Carcass traits and meat quality of different slow growing and fast growing broiler chickens

M. Oblakova1, N. Mincheva1, P. Hristakieva1, I. Ivanova1, M. Lalev1, Sv. Georgieva2

1Agricultural Institute – Stara Zagora, 6000, Bulgaria
2Department of Genetic, Breeding and Reproduction, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 3 July 2017; accepted for publication 5 October 2017)

Abstract. The experiment was conducted in the breeder farm of department Population genetics, reproduction and technologies of poultry and rabbits at the Agriculture Institute of Stara Zagora. Five lines from the National Gene Pool of Bulgaria: line Ss (Sussex), line E (Barred Plymouth Rock), line NG (New Hampshire), line F (NG x Red Rhode Island), line L (White Plymouth Rock) were used as maternal forms in the crossing schedule and line M (Cornish) as a paternal form for production of slow-growing broilers. The birds were grown to 84 days. Feeding was done with compound feeds according to the age: starter (1/14 days of age), grower (14/28 days of age), finisher (28/84 days of age). By the end of the experiment, slaughter analysis was performed with 3 female and 3 male broiler chickens per group with live weight corresponding to the average of each genotype. The live weight was determined, as well as the grill weight, the weights of cuts (breast, thighs, wings), edible offal (heart, liver, gizzard) and abdominal fat. On the basis of these data, the slaughter yield and body parts ratios were calculated. The data for the live body weights of birds at slaughtering indicated the highest values for group V – 4040g, followed by groups ІV and ІІ – 3271.67g and 3186.67g, respectively (p<0.05). There was a statistically significant difference between the sexes with superiority of male birds (p<0.001). In the other 3 groups, breast meat percentage ranged from 19.48 to 19.84%. The share of thighs from the grill was the greatest in slow-growing chickens from group II – 33.01%, followed by group І – 32.35%, group IV – 32.18%, and the lowest- in groups ІІІ and V (31.91% and 31.18%, respectively). The analysis of data exhibited a significant effect of the genotype on water content of breast meat (resp. Dry matter), with lower values in slow-growing birds from group III – 73.19% (p<0.05), whereas in the other groups it ranged between 73.44 and 73.62%. The dry matter higher percentage was associated with better lavor of meat. The analysis of the effect of genotype on meat protein content showed that protein content was the highest in the breast of slow-growing chickens from group III- 24.89% and lowest in the breast meat of conventional broilers from group V – 23.86% (p<0.05). In the other 3 groups, it ranged from 24.55 to 24.59%. The protein content of thighs was the lowest in slow-growing birds from group I- 19.49%, and the difference was the highest when compared to groups II and III, also slow-growing (p<0.05). With respect to the thigh fat content, it was the highest in slow-growing chickens from group IV (5.84%), followed by fast-growing from group V (5.33%) and the lowest- in slow-growing birds from group І – 4.12% (p<0.05). The analysis of data showed a statistically significant effect of the sex on water content (p<0.001), fat (p<0.001) and ash (p<0.01). In males, thigh meat contained water and ash and in females more fat. The interaction of genotype and sex effects were important for thigh meat fat content, with highest values in fast-growing females from group V – 5.98% and lowest in slowly growing males from group I – 3.88% (p<0.001). Weak but statistically significant interaction between both factors was found with respect to thigh protein and ash (p<0.05). The highest protein content was established in slow-growing females from group IV (19.81%), whereas thigh ash was with highest percentage in slow-growing males from group II (1.11%).

Productivity of common wheat (Triticum aestivum L.) grown after various predecessors and nitrogen fertilization rates

M. Gerdzhikova*

Department of Plant Growing, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria (Manuscript received 12 December 2016; accepted for publication 20 February 2017)

Abstract. During the period 2008-2011 the influence of the predecessors wintering peas, spring peas, sunflower and common wheat and different levels of nitrogen fertilization: 0 (N0), 40 (N40), 80 (N80), 120 (N120) kg/ha after legumes and 0 (N0), 60 (N60), 120 (N120), 180 (N180) kg/ha after the other predecessors on the productivity of common wheat was studied on the experimental field of the Department of Plant Growing, Trakia University. It was found that with cultivation of common wheat without fertilization after legume predecessors higher yields by 9.4 % were obtained compared to the other predecessors. The highest yields were obtained at fertilization with the highest nitrogen rates: after legume predecessors 4069.8 kg/ha grain; after sunflower and wheat 3853.2 kg/ha of grain. The strongest influence on the productivity of common wheat had nitrogen fertilization as a factor with 79.80 %. The yield of wheat grain correlates very well with the level of nitrogen fertilization and can be determined approximately by regression equations based on the quantity of nitrogen as an independent variable.

