Heritability and correlation coefficient analysis for grain yield and yield-related traits in spring barley (Hordeum vulgare L.)

B. Dyulgerova1*, D. Valcheva1, D. Valchev1, M. Babulicova2, M. Havrlentova2

1Institute of Agriculture, 8400 Karnobat, Agricultural Academy, Bulgaria
2National Agricultural and Food Centre, Research Institute of Plant Production, Piešťany, Slovak Republic

(Manuscript received 24 February 2021; accepted for publication 14 June 2021)

Abstract. The objectives of this study were to estimate the heritability of yield and yield-related traits and to compute the correlation of grain yield with yield-related traits among the spring barley genotypes. The experiment was laid out in a complete block design with three replications in the Institute of Agriculture – Karnobat, Bulgaria during two consecutive years 2017 and 2018. Genotypes differed significantly for all the traits studied. Genotypic coefficients of variation were lower than the corresponding phenotypic coefficients in all the traits studied, indicating a considerable influence of the environment on the expression of the traits. Estimates for broad-sense heritability ranged from 0.65% for grain number per spike to 44.20% for 1000-grain weight. Moderate heritability coupled with relatively high genetic advance as a percent of the mean was found for 1000-grain weight suggesting a reliable possibility for improvement through selection. A significant and positive correlation between grain yield and number of spikes per m2 and grain weight per spike was found. Results of path analysis showed that grain weight per spike and number of spikes per m2 exhibited the highest direct effects on grain yield. The number of spikes per m2 was highly associated with grain yield but mostly influenced by environmental effects. The grain weight per spike should be prioritized for selection of superior spring barley genotypes under conditions of Southeast Bulgaria due to its highest direct effect on grain yield combined with higher heritability than that of grain yield. Moreover, it must be considered that the grain weight per spike had relatively low heritability in a broad-sense so the selection should be practised in later generations in replicated trials.

Correlations between quantitative traits of winter common wheat-breeding tool for increasing grain yield

N. Tsenov1*, T. Gubatov1, I. Yanchev2

1Department of Wheat Breeding and Technology, Agronom Breeding Company, 9300 Dobrich, Bulgaria
2Department of Plant Science, Faculty of Agronomy, Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 7 November 2020; accepted for publication 15 April 2021)

Abstract. Information on the relationships between quantitative traits affecting yields is extremely important for winter wheat. For it, the annual genotype*environment interaction is palpable and often masks the influence of individual traits on grain yield. The aim of the study is to determine the traits through the selection of which the grain yield could be significantly increased in the future. The data from three field multifactorial experiments were used (FERT, PGR, ABC), in which a significant influence of various factors (year, point, density, fertilization) on the size and variation of all studied traits was established. In the database thus formed the observed strong variance in the values of the traits is a great prerequisite for the established correlations to be accepted with a high degree of reliability. The mutual influence in the formation of each of the traits is a good basis for their grouping, according to the type of their effect on yield. 1) The characteristics, number of grains per m2 (NGm), grain weight per spike (WGS) and number of productive tillers per m2 (NPT) have a significantly positive effect on grain yield, 2) the weight per 1000 grains (TGW) and number of grains in spike (NGS) are traits that have a direct effect, but it is unstable in manifestation and 3) the traits, as height of stem (HOS), total plant biomass (TBM), and harvest index (HI) do not show a direct effect on grain yields. A significant increase in yield in the breeding of winter wheat can be achieved by increasing the number of grains per unit area (NGm). This is possible while maintaining the achieved level of number of grains in spike (NGS) with a parallel increase of tillering productive ability (NPT). The increase of this trait by selection should be taken into account when reducing the grain size (TGW). This will increase the chance of increasing the number of grains in the spike (NGS), will reduce the weight of the grain per spike (WGS), which in turn will be a prerequisite for optimizing the stability of lodging.

