Genetic Variability, Heritability and Genetic Advance for Yield and Yield Associated Traits in Bread Wheat (Triticum Aestivum L.)

Abstract

The experiment carried out during Rabi 2018-2019, ten genotypes and 45 F₁s of bread wheat were assessed for yield and yield associated traits in a Randomized Block Design (RBD) with three replications to determine genetic variability, heritability, and genetic advance percent of mean. The value of GCV ranged from 1.37 (days to maturity) to 19.87 (grain yield per plant) and PCV ranged from 1.59 (days to maturity) to 19.86 (grain yield per plant). The value of GCV and PCV as observed for grain yield per plant, productive tillers per plant, biological yield per plant and flag leaf area are (19.78,19.86), (13.11,14.07), (13.87,13.91) and (12.32,12.46) respectively. The traits like days to heading, plant height, flag leaf area and grains per spike shows high narrow sense heritability which has a great scope of genetic improvement through selection method whereas as flag leaf area and grains per spike shows high narrow sense heritability along with high genetic advance which are mainly governed by additive gene effects.

Keyword: GCV; Genetic advance; Narrow sense heritability; PCV; Wheat

Introduction

Wheat (Triticum aestivum L.) is one of the world's most significant and extensively grown crops, primarily for human consumption and as a major source of animal feed straw especially in India. Hexaploid wheat (Triticum aestivum L.) 2n = 42, AABBDD) is about 1.7 x 1010 bp, which is about 100 times that. The genome of Arabidopsis is 40 times that of rice and about 6 times that of corn. Wheat is the most widely cultivated cereal in the world 224.49 million hectares with production 792.40 million tons in 2020-21 year and in India wheat production 108.75 million tonnes with an average national productivity of 3424 kg/ha during 2020-21 [3]. India is already self-sufficient in fulfilling its population's wheat grain consumption, but a significant increase in wheat production will be necessary to ensure food security for our country's ever-growing population. By 2020, India's population is expected to be approximately 1.3 billion people [19]. As a result, increasing wheat production is one of the options for meeting the country's internal demand. Since the green revolution, continuous increases in wheat productivity have been attributed to genetic improvements in yield as well as improved agronomic practices [4]. The fundamental goal of genetic improvement in any crop generates the information regarding connections, genetic variability and methods involved in inheritance of the genetic factors. The genotypic and phenotypic coefficients of variation are useful in gaining a clear picture of the material's existing variability. Many studies have found genetic differences in wheat genotypes for several yield associated traits [14]. Heritability as accompanied by high genetic advance would be a more beneficial tool for predicting the ensuing effect in genotype selection for yield and yield associated traits. Ibrahim [1]. The greater the chances of heterotic responses in F₁ and a broad spectrum of variability on segregation, the more diverse parents within all fitness constraints [2]. As a result, the current study was carried out with the goal of determining the genetic variability of different wheat genotypes based on their agro-morphological characteristics.

Materials and Methods

The ten genotypes namely HD2967, UP 2748, WH 1105, UP 2565, UP 2572, UP 2628, UP 2526, HD 3059, WH 1021, and HD 3086, were collected from the department of genetics and plant breeding, G. B. Pant University of agricultural technology, Pantnagar (U.K.). The above breeding materials were collected on the basis of their difference in origin, adaptability and morphology. All these parents have genetic variability in terms of yield level and different desirable yield components. In this study, all possible single crosses were made during the year 2017-18 via 10 x 10 half diallel mating design. In the year 2018-2019, ten parental lines and forty five crosses were evaluated in a Randomized Block Design (RBD) with three replications at Crop research farm, Janta Vedic College, Baraut Baghpat (UP). In every replication, the experimental material was sowed in three rows with parents and F₁s. Every row was 2 m long with a 25 cm inter-row gap and a 10 cm intra-row distance. To raise a good crop and for optimum material expression, all of the prescribed agronomic measures were followed. The data was obtained on randomly collected five plants on the basis of following traits i.e. days to heading, days to maturity, Plant height (cm), productive tillers per plant, flag leaf area (cm), spike length (cm), grains per spike, 1000-grain weight, biological yield per plant, harvest index and grain yield per plant. The statistical analyses are as follow:

• The genotypic and phenotypic coefficient of variance was calculated according to Burton’s methods of calculation (1952) and was classified according to Sivasubramanian and Madhavamenon, 1973 i.e. Low (<10%), medium (10-25%), and high (>25%).

