Study On The Ploidy And Morphological Traits Inheritance Of F₁ Hybrids In Actinidia Crossings

In Actinidia genus,ploidy and morphological traits vary extensively in intraspecies and interspecies with complex genetic background.To illustrate inheritance pattern of chromosomes in Actinidia hybrids,ten crossing combinations of nine parents were used to detect ploidy levels.The phenotype of fruits,flowers,branches and leaves in some hybrids were investigated,and the variation and hereditary tendency between parents and offspring were studied.The results were as follows:(1)In ten crossing combinations,including 1754 individual hybrids,the main ploidy races of F1 lines are the middle ploidy levels of their parents.It showed that all parents may be allopolyploids.The ploidy segregation was discovered in hybrid progenies of eight crossing combinations.In these eight crosses,the abnormal ploidy of progenies is more in heteroploidy than homoploidy,and is more various whose mother with higher ploidy level.Among nine parental materials,hexaploid maternal material cXinguan No.21 and diploid paternal material ’Guihai Male’ have more probability to create hybrids with new ploidy levels.(2)Twenty-four progenies with fruit were investigated in the F1 hybrids of’Xinguan No.2,and ’Moshan Male No.3’ Among these 24 progenies,we found a triploid individual ’A856’ with two extremely small fruits,and its seeds unsprouted.The main economic traits of hexaploid fruits showed high diversity,such as fniit size,flesh colour and soft ripeness quality.Some traits values were degenerated,and other traits had a downward trend.The fruit weight of progenies showed to be small genetic trend;the fruit shape was the same as their parents,mainly cylindrical.The flesh colors of progenies varied continuously,and seemed deeper than parents.The fruit soft ripening duration and soluble solid content of progenies showed bias to the female’s genetic predisposition;the dry material showed high super-female’s genetic tendency.The fruit flavor of progenies was inferior to parents9.(3)Twenty-five progenies of ’Xinguan No.2’×’Moshan Male No.3’ and fifteen progenies of ’Huangmao 63122’ x ’Moshan Male No.3’,who have the same patermal parent,were used to analysis inheritance of the phenotypic traits of flowers,branches and leaves.The main inflorescence type of progenies seemed prone to female parent.The flower colors of progenies showed high diversity,including pink flowers as in female,white flowers as in male,and intermediate type with a pink base to the petals and white margins.’Huangmao 63122’ and ’Moshan Male No.3’ are distant relatives,and their hybrids showed intermediate types of parents in branches and leaves.’Xinguan No.2’ and ’Moshan Male No.3’ have closer relationship,and their hybrids showed higher diversity in branches and leaves.There was no significant difference in petiole length,leaf length,leaf shape index and chlorophyll content between female and male progenies,while leaf width and area of female progenies were remarkably higher than male.Both leaves and fruits of hybrids in ’Xinguan No.2’and ’Moshan Male No.3’were superior to those of hybrids in ’Huangmao 63122,and ’Moshan Male No.3’,just as their mother.It indicated that hybrids are genetically closer to the female parent.Therefore,more attention should be paid to the selection of female parent in breeding,and on the premise of cross compatibility,the parent’s leaf and fruit traits should be considered.