Search

Canadian thistle ( Cirsium arvense (L.) Scop.), Milk thistle ( Silybum marianum (L.) Gaertn.) and Scotch thistle ( Onopordum acanthium L.) are weed species, which can also be useful plants because of their medicinal properties. A preliminary seed germination test was conducted, while a greenhouse experiment was also established during 2015 at the Agricultural University of Athens, where seed germination, seedling emergence, first growth rate and biomass production of three biotypes of S. marianum , two biotypes of C. arvense and three biotypes of O. acanthium were evaluated. According to the results of this study, seed germination and seedling emergence were high for all species and biotypes. First growth rate and earliness were significant different between the several species. High biomass production was found in the biotypes originated from arable fields. In conclusion, this research work proved that there is a potential of exploitation of thistles according to their many uses. Seed germination, seedling emergence, first growth, biomass production and earliness of some biotypes seem rather satisfactory, while the high genetic variability of these three weeds can be used as a source for any future breeding attempts.

Monoculture and extensive use of glyphosate, ACCase and ALS inhibitors can greatly increase the risks of reduced efficacy of these herbicides on several weeds. In our study, seed samples of five Lolium rigidum accessions were collected from wheat fields and olive orchards in 2012 and 2013. Most of the sites were known as having poor L. rigidum control and pot experiments were conducted in order to evaluate the sensitivity of the biotypes to glyphosate, clodinafop and chlorsulfuron. Data analysis confirmed significant differences in biomass reduction of the several biotypes in response to the herbicides. In particular, one biotype was found to be resistant to glyphosate, one to clodinafop and two to chlorsulfuron, while several biotypes had an intermediate response. These findings confirm that the reported unsatisfactory control of rigid ryegrass could be attributed to herbicide resistance and therefore rotational use of herbicides and several non-chemical methods are required.

A field experiment was conducted at Pylos, Greece to compare the effect of different types of fertilization on yardlong bean (Vigna unguiculata subsp. sesquipedalis) crop. The conventional treatment plots were fertilized with an inorganic fertilizer, whereas the organic treatments plots received organic compost. Data analysis confirmed no significant correlation between plant height and type of fertilization, but there was significant correlation between length of pods and type of fertilization. In particular, morphological characteristics of yardlong bean were enhanced by inorganic fertilization in comparison with the organic fertilization. Organic farming increased significantly the number on root nodules in comparison with conventional farming.

From May to September 2016, a corn hybrid was sown in a field in central Greece. The experiment was laid out in a randomized complete block design with six replications and five fertilization treatments, namely NutriSphere-N Nitrogen Fertilizer (75%), NutriSphere-N Nitrogen Fertilizer (100%), AVAIL Phosphorus Fertilizer (75%), AVAIL Phosphorus Fertilizer (100%) and unfertilized (control). Data analysis confirmed that the different type of fertilization has a significant effect on the composition of weed flora. In particular, the results of the present study indicated significant differences between the fertilization treatments concerning density and diversity of weeds. Furthermore, weed diversity in the control treatment was highest, while it was lower in plots receiving application of N and P. However, total weed dry mass was lower in plots receiving no fertilizer and P fertilization, and highest in plots receiving N. Differences in terms of weed growth between the two types of fertilization could be attributed to differences revealed in the composition of the weed flora.