Abstract. The objective of this investigation was to study the phenotypic diversity among six-rowed winter barley varieties. The study was conducted in the Institute of Agriculture -Karnobat, during the period 2014/2015-2015/2016. The diversity among 22 barley varieties was estimated using principal component analysis and cluster analysis. Maximum variation was found for grain weight per a spike and grain number per a spike. The presence of significant variation among the evaluated six-rowed winter barley varieties suggests an opportunity for improvement of grain yield through using promising genotypes as parents in the winter barley improvement program.Keywords: barley, phenotipic diversity, cluster analysis, principal component analysis AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. , No , 201 10 1 16 20 8 DOI: 10.15547/ast.2018.01.004 IntroductionBarley is an important cereal crop in Bulgaria. One of the main objectives of winter barley breeding program is to produce highyielding and better-quality lines for release as cultivars (Mihova, 2013;Valcheva et al., 2013;Gocheva and Vulchev, 2014;Dimova, 2015). The presence of genetic diversity among genotypes is a prerequisite and paramount important for a successful breeding programme. The study of genetic divergence can assist in the choice of genotypes to be used in breeding programs for the development of new populations as it estimate the extent of diversity existed among selected genotypes (Mondal, 2003). Genetically diverse parents are able to produce considerable variability, which can enhance the scope of selection. The more diverse the parents, greater are the chances of obtaining broad spectrums of variability in segregating generations (Arunachalam, 1981).A number of methods like principal component analysis, factor analysis and cluster analysis are presently available for the selection of parent and detection of genetic and phenotypic variability (Bertan et al., 2007). Hierarchical clustering techniques with Ward's method and average linkage probably have long been the most popular clustering method (Milligan, 1980). The techniques of multivariate analysis are also often used in genetic improvement programs to predict the genetic distance among the accesses (Hair et al., 2006). With each approach having distinct advantages and disadvantages, it has been proposed to use both methods to gain the benefits of each (Milligan, 1980; Hair et al., 2006).The aim of this study was to identify phenotypic diversity among six-rowed winter barley varieties using principal component analysis and cluster analysis and select varieties with desirable traits for including in Bulgarian winter barley breeding program. The materials used in present study included 22 varieties of sixrowed winter barley: Albacete -Spain, Asterix and Sympa -France, Bagova, Dura, Georgia, Gita, Hasso, Hauters and StructuraGermany, Elassona -Greece, Hongehon Mahrve and Zaizai ShiroRepublic of Korea, Jumbo -Netherlands, Kerajiro and Takayama Sangatsu -Japan, Kujawiak -Poland, Manatou -Belgium, Puebl...

A field experiment was conducted at the Institute of Agriculture – Karnobat, Southeastern Bulgaria in three growing seasons. Twenty barley varieties were laid out in a complete block design with 4 replications. Variability, heritability and genetic advance for yield-related traits and grain yield were studied. There were significant differences among varieties for all studied traits including grain yield. Heritability in broad sense ranged from 10.10% for grain yield to 94.60% for spike length. High heritability estimates and genetic advance as percent of mean was computed for spike length and 1000 grain weight. Besides, genotypic coefficient of variance and phenotypic coefficient of variance had low differences for these characters. Therefore, these traits could be easily improved by selection. Grain yields of the check varieties Veslets and Izgrev were 5.27 t/ha and 5.09 t/ha, respectively. The varieties that performed better than the checks for grain yield were PA86-49-95 (6.43 t/ha), Bojin (6.01 t/ha), and Express (5.90 t/ha). Hence, using these varieties in the breeding program of winter feed barley could lead to the improvement of grain yield.

