Intervarietal hybridization and observation of heterosis in the new hybrids of Iris germanica

Abstract

To produce new, high-quality offsprings, we generated two cross combinations in Iris germanica. Three parental plants were selected after preliminary screening of commercial traits in different cultivars. Fourteen quantitative traits mostly related to the flower organ were investigated on 15 progenies and three parental plants in a randomized complete block design with three replications. Significant positive and negative correlations were observed among different studied attributes at 0.01 and 0.05 probability. The highest positive (+0.86) and negative (-0.76) correlations was recorded between diameter of flowering branch with crown diameter as well as peduncle length, respectively. Cluster analysis using Ward’s method separated most of the progenies from the parental plants based on evaluated morphological characteristics. However, some of the progenies were grouped with their maternal parent. In PCA analysis, five factors explained 87.84% of the total variations; crown diameters as well as diameter of flowering branch were predominant in the first component (34.19%). Some promising progenies with interesting characteristics were observed and several hybrid plants were superior to their parents and showed positive heterosis over their parents. Progenies NIOP5 and NIOP8 were superior in the most studied attributes, therefore, they suggested for further investigations which can be used in breeding programs. Progenies showed a wider range for flower diameter, peduncle thickness, bush height, as well as inner and outer tepal dimensions. Flower color also showed wider range in the progenies and purple, violet and white colors were the most frequent colors in the hybrid plants, while lilac color was the rarest one. Results of our investigation revealed that intervarietal hybridization is an effective way to contribute to the phenotypic variation in the iris flower for producing new plant materials for breeding purposes as well as releasing new cultivars. The inheritance of some of the traits identified in this study will be important for improving plant architecture in German iris plant.