• Heritability in narrow sense was calculated according to the method suggested by Crumpacker and Allard [7], which is based on the component analysis and the estimates of heritability in narrow sense were categorized according to Robinson (1965) i.e. High (>30%), moderate (10-30%) and low (<10%).

• The range of genetic advance as mean percent is classified as suggested by Johnson et al., 1955a. i.e. High (>20%), Moderate (10-20%) and Low (<10%).

Results and Discussion

Significant differences between genotypes were observed for all the traits examined, indicating considerable variability among them. Estimating the genetic diversity parameters of all characters. A future breeding program might be able to capitalize on the significant genetic variability in the material. The phenotypic coefficient of variation component slightly differ from the genotypic coefficient of variation component in terms of value, the phenotypic coefficient of variation component, indicating that the existent variability was due to the combination of the genotypes' inherent character and the influence of environmental factors. The Genotypic Coefficient of Variation (GCV) ranged from 1.37 to 19.87 for (days to maturity) to (grain yield per plant). The current study revealed that none of the traits was found higher at Genotypic Coefficient Variance (GCV) level. Moderate genotypic coefficient variation observed for grain yield per plant (19.78), biological yield per plant (13.87), productive tiller per plant (13.11), flag leaf area (12.32) and grains per spike (10.72)) whereas the rest of the traits shows lower GCV value for harvest index (9.84), spike length (7.17), 1000 grain weight (5.94), plant height (4.58), days to heading (2.19) and days to maturity (1.37). The Phenotypic Coefficient of Variation (PCV) ranged from 1.59 (days to maturity) to 19.86 (grain yield per plant) (Table 1). None of the traits shows higher at Phenotypic Coefficient Variance (PCV) levels. Moderate PCV were observed for grain yield per plant (19.86), productive tiller per plant (14.07), biological yield per plant (13.91), flag leaf area (12.46), and grains per spike (10.82) whereas, the lower value of PCV was observed for harvest index (10.11), spike length (7.37), 1000-grain weight (5.98), plant height (4.61), days to heading (2.34) and days to maturity (1.59).

  

    
Characters 
    
Mean
    
Range
    
GCV
    
PCV
    
Narrow sense

      Heritability 
    
 
    
 
  
  

    
Genetic Advancement 5%
    
Gen. Adv as % of Mean 5%
  
  

    
Days to heading
    
84.95
    
79.67 - 88.67
    
2.19 
    
2.34 
    
51.4 
    
3.59 
    
4.23 
  
  

    
Days to maturity
    
123.02
    
119.33 - 128.33
    
1.37 
    
1.59 
    
16.4 
    
3.01 
    
2.45 
  
  

    
Plant height(cm) 
    
90.70
    
84.33 - 100.57
    
4.58 
    
4.61 
    
50.2 
    
8.50 
    
9.37 
  
  

    
Productive tillers/ plants 
    
6.99
    
4.47 - 9.10
    
13.11 
    
14.07 
    
25.2 
    
1.76 
    
25.16 
  
  

    
Flag leaf Area (cm) 
    
27.52
    
21.29 - 36.41
    
12.32 
    
12.46 
    
38.1 
    
6.91 
    
25.10 
  
  

    
Spike length (cm) 
    
11.58
    
10.45 - 13.07
    
7.17 
    
7.37 
    
17.8 
    
1.67 
    
14.38 
  
  

    
Grains per spike 
    
48.10
    
39.01 - 60.11
    
10.72 
    
10.82 
    
35.4 
    
10.53 
    
21.90 
  
  

    
1000-grain weight 
    
40.17
    
34.83 - 44.33
    
5.94 
    
5.98 
    
21.4 
    
4.89 
    
12.18 
  
  

    
Biological yield/ Plant
    
52.07
    
34.32 - 70.17
    
13.87 
    
13.91 
    
13.7 
    
15.00 
    
28.47 
  
  

    
Harvest Index
    
41.74
    
34.13 - 49-94
    
9.84 
    
10.11 
    
18 
    
8.24 
    
19.74 
  
  

    
Grain yield/ Plants
    
22.21
    
14.7 - 32.51
    
19.78 
    
19.86 
    
21.4 
    
9.02 
    
40.59 
  

Table 1: Estimation of mean, range, coefficient of variance (GCV & PCV), narrow sense heritability and genetic advance for yield and yield associated traits in wheat (Triticum aestivum L.).