The Research On Classification Of 27 Hibiscus Cultivars

Hibiscus syriacus Linn,a kind of garden plant with high practical value,which integrates ornamental application,edible and medicinal.In this paper,27 hibiscus cultivars were used as experimental materials,and identifying them on the base of morphological classification,numerical classification,palynological analysis and ISSR molecular marker technique and analysis by synthesis.It is a preliminary study on the scientific method for the classification of hibiscus cultivars and the research on the basis,standard and grade of the classification of hibiscus species.This can make up for the absence of domestic hibiscus cultivars classification study,and it also provides a better premise and theoretical basis for the study and utilization of hibiscus in other fields.The main results are as follows:First,the 27 hibiscus cultivars were classified by using morphological classification,The petal index and morphological characteristics of 27 hibiscus species were described.17 morphological characters were encoded by the rank quantization coding method,principal component analysis suggested that the characters contained in the first and fourth criterion could be regarded as the morphological factors of red center of petal,the characters contained in the second,third and sixth criterion could be regarded as petals form and other traits of flower,the characters contained in the fifth criterion could be regarded as leaf form.R-type cluster analysis proved the 17 characters have independent influences.Q-type cluster analysis that classified 27 cultivars into 3 groups was considered as reasonable classification.In general,main characters can be regarded as standard and basis,including red center of petal,flower type petals index and relationship of red center line and red center.Secondly,the palynology of 24 hibiscus cultivars was analyzed and it shows that the pollen morphology of various hibiscus cultivars was fairly uniform,7 characters of pollen morphology were encoded and the results of principal component analysis and Q-type cluster analysis proved the important character indexes,which including P/E,length of equator axis(E),distance between spines,number of spine and spine length.The results of palynological analysis differ from those of morphological classification.Furthermore,the external morphology and pollen of 24 hibiscus cultivars were analyzed,principal component analysis of 12 synthetic characters indicated that 10 character indexes have great impact,including shape of red center stem base,red center of petal,flower diameter and so on.Q-type cluster analysis that classified 24 cultivars into 4 groups was considered as reasonable classification.The results of the external morphology and pollen analysis was consistent with the results of morphology classification.By the test of ISSR-PCR molecular identification in 27 hibiscus cultivars,an optimized PCR reaction system for ISSR analysis was established:PCR was performed in a 25?L reaction mixture with 2.5?L 10 x PCR Buffer(Mg2+free),0.15pL Taq DNA polymerase,1pL dNTP,2?L Mg2cl,100ng template DNA.Through screening,obtained 6 primers from ISSR primers.These 6 primers could amplified clear,high genetic diversity bands.In 27 experimental hibiscus cultivars were amplified by 6 ISSR primers and the polymorphic ratio was 83.33%and indicated that there actually existed much genetic diversity at molecular level among the hibiscus cultivars.The results of genetic difference analysis and the UPGMA clustering method shows that classified 27 cultivars into 5 groups was considered as reasonable classification.Through comparison,the results of the three classification methods have certain similarity,the results were different with different characters and different classification criteria.It also shows that 3 cultivars of 'Woodbridge','Rubis'and 'Red heart' have the similar relationship,and it is also speculated that 3 cultivars of 'Paeoniflorus','Elegantissimus' and 'Arang' might be the same one and with different names.