Application of P4 rapid test and exogenous source of progesterone in prevention of early embryonic death in dairy cows

G. Bonev*

1Department of Genetics, Breeding and Reproduction, Faculty of Agriculture, Trakia University, 6000 Stara Zagora, Bulgaria

(Manuscript received 24 September 2020; accepted for publication 15 February 2021)

Abstract. The objectives of this study were: 1) to determine the percent of cows with low P4 at Day 7-8 post-AI; 2) to treat the animal with low progesterone for 14 days with a P4-releasing intravaginal device (PRID DELTA); 3) to analyze the influence of P4 exogenous supplementation on pregnancy rate in treated and non-treated cows and 4) to create a protocol using “P4 Rapid” test allowing increased pregnancy rate under farm conditions. For this purpose, the current study has been conducted on 155 repeat breeding Holstein cows (<3 artificially inseminated – AI) with prolonged estrus cycle (<26 days). At day 7 and 8 post-AI, the milk progesterone levels were measured (P4 Rapid test). The cows with low P4 (n=104 or 67%) were divided into two groups each n=52. In Group I the progesterone devices were inserted for two weeks and control Group II without progesterone devices. At days 40 and 50 post artificial insemination (AI) all animals (n=104) were submitted to ultrasound pregnancy detection. Pregnancy was registered in 27 animals (51.9%) for Group 1, and in 16 cows (30.7%) for Group II. P4 Rapid is a quick, easy and practically applicable test to measure milk progesterone levels in dairy farms. The method is highly accurate and detects animals with low or high P4 at Day 7-8 after insemination. It also allows identification of conditions such as ovarian cysts, ovarian hypofunction and distinguishing of cycling and non-cycling cows. The combination of P4 measurement by P4 Rapid test and treatment with exogenous P4 to increase circulating concentrations in the first few days after conception can prevent embryo death and improve reproductive efficiency in dairy cattle.

Grain quality of mutant lines of six-rowed barley

B. Dyulgerova*, N. Dyulgerov

Institute of Agriculture, 8400 Karnobat, Bulgaria

(Manuscript received 9 December 2020; accepted for publication 26 January 2021)

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.

Date of ear emergence: a factor for notable changing the grain yield of modern winter wheat varieties in different environments of Bulgaria

N. Tsenov1*, T. Gubatov1, I. Yanchev2

1 Department of Wheat Breeding and Technology, Agronom Breeding Company, 9300 Dobrich, Bulgaria
2 Department of Plant Science, Faculty of Agronomy, Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 2 November 2020; accepted for publication 15 January 2020)

Abstract. Wheat is a crop with a very long growing season, during which it is subjected to prolonged exposure to many environmental factors. For this reason, the interaction of genotype with conditions is very common for any character of wheat. This study aims to determine whether the grain yield is affected by the change of the ear emergence date (EED) in various environments. In a four-year period, 30 current for national real grain production winter wheat varieties were studied. The EED and grain yield (GY) were studied as quantitative traits within five locations of the country having various soil and climatic conditions. Using several statistical programs, genotype x environment interaction of two traits was analyzed. The emphasis on data analysis was whether changes of traits due to the conditions were related and that the optimization of the ear emergence date could serve as a breeding tool for increasing grain yield. The date of ear emergence and grain yield are traits that are reliably influenced by growing conditions. The change in the date of emergence is mainly of the linear type, while the grain yield shows linear and nonlinear type changes in the same environmental conditions. It was found that the key roles in the change of characteristics are the conditions of the year, with the relatively weakest impact of the genotype on them. There is a positive relationship between the two traits, although their change depends on environmental factors. Although they change to different degrees and in relation to each other, there is a positive correlation between them. The more favorable the environmental conditions, the weaker the relationship between these two traits and vice versa. Under changing climatic conditions, the change in the relationship between the two traits is a signal of the need to create different varieties by date of ear emergence in order to obtain higher yields in the future.


