Browsing by Person "Losert, Dominik"

Now showing 1 - 2 of 2

Comparison of floral traits in Calibrachoa cultivars and assessment of their impacts on attractiveness to flower-visiting insects
(2021) Marquardt, Melanie; Kienbaum, Lydia; Losert, Dominik; Kretschmer, Lea Annina; Rigling, Marina; Zhang, Yanyan; Schweikert, Karsten; Westermann, Nils; Ruttensperger, Ute; Rosenkranz, Peter
Ornamental plants are appreciated by humans for their colorfulness, beauty, abundant flowering and long blooming periods. Many ornamental plants can also constitute an additional foraging resource for flower-visiting insects. However, the ability of the popular ornamental plant Calibrachoa to support urban insect communities is not well documented. In this study, 20 different Calibrachoa cultivars were selected and tested in regard to their insect friendliness based on standardized observations (I) in flight tents using the large earth bumble bee Bombus terrestris as a model species and (II) in open field trials. To investigate what floral characteristics might constitute attractiveness to bumble bees, various floral traits were recorded and compared across all tested Calibrachoa cultivars. Over a two-year period, a total of 6,327 foraging bumble bees were recorded in the tent observations. In the open field observations, we counted 4,188 flower-visiting insects. Our results revealed that (I) all Calibrachoa cultivars were visited by insects for foraging, (II) the number of insect visitors varied significantly among the 20 tested cultivars and (III) the cultivars displayed different floral traits. For the morphometric floral traits and the aroma profiles of Calibrachoa, only the mean nectar quantity and a few identified compounds could be correlated with attractiveness to the model species B. terrestris. We also found that the petal color of the tested cultivars had a significant impact on the number of visitors. Therefore, B. terrestris clearly preferred red or blue Calibrachoa cultivars over those with other petal colors. However, as the cultivar preferences in the different insect groups differed, it is highly recommended to use various cultivars in urban plantings. Nevertheless, efforts must be made to explain what additional floral traits make Calibrachoa and other ornamental plants generally attractive to flower visitors. This information can then be used for breeding purposes to increase the insect friendliness of ornamental plants.
Phenotypic, genetic, and genomic assessment of triticale lines and hybrids
(2017) Losert, Dominik; Würschum, Tobias
Triticale (×Triticosecale Wittmack) is a small grain cereal used for livestock feeding and as renewable energy source. These diverse types of usage lead to different breeding strategies, ideally resulting in continued increase of both, grain and biomass yield. Briefly, the objectives of this thesis were to explore aspects with relevance for line and hybrid breeding in triticale by phenotypic, genetic and genomic assessment of important traits. More specifically, the objectives of this study were to (i) evaluate agronomic traits, assess trait correlations, and investigate the amount of heterosis in triticale hybrids, (ii) examine the potential of line and hybrid cultivars for production of biomass, (iii) assess the phenotypic and genotypic variability in triticale germplasm, (iv) investigate long-term phenotypic trends based on cultivars registered in the past three decades, and (v) identify QTL for agronomical relevant traits. In conclusion, hybrids of triticale possess an increased biomass yield potential compared with their mid-parent values as well as compared with commercial reference cultivars. The findings on triticale germplasm and its breeding history provide important information for breeding programs. Furthermore, based on the obtained results, genomic approaches like marker-assisted or genomic selection appear promising to assist triticale breeding in the future.