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Department of Genetics and Plant Breeding, S.V. Agricultural College, ANGRAU, Tirupati-517 502.
The experiment was conducted at dryland farm of S. V. Agricultural College, Tirupati during kharif, 2021. In the cross Kadiri 6 × J 11, number of primary branches plant-1, number of mature pods plant-1, harvest index, dry haulms yield plant-1, kernel yield plant-1 showed positive significance for pod yield plant-1. Based on the path analysis, kernel yield plant-1 exhibited high positive direct effect with pod yield plant-1 in all six crosses; hence importance should be given in selection process for the improvement of pod yield in groundnut.
KEYWORDS: Correlation, path analysis, groundnut, yield attributes.
Grоundnut (Аrасhis hyроgаeа L.) is а vitаl сrор аmоng оilseeds, аlsо knоwn аs “The king оf оilseeds”. It is а self-роllinаted сrор, аn аllоtetrарlоid with а сhrоmоsоme number 2n = 4x = 40. The cultivated groundnut belongs to family Fabaceae, sub family Papilionaceae. In the world, it is cultivated in 29.92 m ha, with a total production of 55.30 m t and productivity of 1851 kg ha-1 during 2021 (FAOSTAT, 2021). Globally, 41 per cent of groundnut produced is used for food purposes and 49 per cent is crushed for extraction of oil. In India, the total cultivated area of groundnut is 6.09 m ha, production is 10.21 m t with a productivity of 1676 kg ha-1. In Andhra Pradesh, it is cultivated in an area of 0.87 m ha with a production of 0.78 m t and an average productivity of 894 kg ha-1 (Directorate of Economics and Statistics, 2021).
In the F2 рорulаtiоn, соrrelаtiоn аnd раth аnаlysis hаve tо be studied tо estаblish interrelаtiоnshiр аmоng vаriоus yield attributes аnd аlsо their соntributiоn tоwаrds роd yield. Соrrelаtiоn coefficient аnаlysis is useful tо find оut the nаture аnd degree оf аssосiаtiоn between vаriоus рhysiосhemiсаl trаits inсluding yield. Path coefficient аnаlysis sрlits the correlation coefficient intо direсt аnd indireсt effeсt tоwаrds yield as correlation analysis alone do not give a complete picture of the causal basis of association.
The field experiment was conducted at dryland farm of S.V. Agricultural College, Tirupati during kharif, 2021 in Southern agro-climatic zone of Andhra Pradesh. Each F2 generation of Kadiri 6 × J 11 cross along with the parents was raised in unreplicated plots. Data was recorded for the characters, plant height, number of primary branches plant-1, number of secondary branches plant-1, number of immature pods plant-1, number of mature pods plant-1, shelling per cent, harvest index, dry haulms yield plant-1, kernel yield plant-1, pod yield plant-1. The data of the above have been subjected to statistical analysis for Character association (Johnson et al., 1955) and Path coefficient analysis (Dewey and Lu, 1959).
Observations were recorded for 90 individual plants separately in Kadiri 6 × J 11 cross for all the characters. Yield is a complex character influenced by the environment and controlled by a large number of genes. The study of inter-relationships is necessary for understanding the association of simple traits with complex yield attributing traits. In the cross Kadiri 6 × J 11, pod yield plant-1 showed positive correlation with number of primary branches plant-1, number of mature pods plant-1, harvest index, dry haulms yield plant-1, kernel yield plant-1. Positive and significant correlation of pod yield with haulms yield, number of mature pods was reported by Pushkaran and Nair (1993). Similar findings were found by John et al. (2008) among six crosses and reported significant and positive association of pod yield plant-1 with number of mature pods plant-1, kernel yield plant-1 and harvest index. Byadagi et al. (2018) reported significant and positive association of pod yield plant-1 with branches plant-1 among three crosses.
Plant height showed positive and significant association with dry haulms yield plant-1 (0.6401). It had negative and significant correlation with harvest index (-0.4462). Number of primary branches plant-1 exhibited positive and significant association with number of mature pods plant-1 (0.3502), dry haulms yield plant-1 (0.2947), kernel yield plant-1 (0.2314) and pod yield plant-1 (0.2398).
Number of mature pods plant-1 revealed positive and significant association with shelling per cent (0.3709), harvest index (0.3616), dry haulms yield plant-1 (0.3764), kernel yield plant-1 (0.8694) and pod yield plant-1 (0.8349). Shelling per cent showed positive and significant association with kernel yield plant-1 (0.4728).
Harvest index registered positive and significant association with kernel yield plant-1 (0.4472) and pod yield plant-1 (0.4998). It had negative and significant correlation with dry haulms yield plant-1 (-0.5421). Dry haulms yield plant-1 exhibited positive and significant association with kernel yield plant-1 (0.3596) and pod yield plant-1 (0.3865). Kernel yield plant-1 performed high positive and significant association with pod yield plant-1 (0.9293). Number of secondary branches plant-1 and number of immature pods plant-1 showed no significant association with any other traits.
Path analysis provides information about the cause and effect of different yield components, which gives better index for selection other than mere correlation coefficients. In this cross, plant height exhibited positive correlation (0.1428) and negligible positive (0.0029) direct effect, number of primary branches plant-1 revealed a significant positive correlation (0.2398) and negligible positive (0.0222) direct effect, number of secondary branches plant-1 displayed a positive correlation (0.0898) and negligible positive (0.0251) direct effect, number of immature pods plant-1 displayed a positive correlation (0.0536) and negligible positive (0.0046) direct effect and number of mature pods plant-1 exhibited a significant positive correlation (0.8349) and negligible positive (0.0280) direct effect on pod yield.