Grain combines productivity according to various unloading methods – in the field and at the edge of the field

N. Delchev1*, K. Trendafilov2, G. Tihanov1, Y. Stoyanov1

1Department of Agricultural Engineering, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria
2Department of Machine Engineering, Faculty of Engineering and Technologies – Yambol, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 3 July 2016; accepted for publication 23 August 2016)

Abstract. Grain tank unloading is usually done at a standstill. In some cases the combine has to leave the processed strip and to unload in a vehicle located outside the field. The publication analyses the reasons for unloading grain tanks by leaving the processed strip and the impact of this type of unloading on the combine productivity compared to unloading the grain tank in the field itself. A study has been performed in Bulgarian farms using different ways of unloading and the results of time measured for unloading grain tanks in and at the end of the field have been given when harvesting various agricultural crops. The combine productivity when unloading in the field and at the edge of the field has been compared. It has been determined that when unloading at the edge of the field the productivity is approximately 11% lower than the productivity during unloading at a standstill in the field.


Productivity and quality of open field tomato after application of bio-fertilizers

H. Botеva*

Vegetable Crops Research Institute Maritsa, 32 Bezovsko shoose, 4003 Plovdiv, Bulgaria
(Manuscript received 27 April 2016; accepted for publication 31 May 2016)

Abstract. Field experiments for the effect of bio-fertilizers: Labin, Bio One, Tecamin, Agriful, Humustim and Biohumus on productivity and fruit quality of determinant tomato, variety Trapezitsa were performed on strongly leached meadow cinnamonic soil at the experimental field of the Vegetable Crops Research Institute Maritsa during the period 2008 – 2010. The fruit number per tomato plant increased up to 38.2% towards the control (without fertilization) by using bio-fertilizers Tecamin and Agriful. Similar were the results for the mass of fruits per plant, where the increase was up to 33.3% towards the control. After mineral fertilization the total tomato yield is the highest on average for the period of study. An increase of the yield in tomato with reduced mineral fertilization is established after application of bio-fertilizers 12.1% on average from 7.8% /after fertilization with Labin/ to 18.3% /after fertilization with Tecamin/ towards the control. A positive effect by fertilization with Tecamin (38.8%) and Agriful (36.3%) is established on early production. In mineral fertilization this index is lower (23.7%). Bio-fertilizers Tecamin and Agriful have a positive effect on the content of vitamin C and dry matter.


Achievements and problems in the weed control in common wheat (Triticum Aestivum L.) and durum wheat (Triticum Durum Desf.)

G. Delchev*, M. Georgiev

Department of Plant Production, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. Herbicides combinations and tank mixtures of herbicides with adjuvants, fertilizers, growth regulators, fungicides, insecticides, are more effective than when applied alone on wheat crops. Their combined use often leads to high synergistic effect on yield. Many authors present data from which it is clear that durum wheat differs from common wheat in their reaction to some herbicides, herbicide combinations and herbicide tank mixtures. A serious problem in wheat is Bromus arvensis L. due to their resistance to most antigramineous herbicides. In recent years effective herbicides to fight against them have emerged, but their number is still too limited. A problem is the persistence of some herbicides used in the predecessors on succeeding crops, which is directly related to the weather conditions during their degradation. Contrary opinions are published on some issues due primarily to the different conditions under which the experiments were conducted and the biological characteristics of the tested cultivars. Most of the information on these subjects refers mainly to common wheat and only a limited amount of it is for durum wheat. A serious problem is also the volunteers of Clearfield canola (Brassica napus L.), Clearfield and Express sun sunflower (Helianthus annuus L.). They have resistance to herbicides different from that of conventional canola and sunflower hybrids. A problem is also volunteers of coriander (Coriandrum sativum L.) and milk thistle (Silybum marianum Gaertn.). There is yet no information in the scientific literature as to control of these volunteers.


