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.

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.


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.

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.