Preliminary Study On Distant Hybridization Between Nine Primulina Species

Gesneriaceae has become well-loved because of their excellent ornamental value recent years,the genus Primulina of which has wonderful potential for development.But its intrageneric hybridization compatibility is not clear.In this study,flowering characteristics and breeding system of P.pungentisepala were explored,and other species with big flower,mosaic or yellow flower in Primulina were used to hybridized with the intention of making affinity clear and evaluating filial generation.The main conclusions are as follows:1.The flowering period of P.pungentisepala in Beijing greenhouse is from mid January to mid April.The relative position of stigma was higher than stamen 3 days after flowering,and a large amount of mucus was secreted 5 days after flowering;The viability of pollens was the highest on the 4th day of flowering,reaching 74.6%;The mean P/O value was 1272.19;The percentage of setting seed of P.pungentisepala by artificial pollination was more than 90%,which was higher than that in the natural pollination.P.pungentisepala was self-compatibility but difficult to occur up spontaneous self-pollination because lacked of pollinators.There was no agamospermy with the percentage of setting seed zero.2.There were two kinds of phenomena on the pre-fertilization obstacles:(1)Pollen did not germinate on stigma.(2)The pollen germinated normally,but a large amount of callose appeared at 24 h after pollination.Pollen tube twisted and broken when combining with ovule,only a few pollen tubes could enter it at 48 h after pollination.There were significant differences between the percentage of setting seed and emergence rate in reciprocal crosses which were to get big flower and mosaic,where 11100 seeds and 3546 seedlings were obtained among 620 pollination combinations.P.‘Flying Wings’ and P.‘Purple Sundae’ were used as female better with the percentage of setting seed more than 40%,while P.pungentisepala could be female and male,but it behaved better as male when hybridized with varieties,whose percentage of setting seed was more than 50%.3.It is preliminarily considered that there was a medium or more degree of variation in different traits in reciprocal crosses and self-cross using P.pungentisepala as breeding material,including 473 progenies from 5 populations,and it has great potential for genetic improvement.The corolla and flower diameter of the progeny showed midparent superiority or positive superparent superiority,and filial generations became shorter and their flowers became larger.Corolla and flower diameter were positively correlated with crown width and leaf width,and negatively correlated with plant height and scape length.Among them,four of the progenies whose parents were P.‘Purple Sundae’ and P.pungentisepala had corolla larger than P.‘Flying Wings’(49.69 mm),which made it easier to select plants with large flower while lots of intermediate materials with mosaic could be obtained from selfing of P.pungentisepala.In this study,the compatibility and fertility of distant hybridization of Primulina were discussed,a large number of progenies and breeding intermediate materials were obtained,while the genetic segregation rules of hybrid combination P.pungentisepala as parents were preliminarily summarized,so as to provide theoretical guidance for future distant hybridization of Primulina.