Effect of height of stem on the productivity of winter common wheat

N. Tsenov1*, T. Gubatov1, E. Tsenova2

1Agronom I Holding, 9300 Dobrich, Bulgaria
2Dobrudzha Agricultural Institute, 9525 General Toshevo, Bulgaria

Abstract. Objectives. The height of the stem of wheat has a direct impact on its productivity. Genetics of the trait is very particular in the country environments in terms of positive effects have only some of the known genes. The purpose of this study was to ascertain which of these genes for short stem (semi dwarf) alone or in combination with other could positively influence the yield of wheat in Bulgarian conditions. Methods. The study is on the relationship between the height of the stem and productivity of varieties with different genetics for their height. Selected two groups consisting of seven varieties (one check in each group), with known genetics of the trait, which differ significantly in its phenotypic expression. There are hybrid populations between selected high-stem varieties and a semi dwarf one – Medea. For two consecutive seasons (2012 – 2013) in the varieties and breeding lines created by hybrid combinations several major traits associated with the height of the stem and productivity, are analyzed. All existing differences in each trait of the groups, and the differences in correlations between them are discussed.

Key results. Productivity is highest in wheat that has medium or short height of the stem. In NPT and NGS there were no differences between “short-stem” and “high-stem” varieties. The most significant difference in favor of varieties and breeding lines with a short stem, the trait NGM (9.3 and 10.9%) and the GY (10.2 and 6.1%) and in HOS (20.6 and 44.1%), respectively. For TGW “high-stem” varieties generally have higher values in both groups studied.
Conclusions. The height of the stem has no significant negative correlations with characters specifying the productivity and grain yield itself. Selection on height of the stem in the hybrid populations towards shorter forms substantially alter the correlations between the traits associated with productivity. All tested varieties and lines are carriers of the gene Rht8. The difference in the specific conditions of about 30 cm in height is arising from the various alleles of gene Rht-B1. The semi dwarf lines carrying the genes Rht-B1e, Rht-B1b and Rht-D1b are the shortest in stem. In terms of gene Rht-D1, all varieties without exception have alleles Rht-D1a, which shortens the least stem. Best is a combination of height and grain yield in a combination of genes Rht-B1d, Rht 8 or Rht-B1e, Rht 8. All varieties with different alleles of these genes in the background of several different alleles Rht 8 are higher of 90 cm.


Productivity and stability of the yield from common winter wheat cultivars developed at IPGR Sadovo under the conditions of Dobrudzha region

P. Chamurliyski1*, E. Penchev1, N. Tsenov2

1Dobrudzha Agricultural Institute, 9521 General Toshevo, Bulgaria 2Agronom I Holding, 9300 Dobrich, Bulgaria

Abstract. One of the main directions of the common winter wheat breeding programs in Bulgaria is related to enhancing productivity. Since wheat is a crop of the microclimate, yield is strongly influenced by the conditions of the environment. The contemporary tendencies in the breeding of this crop are directed not only towards achieving high results with regard to productivity but also towards maintaining a relative stability of yield under changeable climatic factors. The aim of this investigation was to study the productivity and determine the stability of the yield from common winter wheat cultivars developed at the Institute for Plant and Genetic Resources (IPGR) Sadovo under the conditions of Dobrudzha region, Bulgaria. The field experiment was carried out in the trial field of Dobrudzha Agricultural Institute (DAI) during 2011 – 2013. Nineteen cultivars, breeding of IPGR, were tested in three replications. Cultivar Enola was used as a standard. The productive potential, the elements of yield and its stability were investigated. Two-factor dispersion, variation and correlation analyses were applied for statistical evaluation of the results, and the method of Kang, PCA analysis and AMMI models were involved to describe stability. With regard to vegetation period, the investigated materials did not differ from the standard cultivar Enola. They possessed typical good combination of high tillering capacity and grain weight per spike. The productivity of the studied accessions was formed mainly by these two indices. The cultivars, which realized highest yields averaged for the tree years of the investigation, were Mustang, Diamant, Tsarevets and Geya 1, and cultivars Bononya, Momchil and Lusil demonstrated stability by this trait. The optimal ratio between high productive potential and yield stability was observed in cultivars Mustang, Tsarevets, Momchil and Boryana.


Intensity of spike increase in Triticum aestivum L. cultivars depending on some agronomy factors

M. Nankova1*, A. Ivanova1, N. Tsenov2

1Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria 2Agronom I Holding, 9300 Dobrich, Bulgaria

