YIELD OF BROOMCORN (SORGHUM VULGARE VAR. TECHNICUM [KÖRN.]) CULTIVATED IN SOUTHERN BULGARIA

A three years’ comparative trial was conducted in Agricultural Experimental Station in the Eastern Rhodopes – Kardzhali, Bulgaria to assess the productive potential of five broomcorn genotypes – cultivar Prima and populations S14, G16, L18 and MI16N. Fresh biomass yield was formed by two to three cuttings per season, depending on annual precipitation quantities. The average duration for cutting formation for the region is from 35 to 45 days. When grown in Southern Bulgaria (Kardzhali region) broomcorn landraces can produced up to 9974 kg/da fresh biomass and up to 1977 kg/da dry mass, depending on the cultivation year. The highest yield of fresh and dry biomass was obtained from the local population MI16N, which exceeds the standard variety Prima from 131.8% to 185.1% and an average of 159.1%. This study demonstrates the potential of growing broomcorn for fodder in the conditions of Southern Bulgaria

Effect of Grain Moisture Content on Popping Yield of Sorghum Genotypes

This paper aimed at providing popping characteristics of different red and white sorghum genotypes according to different moisture content at traditional methods of popping using high temperature for a short time (HTST). To increasing grain moisture level, seven sorghum genotypes - mutant and hybrid lines (M1(6282), 16113, 16121, 1641, 1643, 1651, 1673) were soaked to 0, 60, 120 and 180 min in distilled water. The popping rate and expansion ratio were recorded. The results showed that conventional method of popping is a good main to produce pops sorghum after increasing moisture of grains. Moistening of grains from 13-16 % increased 5.3-10.2% popping rate of all sorghum genotypes. The mutant line M1(6282) with red coloration of pericarp had the highest popping rate and expansion ratio at 16% moisture i.e. 85% and 3.88 %, respectively. There was correlation between diameter of grains and parameters expansion ratio (from 0.604 to 0.724), popping rate (from 0.815 to 0.878) and moisture grains (from 0.815 to 0.878)

Trace Element Content of Polyfloral Honey and Beeswax from the Vicinity of Non-Ferrous Metal Plant

Bees and their products occupy an important place in the trophic chain “toxicant-soil-plant-bee-bee product-man”, so it has been suggested that bees and bee products should be considered as not a costly method for monitoring of the environmental pollution. Aim of the present study was to analyse trace element content of polyfloral honey and beeswax, produced in three beehives, situated in the vicinity of non-ferrous metal plant and to assess the hazardous risk at consummation. For the purposes of the study, three beehives in this area have been chosen, as follows: BH1 – located at distance of 3.8 km from the smelter, SW; BH2 – at 4 km distance, NE; BH3 – at 4.6 km distance, SE. Content of Al, Cr, Co, Cu, Fe, Mn, Ni, Pb, Sr and Zn was determined by ICP-MS. Data revealed approximately low content of heavy metals and toxic elements. Beeswax samples were found to contain significantly more Cr, Cu, Fe, Pb and Zn, in comparison with the honey samples (p BH1 > BH3

Popping characteristics of sorghum genotypes (Sorghum bicolor (L.) Moench)

Twelve genotypes (varieties, hybrids, mutant and hybrid lines) of sorghum (Sorghum bicolor (L.) Moench) were studied. The objective of the study was to determine the popping performance and to establish the relationships with some biochemical parameters (content of crude proteins, starch, moisture) and grain characteristics (pericarp color, grain width, 1000-grain weight). Popping yield of sorghum grain genotypes was in range 32.0% - 72.0%. The highest influence on popping yield had 1000-grain weight (r = 0.831), starch content (r = -0.356), followed by moisture content (r = 0.212) and crude proteins (r = 0.282). It was found that the endosperm of the seeds expanded poorly in most genotypes with white coloring of the pericarp (from 33.3 to 90.1%), while for those with a dark-colored seed pericarp, the expansion was from 50.0% to 160.0%. Mutant line M1 (6282) (dark brown color of the pericarp) and hybrid line 1643 (white color of the pericarp) stood out with relatively better popping characteristics and particle size of popped grains. This study demonstrated one of the qualities of sorghum grain- poppability and opportunities for enrichment of the genetic diversity for the breeding program in this culture

Allelopathic activity of some parasitic weeds

Allelopathic activity of Cuscuta epithymum L. (CVCEY), Cuscuta campestris Yuncker (CVCCA), Phelipanche ramosa (L.) Pomel (ORARA), Phelipanche mutelii (Schultz) Reuter (ORARM) and Phelipanche spp. (PHESS) on germination and initial development of test plats of Lactuca sativa L. cultivar 'Great Lakes' was studied under laboratory conditions. It was found that, water exracts of the parasitic weed species in concentrations 0.4, 0.8, 1.6, 3.2, 6.4 and 12.8% w/v have a relatively high inhibitory effect on the seed germination of test plants. The inhibiting rate of parasitic weed species from family Convolvulaceae ranges from 6.24 to 100.0% and for the species of family Orobanchaceae from 42.1 to 100.0%. Parasitic weed species from family Orobanchaceae (Ph. ramosa, Ph. mutelii and Phelipanche spp.) showed a considerably stronger allelopathic effect (GIaverage 17.9), as compared with the applied concentrations of water exracts of species from family Convolvulaceae (C. epithymum and C. campestris) (GIaverage 22.7)

