EFFECT OF HERBICIDES APPLIED IN DIFFERENT GROWTH STAGES ON HECTOLITER WEIGHT OF BARLEY

Three barley varieties (Rex, NS 293 and Egej), treated with six herbicides (2,4-D, MCPP+dicamba, triasulfuron+dicamba, 2,4-D+florasulam, amidosulfuron+iodosulfuron and florasulam+flumetsulam) were included in this experiment. Herbicides were applied during the three different growth stages tillering (BBCH 24-27), first node (BBCH 31) and second node (BBCH 32). The aim of this experiment was to consider the influence of herbicides (applied in different growth stages) on barley hectoliter weight. In first and third experimental years herbicides did not significantly influence barley seed hectoliter weight. In second experimental year at Rex variety in first and second node stage MCPP+dicamba significantly increase barley hectoliter weight compared with weed free control. In second node stages 2,4-D and florasulam+flumetsulam also increase barley hectoliter weight compared with weed free control. At NS 293 in tillering stage MCPP+dicamba significantly decrease barley hectoliter weight compared with weed free control. Also at Egej variety triasulfuron+dicamba at first node stage was also significantly decrease barley hectoliter weight compared with weed free control. Differences between growth stages during the herbicide applications in all three years of testing were very small, so they have no impact on barley hectoliter weight. If conditions do not allow herbicides to be used in the optimal period, it can be used until second node stage, without having a negative impact on the barley hectoliter weight

Eragrostis pilosa (L) . Beauv. a New Invasive and Economically Important Weed in the Rice Fields in the Kocani Region

Investigations were carried out in rice fields in the Kocani region. The aim for this investigations was to determine the weed species which has never been registered in Kocani rice fields before. Also, to examine in which localities it appears, the reasons for its occurrence in the rice fields and the impact of this weed on rice yield. After determining it was discovered that the examined weed is Eragrostis pilosa (L) P. Beauv (indian love grass). This is a non-typical weed for rice fields in Kocani region. Eragrostis pilosa in the rice fields in Kocani region for the first time was noticed in 2010 in vicinity of ​​the village Mojance. In 2012 it also appears in the rice fields in vicinity of villages Kucicino, Ciflik, Burilcevo and Dolni Podlog. In 2013 it spreads in the rice fields in vicinity of villages Cesinovo and Grdovce and in the majority of the rice fields around the city of Kocani. Water deficiency in the rice fields is the reason for Eragrostis pilosa occurrence. Depending on the weed intensity the rice yield was reduced from ca. 25 to 55%25. Its spreading will be a serious economically problem in the rice production in the Kocani region

ALLELOPATHIC POTENTIAL OF SOME WEEDS IN THE RICE FIELDS OF THE KOCHANI REGION

During the period 2021-2022, the allelopathic effect of three weed species Scirpus mucronatus L., Scirpus maritimus L. and Heteranthera reniformis Ruiz & Pav. was studied under laboratory conditions at the Institute of Forage Crops, Pleven from the rice fields in the Kochani region and determining the allelopathic tolerance of four rice varieties Ronaldo, Opale, San Andrea and Halilbay grown in the Republic of Macedonia. It was established that the developed in vitro test ensures the obtaining of reliable results for the allelopathic effect of S. mucronatus, S. maritimus and H. reniformis and the allelopathic tolerance of the Ronaldo, Opale, San Andrea and Halilbay rice cultivars included in the study. The use of agar-gel as a carrier of allelochemicals and development environment has sufficient water supply and compacted structure to support the optimal development of the accessions included in the experiment development index (GI%) varied from 21.5 to 129.2%) and proof of allelopathic interference in rice. In terms of allelopathic tolerance to weed species, rice varieties can tentatively be ranked in the following order: Halilbay (GI% average 47.5%) → Ronaldo and Opale (GI% average 62.3%) → San Andrea (GI% average 94.1%)

Assessment of seed viability of Oryza sativa L. accessions in long-term storage after more than a decade

The purpose of this research was to evaluate the seed viability of 16 Oryza sativa L. accessions including valuable endangered landraces, a breeder's line, and an advanced/improved cultivar after 13-14 years of long-term storage. Preservation of seed samples has been conducted ex-situ at low temperatures (-18°C). The germination test (germination energy and total germination) was carried out according to ISTA methods and Kameswara (2006). Furthermore, the following variables were examined: the germination index, root length, shoot length, root-to-shoot length ratio, total seedling length, and seed vigour index. The Pearson correlation coefficient was computed to assess the linear relationship between the vigour index and seedling length. All the sixteen accessions have had a high total germination rate, in the range of 89-100%, hence there is no need for their regeneration. The germination energy and total germination showed statistically significant differences for two rice accessions at P-0.05 and P-0.01. The seed showing a high vigour index produced seedlings with higher growth rates. The Pearson correlation of the vigour index and seedling length was found to be very highly positive and statistically significant (r=0.99, p<0.001). Based on the results obtained, it can be concluded that rice as a botanical species retains high seed viability during the long-term conservation, although there are individual differences between the accessions which are due to the genetic constitution of each genotype

EFECTS OF HERBICIDES ON BARLEY SEEDS GERMINATION DEPEND ON GROWTH STAGE

An experiment was carried out including three barley varieties (reks, NS 293 and egej), treated with six herbicides (2,4-D, MCPP+dicamba, triasulfuron+dicamba, 2,4-D+florasulam, amidosulfuron+iodosulfuron and florasulam+flumetsulam) in the three different growth stages (tillering,&nbsp; first node&nbsp; and second node).&nbsp; The aim of this experiment was to consider the influence of herbicides (applied in different growth stages) on germination of barley seeds. In all experimental years herbicides did not significantly influence barley seed germination. The growth stage during herbicide application did not affect germination of barley. If conditions do not allow herbicides to be used in the optimal period, it can be used until second node stage, without having a negative impact on the barley seeds germinations