Influence of mineral nitrogen and organic fertilization on the productivity of grain sorghum

S. Enchev*, G. Kikindonov

Agricultural Institute, 9700 Shumen, Bulgaria

Abstract. The production of grain sorghum has increased in recent years. The modern varieties are hybrids with high productivity potential appropriate for application of intensive forage grain production technologies. The increased requirements for ecological production necessitate optimization of the nutrition parameters in the conditions of unstable agriculture with unbalanced soil nutrient substance accumulation. The effect of nutrition with mineral nitrogen fertilizer and organic fertilizer Humustim on the productivity of 6 varieties of Euralis Semences, popular in the practice, was tested during 2011 – 2013. In the various climatic conditions fertilization is a highly effective factor for productivity increase. The use of organic fertilizers such as Humustim widens the possibilities of the ecological production.


Energy productivity, fertilization rate and profitability of wheat production after various predecessors I.Energyproductivityofwheat

Z. Uhr1*, E. Vasileva2

1Institute of Plant Genetic Resources, 2 Druzhba, 4122 Sadovo, Bulgaria
2University of Agribusiness and Rural Development, 78 Dunav, 4000 Plovdiv, Bulgaria

Abstract. As a consequence of a long-year comparative study of quality, productivity and physiological characteristics of Bulgarian varieties of common winter wheat(Triticumaestivum),wecarriedouta studyontheadaptationofmoderngenotypestotherequirementsofsustainableagricultureandrespectivelytheir effectiveness of breeding methods with respect to these requirements. In the course of this study were also accumulated additional data concerning the influence of the predecessor and nitrogen fertilizer rate on energy productivity of crop, energy and recyclable efficiency of fertilization and profitability of production. In two consecutive publications we summarize and share with the scientific community the data that we have received. The results are up-to-date and useful in both theoretical and practical aspects. The analysis is based on data from field fertilizer experiments carried out with predecessor cereal – regular crop of sorghum, millet, maize and legumes after predecessor–separate sowing of chickpeas. Energy productivity is calculated as a function of yield (grain, straw and total biological yield, (t/ha), multiplied by the energy equivalent unit (MJ/kg). Maximum values of gross energy productivity by grain yields are reported by fertilization rate with 0.18 t/ha nitrogen fertilizer after cereal predecessor and after 0.06 t/ha after legumes. After cereal predecessor the effect of increasing the fertilizer rate to 0.18 t/ha N improves energy productivity of grain by 160% compared to the control N0. After legumes predecessor at N 0.0 t/ha energy productivity with grain was 12%, and in N 0.06 – 21% higher than the maximum (at 0.18 t/ha) after cereal predecessor. Legume predecessor unifies differences between genotypes and fertilizer levels on energy productivity of grain and increases energy productivity of straw by 16% on average. Maximum values of gross energy productivity of straw are reported in fertilization with 0.12 t/ha after wheat and 0.24 t/ha fertilizer nitrogen after legume predecessor. Increasing the fertilizer rate from 0.0 t/ha to 0.18 t/ha nitrogen reduces the difference in the gross energy productivity of crops after legumes and cereal predecessor from 105% in 0.0 t/ha to 10% in 0.18 t/ha. The differences between both varieties regarding the studied parameters are statistically significant at P < 0.001.


Phosphorus fractions in alluvial meadow soil after long-term organic-mineral fertilization

S. Todorova*, K. Trendafilov, M. Almaliev

Department of Agro-chemistry and Soil Science, Faculty of Agronomy, Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria

Abstract. The aim of our study was to investigate phosphorus fractions, their content and distribution in alluvial meadow soil after continuous fertilization. Our research was focused on a long-term field experiment with different variants of fertilization set in 1959 in the Experimental field of Agricultural University of Plovdiv. Since 2006 the fertilization has been discontinued. In 2011, we collected soil samples from two depths (0 – 30 and 30 – 40 cm) and from the following variants: variant 1 (control, without fertilization), variant 2 (N50P30K20), variant 3 (N25P15K0 + 6t/da manure), variant 4 (N50P0K20). The studied soil is characterized by relatively good natural phosphate regime. The amount of available phosphates determined by the Egner-Rheem method is high – average 16.76% of the total phosphorus. Over 50% of the mineral phosphates in the soil are in available (in varying degree) form. Relatively high is the amount of organic phosphates, which during the mineralization can also be involved in the plant nutrition. The amount of available phosphates (according to Egner-Rheem) is determined to the highest degree by the total phosphorus in soil, which in turn is highly correlated with the content of hardly soluble calcium phosphates.


