**3. Results**

**2.2. Effects of pinching treatment (shoot removal) on plant growth, flowering, and yield in** 

The determinate-type "Shuho" (Nagano Chushin Agricultural Institute Experimental Station, Shiojiri, Japan) was used for this experiment. Seeds were sown in plastic containers. All containers were placed in a greenhouse at Shimane University, Matsue, Japan. One plant was potted black plastic pots at a ratio of sandy loam:bark compost of 1:1 (v/v). After the third and sixth true leaves had expanded, the plants were pinched at the stem above the third and sixth true leaves (**Figure 2**). No pinching treatments were performed in the untreated control. The tomato plants were transplanted into the experimental field with the soil surface covered with black 0.02-mm polyethylene film at Yatsuka-cho, Matsue, Japan. The plants were arranged in a single 1.6 m wide row, with 0.8 m spacing between rows, 0.45 m spacing between plants, and a planting density of 1.39 plants m−2. A randomized complete block design was used with three replicates. In total, eight plants per treatment were used. Six plants were used to measure the lateral shoot growth, flowering, and fruit yields, and the remaining plants were used

At 18 and 59 days after transplanting (DAT), the lengths of the lateral shoots generated from each node were measured. At 18 DAT, the plants were sampled and divided into stems, leaves on the main shoot, and lateral shoots, and then washed with deionized water. After being air-dried at 80°C for 72 h, the dried plants were ground using an electric mill (WB-1; AS ONE Corp., Osaka, Japan). Total nitrogen (N) contents were determined using a CN

**Figure 2.** Pinching treatments (shoot removal) in determinate-type tomato (schematic diagram). Left is control (a), center is Pinch-3 (b), and right is Pinch-6 (c). Pinch-3 or -6 indicates pinching treatment with the plant left with three or six true

leaves, respectively. A is terminal flower bud (TFB) of main stem. X is pinching position.

*2.2.1. Experimental site, plant materials, growing conditions, and treatments*

38 Physical Methods for Stimulation of Plant and Mushroom Development

**determinate tomato**

*2.2.2. Measurements*

to analyze the mineral nutrient contents.

#### **3.1. Lateral shoot elongation after TFB or shoot removal in indeterminate tomato**

The lateral shoot length at the second node below TFB in the indeterminate-type cultivar "Mini Carol" was significantly suppressed by flower bud removal at 6 and 9 days after treatment, compared to that in untreated plants (**Figure 3**). On the other hand, lateral shoot lengths at the second node below TFB did not differ after shoot removal compared with untreated plants.

**Figure 3.** Lateral shoot length of the second node below the terminal flower bud (TFB) after flower bud removal and shoot removal at the upper position of second node below TFB of indeterminate cultivar, "Mini Carol". Significant difference was shown as \*\*: *P* < 0.01, NS: not significant (*t*-test). Vertical bars indicate standard error (Source: Ohta and Ikeda [28]).

#### **3.2. Lateral shoot elongation after TFB or shoot removal in determinate tomato**

The lateral shoot length at the second node below TFB in the determinate-type cultivar "Suzukoma" was not significantly different between plants with flower buds removed and untreated plants (**Figure 4**). However, the lateral shoot length at the second node below TFB increased significantly at 6 and 9 days after shoot removal compared with that of untreated plants.

**Figure 5** summarizes the results of **Figures 3** and **4**. Lateral shoot (C<sup>1</sup> ) growth at the second node below TFB was analyzed in indeterminate-type cultivars in the presence of either TFB (A<sup>1</sup> ) or AB (B<sup>1</sup> ). The growth of C<sup>1</sup> was suppressed in the presence of only B1 , and the growth of C1 did not change even if both A<sup>1</sup> and B1 were removed. Therefore, the presence of A<sup>1</sup> promoted the growth of C1 in indeterminate-type cultivars. On the contrary, when the growth of lateral shoot (C<sup>2</sup> ) was analyzed in determinate-type cultivars in the presence of either TFB (A<sup>2</sup> ) or AB (B<sup>2</sup> ), the growth of C<sup>2</sup> in the presence of only B2 did not change (growth was suppressed). However, the growth of C<sup>2</sup> was accelerated if both A<sup>2</sup> and B2 were removed. Thus, the presence A<sup>2</sup> did not promote the growth of C2 in determinate-type cultivars.