Characterization of testicular and epididymal parameters in Algerian Arabia bucks

N.A. Ouchene-Khelifi*, N. Ouchene, A. Dahmani

Institute of veterinary sciences, Saad Dahlab University Blida 1, Road of Soumaa, BP 270, Blida-09000, Algeria

(Manuscript received 20 June 2020; accepted for publication 24 September 2020)

Abstract. In goat production, the reproductive efficiency of bucks must be taken into account. Testicle size is the most appropriate parameter to directly improve the reproductive performance of females. In this study, body weight (BW), body condition score (BCS) and testicular and epididymal parameters of Arabia goats were studied. A total number of 200 bucks wеre randomly selected and classified into three age categories (6-12 months, 13-24 months and >2 years). BW, BCS, mean scrotal circumference, testicular volume, testicular diameter, testicular length, testicular weight, testicular density, epididymal weight, epididymal length, epididymal tail length, caput weight, corpus weight, caudal weight, Gonadosomatic Index, Epididymosomatic index and Epididymal-Testicular weight ratio were measured. A highly significant correlation was found between all parameters (p<0.05). The values of all parameters increased significantly with age, with the exception of the gonadosomatic and epididymosomatic indices, which decreased with age (p<0.05). These results provide data that can be used to anticipate an adequate ante-mortem sperm reserve based on testicular size in the preliminary selection of breeding males from the local sexually mature population.


Morphological characterization and genetic analysis in bread wheat germplasm: A combined study of heritability, genetic variance, genetic divergence and association of characters

  1. Gerema1*, D. Lule2, F. Lemessa4, T. Mekonnen3

1Bako Agriculture Research Center, Oromia, Ethiopia

2Oromia Agriculture Research Institute, Finfinne, Ethiopia

3Institute of Biotechnology, Addiss Ababa University, Ethiopia

4Department of Horticulture and plant Science, Jimma University, Jimma, Ethiopia

(Manuscript received 20 May 2020; accepted for publication 5 November 2020)

Abstract. The present study was conducted to assess the nature and magnitude of genetic variability and traits association of bread wheat genotypes for yield and related traits. A total of 180 genotypes were evaluated in alpha lattice design with three replications in 2017/18 cropping season. Data for 10 quantitative traits were collected and subjected to analysis of variance. The result from the analysis of variance revealed highly significant variability observed among genotypes for all traits studied. Phenotypic coefficient of variation (PCV) is superior over genotypic coefficient of variation (GCV) for most traits but narrow variations were found between PCV and GCV for most of the traits. Heritability in broad sense and genetic advance as percent of the mean (GA%) were relatively higher for Kernels per spike and grain filling period. Grain yield showed positive and highly significant (p≤0.01) association with number of tillers, kernel per spike and plant height both on genotypic and phenotypic levels.The path coefficient analysis showed that spike length, plant height and kernels per spike had positive direct effect on grain yield on both genotypic and phenotypic levels. Divergence analysis (D2) grouped the total test germplasm into 10 clusters. Among those, clusters IV and IX showed the highest genetic distance and thus the possibility to develop segregating populations upon the crossing of widely related genotypes in those clusters. The results could help researches to utilize the most promising wheat genotypes of this study in future breeding programmes for enhancing desirable traits.

Correlations between grain yield and related traits in winter wheat under multi-environmental traits

  1. Tsenov1*, T. Gubatov1, I. Yanchev2


1Department of Wheat Breeding and Technology, Agronom Breeding Company, 9300 Dobrich, Bulgaria

2Department of Plant Science, Faculty of Agronomy, Agricultural University, 4000 Plovdiv, Bulgaria

(Manuscript received 7 August 2020; accepted for publication 29 October 2020)

Abstract. In a series of field trials, a database of quantitative traits associated with winter wheat grain yield has been collected. The aim of the present study is to determine the relationships between the winter wheat (Triticum aestivum L.) traits of productivity in environments causing the maximum possible variation of each of the traits. In order to determine the correlations between the quantitative characters studied, all possible statistical methods have been applied (regression analysis, PCA, Multiple Correspondence analysis), which complement each other. It was found that the nature of the correlations between traits depends to a large extent on the methods for their evaluation. There are high and significant correlations between grain yields and the grain number per spike (weight of grain per spike and number of grains per m2) even under strong genotype by environment interaction of all the traits in trails. The established results are related to possible options for increasing winter wheat grain yield by breeding.