Shelling per cent exhibited a positive correlation (0.1557) and negligible negative (-0.2824) direct effect, harvest index exhibited a significant positive correlation (0.4998) and moderate positive (0.2342) direct effect, dry haulms yield plant-1 revealed significant positive correlation (0.3865) and moderate positive (0.2149) direct effect and kernel yield plant-1 revealed significant positive correlation (0.9293) and high positive (0.8486) direct effect on pod yield (Table 2).
With regard to indirect effects, plant height showed low positive indirect effect via dry haulms yield plant-1 (0.1375), kernel yield plant-1 (0.1213); negligible positive indirect effects via other traits viz., number of primary branches plant-1 (0.0041), number of immature pods plant-1 (0.0001), number of mature pods plant-1 (0.0040). It showed negligible negative indirect effect through number of secondary branches plant-1 (-0.0029), shelling per cent (-0.0197) and low indirect effect via harvest index (-0.1045).
Number of primary branches plant-1 showed low positive indirect effect via kernel yield plant-1 (0.1964); negligible positive indirect effects via other traits viz., plant height (0.0005), number of mature pods plant-1 (0.0098), shelling per cent (0.0225) and dry haulms yield plant-1 (0.0633). It showed negligible negative indirect effect through number of secondary branches plant-1 (-0.0048), number of immature pods plant-1 (-0.0001) and harvest index (-0.0200).
Number of secondary branches plant-1 showed negligible positive indirect effects via other traits viz., number of immature pods plant-1 (0.0007), harvest index (0.0333) and kernel yield plant-1 (0.0658). On the contrary, it showed negligible negative indirect effect through plant height (-0.0003), number of primary branches plant-1 (-0.0042), shelling per cent (-0.0222) and dry haulms yield plant-1 (-0.0083).
Number of immature pods plant-1 showed negligible positive indirect effects via other traits viz., number of secondary branches plant-1 (0.0040), number of mature pods plant-1 (0.0008), harvest index (0.0031) and dry haulms yield plant-1 (0.0150), kernel yield plant-1 (0.0667). On the contrary, it showed negligible negative indirect effect through number of primary branches plant-1 (-0.0003), shelling per cent (-0.0404).
Number of mature pods plant-1 recorded high positive indirect effect via kernel yield plant-1 (0.7377); negligible positive indirect effects via other traits viz., plant height (0.0004), number of primary branches plant-1 (0.0078), number of immature pods plant-1 (0.0001), harvest index (0.0847) and dry haulms yield plant-1 (0.0809). Conversely, it showed low negative indirect effect through shelling per cent (-0.1047).
Shelling per cent recorded high positive indirect effect via kernel yield plant-1 (0.4012); negligible positive indirect effects via other traits viz., plant height (0.0002), number of secondary branches plant-1 (0.0020), number of immature pods plant-1 (0.0007), number of mature pods plant-1 (0.0104), harvest index (0.0065) and dry haulms yield plant-1 (0.0189). Conversely, it showed
negligible negative indirect effect through number of primary branches plant-1 (-0.0018).
Harvest index recorded high positive indirect effect via kernel yield plant-1 (0.3795); negligible positive indirect effects via other traits viz., number of secondary branches plant-1 (0.0036), number of immature pods plant-1 (0.0001) and number of mature pods plant-1 (0.0101). In contrast, it showed negligible negative indirect effect through plant height (-0.0013), number of primary branches plant-1 (-0.0019), shelling per cent (-0.0079) and dry haulms yield plant-1 (-0.1165).
Dry haulms yield plant-1 recorded high positive indirect effect via kernel yield plant-1 (0.3051); negligible positive indirect effects via other traits viz., plant height (0.0018), number of primary branches plant-1 (0.0065), number of immature pods plant-1 (0.0003) and number of mature pods plant-1 (0.0105). In contrast, it showed negligible negative indirect effect through number of secondary branches plant-1 (-0.0010), shelling per cent (-0.0249) and harvest index (-0.1270).
Kernel yield plant-1 recorded low positive indirect effect via harvest index (0.1047); negligible positive indirect effects via other traits viz., plant height (0.0004), number of primary branches plant-1 (0.0051), number of secondary branches plant-1 (0.0019), number of immature pods plant-1 (0.0004), number of mature pods plant-1 (0.0243) and dry haulms yield plant-1 (0.0773). In contrast, it showed low negative indirect effect through shelling per cent (-0.1335).
The results obtained from path analysis indicated that kernel yield plant-1 had high positive direct effect; harvest index and dry haulms yield plant-1 had moderate positive direct effect. Hence, due emphasis should be given to these traits in selection programme to improve pod yield plant-1.
Harvest index exhibited moderate positive direct effect on pod yield and these results were in agreement with the findings of Suneetha et al. (2004) in fifteen F1 s of groundnut. Dry haulms yield plant-1 exhibited a positive direct effect and the results obtained in the present study are in conformity with the findings of Moinuddin (1997) and John et al. (2011). Kernel yield plant-1 showed a high positive direct effect and these results were in accordance with the reports of Rao et al. (2012) on pod yield plant-1 in groundnut.
By and large, based on correlation coefficient analysis, it was concluded that the traits viz., number of mature pods plant-1, harvest index and kernel yield plant-1 had positive significant correlation with pod yield plant-1 in the cross studied. The data on path analysis elucidates the importance of kernel yield plant-1 to improve pod yield plant-1 in the F2 populations studied.
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