#### **3.3. Effects of pinching treatment (shoot removal) on plant growth, flowering, and yield**

At 18 DAT, the mean lateral shoot lengths in the three-true-leaf pinching treatment had extend significantly longer, at 14.7 cm, than those in the control, at 5.5 cm. CVs of mean lateral shoot length did not differ among the all treatments, at 50–55%. The lateral shoot lengths generated from the lower nodes in the six-true-leaf pinching treatment was no difference compared

with those in the control, however, the lateral shoots generated from the second to sixth true leaf nodes had extended significantly longer than those in the control (data not shown). At 59 DAT, the lateral shoot lengths in the pinching treatments showed the same tendencies as seen at 18 DAT. The mean lateral shoot lengths in the both pinching treatments were significantly longer, at 44.6 and 35.5 cm, than those in the control, at 27.8 cm. CV of the mean lateral shoot length in the three-true-leaf pinching treatment was smaller, at 28%, than the other treat-

, A<sup>2</sup>

), axillary bud (AB) (B<sup>1</sup>

, B2

Branch Formation and Yield by Flower Bud or Shoot Removal in Tomato

http://dx.doi.org/10.5772/intechopen.71519

) and lateral shoot growth (C<sup>1</sup>

, C2 ) 41

**Figure 6** shows the effect of pinching treatments (shoot removal) on the dry weight (DW) of the plants. Although total DW did not differ among the all treatments, DW in the stem in the three-true-leaf pinching treatment were significantly less compared with those in the sixtrue-leaf pinching treatment and the control. DW in the leaves in the three-true-leaf pinching treatment was significantly less compared with that in the control. However, DW in the lateral

**Table 1** shows the effect of pinching treatments (shoot removal) on the content and distribution of N, P, K, Ca, and Mg at 18 days after transplanting (DAT) in each organ of plant. Although in the stem the contents of P and K in the three-true-leaf pinching treatment were significantly lower than that in the control, the contents of these mineral nutrients in the sixtrue-leaf pinching treatment did not differ compared with that in the control. In the leaves, the contents of all the mineral nutrients were no differences among the all treatments. In the lateral shoots, the contents of N, P, K, Mg, and Ca in the three-true-leaf pinching treatment were significantly increased compared with those in the control. In the lateral shoots, the

shoots in the three-true-leaf pinching treatment was highest among the all treatments.

ments, at 33 and 37%.

**Figure 5.** Relationships among terminal flower bud (TFB) (A<sup>1</sup>

of indeterminate and determinate-type tomatoes (Source: Ohta and Ikeda [28]).

**Figure 4.** Lateral shoot length of the second node below the terminal flower bud (TFB) after flower bud removal and shoot removal at the upper position of the second node below TFB of determinate cultivar, "Suzukoma". Significant difference was shown as \*\*: *P* < 0.01, \*: *P* < 0.05, NS: not significant (*t*-test). Vertical bars indicate standard error (Source: Ohta and Ikeda [28]).

**3.2. Lateral shoot elongation after TFB or shoot removal in determinate tomato**

**Figure 5** summarizes the results of **Figures 3** and **4**. Lateral shoot (C<sup>1</sup>

did not promote the growth of C2

and B1

). The growth of C<sup>1</sup>

40 Physical Methods for Stimulation of Plant and Mushroom Development

), the growth of C<sup>2</sup>

did not change even if both A<sup>1</sup>

pressed). However, the growth of C<sup>2</sup>

plants.

