Table 1 Constructed models using gene expression programming to predict explant growth traits in Persian walnut

Chandler

\(\begin{aligned}PR=\left[X3-\left({\left(\mathrm{cos}\left(\frac{X8}{X1}\times 6.178\right)\right)}^{3}\times X5\times X6\right)\right]+\left[X6+\left(8.010-\left(\frac{\mathrm{cos}\left(X4\right)\times 0.989}{\mathrm{cos}\left(X8+X3\right)}\right)\right)\right]+\left[-3.539-\mathrm{sin}\left(\left(\left(5.549+X1\right)\times \left(-0.883\right)\times X4\right)+\left(X7-X9+\left(X2-3.579\right)\right)\right)\right]+\left[X4+\left(X7-\left(\mathrm{cos}\left(\left(\left(X2\times X1\right)\times \left(-8.741\right)\times X7\right)\times X1\times X5\right)\right)\right)\right]\end{aligned}\)

\(\begin{aligned}CW=\left[4.719\times \frac{X1}{{\left(5.715\right)}^{X1}-\left({X8}^{4.879}+\frac{6.250}{X8}\right)}\right]+\left[\mathrm{cos}\left(-4.432-\left(\left(X9-X3-0.208\right)\times \left({X5}^{X5}\times 10.590\right)\right)\right)\right]+\left[\left(\frac{7.082-6.718X4}{{\left(X6-6.287\right)}^{3}}\right)\times \left(X3-X7X4\right)\right]+\left[{\mathrm{cos}}^{2}\left(X9-{\left(\mathrm{cos}\left(\left(4.957-X2\right)-\mathrm{cos}\left(X4\right)\right)\right)}^{4}\right)\right]\end{aligned}\)

\(\begin{aligned}STN=\left[-5.448\times \mathrm{sin}\left(X7\times \left(X7+\left(\left(X5+5.490\right)\times \left(X1X4\right)\right)\right)\right)\right]+\left[7.232\times \left(3.087-\left(\left({\mathrm{sin}}^{2}\left(X2-X6\right)\right)\times \mathrm{sin}\left(X5-3.272\right)\right)\right)\right]+\left[\left(X7\times \left(X7-X3+X2\right)\right)\times \left(X8+\mathrm{sin}\left(3.793X9\right)\right)\right]+\left[X6\times \left(X9+\left(X8+\left(X7\times \left({X8}^{2}-6.451\right)\right)\right)\right)\right]\end{aligned}\)

\(\begin{aligned}Vit=\left[\mathrm{sin}\left(X6-\left(X2\times \left({1.392X1}^{{F8}^{3}}+1.334X9\right)\right)\right)\right]+\left[\mathrm{sin}\left(X1\right)+X1+{X1}^{3}+\left(\frac{X9}{X7}\times 2X8\right)\right]+\left[\mathrm{cos}\left(\left(\left(2X1+X2\right)\times \left(X1+X4-{X3}^{3}\right)\right)\right)\right]+\left[{X5}^{{F9}^{\left(\left(\frac{6.882-X5}{X2+X5}\right)\times \left(\mathrm{sin}\left({X7}^{X1}\right)\right)\right)}}\right]\end{aligned}\)

Rayen

\(\begin{aligned}PR=\left[\mathrm{sin}{\left(\mathrm{cos}\left({X2}^{3}\times \left(\left(X4+X6\right)\times \frac{-2.567}{X9}\right)\right)\right)}^{9}\right]+\left[X1+\left(\mathrm{sin}\left(\left(\mathrm{cos}\left(X3\times X1\right)\right)-\left(\mathrm{sin}\left({X3}^{X9}\right)\right)\right)+3.955\right)\right]+\left[\left(X6\times \frac{\mathrm{sin}\left(X5\right)}{\mathrm{sin}\left(X7\right)+{X5}^{X9}}\right)+X3\right]+\left[\mathrm{sin}\left(X5\times \left({X8}^{39.898}\right)\right)-0.108X7\right]\end{aligned}\)

\(\begin{aligned}CW=\left[\mathrm{sin}\left(\frac{\mathrm{sin}\left(\left(\frac{X9}{X6}+1.351X7\right)-\left(\frac{\mathrm{cos}\left(X5\right)}{-2.359}\right)\right)}{-1.721}\right)\right]+\left[\mathrm{sin}\left(\mathrm{cos}\left({\left({\left(\mathrm{sin}\left(X7\right)+0.566\right)}^{2}\right)}^{\left({X6}^{3}\times \frac{X3}{-7.132}\right)}\right)\right)\right]+{\left[\mathrm{cos}\left(0.089+\left(\mathrm{cos}\left(\frac{X6}{X4-3.919}\right)\right)\right)\right]}^{X2}+\left[\mathrm{sin}\left(\left(X1-X5+0.282\right)\times \left(\frac{\mathrm{cos}\left(X1\right)}{-1.095-X8}\right)\right)\right]\end{aligned}\)

\(\begin{aligned}STN=\left[6.002\times \left(\left(\mathrm{cos}\left(\left(3.862X3+X9-X1\right)\times \left(\mathrm{sin}\left(X7\right)\right)\right)\right)-X4\right)\right]+{\left[X2\times \left(X3+\mathrm{cos}\left(X2\times \left(X8-X8+3.742\right)\right)\right)\right]}^{2}+\left[\left({\left(X9-4.711\right)}^{2}-\left(X6\times X4\times X1\right)\right)+45.170\right]+\left[\frac{\mathrm{cos}\left(F1\right)}{\left(X5-1.460\right)-\left(\mathrm{cos}\left(X2\right)\times {X2}^{X1}\right)}\right]\end{aligned}\)

\(\begin{aligned}Vit=\left[\frac{X4}{\mathrm{sin}\left(F1\times \left(9.069+F4F6-F4F3\right)\right)}\right]+\left[X2+\left({X1}^{3}-\left({\left(X8+X5\right)}^{-2.497X9}+X1\right)\right)\right]+\left[8.504+\left({X7}^{X7}\times \left(\left({X9}^{-1.651}-X6\right)\times \left(X3-X6\right)\right)\right)\right]+\left[\frac{X8\times \left(\mathrm{sin}\left(X2-X6\right)\times \left(X9\times \left(X2-X5\right)\right)\right)}{\mathrm{sin}\left(X7\right)}\right]\end{aligned}\)