Abstract. Seeds of Hordeum vulgare L. cultivar Izgrev were treated with different concentrations of sodium azide to induce genetic variability for the selection of genotypes with improved traits. After passing through different stages of selection, 18 promising mutants were selected for further studies. Eighteen mutants and their parent and national standard cultivar Veslets were evaluated in Complete Block Design with four replications. The research was conducted in 2013 -2014 and 2014 -2015 growing Keywords: barley, mutation, sodium azide, grain yield AGRICULTURAL SCIENCE AND TECHNOLOGY, VOL. 9, No 2, pp , 2017 DOI: 10.15547/ast.2017 Introduction mM and 3 mM sodium azide for 2 hours, prepared in buffer solution (pH=3) at room temperature and washed for 6 hours after treatment.The M1 plants grown in field were harvested in bulk. In M2 To improve yield and other traits in barley, many breeding generation one spike per selected plant was harvested and seed of techniques are being successfully used. Mutation breeding is one of each M2 spike was sown in the field as spike to row progeny for M3 the important techniques to induce variation. Induced mutation had generation. The parent variety was planted in every 10 rows as a significantly contributed in developing superior crop varieties of seed check. The mutants were developed through selection for higher and vegetatively propagated crops. The mutant cultivars in different yield than the parental material by applying selection pressure from crops had great economic impact on agriculture and food production M2-M6. Finally, the selected lines were tested in yield trial in the in many countries, including Bulgaria (Ahloowalia et al., 2004; Jain, present The characters studied included days to heading, plant height been created for many cereal crops, including rice (Singh et al., (cm), lodging (scale 9-1, where 9 = no lodging and 1 = 100% 1998; Suzuki et al., 2008), Triticum durum (Sakin and Yildirim, 2004) lodging), peduncle length (cm), spike length (cm), awn length (cm), and bread wheat (Slade et al., 2005).spikelet number per spike, grain number per spike, grain weight per The mutants developed in barley had great potential for direct spike (g), 1000 grains weight (g), grain yield (kg/ha). The data were release and to include them in cross breeding programs recorded on plant basis by randomly selecting 10 plants from each (Maluszynski and Szarejko, 2005). Many barley cultivars with plot. Days for heading, lodging, 1000 kernel weight and grain yield tolerance to different biotic and abiotic stresses and improved traits were estimated on plot basis. have been developed in the world through induced mutagenesisThe significance of differences among means was compared (Ahloowalia et al., 2004).by using Least Significant Difference (LSD) test at the 0.05 level of The aim of the present study was to evaluate mutant lines from probability and the correlations were analysed by Pearson's Hordeum vulgare cultivar Izgrev for grain yield and yield associated correlation...

Abstract. The aim of this investigation was to study agronomic and morphological traits of winter two-rowed barley mutant lines in the M6 and M7 generations. Eight mutant lines, their parent -breeding line 244D and national standard cultivars -Obzor and Emon were evaluated in Complete Block Design with four replications. The research was conducted in the 2013/2014, 2014/2015 and 2015/2016 growing IntroductionBarley is one of the major grain crop. Its distribution is worldwide and is of considerable economic importance for animal feed and malt production. To improve yield and other traits in barley, many breeding techniques are being used successfully. Mutation breeding is one of the important techniques to induce variation. The mutant cultivars in different crops had a great economic impact on agriculture and food productions (Ahloowali et al., 2004). More than 300 varieties of barley have been officially released by mutation breeding technique (Joint FAO/IAEA Mutant Variety Database).Mutation breeding is part of the winter barley breeding program at the Institute of Agriculture, Karnobat and it has led to improved barley cultivars with higher yield (Vulchev and Dyulgerova, 2011;Dyulgerova and Vulchev, 2012; ). Dyulgerova, 2017 Natural or induced genetic diversity can be promoted for the improvement of all major crops and the use of mutagenesis to create novel variation in particularly valuable crops with limited genetic variability. The use of mutagenesis in breeding has involved the selection of individual mutants with improved traits and their incorporation into breeding programmes (Parry et al., 2009). The mutants developed in barley had great potential for direct release and to include them in cross breeding programme. Many barley cultivars possess tolerance to biotic and abiotic stress and improved traits developed in the world through induced mutagenesis (Ahloowali et al., 2004).The aim of this investigation was to study agronomic and morphological traits of winter two-rowed barley mutant lines in the M6 and M7 generations. Material and methodsThe research work was conducted during 2013/2014, 2014/2015 and 2015/2016 growing seasons at the Institute of Agriculture,Karnobat. For mutation induction the seeds pre-soaked in water for 16 hours were treated with 2 mM sodium azide for 2 hours, prepared in a buffer solution (pH=3) at room temperature and washed for 6 hours after treatment. The M1 plants grown in field were harvested in bulk. In M2 generation one spike per selected plant was harvested and the seeds of each M2 spike were sown in the field as spike to row progeny for M3 generation. The parent variety was planted in every 10 rows as a check. The mutants were developed through selection for higher yield than the parental material by applying selection pressure from M2-M6. Finally, the selected lines were tested in yield trial in the present investigation. The 8 mutants and their parent -breeding line 244D and national standard cultivars -Obzor and Emon were evaluated in yield trial in Complete Bl...