Ethological and haematological indices in yearling sheep fed various dietary nitrogen sources

I. Varlyakov*, V. Radev, Т. Slavov, R. Mihaylov

Departmet of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. A physiology experiment was conducted to evaluate the effects of diet supplementation with non-protein nitrogen compounds Optigen and urea. The trialcomprisedthreeperiods:control–yearlingsheepwerefed rationwithbarley,sunflowermealandmeadowhay;firstexperimental–thesamerationwas supplemented with 12 g Optigen and second experimental – the ration was supplemented with 10.6 g urea. The addition of Optigen resulted in increased appetite and faster consumption of the food as seen from lower feeding time and increased rumination time. The welfare of animals was good as seen from the low ratio of time spent ruminating in standing position to total rumination time and the dominating values of rumination and rest times without statistically significantdifferencesbetweenexperimentalperiods.Therewerenodifferencesbetweentimesspentstandingand loafing,includingmovementinsidethe box, which is an indirect index for lack of discomfort and reliable testimony for the conditions of the present experiments. The blood picture results allowed affirming that the health status of experimental animals was within the reference limits. Proofs in support of this thesis were the fact that lower red blood cell counts were compensated by the higher haemoglobin content, whereas white blood cell counts were normal and accompanied by nutritional leukocytosis during all three study periods.


Hybridization between cultivated sunflower and wild annual species Helianthus petiolaris Nutt.

D. Valkova*, G. Georgiev, N. Nenova, V. Encheva, J. Encheva

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

Abstract. InterspecifichybridizationwascarriedoutbetweensterileanaloguesofcultivatedsunflowerlineswithnormalcytoplasmandwildannualHelianthus petiolaris accessions from a collection of DAI-General Toshevo. The obtained F1 progenies were characterized from morphological, phenological, biochemical and phytopathological point of view. Hybrid forms with resistance to leaves pathogens, downy mildew and broomrape were obtained. They were distinguished with diversity of seed oil content. The most variable phenological phases of hybrid plants from all crosses were duration of flowering period and germination. The hybrid plants from crosses 325 A x E-142 and 813 A x E-142 were characterized with higher seed oil content than the other studied crosses. All hybrid plants, originating from wild Helianthus petiolaris accession E-142 were resistant (100%) to downy mildew and to the parasite broomrape. They were also with immune type of reaction to the leaves pathogens and with the highest oil content in seeds. Among the included in the investigation accessions, E-142 was characterized with the highest crossability. The hybrid plants of the crosses included in this study were carriers of Rf genes and could be used for developing restorer lines.


Investigation on the parthenogenetic response of sunflower lines and hybrids

M. Drumeva*, P. Yankov

Department of Plant Production, Faculty of Marine Sciences and Ecology, Technical University Varna, 1 Studentska, 9010 Varna, Bulgaria

Abstract. When applying gamma-ionizing radiation for induction of parthenogenetic doubled haploidy, the female genotype exercises certain effect. The effect of the female may be expressed in lack of parthenogenetic response, in lower responsiveness or in specific selectiveness with regard to the type of parthenogenetic development. This investigation studied the parthenogenetic response of two lines and three hybrids of sunflower used as initial female material. Parthenogenetic reaction were registered in the tested hybrids, while parthenogenetic embryos were not obtained from some variants including lines, and, on the whole, lower responsiveness was determined. The effect of the female genotype was expressed in differences both in the responsiveness of the investigated lines and hybrids to induction of parthenogenetic development and in the variable reaction among the different lines and hybrids. The variations in the parthenogenetic response of the individual hybrids subjected to this investigation, which differed between themselves by their nuclear-cytoplasmic characteristics, were indicative for the dependence of the method on the genotypic and cytoplasmic specificity of the initial female material.


Screening Pisum sp. accessions for resistance to Pseudomonas syringae pv. pisi

M. Koleva1*, I. Kiryakov2

1Department of Crop Science and Plant Protection, College Dobrich, Konstanin Preslavski University of Shumen, 9300 Dobrich, Bulgaria 2Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria

