Heterosis and degrees of dominance of grain yield and grain yield elements in maize hybrids in different groups of ripeness

M. Ilchovska*

Maize Research Institute, 5635 Knezha, Bulgaria
(Manuscript received 10 Juny 2016; accepted for publication 29 November 2016)

Abstract. This study is conducted in the period 2014 – 2015 in the experimental field of the Maize Institute, Knezha by using an agro technique adopted for the region. For the purposes of the study four maize hybrids Kn 307, Kn 435, Kn 509 and Kn 625М are included at different degree of maturity – FAO 300-399; 400- 499; 500-599 and FAO above 600. The hybrids together with their parental forms are studied in competitive variety trials under conditions without irrigation at three densities of the crop 45000pl/ha; 55000рl/ha and 65000рl/ha. From the presented results obtained based on the data of manifestation of heterosis and the degrees of dominance of the hybrids clearly expressed heterosis is established for the traits grain yield, length of cob and number of grains per row. For the trait number of rows in the cob both presence and absence of heterosis is observed. The degrees of dominance in F1 also vary widely, from intermediate inheritance to incomplete positive dominance and over-dominance.

Heterosis manifestations by survival and larval duration of F1 Bombyx mori L. Hybrids reared with artificial diet

R. Guncheva1*, M. Panayotov1, P. Tsenov2, Y. Dimitrova2

1Department of Animal Science – Non-ruminants and other Animals, Faculty of Agriculture, Trakiа University, 6000 Stara Zagora, Bulgaria 2Sericulture and Agriculture Experiment Station, 3000 Vratsa, Bulgaria

(Manuscript received 2 July 2016; accepted for publication 22 November 2016)

Abstract. The aim of this paper was to study the influence of the degree of heterosis (compared to higher parent value- HP and mean parental values- MP) on the signs, survival and duration of development in F1 hybrids of Bombyx mori L. from different geographical origin, fed by artificial diet. The study was conducted at the Training Experimental Station of the Sericulture section of the Faculty of Agriculture at Trakia University. A total of 10 hybrids were tested featuring 6 breeds from the genetic bank of Sericulture and Agriculture Experiment Station (SAES)-Vratsa. Silkworms were reared with artificial diet containing 15% powder of dried mulberry leaf produced at SAES-Vratsa and prepared by methods, developed by the manufacturer, whereby 250g of dry substance and 675ml of distilled water are homogenized using a mixer. The mixture is cured thermally in a microwave for 10min. at ~800W. The receptivity of specimens was determined based on the results from the survival and the duration in the I-st age of the larval stage. In heterogeneous crossbreds higher survival rate in the first age is exhibited by hybrids in which a Japanese type breed was used as dam. Homogeneous crossbreds created with the participation of Japanese breeds excel in both analyzed traits those involving a Chinese type. For the survival trait heterosis manifestations to higher parent value (HP) and mean parental values (MP), were detected in the majority of hybrids (90.91%). Regarding the duration of development, heterosis effect to MP was observed in all F1 hybrids, while to HP heterosis is exhibited by 60% of the tested F1 hybrids.

Breeding programme for developing new sweet cherry cultivars in the Fruit Growing Institute, Plovdiv, Bulgaria

S. Malchev*, A. Zhivondov

Fruit Growing Institute, 12 Ostromila, 4004 Plovdiv, Bulgaria
(Manuscript received 2 June 2016; accepted for publication 21 September 2016)

Abstract. Sweet cherry is a major structural species in Bulgaria. According to the Ministry of Agriculture and Food, in 2010 it occupied 21% of the fruit tree areas, which defined it as a leading fruit crop. It represents 16% of the total fruit production in the country, as is the relative share of peach, being surpassed only by apple and plum production. The increased interest in establishing new cherry plantations necessitates the provision of new market-oriented cultivars with a better sensory profile of the fruits, resistant to biotic and abiotic stress factors, suitable for creating modern intensive cherry plantations. The Bulgarian sweet cherry cultivars are chronologically discussed and a thorough description of the development of the sweet cherry breeding programme, launched at the Fruit Growing Institute in Plovdiv in 1987, is presented. Current objectives comply with the world’s major breeding trends and the changing market requirements. The paper reflects the main objectives of the programme and the finalized products obtained in the last twenty years of the past century and first decade of the new millennium, i.e. the new cultivars ‘Kossara’, ‘Rosita’, ‘Rozalina’ and ‘Thrakiiska hrushtyalka’ and some promising hybrids.

