An experiment was laid out on green gram to study the genetic variability among the yield and yield contributing characters was conducted at the research farm of Lovely Professional University, Phagwara during the summer season of 2022. The experiment followed a Randomized Complete Block Design with three replications. Morphological traits were recorded from five random plants selected from each recombinant genotype in each replication. Analysis of Variance revealed a highly significant difference among the genotypes for all the traits. Conversely, low genetic variability was observed in traits such as days to maturity, Pod length, and days to fifty percent flowering. Heritability estimates based on broad sense were highest for plant height, 100 Seed Weight, Number of Pods per Plant, Number of Seeds per Pod, and Number of Primary Branches per plant. Genetic advance as a percentage of the mean at a selection intensity of five percent was high for the traits Number of Pods per Plant, Number of Seeds per Pod, 100 Seed Weight, Number of Primary Branches per plant, and Seed Yield per Plant. The combination of heritability estimates and genetic advance indicated the influence of additive gene action. Based on the findings of this study, the inbred lines MGG-336, MGG-351, MGG-348, and Vijetha SRPM-26 were identified as superior genotypes in terms of yield attributing traits.

Greengram [(Vigna radiata L. Wildzek) (Diploid, 2n=22)] from the family of Leguminosae whereas the Origin is India and Central Asia. Its cultivation prevalent in prehistoric times. Green gram is an erect or semi erect herbaceous annual. Leaves trifoliate with long petioles, stipules with basal appendage, stipules minute and leaflets entire ovate, flower bear on axillary racemes, diadelphous stamens, ovary with long bearded style Thanniru et al. (2022). Pod longer than in black gram with short hairs. Seeds globular, yellow cotyledons (Source: Online directory, KVK, ICAR). According to the 'Outlook report from ANGRAU', during the period of 2021-2022, the production of green gram was 31.5 lakh tonnes, at a productivity rate of 783 kg/ha. This accounted for 11% of the total pulse production across an estimated 40.38 million hectares of land. The first advance estimates for Kharif 2022-2023 state that on an area of 33.37 lakh hectares, 17.5 lakh tonnes of green gram were produced. 

The degree of genetic diversity and the heritability of desired characteristics are key factors in crop genetic improvement. When choosing the optimal yield traits for selection or hybridization, genetic diversity is helpful. It is crucial since it serves as the foundation for wise choosing. The splitting of the correlation coefficient into the direct and indirect effects of numerous characters on seed production is made easier by correlation and route analysis (Makeen et al., 2007).

The experimental study titled  Exploring Genetic Variability, Correlation, and Path Coefficient Assessment for Yield and its Attributing Traits in Summer Green Gram (Vigna radiata L.): Insights into Crop Improvement" was conducted during the summer of 2022 at the Research Farm, Department of Plant Breeding and Genetics, Lovely Professional University, Phagwara (Punjab). The experimental area had a pH ranging from 7.8 to 8.5. Soil was sandy loam, Various observations were recorded in this study, including DFF, DM, PH (cm), NPP, PL (cm), NSP, NPB, NSB, NCP, NPC, SYP, HI(%), and 100 SW. The mean values obtained from the analysis were used to estimate genotypic and phenotypic coefficients of variation, heritability (broad sense), and genetic advance, following the methods described by Johnson et al. (1955); Al Jibouri et al. (1958). Correlation and path analysis were conducted based on the approach outlined by Dewey and Lu (1959). The experimental material consisted of 15 diverse genotypes like MGG 336 (G1), MGG 295 (G2), Rajendran G-65 (G3), WGG 37 (G4), TM 96-2 (G5), MGG 348 (G6), MGG 347 (G7), MGG 351 (G8), WGG 42 (G9), LGG 460 (G10) from KVK, Rudroor, Telangana. Whereas Moong Tilak (G11), Tilak Gold (G12), Banshi Moong (G13), Vijetha SRPM 26 (G14), Virat Gold (G15) collected from ARS, Sri Ganganagar.

[Where; DFF- Days to 50% percent flowering, DM- Days to maturity, PH- Plant height (cm), NPP- Number of pods per plant, PL- Length of the pod (cm), NSP- Number of seeds per pod, NPB- Number of primary branches per plant, NSB- Number of secondary branches per plant, NCP- Number of clusters per plant, NPC- Number of pods per cluster, Number of seeds per plant, HI- Harvest Index (%), and 100 SW- 100 grain weight (g), SYP- Seed yield per plant Whereas P1 =days to 50 % flowering, P2 =plant height, P3 =primary branches per plant, P4 =secondary branches per plant, P5=clusters per plant, P6 = days to maturity, P7 = no. of pods per plant, P8 = pod length), P9 = no. of seeds per pod, P10 = test weight, P11= harvest index, P12 = biological yield P13=Seed yield per plant].

