and improving resources in breeding programs, a total of 117 accessions of colored calla lily (Zantedeschia hybrid), collected from New Zealand, the Netherlands and the United States, were genotyped using 31 transferable expressed sequence tags-simple sequence repeats (EST-SSR) markers from the white calla lily (Zantedeschia aethiopica). A moderately high level of genetic diversity was observed, with 111 alleles in total, an observed/expected heterozygosity (Ho/He) of 0.453/0.478, and polymorphism information content (PIC) of 0.26. Genetic distance and STRUCTURE-based analysis further clustered all accessions into four subgroups (G-Ia, G-Ib, G-IIa and G-IIb), which mostly consisted of Zantedeschia pentlandii, Zantedeschia elliotiana, Zantedeschia albomaculata and Zantedeschia rehmannii, respectively. Significant genetic differentiation was observed between all inferred subgroup pairs, with the Fst ranging from 0.142 to 0.281. Finally, the accessions assigned into G-IIb (Z. rehmannii) were recommended as top priority parents in efficient Zantedeschia breeding program designs.

• Premise of the study: Microsatellite markers within regulators of heat stress transcription factors were identified in the Populus trichocarpa genome, and then developed for P. simonii to investigate the genetic diversity of germplasm resources and to further identify favorable alleles significantly associated with stress-resistant traits.• Methods and Results: Thirty-five novel microsatellite markers were identified from genes controlling heat stress transcription factors in P. simonii using a Sanger sequencing protocol. Polymorphisms in 48 individuals from 16 populations of P. simonii revealed that the number of alleles per locus ranged from two to nine with an average of 4.6; the observed heterozygosity and expected heterozygosity per locus varied from 0.143 to 0.857 and from 0.257 to 0.948, respectively.• Conclusions: The new polymorphic markers developed during this study will facilitate the construction of genetic linkage maps and will aid in marker-assisted breeding of a new germplasm with desirable abiotic stress resistance in Populus species.

UNLABELLED PREMISE OF THE STUDY A new set of microsatellite or simple sequence repeat (SSR) markers from expressed sequence tags (ESTs) was developed for arum lily (Zantedeschia aethiopica), which is one of the most iconic and widely recognized ornamental plants in the world. • METHODS AND RESULTS Using 2175 unigenes derived from 4283 random ESTs in arum lily, 166 primer pairs were designed and tested for amplification in 24 accessions from Asia, Europe, and Africa. A total of 43 loci were polymorphic, with the number of alleles per locus ranging from two to 10. The observed heterozygosity, expected heterozygosity, and polymorphism information content ranged from 0.2313 to 0.8480, 0.3034 to 0.8648, and 0.1015 to 0.7364, respectively. • CONCLUSIONS These novel polymorphic EST-SSR markers will facilitate future studies of genetic variation and molecular-assisted breeding systems in arum lily.

Background To optimize marker-assisted selection programs, knowledge of the genetic architecture of phenotypic traits is very important for breeders. Generally, most phenotypes, e.g. morphological and physiological traits, are quantitatively inherited, and thus detection of the genes underlying variation for these traits is difficult. Association mapping based on linkage disequilibrium has recently become a powerful approach to map genes or quantitative trait loci (QTL) in plants. Results In this study, association analysis using 20 simple sequence repeat (SSR) markers was performed to detect the marker loci linked to 13 morphological traits and 10 physiological traits in a wild P. simonii population that consisted of 528 individuals sampled from 16 sites along the Yellow River in China. Based on a model controlling for both population structure (Q) and relative kinship (K), three SSR markers (GCPM_616-1 in 31.2 Mb on LG I, GCPM_4055-2 in 5.7 Mb on LG XV, and GCPM_3142 of unknown location) were identified for seven traits. GCPM_616-1 was associated with five morphological traits (R2 = 5.14-10.09%), whereas GCPM_3142 (15.03%) and GCPM_4055-2 (13.26%) were associated with one morphological trait and one physiological trait, respectively. Conclusions The results suggest that this wild population is suitable for association mapping and the identified markers will be suitable for marker-assisted selection breeding or detection of target genes or QTL in the near future.