| Chrysanthemum(Chrysanthemum morifolium Ramat.) originated from China, is one of the ten traditional famous flowers and one of the four most popular cut-flowers in the world. The flower occupies an important place in the production and landscaping. Anemone type chrysanthemum is famous for its oddly shaped, colorful petals, with higher ornamental value, anemone type is also one of the important goal of chrysanthemum breeding. At present, the genetic mechanisms of anemone type chrysanthemum’s inflorescence traits remained unclear, in view of this, in present study, the perspective of quantitative genetics, heterosis and major gene plus polygene mixed model were investigated on 10 inflorescence traits via a two-year data in 2012,2013 of a F1 progeny derived from a cross between anemone type chrysanthemum’QX-053’and non-anemone type chrysanthemum ’Nannong Jingyan’. Marker locis which is associated with anemone floral traits were searched through the one-way ANOVA analysis. And the F1 progeny was used as mapping population to construct genetic linkage maps for chrysanthemum according to "double pseudo-testcross mapping strategy" and quantitative trait loci (QTL) mapping analyses on most ornamental traits of chrysanthemum were carried out in WinQTL 5.0 software with composite interval mapping (CIM) method and LOD threshold of 2.5. The main research results were as follows:1. Heterosis and mixed genetic analysis of inflorescence traits of anemone type of chrysanthemumIn this study, taking anemone type chrysanthemum ’QX-053’(female parent) and non-anemone type chrysanthemum ’Nannong Jingyan’(male parent) formulated combination,10 floral traits of F1 generation in the two years (2012 and 2013) phenotypic data were surveyed, single generation segregation analysis method of major gene plus polygene mixed genetic model were used for genetic analysis. The results showed that 10 floral characters including flower diameter, number of ray florets, ray florets length, Tubular florets width, center flower diameter, ray florets width, number of tubular florets, tubular florets length, longest lobe length and style length all have certain heterosis, the mid-parent value of six floral traits (center flower diameter, ray florets width, number of tubular florets, tubular florets length, longest lobe length and style length) are of highly significant.seven floral traits including flower diameter, center flower diameter, ray florets length, ray florets width, number of tubular florets, tubular florets length and style length are in line with A-0 model without major genes, which may be subjected to environmental impact relatively large multi-gene control; while the number of ray florets, tubular florets width, longest lobe length meets the B-1 model, the main gene expression is additive-dominance-epistatic of two pairs major genes control, and their major gene heritability was 93.85%,42.86% and 52.00%, respectively.2. Detection of SRAP and SSR makers associated with inflorescence traits of anemone type chrysanthemumTaking anemone type chrysanthemum ’QX-053’ and non-anemone type chrysanthemum ’Nannong Jingyan’ and their 160 F1 generation plants as materials, the one-way ANOVA analysis was used to search SRAP and SSR marker loci associated with anemone floral traits. From 425 pairs of SRAP primer combinations and 350 pairs of SSR primers combinations, from which 72 pairs of SRAP and 56 pairs of SSR primers, respectively, are screened for better performance in polymorphic. Totally,631 SRAPs and 215 SSRs fragments were amplified, of which intercross markers are 349, testcross markers of the female ’QX-053’and the male ’Nannong Jingyan’ are 210 and 287, respectively. Through the association analysis of SRAP and SSR markers with ten floral traits, we found that, except number of ray florets without significant marker, the number of genetic makers significantly associated with flower diameter, center flower diameter, ray florets length, ray florets width, number of tubular florets, tubular florets length, tubular florets width, longest lobe length and style length were 3,6,3,5,4,8,8,5 and 5, respectively. The cumulative contribution ratio were 19.66%,53.18%,17.17%,28.46%,23.80%,63.47%,61.34%, 43.21% and 33.37%, whereas the contribution ratio of each single genetic ranged from 5.04% to 14.84%. SRAP marker such as N-M20E5-150, N-M20E7-170, Q-M10E7-511, Q-M25E2-137, Q-M6E11-198 and SSR markers such as N-SSR336-431, N-SSR67-286, N-SSR94-133 are of high contribution ratio to several floral traits’variance, especially SSR marker loci N-SSR94-133 whose contribution ratio to center flower diameter, ray florets length, ray florets width, and longest lobe length are above 12%.3-Detection of quantitative trait loci (QTL) controlling Inflorescence traits in chrysanthemumTaking anemone type chrysanthemum ’QX-053’ and non-anemone type chrysanthemum ’Nannong Jingyan’ and their 160 F1 generation plants as a mapping population, ten floral traits (flower diameter, center flower diameter, number of ray florets, ray florets length, ray florets width, number of tubular florets, tubular florets length, tubular florets width, longest lobe length and style length) were investigated in 2012,2013 years for genetic variation and correlation, genetic linkage map for the QTL analysis of these ten floral traits were constructed using SRAP and SSR markers.There was no significant difference in the ten inflorescence-related traits between 2012 and 2013, and the average of these traits in F1 population were between both parents with wide existance of extra-parent plants; a significant phenotypic correlation relationships were found among most of the inflorescence traits. QTL mapping shows that, in 2012,2013 two years data set, a total of 36 detected QTLs were significantly associated with the above ten inflorescence traits, which are mainly distributed in parents’ QX-053 genetic map of Q1, Q2 and Q3 (a total of 3 linkage groups) and parents’ Nannong Jingyan’ genetic map of N1, N2, N3,N4, N5, N6, N7, N8, N9, N10, N11 (a total of 11 linkage groups) at LOD values between 2.52～5.85, with a contribution ratio to the phenotypic variation of 9.00%～34.80% for single QTL. A total of four QTLs were identified at the same marker interval on genetic maps both in 2012 and 2013, of which the contribution ratio of CfdE1Q1-1 (CfdE2Q1), CfdE1Q2 (CfdE2Q2), TflE1Q1 (TflE2Q1), TfwE1Q1-1 (TfwE2Q1) were above 10%, suggesting these QTLs were major QTL little affected by environment factors. |
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