Seed Production Technology And SSR Molecular Markers Linked To Heterostyly In Primula Forbesii

Primula forbesii is a unique flowering species in China,characterized by production of plenty of attractive flowers and stable florescence lasting for three months.These attributes make it one of the most important ornamental floriculture crop,especially in winter when the other flowers remain dormant.Despite the immense economic and aesthetic value,studies about the production application or characterisation of important ornamental traits of Primula have rarely been reported.Being a biennial plant,renovation of seed production technology holds a key value for the industrial development of P forbesii.Based on this significant commercial aspect,present study was aimed at exploring the effects of the ratio of short to long styles and different cultivation methods on the seeding efficiency of P forbesii.The insect vectors were introduced as an innovative approach to explore the possibility of artificial replacement by insects.In addition,we found the SSR molecular marker of heterostyly,which could provide a theoretical basis on early selection.In an effort to find the best way for efficient production of P.forbesii this research produced following conclusions:1)Using P.forbesii 'red star' as the test material,three pollination methods(bumble bees,bees and artificial pollination),three plant type ratios(1:2,1:1 and 2:1)and two spatial arrangements(dislocation and alternation)were set to investigate the effects on the seeding efficiency and seed quality The results showed that with pollination method of bumble bee and the thrum-style to pin-style ratio of 1:2,the seed production efficiency was the highest(i.e.,thousand seed weight of 0.0760g,75.00%seed germination rate,47.50%seed germination potential,60.10%ovary swelling rate,single fruit seed number of 122.21 seeds/fruit).Attributes like seed cultivation population,flower color,flower diameter,crown and other properties remained unaffected2)450 pairs of EST-SSR primers were screened by PCR,out of which 103 pairs of primers were successfully amplified with an amplification success rate of 23.41%.Next,28 pairs of primers with good polymorphism were selected for further screening(all were derived from transcription of P.forbesii,accounting for 27.18%of the total amplified primers).The F1 generation isolates of thrum-style type(T2)and X pin-style type(P2)were used as test materials and 28 pairs of EST-SSR primers with good polymorphism were screened by BSA.The SSR marker c64326,which was closely linked to the target gene,was obtained with a genetic distance of about 3.70 cM,suggesting that the fragment might be located in an area between introns or genes.With the above in mind,present study gives significant insights into the seed production technology of P.forbesii.A seed production plan of using bumble bees to pollinate and setting the thrum-style to pin-style ratio of 1:2 was found best for efficient seed production.Moreover,a marker(c64326)linked to heterostyly was exploited as an important means to ensure the best plant type selection for quality seed production.Therefore,results of this study can do a great deal to improve the efficiency and shorten the time of seed production,thus providing a theoretical basis for industrial production of quality seeds of P.forbesii.