The present research focused on 15 genotypes of green gram [Vigna radiata (L.) Wilzeck]. The experiment included 13 different characteristics, and their analysis of variance revealed highly significant differences. The yield per plant exhibited a variability range of 8.03 g to 14.28 g, with an average of 11.07 g. Similar ranges of variability were observed in other traits such as DFF, DM, PH (cm), number of productive branches per plant, number of productive pods per plant, NSP, HI, and SYP (g).

The estimation of GCV and PCV revealed significant values for traits such as seed yield per plant, harvest index, and number of pods per plant, indicating the potential for improvement through selection. These findings align with the results reported by Nand et al. (2013) regarding seed yield per plant and pods per plant. On the other hand, moderate values of GCV and PCV were observed for traits like plant height, biological index, and NSB. In terms of yield per plant, GCV values were lower than PCV values, which is consistent with the findings of Siddique et al. (2006); Makeen et al. (2007).

The heritability estimates coupled with genetic advance in this study were high, indicating a lesser influence of the environment and a more significant role of genotype in traits such as NPP, SYP, 100 SW, and NPB. However, for traits like DFF, NCP, and HI, the heritability was comparatively low. These findings align with previous studies that reported high heritability estimates, including the works of Momin and Misra (2004); Idress et al. (2006); Babu et al. (2007); Tabasum et al. (2010); Rahim et al. (2010); Reddy et al. (2011); Makeen et al. (2007); Roy Chowdhury et al. (2012).

According to Johnson et al. (1955), genetic gain tends to be low when there is no additive gene interaction, whereas genetic advance is higher in the presence of additive gene interaction. In the current experimental study, traits such as pods per plant, number of seeds per pod, and number of primary branches exhibited high heritability, accompanied by significant genetic advance. This suggests that the high heritability observed in these traits is attributed to additive gene interaction, and simple selection practices can be employed to improve them. These results highlight that considering both heritability and genetic advance provides better outcomes compared to solely focusing on heterosis alone, as stated by Johnson et al. (1955), Singh et al. (2010). Additionally, high heritability combined with a high expected genetic advance was observed in SYP, indicating the influence of additive gene expression, which aligns with the findings of Das et al. (1998) for pods per plant and Chakraborty et al. (2001). However, these findings contrast with the results reported by Loganathan et al. (2011).

The selection index, determined using phenotypic correlation coefficients, provides an assessment of the close relationship between different traits and helps in identifying their collective contribution to overall crop improvement. On the other hand, the use of genotypic correlations allows us to understand the specific associations between traits and indicates their relative importance in crop improvement. In this study, at the genotype level, yield per plant exhibited significant positive correlations with PH, NSB, NPP, test weight, HI, and biological yield. Similarly, DFF showed significant positive correlations with DM, NSB, 100 SW, and NSP, which align with the findings of Ebenezer Babu Rajan et al. (2000). Additionally, plant height demonstrated a significantly positive correlation with traits such as pods per plant, harvest index, and test weight.

The traits of DFF, NPB, NSB, NCP, and NPP exhibited significant and strong direct effects on SYP, indicating a true and strong relationship between these traits and seed yield. This finding is valuable for selecting high-yielding genotypes. However, these results contradict the findings of Pooran Chand and Rabhunandha Rao (2002) regarding the NPC, Chauhan (2007) for number of pods per cluster, and Govindaraj and Subramanian (2001) for cluster per plant.

Source, it  is designated  as “poor  man’s meat”  (Potter and  Hotchkiss, 1997)

Table 1:  Analysis of variance in green gram for 13 different characters.

* and ** denotes significance at 5 % and 1 % level of probability respectively

Table 2: Genetic Parameters of traits showing variability variation coefficient.

Table 3: Genotypic (rg) (above diagonal) and Phenotypic (rp) (below diagonal) correlation coefficients among 13 characters of green gram.

Table 4:  Genotypic path coefficient analysis showing direct and indirect effect of different contributions on yield per plant in green gram.

R Square =1.1248; Residual Effect =Sqrt (1- 1. 1 2 4 8)

Table 5:   Phenotypic path coefficient showing direct and indirect effect of different contributions on yield per plant in green gram.

Square = 0.9943; Residual Effect = 0.0755

Fig. 1.  Phenotypic path Diagram for seed yield per plant.

Thanniru Bhavya Sri, I.R. Delvadiya, Murakonda Sai Dinesh and A.V. Ginoya (2024). Exploring Genetic Variability, Correlation, and Path Coefficient Assessment for Yield and its Attributing Traits in Summer Green Gram (Vigna radiata L.): Insights into Crop Improvement. Biological Forum – An International Journal, 16(1): 260-264.