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.

Association between physiological parameters and yield in Triticum aestivum L. genotypes under rainfed conditions

İ. Öztürk

Trakia Agricultural Research Institute, Edirne, Turkey

(Manuscript received 22 July 2019; accepted for publication 6 April 2020)

Abstract. The purpose of the study was to assess the relationships between physiological parameters and grain yield of different bread wheat genotypes. In the present research a total of 25 bread wheat genotypes were tested during the 2016-2017 seasons under rainfed conditions. The experiment was conducted in a randomized complete blocks design with four replications. Grain yield, days of heading, plant height, biomass (NDVI) from GS25 up to GS85 growth stage, chlorophyll content (SPAD) during the heading stage, canopy temperature (CT) at GS60 and GS75 growth stages, and glaucousness were investigated. The results of variance analyses showed that there were significant differences (p<0.01) among genotypes for yield. The mean grain yield was 7948 kg ha-1 and yield ranged from 7033 kg ha-1 to 8759 kg ha-1, the highest grain yield performed by TE6744-16 line. According to the results, significant differences among cultivars in terms of plant height, days of heading, biomass, chlorophyll content, canopy temperature, glaucousness were found. TE6627-6 line had the highest chlorophyll content and also, chlorophyll content positively affected grain yield. Canopy temperature is generally related to yield under drought stress condition in bread wheat. In the study early maturing (days of heading) genotypes had lower canopy temperature. An increase in biomass after the heading phase has positively affected grain yield. In the study, no correlation was found between grain yield and biomass at GS25 and GS45 growth phase. There was a negative correlation between glaucousness with biomass at GS60, GS75 and GS85 growth phase. These results showed that physiological parameters such as biomass (at GS75 and GS85), canopy temperature (at GS60 and GS75), and chlorophyll content (at GS60), and glaucousness could be used for selection parameters under rainfed conditions for yield in bread wheat.

Genotype x environment interaction analysis of Triticum aestivum L. for yield components

İ. Öztürk1*, K.Z. Korkut2

1Trakia Agricultural Research Institute, Edirne, Turkey
2 Department of Field Crops, Faculty of Agriculture, Namık Kemal University, Tekirdağ, Turkey

(Manuscript received 5 December 2019; accepted for publication 26 February 2020)

Abstract. Genotypes performance changes due to environmental pressures or stresses and differences in their ability to adapt to the stress factors. Drought is the main abiotic stress factor affecting bread wheat yield and yield component. The experiment was carried out in the experimental field of Trakia Agricultural Research Institute, Edirne (Turkey), in 2008-2009 and 2009-2010, and 15 wheat genotypes were planted in RCBD in a split-plot with three replications. The main plots were assigned to five moisture regimes, which included 3 drought stress environments, one non-stress and one non-treatment environment. Principal component analysis (PCA) and cluster analysis were used to determine genotypes environment interaction. Grain yield, biological yield, harvest index, spike number per square meter, kernel and spikelet number per spike, length of spike and plant height were investigated. PCA indicated that the first (46.31%) and second (25.32%) components justified 71.63% of variations in the investigated yield parameters of the genotypes. Based on GGE biplot results, Kate A-1 and Tekirdağ genotypes were determined as the most stable cultivars for grain yield. Mean values of the genotypes varied between 3830-6583 kg ha-1 for grain yield, 20170-25394 kg ha-1 for biological yield, 68.6-110.9cm for plant height, 30.2-38.3 for kernel number in spike, 328.8-486.6 for spike number per square meter and 6.57-9.17cm for spike length. Clusters I and II were more clearly separated. In the first group of clusters 6 genotypes are located including one line and five cultivars. In the second group of clusters 8 genotypes are located including five advanced lines and four cultivars.

Karyotype variability of the Ukrainian Mountain-Carpathian sheep breed

K. Typylo*

Institute of Animal Breeding and Genetics nd.a. M.V. Zubets of National Academy of Agricultural Sciences, Chubinsk Boryspil district, Kyiv region, 08321, Ukraine

(Manuscript received 5 September 2019; accepted for publication 25 November 2019)

Abstract. The main purpose of this work was to describe the karyotype variability of the Ukrainian Mountain-Carpathian sheep breed. Cytogenetic studies were carried out on a group of 25 sheep from that breed. The cultivation of lymphocytes, preparing the cytogenetic samples, classification and registration of chromosome aberrations were held using conventional methods. It was established that the number and structure of the chromosomes of sheep of the Ukrainian Mountain-Carpathian breed correspond to the norm typical for this species of animals. Chromosomal variability of the studied population includes 19.22% of numerical and structural aberrations. By the number and structure of the chromosome set the Ukrainian Mountain-Carpathian sheep breed does not differ from other breeds of sheep. Accurate identification of individual chromosomes with routine coloring allows using cytogenetic studies in breeding practice in sheep breeding.

Heterosis manifestations for spike productivity traits in durum wheat

R. Dragov*
Field crops institute (FCI), 6200 Chirpan, Bulgaria
(Manuscript received 5 September 2019; accepted for publication 18 October 2019)

Abstract. The aim of the study is to investigate the heterosis manifestations in durum wheat for quantitative traits related to spike productivity. Diallel cross includes five modern varieties of durum wheat: Victoria (BG), Deni (BG), Superdur, Progress (BG), Predel (BG). The heterosis manifestations of the ten crosses are traced for the traits: spikelet number per spike, number of kernel per spike, grain weight per spike and thousand kernel weight. The experiment is conducted in the 2014-2016 period in the experimental field of FCI- Chirpan. Standard technology for the cultivation of durum wheat is applied. The trials are organized in a randomized block design with three replications. Of each replication 30 plants are randomly picked and harvested for biometric analysis. The mean values by years from the F1 spike biometric measurements are included in the statistical analysis to determine the mid parent and better parent heterosis. For spikelet number per spike, seven crosses show high parent heterosis in the first year, four in the second and six in the third year. In all years, hybrids with a variety of Victoria have more spikelet number per spike and show better parent heterosis. For the trait kernel number per spike it is observed that combinations with Deni variety in most cases have better parent heterosis. In all years, the cross Superdur x Predel indicates high parent heterosis for this trait. For grain weight per spike most of the combinations exhibit high levels of better parent heterosis. When the Deni variety is used as female parent, all hybrid combinations show high levels of heterosis for the trait grain weight per spike. In regard to the thousand kernel weight different heterosis levels are observed, with only negative values in the first year. In the other two years in hybrid combinations there is positive heterosis in one year and negative in another year. The participation of the Deni variety in hybrid combinations leads to better parent heterosis for this trait. The data allow the use of these crosses directly in the breeding of durum wheat to increase individual traits and/or increase productivity.