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%)

Alelopatski uticaj vodenih ekstrakta Sorghum halepense (L.) Pers., Convolvulus arvensis L. i Cirsium arvense Scop. na početni razvoj izdanaka nekih leguminoznih useva

In order to study the allelopathic effect of aboveground dry biomass of Sorghum halepense, Convolvulus arvensis and Cirsium arvense on seed germination and early seedling growth of Pisum sativum (L.), varieties Mir (winter form) and Kerpo (spring form); Vicia sativa (L.), variety Tempo, and Medicago sativa (L.), variety Dara, a laboratory experiment was conducted at the Institute of Forage Crops - Pleven. Four concentrations: 1.25, 2.5, 5.0 and 10.0% were applied to each weed biotype used to study allelopathic effects. The results showed that weed extracts significantly decreased germination percentage, shoot and root length (cm), shoot and root weight (g), and seed vigor index (SVI1 and SVI2) of the tested species. In general, the variable effects are related to the weed species and extract concentrations.Kako bi se proučio alelopatski uticaj suve biomase nadzemnih delova biljaka Sorghum halepense, Convolvulus arvensis i Cirsium arvense na klijanje semena i početni razvoj izdanaka Pisum sativum (L.), var. Mir (ozima) i Kerpo (jara); Vicia sativa (L.), var. Tempo, i Medicago sativa (L.), var. Dara, izveden je laboratorijski eksperiment u Institutu za krmno bilje - Pleven. Četiri koncentracije - 1.25, 2.5, 5.0 i 10.0% - primenjene su na svaku korovsku vrstu kako bi se proučio alelopatski uticaj. Rezultati su pokazali da su ekstrakti korova značajno smanjili procenat klijanja, dužinu izdanaka i korena (cm), težinu izdanaka i korena (g) i indeks vigora semena (SVI1 i SVI2) testiranih vrsta. Uopšte, promenljivost delovanja zavisi od korovske vrste i koncentracije ekstrakta

Allelopathic effects of water extracts of Sorghum halepense (L.) Pers., Convolvulus arvensis L. and Cirsium arvense Scop. on early seedling growth of some leguminous crops

In order to study the allelopathic effect of aboveground dry biomass of Sorghum halepense, Convolvulus arvensis and Cirsium arvense on seed germination and early seedling growth of Pisum sativum (L.), varieties Mir (winter form) and Kerpo (spring form); Vicia sativa (L.), variety Tempo, and Medicago sativa (L.), variety Dara, a laboratory experiment was conducted at the Institute of Forage Crops - Pleven. Four concentrations: 1.25, 2.5, 5.0 and 10.0% were applied to each weed biotype used to study allelopathic effects. The results showed that weed extracts significantly decreased germination percentage, shoot and root length (cm), shoot and root weight (g), and seed vigor index (SVI1 and SVI2) of the tested species. In general, the variable effects are related to the weed species and extract concentrations

A study of suitability of some conventional chemical preservatives and natural antimicrobial compounds in allelopathic research

The impact of three conventional chemical preservatives (sodium benzoate, potassium sorbate and salicylic acid) and a natural antimicrobial compound (thymol) on germination, dynamics of growth and accumulation of fresh biomass (g per seedling) of Lactuca sativa L., cultivar Great Lakes, was studied under laboratory conditions. The tested conventional chemical preservatives demonstrated strong inhibitory effects (GI 27.1-0.0%) on germination and initial development of L. sativa, and they cannot be used in allelopathic studies in the laboratory. An addition of thymol at 0.5-1.0 ‰ concentration showed no inhibitory effect (GI varied 81.7-84.6%) on germination and initial development of L. sativa. Thymol can therefore be used as a natural antimicrobial compound in allelopathic studies in the laboratory

Allelopathic Effect of Dodder on Different Varieties of Lucerne and Bird’s Foot-Trefoil

The aim of this study was to evaluate the allelopathic effect of cold aqueous extracts, both fresh and dry biomass of dodder (Cuscuta epithymum L.) on lucerne (Medicago sativa L.) and bird’s foot-trefoil (Lotus corniculatus L.). Four different varieties of lucerne “Pleven 6”, “Dara”, “Roly”, “Multifoliolate”) and bird’s foot-trefoil (“Gran San Gabriele”, “Leo”, “Local population 1”, “Local population 2”) were studied in order to find some varieties with allelopathic tolerance. Ex-situ experiment was carried out as follows: 100 seeds of each variety were put in Petri dishes between filter paper, both cold extracts of parasitic weed biomass were pipetted at a ratio of 1:20 as against the seed mass and then were placed in a thermostat-operated device at a temperature of 22 ± 2°С. Distilled water was used as a control. Percentage inhibition, Index of tolerance and Index of plant development were calculated for assessment of the allelopathic effect of dodder on the early seedling growth, biomass synthesis and initial development of experimental varieties. As a whole, dry weed biomass was found as more toxic for the tested plants than the fresh one. Medicago sativa var. multifoliolate and Lotus corniculatus var. Local population 1 and Local population 2 showed a significant tolerance to the allelopathic influence of Cuscuta epithymum in all studied concentrations of aqueous extract of fresh weed biomass (25, 50 and 100 g l−1) and medium tolerance to aqueous extract of dry weed biomass (concentrations of 25 and 50 g l−1)