The aim of the present study was to investigate the variability, heritability and correlation between grain yield and yield-related traits of hulless accessions of spring barley under Southeast Bulgarian conditions. The research work was conducted in the experimental field of the Institute of Agriculture - Karnobat, South-eastern Bulgaria during the 2016 and 2017 growing seasons. The trail consisted of 20 six-rowed hulless barley accessions from ICARDA. A significant variation of grain yield and yield-related traits among the studied hulless barley accessions was found. The values of broad-sense heritability were from 1.81% for grain yield to 81.84% for the number of spikelets per spike. The number of spikes per plant had a direct positive effect on grain yield of hulless spring barley in both growing seasons. In a condition of water stress (the second year of study), the weight of grains per spike shows the highest direct effect on grain yield. Since the number of spikes per plant and weight of grains per spike had low heritability, these traits can be used as additional traits for selection for improving grain yield in the hulless barley breeding program of hulless barley only if the selection be practiced in later generations in replicated trials.

Abstract. The aim of this study was to assess the variation in grain quality traits among mutant lines of winter feed barley. Nine mutant lines derived from the advanced breeding line Kt3029 and 10 mutant lines derived from variety GA-Luttrell along with their parent forms were evaluated. The study was conducted at the Institute of Agriculture – Karnobat during the period 2015-2017. Test weight, 1000-grain weight, the content of protein, starch, lysine, fat, ash, and fibre were determined. Significant differences between the mutant lines and the parent forms for the studied traits were observed. Significantly higher protein content compared to parent was found in the grain of mutant lines 22/1-5, 22/2-10 and 22/1-12 from line Kt3029 and 26/1-1, 26/1-3 and 26/2-11 from variety GA-Luttrell. The grain of mutant line 26/2-12 had the best combination of protein and starch. Mutant lines 22/1-11 and 22/1-12 from Kt3029 and 26/1-1, 26/2-1 and 26/2-12 from variety GA-Luttrell showed a good combination between protein content and 1000-grain weight. Those mutant lines can be included in the breeding program for the development of varieties with improved feed quality.

Abstract. The aim of the study was to evaluate the range of variation in chemical composition

The aim of the present study was to study some seed and seedling characteristics and their relationship with plant height in semi-dwarf and non-dwarf spring barley varieties. The study was conducted at the Institute of Agriculture - Karnobat, Southeastern Bulgaria during the 2019 and 2020 growing seasons. Ten semi-dwarf and ten non-dwarf cultivars of spring barley from the USA and Canada were studied. The semi-dwarf cultivars showed significantly lower mean values for the length of coleoptile and seedling and seminal root number compared to non-dwarf cultivars. However, there were semi-dwarf cultivars with a coleoptile length similar to that of non-dwarf cultivars. Correlation analysis showed a significant association of plant height with seedling length and seminal root number. The rest of the seedling characteristics were uncorrelated with plant height and, hence allowing breeding for that trait without compromising high seedling vigour.