Grain yield is a complex character and is highly influenced by environment. Moreover, this character is intricate in inheritance and may involve several related quantitative characters. Hence, correlation coefficient analysis is widely used to measure the degree and direction of relationship between various characters and grain yield. In present experiment, grain yield per plot showed highly significant and positive correlation with number of primary branches per plant (0.501** and 0.444**), number of pods per plant (0.714** and 0.684**), number of pods per cluster (0.709** and 0.673**), number of nods per plant (0.746** and 0.687**) and plant height (0.253* and 0.214*) respectively at both the genotypic and phenotypic levels (Table 2 and Table 3). It is indicating that selection of plants with a higher number of primary branches per plant, number of pods per plant, number of pods per cluster, number of nods per plant and plant height would result more productive plants. So, these characters may serve as a marker/indicator for the improvement of soybean grain yield. The results obtained from this study are in agreement with the results of
Saharan et al., (2006), Okonkwo et al., (2013), Barh et al., (2014), Mahbub et al., (2015), Chavan et al., (2016), Neelima et al., (2017) and
Dvorjak et al., (2019) for number of pods per plant,
Okonkwo et al., (2013),
Ghodrati (2013) and
Neelima et al., (2017) for number of nods per plant,
Ganesamurthy and Seshadri (2004),
Balla and Ibrahim (2017) for plant height and number of pods per plant. This suggests that while selecting for improvement in seed yield these characters can be kept in mind provided the character should show high variability in correlation which is basis for selection. Path analysis of nine quantitative characters with grain yeild (gm) is presented in Table 4 and Table 5.
Path analysis depicted that out of nine, five characters had positive direct effect on seed yield per plot. Highest positive direct effect on seed yield per plot was exhibited by number of pods /plant (0.4197) followed by number of nods /plant (0.3546), number of pods /cluster (0.2101) number of primary branches per plant (0.1658)and days to 50% flowering (0.1017).
Neelima et al., (2017) also observed positive effect of pods per plant on seed yield. Similarly
Chavan et al., (2016); Baig et al., (2017); Khan et al., (2022) also reported positive direct of days to 50% flowering and number of pods per plant on seed yield. The phenotypic path coefficient analysis revealed that the number of pods per plant exhibited high and positive direct effects on seed yield. The character number of pods per plant also expressed highly significant positive correlation with seed yield. This trait turned out to be major component of seed yield for direct selection. Character, number of pods per plant is the most influential character in soybean yield improvement because it is the major production component that imposed the highest direct effect on the grain yield (0.3546). Similar results has been reported by for number of pods per plant by
Patil et al., (2011), Haghi et al., (2012), Baraskar et al., (2014), Jain et al., (2017), Neelima et al., (2017), Dubey et al., (2018), Dvorjak et al., (2019), Bhuva et al., (2020). The character, number of primary branches per plant depicted low and positive direct effect towards seed yield. Similar finds was registered by
Gaikwad et al., (2007) and
Bhuva et al., (2020).
Highest negative direct effect on seed yield was recorded by days to 50% pod initiation (-0.3169) followed by days to maturity (-0.0138), plant height (-0.0311)and 100 Seed weight (gm) (-0.0856) as presented in Table 4. However, among these four characters which have directly impact on seed yield, characters namely plant height was significant and positive associated (0.214*) with seed yield and days to maturity was only positive associated (0.030) at phenotypic level with seed yield, because of the minor cumulative positive indirect effect via other characters except days to 50% flowering (-0.0084) and 100-seed weight (-0.0037) in phenotypic path for character plant height and days to 50% pod initiation (-0.1289) and number of primary branches per plant (-0.0214) for days to maturity. Similar negative effect on seed yield was also recorded by
Khan et al., (2022) for characters plant height and days to maturity respectively, for plant height by
Shrivastava et al., (2001), Balla and Ibrahim (2017) and
Chavan et al., (2016) for plant height and 100 seed weight by
Bhuva et al., (2020) in soybean. The above results reveal that the characters number of pods /plant
, number of nods /plant, number of pods /cluster
, number of primary branches per plantand days to 50% flowering are directly affecting to seed yield. These characters will be fruitful for identification and further selection of high yielding genotypes. So, improvements in seed yield, this information may be used in determine selection criteria in soybean breeding program. A considerable amount of residual effects was observed at both genotypic and phenotypic levels showing the contribution of other traits for seed yield than the traits observed in the investigation.