In the present investigation forty diverse wheat genotypes were studied to assess genetic diversity under two different environments (early sowing and late sowing). The analysis of variance for different characters is presented in Table 1. Highly significant differences was observed among the genotypes for all the characters studied in both the environments (early and late sowing). Significant differences among the genotypes for all characters were reported earlier (
Mishra et al., 2019,
Chaudhary et al., 2020 and
Haydar et al., 2020).
The magnitude of phenotypic coefficient of variation (PCV) was greater than genotypic coefficient of variation (GCV) for all the characters studied indicating vital role of environmental interaction in the expression of the characters. The estimates of GCV and PCV in both the environments (early and late sowing) were high for flag leaf area, number of tillers per plant, grain yield per plant, plant height and spike length (Table 2) in both the environments. Similar results were also reported by
Kumari et al., 2017, Kumar et al., 2019 and
Ferede and Worede, 2020.
In the early sowing Environment (I) the estimates of heritability were higher for plant height followed by days to 50% heading, grain yield per plant, flag leaf area, number of spikelet per spike and spike length and moderate for the biological yield, 1000 grain weight, days to maturity and number of tillers per plant. High heritability for these characters was also reported earlier by
Gaur, 2019 and
Saini et al., 2019. In the Environment II heritability was high for plant height followed by gluten content, grain yield per plant, 1000 grain weight, flag leaf area, biological weight, days to maturity and days to 50% heading and moderate for harvest index spike length and number of tillers per plant. These results were in accordance with the results of
Saini et al., 2019 and
Upadhyay et al., 2020. Higher values of genetic advance as percent of mean was recorded for flag leaf area, grain yield per plant, number of tillers per plant and plant height in both environmental (early and late sowing) conditions (Table 2). Similar result was also observed by
Gaur, 2019.
Grain yield showed significant and positive correlation with number of tillers per plant, biological yield and harvest index in both the environments (Table 3). Further, the trait grain yield showed significant and positive correlation with spike length (Environment I) and flag leaf area (Environment II). The grain yield also showed significant and negative correlation with days to 50% heading (Environment I and II) and days to maturity (Environment II). Among the
inter se associations the magnitude of correlation coefficient of grain yield with harvest index and biological yield was maximum and positive followed by correlation of spike length with number of spikelets per spike (Table 3). Similar results were also observed by
Verma et al., 2019,
Khanal et al., 2020,
Rathod et al., 2020 and
Jan et al., 2020.
The path coefficient analysis showed that biological yield and harvest index exhibited maximum positive direct effect on grain yield in both the environments. The number of tillers per plant, spike length and flag leaf area contributed indirectly towards grain yield via biological yield and harvest index (Table 4 and Table 5). Similar results was also observed by
Verma et al., 2019,
Baye et al., 2020 and
Upadhyay, 2020.
The divergence analysis showed that all the forty genotypes were grouped into seven clusters in Environment I and six clusters (Environment II). Maximum number of genotypes was grouped into cluster V (Environment I) and clusters I (Environment II). Maximum inter cluster distance was observed between clusters VI and IV in Environment I and Cluster III and II in Environment II. Genotypes namely PBW-34, HD-2985, HD-2189, HUW-234 and UP-2485 in Environment I and genotypes namely HD-3059, HD-3116, LOK-1, WH-1105, DPW-621-50, WH-1124, MACS-2496, NW-1014, DBW-17, PBW- 34 and HD-2967 showed wide genetic diversity and could be used in the hybridization programme. Hybridization between the genotypes of these clusters might yield desirable segregants (Table 6-8). Similar results were also reported by
Santosh et al., 2019 and
Upadhyay et al., 2020.