Meiosis and pollen grain viability in Helianthus mollis,Helianthus salicifolius,Helianthus maximiliani and their F1 hybrids with cultivated sunflower

Three diploid perennial sunflower species are useful for variety improvement: Helianthus mollis, because of sessile leaves, H. salicifolius, because of a high oil concentration, and H. maximiliani, a potential source of resistance to Sclerotinia sclerotiorum. The crossability of these species to cultivated sunflower was examined.Hybrids were obtained from eight combinations, with 3–15 F₁ plants per combination. The F₁'s exhibited the dominant phenotype of the wild species. Pollen viability varied between 32.1 and 69.9%. Meiosis was irregular in the F₁ hybrids. At diakinesis, bivalents (62.7–97.9% of meiocytes), univalents (0–31.23%), and multivalents (3.84–7.68%) were detected. At anaphase I, chromosome bridges were detected in 6.77 to 11.44% of meiocytes. Fast chromosomes in metaphase I, and lagging chromosomes in anaphase I and telophase II were evidenced in a high percentage of meiocytes.     

Staining and fluorescent microscopy methods for pollen viability determination in sunflower and other plant species

Results shown in this paper imply a successful application of staining method by Alexander (1969) which is simplified in comparison to the original method and adapted for pollen viability estimation in sunflower, rapeseed, sugar beet, maize, wheat, alfalfa, etc. Aspects of research in which this method is frequently used are described.This paper also shows the results of fluorescent microscopy method (Kho and Baër, 1968) adaptation for pollen germination and pollen tube growth monitoring in sunflower, as well the possibility for its application in fertilization potential estimation.     

Wirtschaftlichkeitsbewertung von Pflanzenschutzstrategien in E- und A‑Weizen anhand eines Feldversuches in Brandenburg mit sechsgliedriger Fruchtfolge in den Jahren 2004 bis 2016

Plant protection strategies are mostly assessed with respect to their efficacy and yield stability rather than their economic result. Therefore, this study aimed at evaluating the economic excellence of different strategies. Based on a long term field trial, the economics of four plant protection strategies in two different winter wheat quality classes (A wheat and E wheat) were evaluated. The field trial located in Dahnsdorf in Brandenburg comprised a crop rotation with six rotation components which is rather untypical for agricultural practice in that region. The economic analysis was based on field trial data from 13 years between 2004 and 2016 which was supplemented by secondary statistical data. Four plant protection strategies were considered: (S1) harrowing without chemical plant protection, (S2) plant protection in accordance to good farming practice taking into account the general principles of integrated pest management and a reduction of the treatment frequency index by (S3) 25% or rather (S4) 50% compared to good farming practice. By calculating the plant protection and labor cost free revenues for each year and strategy and by transferring these into annuities the four plant protection strategies were compared economically. The results for E wheat (elite wheat) were similar to those of A wheat (quality wheat) in terms of economic performance. A comparison of the plant protection strategies showed, that the abandonment of pesticides (S1) led to considerable economic disadvantages compared to the other three strategies. These three strategies which included the application of pesticides (S2, S3, S4) led to almost equivalent revenues, however, a reduction of the treatment frequency index by 25% compared to the good farming practice resulted in the best economical outcome for both wheat qualities. The applied crop rotation with six rotation components in combination with an intensive monitoring of the plant pests clearly supported the reduction of pesticide use in winter wheat without economic disadvantages. The results suggest, that such crop rotations have the potential to contribute to a sustainable crop production.     

Meiosis and Pollen Viability in Helianthus tuberosus L. and its Hybrids with Cultivated Sunflower

The hexaploid species of Helianthus tuberosus is a potential source of resistance to several sunflower pathogens. But crossed with cultivated sunflower, it produces F, hybrids which have low values of fertility or even full sterility. Pollen viability and meiotic features were studied in 17 populations of the species H. tuberosus and in F¹ hybrids. Significant differences in pollen viability existed between populations (47.1–98.8%). In the 15 FI hybrids, plant fertility ranged from 0 to 100 per combination, while pollen viability ranged from 12.4 to 57.1. Meiosis was almost normal in the analyzed species, and irregular in the F, hybrids. The highest percentage of meiocytes was with bivalents (85.9), but univalents (0.3) and multivalents (13.8) occurred as well. In metaphase and anaphase, the percentage of meiocytes with fast and lagging chromosomes was high. In anaphase, chromosome bridges were detected in 9.9 of the meiocytes.