(A<sup>1</sup>

(A<sup>2</sup>

of C1

) or AB (B<sup>1</sup>

of lateral shoot (C<sup>2</sup>

) or AB (B<sup>2</sup>

the presence A<sup>2</sup>

Ohta and Ikeda [28]).

moted the growth of C1

The lateral shoot length at the second node below TFB in the determinate-type cultivar "Suzukoma" was not significantly different between plants with flower buds removed and untreated plants (**Figure 4**). However, the lateral shoot length at the second node below TFB increased significantly at 6 and 9 days after shoot removal compared with that of untreated

node below TFB was analyzed in indeterminate-type cultivars in the presence of either TFB

in the presence of only B2

**3.3. Effects of pinching treatment (shoot removal) on plant growth, flowering, and yield**

At 18 DAT, the mean lateral shoot lengths in the three-true-leaf pinching treatment had extend significantly longer, at 14.7 cm, than those in the control, at 5.5 cm. CVs of mean lateral shoot length did not differ among the all treatments, at 50–55%. The lateral shoot lengths generated from the lower nodes in the six-true-leaf pinching treatment was no difference compared

**Figure 4.** Lateral shoot length of the second node below the terminal flower bud (TFB) after flower bud removal and shoot removal at the upper position of the second node below TFB of determinate cultivar, "Suzukoma". Significant difference was shown as \*\*: *P* < 0.01, \*: *P* < 0.05, NS: not significant (*t*-test). Vertical bars indicate standard error (Source:

was accelerated if both A<sup>2</sup>

was suppressed in the presence of only B1

) was analyzed in determinate-type cultivars in the presence of either TFB

in indeterminate-type cultivars. On the contrary, when the growth

were removed. Therefore, the presence of A<sup>1</sup>

and B2

in determinate-type cultivars.

) growth at the second

were removed. Thus,

did not change (growth was sup-

, and the growth

pro-

**Figure 5.** Relationships among terminal flower bud (TFB) (A<sup>1</sup> , A<sup>2</sup> ), axillary bud (AB) (B<sup>1</sup> , B2 ) and lateral shoot growth (C<sup>1</sup> , C2 ) of indeterminate and determinate-type tomatoes (Source: Ohta and Ikeda [28]).

with those in the control, however, the lateral shoots generated from the second to sixth true leaf nodes had extended significantly longer than those in the control (data not shown). At 59 DAT, the lateral shoot lengths in the pinching treatments showed the same tendencies as seen at 18 DAT. The mean lateral shoot lengths in the both pinching treatments were significantly longer, at 44.6 and 35.5 cm, than those in the control, at 27.8 cm. CV of the mean lateral shoot length in the three-true-leaf pinching treatment was smaller, at 28%, than the other treatments, at 33 and 37%.

**Figure 6** shows the effect of pinching treatments (shoot removal) on the dry weight (DW) of the plants. Although total DW did not differ among the all treatments, DW in the stem in the three-true-leaf pinching treatment were significantly less compared with those in the sixtrue-leaf pinching treatment and the control. DW in the leaves in the three-true-leaf pinching treatment was significantly less compared with that in the control. However, DW in the lateral shoots in the three-true-leaf pinching treatment was highest among the all treatments.

**Table 1** shows the effect of pinching treatments (shoot removal) on the content and distribution of N, P, K, Ca, and Mg at 18 days after transplanting (DAT) in each organ of plant. Although in the stem the contents of P and K in the three-true-leaf pinching treatment were significantly lower than that in the control, the contents of these mineral nutrients in the sixtrue-leaf pinching treatment did not differ compared with that in the control. In the leaves, the contents of all the mineral nutrients were no differences among the all treatments. In the lateral shoots, the contents of N, P, K, Mg, and Ca in the three-true-leaf pinching treatment were significantly increased compared with those in the control. In the lateral shoots, the

