Table 4 Mean root mass and length of six clones of poplar established from cuttings

Clone

  P. deltoides × P. ciliata San Rosa

1.7^ab (0.5)

2.6^bc (0.9)

2.0 (1.3)

1.5 (0.4)

1.2^abc (0.3)

0.2 (0.1)

  P. deltoides × P. nigra Fraser

1.0^b (0.3)

2.8^bc (0.9)

4.5 (3.0)

1.2 (0.3)

1.1^bc (0.3)

0.3 (0.2)

  P. deltoides × P. nigra Veronese

1.1^b (0.3)

3.8^b (1.2)

2.0 (1.3)

1.3 (0.4)

1.5^abc (0.4)

0.2 (0.1)

  P. deltoides × P. yunnanensis Kawa

2.7^a (0.8)

5.9^ab (1.9)

12.9 (8.6)

2.1 (0.6)

2.1^ab (0.6)

0.8 (0.6)

  P. maximowiczii × P. nigra Geyles

2.5^a (0.8)

9.4^a (3.0)

8.6 (5.7)

1.6 (0.4)

2.8^a (0.8)

0.6 (0.4)

  P. trichocarpa PN471

0.8^b (0.2)

1.5^c (0.5)

6.7 (4.5)

1.1 (0.3)

0.7^c (0.2)

0.5 (0.4)

  P value

0.027

0.005

0.118

0.333

0.013

0.322

Width (m)

 0 < 0.5

4.2^a (0.7)

7.2^a (1.2)

9.8^a (3.6)

3.2^a (0.5)

2.1^a (0.3)

0.7^a (0.3)

 ≥0.5

0.5^b (0.1)

1.8^b (0.3)

2.4^b (0.9)

0.7^b (0.1)

1.0^b (0.1)

0.2^b (0.1)

  P value

<0.001

<0.001

<0.001

<0.001

0.002

0.006

Year after planting

 1

1.2 (0.2)

1.5^b (0.3)

2.9 (1.3)

1.2 (0.2)

0.9^b (0.1)

0.3 (0.1)

 2

1.9 (0.4)

8.9^a (1.7)

8.2 (3.7)

1.7 (0.3)

2.2^a (0.4)

0.7 (0.3)

  P value

0.085

<0.001

0.137

0.081

<0.001

0.158