Quality of grain and flour of foreign bread wheat cultivars (Triticum aestivum L.) under the conditions of south Dobrudzha region

P. Chamurliyski1*, N. Tsenov2, I. Stoeva3, S. Doneva3, E. Penchev3

1Department of Crop Science and Plant Protection, College Dobrich, Konstantin Preslavski University of Shumen, 9300 Dobrich, Bulgaria 2Agronom I Holding, 9300 Dobrich, Bulgaria
3Dobrudzha Agricultural Institute, 9521 General Toshevo, Bulgaria

(Manuscript received 23 March 2016; accepted for publication 28 September 2016)

Abstract. One of the main directions of the breeding programs in common winter wheat, besides increasing productivity, is developing of cultivars with excellent baking properties. An important prerequisite for this is the involvement of new gene plasma of variable origin, which is adequate to the growing conditions and the desired breeding direction. The aim of investigation is study of some main properties related to the grain quality and the baking properties of bread wheat accessions of foreign origin under the conditions of the South Dobrudzha region. Twenty-five foreign bread wheat cultivars of various origins were investigated for a three year period. Cultivars Aglika, Enola, Pryaspa and Yantur were used as standards. Some indices related to the quality of grain and flour were analyzed at the Bread Making Laboratory of Dobrudzha Agricultural Institute (DAI). The expression of the following parameters was followed: test weigh, % of protein, sedimentation, wet gluten yield, softening degree, pharinographic value, bread volume, and the quality index (QI) was calculated. The cultivars, which demonstrated high grain quality, were the Romanian Faur, Moldovan Dobropolka, American Wahoo and the Ukrainian Zmina. Averaged for the three years, highest variation was found for the index pharinographic value. On the whole, the materials with origin from Romania, Ukraine and USA were characterized with high values of the quality indices. Cultivars Faur and Zmina can be successfully included in the breeding program of DAI for development of strong wheat varieties.

Production properties of flax (Linum usitatissimum L.) cultivated in Strumica region, Republic of Macedonia

P. Vuckov*, M. Ilievski, D. Spasova, L. Mihajlov, N. Markova-Ruzdić

Department for Crop Production, Faculty of Agriculture, University Goce Delchev, 2400 Stip, Republic of Macedonia (Manuscript received 30 May 2016; accepted for publication 16 September 2016)

Abstract. The purpose of this research was to determine the production properties of 5 flax genotypes cultivated in agro-ecological conditions in the Strumica region, Republic of Macedonia.The research was conducted in a period of two years (2014 and 2015), on the research fields in Strumica at Uni Service – Agro, Faculty of Agriculture, University Goce Delchev, Stip.The research was conducted on 5 genotypes of flax, 4 of which are domestic intermediate genotypes (transitive) flax (Velusina, Duferin, Belan, Belinka) and one French introduced fiber flax variety (Viking). The experiment consisted of five variants in three iterations, divided by the method of random block system for each genotype.The number of fruit per plant in both years of testing is statistically different among different genotypes. In the first year of the examination (2014), the largest number of fruit per plant had genotype Velusina (156) and the lowest (70.3) genotype Belan. In the second year of the examination (2015), the largest number of fruit per plant had the genotype Velusina (102.3) and the lowest (54.7), genotype Belinka.There is no statistically significant difference in number of seeds in the fruit among the tested genotypes. In the first year of the examination (2014), the largest number of seeds in fruit had genotype Velusina (4.63) and the lowest (2.26) – genotype Viking. In the second year of the examination (2015), the largest number of seeds in fruit had genotype Belan (9.96) and the lowest (7.06) – genotype Duferin. In the first year of the examination (2014), the largest number of seed yield per plant in kg/ha had the genotype Viking (500 kg/ha) and the lowest – genotype Belinka (210 kg/ha). In the second year of the examination (2015), the largest number of seed yield per plant in kg/ha had genotype Velusina (1100 kg/ha) and the lowest – genotype Belinka (780 kg/ha). In both years of research (2014 and 2015) there were statistically significant differences on the level of probability of 0.05 and 0.01 among the examined genotypes. Based on the survey results the most promising genotypes in terms of stability, yielding and quality are proposed to producers and industry, both at home and abroad.