**Figure 6.** Effect of pinching treatments (shoot removal) on the dry weight (DW) at 18 days after transplanting (DAT) in determinate-type tomato. Pinch-3 or -6 indicates pinching treatment with the plant left with three or six true leaves, respectively. Different letters within each organ indicate significant difference at *P* < 0.05 (Tukey's test) (Source: Ohta and Ikeda [29]).

contents of N, K, and Ca in the six-true-leaf pinching treatment were significantly greater than that of the control. The total contents of N and Ca in the three-true-leaf pinching treatment were greater than those of the control. Although the distributions of P and K to the stem in the three-true-leaf pinching treatment were decreased compared with those in the control, the distributions of all the mineral nutrients to the lateral shoots in the three-true-leaf pinching treatment were increased compared with those in the control.

The first flowering days from sowing in the control was decreased, at 57.5 days, compared with those in the both pinching treatments, at 64.5 and 64.6 days, respectively. The number of days between the both pinching treatments and the control to the first flowering of the lateral shoots did differ. The number of days between the first and last flowering of the terminal flower truss of main and/or each the lateral shoots in the three-true-leaf pinching treatment was significantly lower, at 13.1 days, than that in the control, at 18.7 days, but the number of days between the first and last flowering of the terminal flower truss of each lateral shoot did not differ between the six-true-leaf pinching treatment and the control.

**Table 2** shows the effect of pinching treatments (shoot removal) on the number of flowers per plant, per primary lateral shoot, and flowered lateral shoots. Although the number of flowers per whole plant in the six-true-leaf pinching treatment was significantly higher than that of the control, the number of flowers per plant in the three-true-leaf pinching treatment was significantly lower compared with that of the control. The total numbers of flowers per lateral shoot in both pinching treatments were significantly higher than that in the control. The number of flowers per primary lateral shoot did not differ among the all treatments; whereas, the

**Organ**

Stem

Control Pinch-3c

Pinch-6

> Leaf

Control Pinch-3 Pinch-6

> Lateral shoot

Control Pinch-3 Pinch-6

> Total

Control Pinch-3 Pinch-6

*P*

Organ (A) Treatment (B)

A × B

NS

\*\* NS aDifferent letters within each column indicate significant difference at *P*

bValues are the ratio of the nutrient amount in each organ to the total in each treatment.

cPinch-3 or -6 indicates pinching treatment with the plant left with three or six true leaves, respectively.

\*,\*\*NS: significant at *P* < 0.05 and *P* < 0.01 or not significant, respectively (ANOVA).

Effect of pinching treatments (shoot removal) on the content and distribution of N, P, K, Ca, and Mg (mg plant−1) at 18

days after transplanting (DAT) in

43

http://dx.doi.org/10.5772/intechopen.71519

**Table 1.**

determinate-type tomato (Source: Ohta and Ikeda [29]).

 <

0.05 (Tukey's test).

NS

\*\* NS

NS

\*\* NS

\* \*\* NS

NS

Branch Formation and Yield by Flower Bud or Shoot Removal in Tomato

NS

\*

74.4

ab

(100)

13.0

a

(100)

59.8

a

(100)

72.8

a

(100)

14.7

a

(100)

85.2

b

(100)

12.2

a

(100)

54.1

a

(100)

90.5

b

(100)

16.3

a

(100)

62.3

a

(100)

11.8

a

(100)

53.4

a

(100)

72.7

a

(100)

14.1

a

(100)

42.9

b

(58)

6.7

b

(52)

30.3

b

(51)

19.9

b

(27)

5.2

ab

(35)

56.8

c

(67)

7.2

b

(59)

31.8

b

(59)

29.1

c

(32)

6.3

b

(39)

28.2

a

(45)

4.6

a

(39)

22.4

a

(42)

15.0

a

(21)

3.9

a

(28)

23.3

a

(31)

3.6

a

(28)

13.7

a

(23)

36.6

a

(50)

5.3

a

(36)

21.6

a

(25)

3.1

a

(25)

11.9

a

(22)

44.4

a

(49)

