title: Combination of multiple resistance traits from wild relative species in Chrysanthemum via trigeneric hybridization.
abstract: BACKGROUND
  With the objective of combining multiple resistant traits from wild relative species in florist's chrysanthemums, trigeneric hybridization was conducted by crossing two intergeneric F(1) hybrids Chrysanthemum grandiflorum × Artemisia vulgaris and Chrysanthemum crassum × Crossostephium chinense.
  
  
  RESULTS
  To assess post-pollination phenomena, we investigated pollen germination on the stigma and embryo development, using fluorescence and scanning electron microscopy and paraffin-embedded sections, respectively. We selected eight putative trigeneric hybrid lines that showed the greatest morphological differences from the parents from among the progeny derived via embryo rescue. The hybridity of one trigeneric hybrid was further confirmed by fluorescent genomic in situ hybridization; in addition, the aphid resistance and salt tolerance of this hybrid were higher than those of the chrysanthemum parent and the C. grandiflorum × A. vulgaris F(1) hybrid, respectively.
  
  
  CONCLUSIONS
  The enhanced aphid resistance of the hybrid line reflects the inheritance of chromosomes from A. vulgaris, which carries genes that encode bioactive components. The enhanced salt tolerance of the trigeneric hybrid is attributable to inheritance of genetic materials from Chrysanthemum crassum and Crossostephium chinense, which act to maintain the compartmentation of Na(+) and K(+) ions and their selective transportation among different organs to avert deleterious effects and protect the photosynthetic apparatus. The results indicate that trigeneric hybridization between different bigeneric hybrids is a promising method for combination of multiple stress-resistance traits for improvement of chrysanthemum.
authors.affiliation: College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China.
authors.forename: Yanming
authors.initials: Y
authors.lastname: Deng
authors.forename: Jiafu
authors.initials: J
authors.lastname: Jiang
authors.forename: Sumei
authors.initials: S
authors.lastname: Chen
authors.forename: Nianjun
authors.initials: N
authors.lastname: Teng
authors.forename: Aiping
authors.initials: A
authors.lastname: Song
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Guan
authors.forename: Weimin
authors.initials: W
authors.lastname: Fang
authors.forename: Fadi
authors.initials: F
authors.lastname: Chen
mesh_terms: D000818:Animals; D001042:Aphids / Q000502:physiology; D031202:Chrysanthemum / Q000033:anatomy & histology / Q000187:drug effects / Q000196:embryology / Q000235:genetics*; D003433:Crosses, Genetic; D060467:Disease Resistance / Q000187:drug effects / Q000235:genetics*; D056625:Endosperm / Q000187:drug effects / Q000254:growth & development; D018745:Genome, Plant / Q000235:genetics; D018525:Germination / Q000187:drug effects / Q000235:genetics; D006824:Hybridization, Genetic / Q000187:drug effects; D017403:In Situ Hybridization; D007477:Ions; D058503:Mesophyll Cells / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D010935:Plant Diseases / Q000235:genetics / Q000469:parasitology; D053205:Pollen Tube / Q000187:drug effects / Q000254:growth & development; D011188:Potassium / Q000378:metabolism; D019655:Quantitative Trait, Heritable; D055049:Salt Tolerance / Q000187:drug effects / Q000235:genetics; D012964:Sodium / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology; D013045:Species Specificity; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics
chemical_list: D007477:Ions; D012965:Sodium Chloride; D012964:Sodium; D011188:Potassium