Productivity performance of bread winter wheat genotypes of local and foreign origin

G. Raykov1*, P. Chamurliyski1, S. Doneva1, E. Penchev1, N. Tsenov2

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

(Manuscript received 12 October 2015; accepted for publication 18 October 2016)

Abstract. The proper choice of parental forms is the basis for developing superior varieties with valuable agronomic properties. A priority in modern breeding is increased productivity. The aim of this study was to establish the relative contribution of the yield traits to the productivity of common wheat accessions of different geographical origin. The trial was conducted during 2012 – 2014 at Dobrudzha Agricultural Institute, General Toshevo. The study included 118 varieties and lines originating from Europe, Asia and North America. The tested materials were grown in a randomized block design in three replications, the plot size being 7.5 m2. Six cultivars were used as standards: Aglika, Pobeda, Enola, Sadovo 1, Antonovka and Pryaspa. Number of grains per spike, number of grains per m2 and thousand kernel weight had the highest positive influence on grain yield. The highest levels of productivity were reported in cultivars PKB Vizelika, PKB Rodika, Joana and Midas averaged for the two years of the study, cultivar Vizelika with origin from PKB – Serbia realizing a yield of 9.03 t.ha-1. Despite environmental effect and interaction, significant genotypic modality on the investigated traits was observed and analyzed. All studied accessions can be successfully included in a breeding program to increase productivity.

Sensitivity of promising cherry hybrids and new cultivars to economically important fungal diseases

K. Vasileva1, S. Malchev2*, A. Zhivondov2

1Agricultural University, 12 Mendeleev, 4000 Plovdiv, Bulgaria 2Fruit Growing Institute, 12 Ostromila, Plovdiv, Biulgaria

(Manuscript received 2 June 2016; accepted for publication 29 August 2016)

Abstract. As a result of years of developing the breeding programme for creating novel sweet cherry cultivars in the Fruit Growing Institute (FGI), Plovdiv, a reach hybrid fund from first and second hybrid generation is created. Of the selected and propagated hybrids at a more advanced stage of testing are 11 hybrids along with three new cultivars of the FGI Plovdiv (‘Kossara’, ‘Rosalina’ and ‘Trakiiska hrushtyalka’) grafted on three rootstocks were tested for sensitivity to causers of economically important fungal diseases in sweet cherry – cherry leaf spot (Blumeriella jaapii (Rehm) Arx), shothole blight (Stigmina carpophila (Lev.) Ellis) and brown rot (Monilinia fructigena (G. Wint) Honey). The degree of infestation under field conditions is reported by determining the index of attack on leaves and fruit, using the formula of McKinney. As the most sensitive elites are outlined elite El.17-31 (to cherry leaf spot) and elite El.17-136 (to shothole blight). The cultivars ‘Kossara’ and ‘Trakiiska hrushtyalka’ exhibit an average resistance to the three diseases, as the values for the index of infestation are lower or similar to those of standard cultivars ‘Van’ and ‘Bing’, while ‘Rosalina’ demonstrated sensitivity to shothole blight and brown rot. Interesting is the elite El.17- 37 demonstrating the least infestation of Blumeriella jaapii – 7.33% and Monilinia fructigena – 6.67%. The same has a set of valuable qualities as late maturing date and very large fruits with excellent sensory profile, making it a potential candidate cultivar.


