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

**Branch Formation and Yield by Flower Bud or Shoot** 

DOI: 10.5772/intechopen.71519

#### Katsumi Ohta Additional information is available at the end of the chapter

Katsumi Ohta

Additional information is available at the end of the chapter

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

#### **Abstract**

Branch formation might be used as indices for improving productivity in tomatoes. However, there has been little research to elucidate the relationship between the emergence of terminal flower bud (TFB) and the elongation of lateral shoots. Therefore, the effects of flower bud or shoot removal on plant growth, flowering, and yield were investigated. In indeterminate cultivar, the lateral shoot of the second node below TFB was suppressed by flower bud removal but not by shoot removal compared with untreated plants. In determinate cultivar, the opposite results were observed. TFB emergence was affected and not affected during lateral shoot elongation of both type cultivars, respectively. In determinate-type tomato, growth, dry weight, and the distribution of nitrogen and calcium in the lateral shoots in the pinching treatments (shoot removal) were greater than those in the control. The flowering periods and number of flowers per lateral shoot in the pinching treatments were shorter and greater, respectively, than those in the control. Initial weekly yields in the pinching treatments were increased compared with those in the control. From these results, since the branch formation and productivity by flower bud or shoot removal was clarified, it would be useful information for future tomato production.

**Keywords:** flower bud, lateral shoot, morphogenesis, *Solanum lycopersicum*, yields

#### **1. Introduction**

Tomatoes are an important fruit vegetable in many countries. Tomato plants differentiate terminal flower buds (TFB) on the apex of the main stem and formed flower truss, known as the determinate pattern with branching characteristics [1, 2]. The axillary bud (AB) adjacent to TFB differentiates and forms a lateral shoot as a sympodial branching. As mentioned above, the lateral shoot that grows as a main branch is a characteristic of indeterminate-type

Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons

tomatoes that are cultivated mainly for the fresh market. On the contrary, determinate-type tomatoes with a self-pruning growth habit with only short sympodial branches form a few flower trusses [3]. These cultivars are mainly grown for processing and cooking tomatoes [4].

there has been little information about the effects of pinching treatments on the harvest term, yield, growth of lateral shoots, flowering, and number of flowers in determinate processing tomatoes, and about the relationship between the growth of lateral shoots and the uptake of mineral nutrients. Therefore, the objective of this study was to clarify and summarize the effects of flower bud or shoot removal on these parameters based on the previous

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

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

37

**2.1. Lateral shoot elongation after terminal flower buds (TFB) and shoot (including TFB** 

Indeterminate-type "Mini Carol" (*Solanum lycopersicum* l.) (Sakata Seed Co. Ltd., Japan) and determinate-type "Suzukoma" (Tohoku Agricultural Research Center, National Agriculture and Food Research Organization and ZEN-NOH, Japan) were used for this experiment. Seeds were sown in plastic containers (34.5 × 27.0 × 7.5 cm). One plant was potted black plastic pots at a ratio of sandy loam:bark compost of 1:1 (v/v). Tomato plants were transplanted into Wagner pots (1/5000 a) in the same potting substrate described above. All pots were placed in a greenhouse at Shimane University, Matsue, Japan. TFB (maximum bud length of about 1 mm) were removed by pinching them off, and the stems were decapitated at the upper portions of shoots of the second node below TFB (**Figure 1**). Ten plants per treatment

The lateral shoot length of the second node below TFB was measured at 0, 3, 6, and 9 days

**Figure 1.** Axillary bud of the second node (AB-S) below the terminal flower bud (TFB) in indeterminate-type cultivar "Mini Carol" (a) and determinate-type cultivar "Suzukoma" (b) tomatoes. Axillary buds (AB) of the first node below TFB

exist behind TFB. Flower bud removals are shown by bars (Source: Ohta and Ikeda [28]).

**and axillary bud (AB) at the first node below TFB) removal**

*2.1.1. Plant materials, cultivation, and treatments*

research [28, 29].

were evaluated.

*2.1.2. Measurements*

after the treatments.

**2. Materials and methods**

In general, the lateral shoots of indeterminate tomato cultivars are periodically removed to prevent nutrient competition between vegetative and reproductive organs during cultivation period. Several lateral shoots extends greatly unless all the lateral shoots are removed [5]. Since the sink strength of lateral shoots with flower buds and trusses is stronger than that of the main stem or lateral shoot without flower buds and trusses [6], strong growth of some lateral shoots may cause uneven distribution of photosynthetic products, resulting in undesirable effects on fruit production. As an example of using lateral shoots, during tomato cultivation during winter in the Netherlands, lateral shoots generated from the first or second nodes below TFB are used to increase stem numbers per area in indeterminate cultivars and increase tomato yield [7]. The utilization of lateral shoots can both promote high-quality fruit production [8–10] and also increase crop yield [11]. In contrast, for determinate tomato cultivars, lateral shoots are generally not removed to save labor and ensure yield [12–15]. However, lack of fruit set on the first flower truss due to low or high temperatures or rainfall or due to pinching at the seedling stage could affect the lateral shoot lengths and flowering periods of determinate processing tomatoes.

Differentiation of AB occurs at every node during the growth of most commercial cultivars. Although AB at lower nodes extends during the vegetative stage, AB at the upper nodes below TFB does not extend much due to apical dominance [1, 16]. When TFB at the shoot apex emerges and grows, the entire AB in general begins to elongate. Branch formation in indeterminate cultivars differs from that in determinate ones because of generally remaining the lateral shoots. Also, to investigate the growth properties of lateral shoots generated from each node could be used to increase productivity in tomato cultivation.

The growth of lateral shoots in the indeterminate cultivars can be extended by pinching (shoot removal) from the results of the previous reports [17–20]. In some tomato cultivars, the numbers and weights of fruits that grew on double-stemmed plants created by pinching treatments were greater than those that grew on single-stemmed plants [21–23]. Pinching at the seedling stage can increase the number of double clusters and flowers on lateral shoots of cherry tomatoes [24, 25]. Pinching is often performed to increase initial tomato yield, but there are differences among cultivars as to the effects of pinching [26, 27]. In addition, the lengths of the lateral shoots at each node do differ depending on the pinching position [14]. As the number of remaining true leaves is increased by pinching, there is a difference among the lateral shoot lengths. Since a relationship among the lengths of lateral shoots, the number of flowers per plant, and per lateral shoot is expected to be changed by pinching in determinate processing tomatoes, growth of the lateral shoot would be influenced by the uptake and distribution of mineral nutrients in each organ. Furthermore, because pinching can enhance the uniformity of fruit maturity [14], pinching could shorten the harvest term while also, due to this shorter flowering period, leading to harvest periods with more than 80% total fruit yield.

However, there has been little research to elucidate the relationships between the TFB and the elongation of lateral shoots in indeterminate and determinate-type tomatoes. Furthermore, there has been little information about the effects of pinching treatments on the harvest term, yield, growth of lateral shoots, flowering, and number of flowers in determinate processing tomatoes, and about the relationship between the growth of lateral shoots and the uptake of mineral nutrients. Therefore, the objective of this study was to clarify and summarize the effects of flower bud or shoot removal on these parameters based on the previous research [28, 29].
