Cross Breeding And Hybrid Phenotype Analysis Of Gazania Rigens L.

Gazania rigens L.,perennial herbaceous from Gazania spp.,Asteraceae,has many advantages compared with traditional herb ground cover plants,such as its rich flower color,long flower life,high resistance,etc.Particularly,it has the characteristics of flowering in three seasons and evergreen.This study investigated Gazania rigens L.by observing morphology,movement,pollen vitality,and stigma receptivity.Diploid and tetraploid hybrid parents were used to analyze the seed setting rate,seedling emergence rate,seedling rate of the hybrid combinations and genetic tendency of hybrids.The main results were as follows:(1)The research observed the stigma morphological change,pollen vitality and the stigma receptivity during flowering process.The results showed that the stigma morphology showed changes: ‘rod-shaped'-‘Y-shaped'-‘big Y-shaped'-‘rolled horn-shaped'-‘decayed shape';pollen vitality was highest at 13:30;the receptivity of ‘big Y-shaped' stigma was higher than other stigma and receptivity was highest at 13:30.(2)The chromosomes number of the Gazania rigens L.cross-breeding parents was identified by using conventional tablets.The chromosomes number of the cross parents‘Xingbai',‘Richu',‘Yuechu' and ‘Chunhuang' was 10,indicating that these materials belong to diploid individuals;while chromosomes number of cross parents ‘Erhao',‘Sihao'was 20,which belong to quadruple individuals.(3)‘Chunhuang' and ‘Yuechu' were choosed as hybrid parents to design 2 hybrid combinations(including orthogonal and reverse combination).The seed setting rate,seedling emergence rate,and seedling rate,agronomic characteristics of F1 generation were researched.The seed setting rate of ‘Chunhuang'בYuechu' was higher than reversecombination ‘Yuechu'בChunhuang';the seedling emergence rate of 2 cross combinations was more than 70%;the seedling rate of ‘Chunhuang'בYuechu' was lower than ‘Yuechu'בChunhuang';there existed both midparent and superparent advantages in hybrids F1.(4)‘Yuechu' and ‘Richu' were choosed as hybrid parents to design 2 hybrid combinations(including orthogonal and reverse combination).The seed setting rate,seedling emergence rate,and seedling rate,agronomic characteristics of F1 generation were investigated.The seed setting rates gap of 2 combinations were small;the seedling emergence rates of the two hybrid combinations were both higher than 70%;the seedling rate was both greater than 50%;there were mid-parent and super-parent advantages in the hybrids F1.(5)‘Xingbai',‘Erhao',‘Sihao' were choosed as hybrid parents to study the possibility of multiplex hybridization by 10 hybrid combinations.The results showed 8 hybrid combinations were successed;the seed setting rate of ‘Sihao'בXingbai' was the highest at 10.27%;the seed setting rate of ‘Xingbai' × ‘Erhao' and ‘Xingbai' בXingbai'(Self-inflicted with the same strain)were 0;the orthogonal and reverse combination of the cross combinations were different and the differences were large.