Evaluation of small size fruit peppers Capsicum annuum spp. microcarpum with cluster and factor analysis

V. Kuneva1*, M. Nikolova

1Department of Mathematics, Informatics and Physics, Faculty of Economics, Аgricultural University, 4000 Plovdiv, Bulgaria 2Institute of Plant Genetic Resources K. Malkov, 4122 Sadovo, Bulgaria

(Manuscript received 4 July 2016; accepted for publication 28 August 2016)

Abstract. 43 specimens of local small size fruit peppers (Capsicum annuum sub. microcarpum) were examined and characterized with reference to the indicators: shrub height, number of shrub branches, leaf length, leaf width, fruit length, fruit diameter, one pepper mass, 1000 seeds mass, number of fruit on one plant. The research was conducted in the experimental field of Institute of Plant Genetic Resources (IPGR), Sadovo, in the period of 2009 – 2011. On the base of the examined indicators, the specimens were evaluated complexly through a hierarchical cluster analysis. Genetically close specimens were grouped in 7 main clusters and presented with the help of a dendrogramm. In addition, a factor analysis was made to establish the indices with the highest influence of distribution of the specimens in the received clusters. The main 10 indicators from the research are reduced to 4 factors, which are responsible for 76.16% from the total dispersion of variables. The principal indicators that separate the examined specimens in clusters are: leaf length and width, fruit length and diameter, as well as mass of one pepper. This classification helps for a higher objectiveness of evaluation. It leads to a more complete characterization of small size fruit peppers for their more rational use in different selective programs.


Evaluation of the combining ability of mutant maize lines

V. Valkova*, N. Petrovska

Maize Research Institute, 5835 Knezha, Bulgaria
(Manuscript received 6 June 2016; accepted for publication 18 August 2016)

Abstract. The study shows the results of a preliminary evaluation of the combining ability for grain yield of 17 mutant maize lines. For the purpose the top cross method for early testing and the mathematical model of Savchenko for analysis of the general and the specific combining ability were used. The lines were tested on three testers with high general combining ability that belong to two genetic groups: K 46 52 and XM 552 from SSS and N 192 – Lancaster. For the purposes of evaluation of the productive abilities of the received top cross two preliminary varietal experiments were carried out at the experimental field of Maize Research Institute, Knezha As a result of the conducted experimental work and the analysis it was found that the highest general combining ability have lines XM 11 6 and XM 12 1. These lines can be included as components of high-yielding synthetics or as testers in analyzing crosses to determine general combining ability in early stages of the selection process. The above lines with high specific combining ability – XM 11 13 and XM 11 46 are suitable for inclusion in combinations to develop high-yielding hybrids. Three of the tested lines XM 11 7 11 XM 10 and XM 11 11 have both high GCA and SCA. These lines can be used in corresponding breeding in the selection programs.


Characterization of the Bulgarian sunflower hybrid Valin

G. Georgiev*

Dobrudzha Agricultural Institute, 9520 General Toshevo, Bulgaria (Manuscript received 1 July 2016; accepted for publication 26 August 2016)

Abstract. A male sterile two-linear sunflower hybrid was developed at Dobrudzha Agricultural Institute – General Toshevo using the method of inter-linear hybridization. The mother component is line 10517 which possesses cytoplasmic male sterility, and the father component is line 10595R, a fertility restorer of branched type. Both parental forms have very good general and specific combining ability. Hybrid Valin is medium early, with vegetation period of 110 – 115 days, plant height 165 – 175 cm and head diameter 17 – 18 cm. The percent of kernel in seed is within the range of 65 – 73%. Seeds have absolute weight 50 – 55 g, and oil content in seed is 46 – 50%. The hybrid is resistant to lodging and moderately resistant to phoma and phomopsis. The resistance to downy mildew is as high as 95 % up to race 700, and the resistance to the parasite Orobanche is 100% (races A-F). In the breeding fields of DAI the hybrid went through three- year testing according to a scheme and growing technology approved for this crop. During the first two years of the control testing it exceeded the mean standard by seed yield with 11.0% and 14.4%, respectively. During the third year, hybrid Valin was above the mean standard with 10.9% by seed yield and with 6.6% by oil yield in a unified competitive varietal testing. The maximum yield obtained at DAI was 4483 kg/ha, and the maximum oil content was 50.1%. In 2007 and 2008 hybrid Valin went through official testing within the structure of the Executive Agency of Variety Testing, Field Inspection and Seed Control of Bulgaria. By the index seed yield, the exceeding of the mean standard was 23.6 % in the first year, and in the second the yield was with 1.4 % below the standard. Oil content was a little below the standard in both years. The aim of this investigation was to make as full as possible a characterization of the new registered sunflower hybrid Valin on the base of biological,phytopatological and economical indices.