Statistical analysis of genetic diversity using faba bean landraces database

N. Velcheva*, S. Petrova

Agricultural Academy, Institute of Plant Genetic Resources K. Malkov, 2 Druzhba Str., 4122 Sadovo, Bulgaria

(Manuscript received 20 May 2020; accepted for publication 24 July 2020)

Abstract. Evaluation of genetic diversity among landraces could be an invaluable aid related to the sustainable use of ex situ collections. Statistical methods are currently available for analysis of databases from investigation of stored germplasm. Faba bean (Vicia faba L.) is a self-pollinating with high percentage of foreign pollination legume crop with a great importance for food and forage due to its high protein content as well as the important role in soil fertility and nitrogen fixation. The local populations are well adapted to specific agro-climatic conditions in the growing areas and are a rich initial material for the breeding programs. The purpose of this study is to establish the genetic diversity of 21 Bulgarian faba bean landraces by important traits in order to review the current potential of conserved germplasm for its sustainable use. All genotypes, included in the study, are collected from expeditions in the country, recorded in the National Register for Plant Genetic Resources and long term stored at the National Genebank. They are characterized according to the International Faba Bean Descriptors. The cluster analysis results show a high genetic diversity in the collection and the variability of each studied trait is presented. The factor analysis, which complements the cluster analysis, gives a reason to group the genotypes with their features into groups that have a breeding value. Genetic diversity in the studied collection has been identified and some of the landraces could be included in future breeding programs.

Contribution of Parastagonospora nodorum to the leaf and glume blotch of durum wheat in Bulgaria

Nedyalkova1, Z. Stoyanova2, R. Rodeva2*

1Field Crop Institute, Agricultural Academy, 6200 Chirpan, Bulgaria

2Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, 21 Acad. G. Bonchev Str.,

1113 Sofia, Bulgaria

(Manuscript received 12 February 2020; accepted for publication 4 May 2020)

Abstract. Parastagonospora nodorum is an important necrotrophic fungal pathogen causing leaf and glume blotch of wheat worldwide. The disease can result in significant losses in grain yield and quality. The purpose of the current investigation was to estimate the occurrence of P. nodorum as a foliar and ear pathogen of durum wheat and disease severity on a set of cultivars under natural infection. Field experiments were performed at two locations (Sofia and Chirpan) in the period 2010-2017. Twelve winter cultivars of durum wheat were involved in the study. P. nodorum was not found at both locations in 2010 and 2011. Thereafter the pathogen was recorded on the leaves of durum wheat in Sofia every year except 2013. Symptoms included chlorosis and necrosis of the leaf tissue. The strongest manifestation of the disease was observed in 2016 and especially in 2017. In Chirpan leaf blotch was noticed only in 2 out of 8 growing seasons. The ear infection led to development of dark brown patches on the glumes, which later became purple-brown. These symptoms were noted in Sofia in 2014, 2016 and 2017. In Chirpan, glume blotch of studied cultivars was recorded in 2017 but in the previous year the symptoms were widely observed on some genotypes among the initial breeding material of durum wheat. In the present investigation P. nodorum caused leaf and glume blotch only. Symptoms on stems, nodes and leaf sheaths were not noted at both locations. The 12 cultivars under study differed in their susceptibility to leaf and glume blotch. The leaf symptoms caused by P. nodorum were recorded on all cultivars, but were more pronounced on Zvezditsa, Deyana and GK Bétadur. The glume blotch was more noticeable on Vazhod. The results of this multiyear research showed that although P. nodorum did not appear every year, the pathogen could contribute to the leaf and glume blotch of durum wheat under conditions favourable for disease development. The evaluation of cultivars demonstrated encouraging preliminary results. Several cultivars showed lower disease severity on flag leaf and no or little infection on the ear. They deserve further studies on resistance to P. nodorum.