6.5

a

(40)

26.2

a

(42)

4.2

a

(36)

14.4

a

(27)

40.0

a

(55)

5.9

a

(42)

8.2

a

(11)

2.6

b

(20)

15.8

b

(26)

16.3

a

(23)

4.2

a

(29)

6.8

a

(8)

1.9

a

(16)

10.4

a

(19)

17.0

a

(19)

3.5

a

(21)

7.9

aa

(13)b

2.9

b

(25)

16.5

b

(31)

17.8

a

(24)

4.3

a

(30)

**Treatment**

**N**

**P**

**K**

**Ca**

**Mg**


contents of N, K, and Ca in the six-true-leaf pinching treatment were significantly greater than that of the control. The total contents of N and Ca in the three-true-leaf pinching treatment were greater than those of the control. Although the distributions of P and K to the stem in the three-true-leaf pinching treatment were decreased compared with those in the control, the distributions of all the mineral nutrients to the lateral shoots in the three-true-leaf pinching

**Figure 6.** Effect of pinching treatments (shoot removal) on the dry weight (DW) at 18 days after transplanting (DAT) in determinate-type tomato. Pinch-3 or -6 indicates pinching treatment with the plant left with three or six true leaves,

*P*

< 0.05 (Tukey's test) (Source: Ohta

The first flowering days from sowing in the control was decreased, at 57.5 days, compared with those in the both pinching treatments, at 64.5 and 64.6 days, respectively. The number of days between the both pinching treatments and the control to the first flowering of the lateral shoots did differ. The number of days between the first and last flowering of the terminal flower truss of main and/or each the lateral shoots in the three-true-leaf pinching treatment was significantly lower, at 13.1 days, than that in the control, at 18.7 days, but the number of days between the first and last flowering of the terminal flower truss of each lateral shoot did

**2** shows the effect of pinching treatments (shoot removal) on the number of flowers per



plant, per primary lateral shoot, and flowered lateral shoots. Although the number of flow

ers per whole plant in the six-true-leaf pinching treatment was significantly higher than that of the control, the number of flowers per plant in the three-true-leaf pinching treatment was significantly lower compared with that of the control. The total numbers of flowers per lateral shoot in both pinching treatments were significantly higher than that in the control. The num

ber of flowers per primary lateral shoot did not differ among the all treatments; whereas, the

treatment were increased compared with those in the control.

respectively. Different letters within each organ indicate significant difference at

42 Physical Methods for Stimulation of Plant and Mushroom Development

not differ between the six-true-leaf pinching treatment and the control.

**Table**

and Ikeda [29]).


control. The harvest term in the both pinching treatments was shortened until 3 WAH compared with that in the control until 4 WAH. The fruit set ratio in the three-true-leaf pinching treatment was higher, at 20.4%, than in the other treatments, at 12.7 and 15.8%. However, the fruit yield per plant, at 2968–3018 g, the mean fruit weight, at 94.7–98.3 g, the number of harvested fruits per plant, at 30.3–31.7 fruits, the marketable fruits ratio, at 87.6–89.6%, and SSC, at 4.9–5.1°Brix, did not differ among the treatments. Although the numbers of flowers per whole plant in the six-true-leaf pinching treatment and the control were greater than those in the three-true-leaf pinching treatment, the numbers of harvested fruits were not different

Branch Formation and Yield by Flower Bud or Shoot Removal in Tomato

http://dx.doi.org/10.5772/intechopen.71519

45

Flower bud removal or shoot removal was carried out to clarify the roles of TFB and AB at the first node below TFB, and to clarify the reason that lateral shoots at the second node below TFB elongate. In indeterminate-type cultivar, the lateral shoot lengths at the second node below TFB were suppressed significantly at 6 and 9 days after flower bud removal, but these shoots did not elongate upon shoot removal (**Figure 3**). In determinate-type cultivar, growth of the lateral shoots at the second node below TFB was not suppressed by flower bud removal compared with untreated plants, but lengths of these shoots increased significantly at 6 and 9 days after shoot removal (**Figure 4**). Hence, these results suggest that TFB promoted the growth of lateral shoots at the second node below TFB in indeterminate-type cultivar, but not in determinate-type cultivar (**Figure 5**). In contrast, the presence of AB at the first node below TFB seemed to suppress elongation of AB at the second node in both types of cultivars. Because emergence of TFB occurred earlier than emergence of AB at the second node [28], the effect of TFB on lateral shoot growth might be stronger than that on

