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.

Genetic interrelationship among quantitative traits and path analysis of some West African okra (Abelmoschus caillei) genotypes

P.M. Jonah, Y.M. Kwaga

Department of Crop Science, Adamawa State University, PMB 25, Mubi, Nigeria

(Manuscript received 5 July 2018; accepted for publication 30 November 2018)

Abstract. Thirty-six entries of a half diallel cross were evaluated at the Teaching and Research Farm, Adamawa State University, Mubi in 2012 and 2013 under rain fed conditions. The investigation was conducted to study inter-character correlations and path coefficient analyses of yield related traits in West African okra. Fresh pod yield exhibited highly significant (P≤0.01) positive correlation with pods/plant, pod length, branches/plant, pod diameter and leaves/plant. Pod length recorded a highly significant positive correlation with plant height, pod diameter, number of leaves/plant, branches/plant and pods/plant. Similarly, pod diameter had a highly significant positive correlation with plant height, number of leaves, branches and pods/plant. Furthermore, number of pods/plant and branches/plant recorded highly significant positive correlation among yield related traits except plant height. The path coefficient analysis of fresh pod yield and yield related traits showed that number of pods/plant gave the highest direct contribution and percentage yield contribution of 47.83%, followed by pod diameter which contributed 4.58%. Also the highest combined contribution of 14.43% came from pods/plant and pod diameter. Residual percentage contribution was 30.64% revealing that pod yield attributes in this study explained 69.36%. This investigation suggests that pods/plant and pod diameter can be considered as selection criteria for the improvement of West African okra genotypes.

Application of path coefficient analysis in assessing the relationship between growth-related traits in indigenous Nigerian sheep (Ovis aries) of Niger State, Nigeria

S. Egena*, D. Tsado, P. Kolo, A. Banjo, M. Adisa-Shehu-Adisa

Department of Animal Production, Federal University of Technology, P.M.B 65, Minna, Niger State, Nigeria

Abstract. Indigenous Nigerian sheep raised under extensive management were evaluated with the aim of assessing variability among body weight and body measurement traits thereby deducing components that best describe the relationship using path coefficient analysis. The parameters measured were body weight (BW), body length (BL), head length (HL), head width (HW), height at withers (HAW), chest depth (CD), chest girth (CG) and shin circumference (SC). Pair wise correlation between body weight and body measurements were positive and significant (r = 0.475 – 0.655 in males, 0.262 – 0.449 in females, and 0.336 – 0.509 in the combined population, P<0.01). Path analysis showed that shin circumference and chest depth had the greatest direct effect on body weight in male, female and the combined population (path coefficient = 0.250, 0.252 and 0.250, respectively) while the least direct effect was observed for head width (in male and female with path coefficient = 0.007 and -0.017, respectively), and height at withers in the combined population (path coefficient = -0.020). Percentage direct contribution to body weight was 6.25, 6.35 and 6.25% from shin circumference (male), chest depth (in female and the combined population respectively). The optimum linear regression models with coefficient of determination (R2) value of 0.45, 0.31 and 0.37 included forecast indices such as chest depth and shin circumference in males, body length, head length and chest depth in females and the combined population, respectively.