Abstract. Under conditions of Haplic Chernozems, the dynamics and the intensity of dry matter increase in the spikes of the common winter wheat cultivars Pryaspa, Enola, Iveta, Bolyarka and Dragana were followed in the trial field of Dobrudzha Agricultural Institute, General Toshevo during 2009 – 2011. The investigation was carried out during stages 57-59, 69, 73, 83 and 94-95 according to Zadoks in a stationary field trial designed by the split plot method. The cultivars were grown after 4 previous crops – pea, oilseed rape, sunflower and grain maize at four levels of nutrition regime formed after main mineral fertilization. The nitrogen fertilization norms after oilseed rape, sunflower and grain maize were 60, 120 and 180 kg/ha, and after pea – 30, 60 and 90 kg/ha, respectively. The phosphorus and potassium fertilization was applied as a background, with 60 kg/ha. Each of the previous crops had a check variant without mineral fertilization. The dynamics of spike increase was influenced most by the meteorological conditions of the investigated years. The strength of effect of this factor increased in the course of vegetation. Mineral fertilization and the type of cultivar were next in significance. The role of the previous crop in the course of vegetation was low, being statistically significant only at the final stage. Similar tendency was observed in the daily rate of spike increase, but at the beginning of heading the cultivar had a better expressed effect in comparison to mineral fertilization. The intensity of spike increase was highest after nitrogen fertilization with 120 and 180 kg/ha. The cultivars had higher daily rate of spike increase during inter-stage periods 73–69 and 83–73 according to Zadoks. The spikes of cultivar Dragana increased with the highest mean daily rate from heading to maturity (16.126 kg/da/day). Depending on the type of previous crop, the mean values of daily intensity varied from 13.418 kg/da/day (maize) to 15.106 kg/da/day (pea). The differentiation with regard to the meteorological conditions of the year was very well expressed; the spikes increased with highest rate in 2011 – 20772 kg/da/day, averaged for heading-maturity. High values were determined of the correlations between the dry matter formed in the spikes during the separate stages of development and the rate and intensity of dry matter accumulation.


Productivity and grass density of the main types of pastures in Sakar and Strandja region

V. Vateva*
Department of Engineering and Technologies, Faculty of Technics and Technologies, Trakia University, 6000 Stara Zagora, Bulgaria
Abstract. Grassland associations are natural resource, which in their proper use might affect the welfare and economic development of the region in which they are located. In Sakar and Strandja regions such herbaceous plant associations occupy about 107.3 thousand hectares. Only in those regions of the country there is a favorable combination of environmental and climatic conditions allowing almost all year round utilization of pasture grass associations. They are the main potential to supply feed for the animals. In this experiment, the goal is to tracce and identify the productivity of natural pasture grass associations in Sakar and Strandja mountain. Observations were performed on the most typical, the most common and most used pastures located in these regions. The density of the pasture types was established. A comparative analysis of productivity of fresh mass and dry pasture grass of Sakar and Strandja region was performed. The results show that the pasture types in Strandja region possess higher density and greater productivity than those in Sakar region. With the highest density in Sakar region are the grassland type Agrostis capillaris – Festuca fallax, with a density of up to 1972 pieces/m2 at least. In Strandja region pasture type Agrostis capillaris – Cynosurus cristatus – Lolium perenne reaches density 3716 pieces/m2. These types of pastures are distinguished with the highest productivity of fresh and dry biomass. In Sakar region from pastures of type Agrostis capillaris – Festuca fallax 16680 kg/ha green mass and 4920 kg /ha dry matter can be obtained, and in Strandja region from grassland of type Agrostis capillaris – Cynosurus cristatus – Lolium perenne, 31700 kg/ha fresh mass and 7380 kg/ha dry matter can be obtained.


Sulfo technology for multiplication of sunflower hybrids resistant to tribenuron metil-based herbicides

C. Melucă, N. Pîrvu, T. Nistor, R. Sturzu, A. Stoilova
Abstract. Certain experiments with sunflower hybrids realized through Sulfo technology, resistant to tribenuron methyl 75% based herbicides were performed at Agricultural Research and Development Station(ARDS)Teleorman, Romania. There is a response to the hypothesis that the herbicide application (4–6 real leaves) when night temperatures (after application) are lower than 12°C could provoke higher damages at green tissue level. Damages were registered of 6.5–11.8% and decreased to 0.8–5.6% when temperatures were higher than 12°C. The yielding ability of these sunflower hybrids is not affected as compared to the conventional check hybrid Favorit, its level was, on three year average, of 3652–4985 kg/ha, versus 3735 kg/ha achieved by the Favorit hybrid. It may emphasize that the hybrid Toro showed the highest gain in yield versus the check hybrid Favorit (1250 kg/ha, respectively 33.5%). The yielding ability of the hybrid Toro exceeded by 774 kg/ha (11.8%) the yield achieved by the hybrid PR 64 LE20 (Pioneer registration).