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Phenotypic variations and heritability of bearded iris breeding

Fan, Zhuping, Gao, Yike, Guo, Yanchao, Liu, Rong, Zhang, Qixiang
Euphytica 2017 v.213 no.11 pp. 252
Iris (Iridaceae), corolla, correlation, females, genetic correlation, genetic variance, genotype, heritability, heterosis, hybrids, leaves, males, parents, phenotype, phenotypic variation, plant breeding, plant height, pollen, pollination, specific combining ability, vegetative growth
Bearded iris (Iris × hybrida Hort.) refers to the large population of iris hybrids, which is identified by thick, bushy ‘beards’ on each falls (lower petals) of the blossoms. However, the selection of iris is extremely limited due to the lack of information about genotype and phenotype. According to North Carolina Design II (NC II), a statistical method to estimate the combining ability, genetic variance components and heritability, seven male parents and two female parents were hybridized to generate 14 populations of first filial generation (F₁). Each F₁ family was generated through artificial pollination in 3 years and included 60 individuals. 11 key ornamental characters, including plant height (PH), length of leaf (LL), number of flower per scape (NFS), height of individual flower (HF), diameter of flower (DF), length of fall (LF) and width of fall (WF), were measured, and some genetic parameters (heterosis, heterobeltiosis, combining ability, heritability as well as genetic correlations) were evaluated. The results showed that HF and LW had the largest number of F₁ populations gaining heterosis, thus more likely to generate taller progenies with larger blossoms. The estimates of combing ability revealed that I. ‘White and Blue’(M1) and I. ‘Sugar Blues’(M5) appeared to be ideal pollen donators. The combination of I. ‘India Chief’ × I. ‘Champagne Elegance’ (FM1 × M6) exhibited positive special combining ability (SCA) on all the tested characters, becoming the most potential populations of all. WF and NFS had the highest broad-sense heritability (91.47%) and strict-sense heritability (53.96%), respectively. Correlation analysis showed that PH was closely associated with NBS and NFS, while LL had significant correlations with HF and LF, making it possible to select taller individuals in the vegetative stage to obtain those with abundant flowers.