Abstract. Pea (Pisum sativum L.) is a main grain leguminous crop in Bulgaria. Breeding resistant pea varieties is the most economically important method for disease control especially in pea bacterial blight, caused by Pseudomonas syringae pv. pisi. The investigation was carried out during 2013 – 2014 at Dobrudzha Agricultural Institute, General Toshevo. Forty-eight Pisum sp. accessions were used. Two strains of P. syringae pv. pisi (Bz4 and NCPPB 2585) were used. The plants were inoculated twice: at phenophase budding (petioles) and grain filling (pod) with bacterial suspension in concentration 1 х 108 CFU/ml using 1ml syringe. The reaction of the accessions was read 10 days after inoculation. A nine-degree scale was applied. According to the mean disease index (MDI) the accessions were divided into five groups: immune (I), resistant (R), middle resistant (MR), susceptible (S), very susceptible (VS). Twenty-five Pisum sp. accessions had resistant to moderately resistant reaction of leaves and pods to strain NCPPB and twelve accessions to strain Bz4, respectively. Eleven accessions (including P. sativum ssp. sativum, P. humile, P. elatius, P.s. var. hibernicum, P. abyssinicum, P. transcaucasicum, P. tibetanicum) had resistant reaction to leaves and pods to both strains. One of them is resistant to pea powdery mildew (Erysiphe pisi). Some accessions had different response of leaves and pods to both strains which confirms the position for different genetic control of resistance of leaves and pods. The results of our investigation showed that some Pisum sp. accessions could be used as a donor parent in a breeding program for bacterial or complex resistance on pea.


Study of factors affecting sporophytic development of isolated durum wheat microspores

V. Bozhanova1*, Horst Lorz

1Field Crops Institute, 6200 Chirpan, Bulgaria
2Biocenter Klein-Flottbek, AMP II, University of Hamburg, D-22609 Hamburg, Germany

Abstract. A microspore culture technique is used to produce homozygous lines of agronomic interest in a single generation. Several factors affecting the efficiency of in vitro sporophytic development of durum wheat microspores such as genotype, stress preatreatment, density and co-cultivation of isolated microspore and induction medium were studied in order to develop a protocol for dihaploid plants production. Strong genotype dependence in in vitro response and callus/embryoid capacity was observed. Cultivated microspores developed into macrostructures only after cold pretreatment of the collected spikes at +4°C for 4 weeks. The best results were achieved at density 10000 microspores/mlonthemod. Chu Medium (Chu et al., 1990) + 0.5mg/lBAP + 0.5mg/l2,4D + 90g/l maltosa with ovaries co-cultivation. A lot of macrostructures developed to embryoids, but only a few produced poorly-developed shoots–most of them were albinos.


Involvement of the transcriptional variants of histone H3.3 in the development and heat stress response of Arabidopsis thaliana

M. Naydenov*, B. Georgieva, V. Baev, G. Yahubyan

Department of Plant Physiology and Molecular Biology, University of Plovdiv, 24 Tsar Assen, 4000 Plovdiv, Bulgaria

Abstract. Unlike prokaryotic DNA, eukaryotic DNA is packed in a chromatin with a number of proteins, of which histones are the most important for chromatin structure and dynamics. Along with the 5 canonical histones- H2A, H2B, H3, H4 and H1 linker histone, there are many histone variants. The latter proteins play a crucial role in chromatin remodeling and gene regulation. Studies investigating the involvement of the H3 variant – H3.3 in later developmental stages and stress response of plant are few. In this work we searched available databases for histone variants of A. thaliana and 54 genes coding histones in A. thaliana were identified, 14 of them belonged to the H3 family. In order to analyze this family, multiple alignments of the corresponding amino acid sequences were performed. The gene AT4G40030 which encodes H3.3 showed 3 transcriptional variants. The expression analysis revealed that the two of variants – H3.3 (1) and H3.3 (2) were found in all overground organs, but the third one – H3.3 (3) was not detected in any of them. Semi-quantitative PCR analysis of heat-treated plants revealed that H3.3 (1) and H3.3 (2) had a higher expression compared with untreated control. These results suggest participation of these H3.3 (1) and H3.3 (2) variants in development processes and plants response to abiotic stress.


Effect of feeding program for first two months after birth of female calves on growth, development and first lactation performance

G. Ganchev*, E. Yavuz, N. Todorov

Departmet of Morphology, Physiology and Animal Nutrition, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

Abstract. The aim of this paper was to review the available literature examining the relationship between milk feeding method of dairy calves during preweaning period on their growth and development. We conclude that delayed and inadequate colostrum feeding can result in increased morbidity and mortality. The higher level of milk feeding for dairy calves has the potential to increase growth rates during the preweaning period, to reduce time needed to reach a necessary body weigh at first calving and improve milk yield at first calving. Providing more milk however, may decrease intake of solid feed during the period of feeding milk. So far is it not clear, whether it is possible to combine intensive liquid feeding with sufficient dry feed intakes at weaning to continue normal growth of calves; otherwise, what is the level of milk feeding allowing small, or even to avoid, slump in growth at weaning. It is not known what level of milk feeding plus free access to starter allows obtaining a high level of live body gain during the first two months necessary for enhancing future milk yield of heifer calves. Additional studies are needed to clarify effect of different levels of milk feeding and scheme of feeding female dairy calves on growth rate, development, feed efficiency and health status during pre weaning and post weaning period.