In relation to the inner plant growth regulators, auxin is produced in the apical bud and young expanding leaves in *Arabidopsis*, Brussels sprouts, pea, and tomato [30–33]. In the indeterminate-type cultivars, if the auxin concentration that suppresses lateral shoot elongation decreases temporarily upon ablation of the apical meristem or emergence of TFB, the lateral shoot at the second node below TFB elongates due to high cytokinin concentrations in the main stem. According to Shimizu-Sato et al. [34], reduced auxin concentration in the apical organs is a factor involved in increased cytokinin concentrations. However, in determinatetype cultivars, emergence of TFB did not promote the growth of lateral shoots. The much shorter stem lengths in determinate-type cultivars compared indeterminate-type cultivars [28] suggests that auxin concentrations in the apical organs including TFB might differ much from those of non-flowering terminal buds. Furthermore, auxin concentrations in apical organs including TFB might be related to branching habit in tomato plants. Some researchers [35–39] reported that plant growth regulators such as auxin, cytokinin, and strigolactone are related each other to the outgrowth of AB in several plants. Further study is desired to clarify the differences between the two branching types in tomato and the fluctuations in

among the all treatments.

AB in both types of cultivars.

plant growth regulator concentrations.

**4. Discussion**

b Pinch-3 or -6 indicates pinching treatment with the plant left with three or six true leaves, respectively.

**Table 2.** Effect of pinching treatments (shoot removal) on the number of flowers, flowering lateral shoots, flowers per lateral shoots, and secondary and higher lateral shoots per primary lateral shoot in determinate-type tomato (Source: Modified from Ohta and Ikeda [29]).

parameter per secondary and higher lateral shoot in the three-true-leaf pinching treatment was highest among the all treatments. The number of flowered lateral shoots per whole plant in the three-true-leaf pinching treatment was significantly lower compared with those in the other treatments.

**Figure 7** shows the effect of pinching treatments (shoot removal) on the weekly marketable fruit yield. At 0 week after the start of the harvest (WAH), the weekly yield in the control was higher than those in both pinching treatments. However, at 1 WAH in the three-trueleaf pinching treatment was higher compared with that in the control. The weekly yield in the six-true-leaf pinching treatment at 2 WAH was also higher compared with that in the

**Figure 7.** Effect of pinching treatments (shoot removal) on weekly marketable fruit yield in determinate-type tomato. Pinch-3 or -6 indicates pinching treatment with the plant left with three or six true leaves, respectively. Different letters within each week indicate significant difference at *P* < 0.05 (Tukey's test). Vertical bars indicate standard error (Source: Ohta and Ikeda [29]).

control. The harvest term in the both pinching treatments was shortened until 3 WAH compared with that in the control until 4 WAH. The fruit set ratio in the three-true-leaf pinching treatment was higher, at 20.4%, than in the other treatments, at 12.7 and 15.8%. However, the fruit yield per plant, at 2968–3018 g, the mean fruit weight, at 94.7–98.3 g, the number of harvested fruits per plant, at 30.3–31.7 fruits, the marketable fruits ratio, at 87.6–89.6%, and SSC, at 4.9–5.1°Brix, did not differ among the treatments. Although the numbers of flowers per whole plant in the six-true-leaf pinching treatment and the control were greater than those in the three-true-leaf pinching treatment, the numbers of harvested fruits were not different among the all treatments.
