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 determinate-type tomato (Source: Ohta and Ikeda ).
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.
- flower bud
- lateral shoot
- Solanum lycopersicum
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 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 . These cultivars are mainly grown for processing and cooking tomatoes .
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 . 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 , 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 . The utilization of lateral shoots can both promote high-quality fruit production [8, 9, 10] and also increase crop yield . In contrast, for determinate tomato cultivars, lateral shoots are generally not removed to save labor and ensure yield [12, 13, 14, 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, 18, 19, 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, 22, 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 . 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 , 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].
2. Materials and methods
2.1. Lateral shoot elongation after terminal flower buds (TFB) and shoot (including TFB and axillary bud (AB) at the first node below TFB) removal
2.1.1. Plant materials, cultivation, and treatments
Indeterminate-type “Mini Carol” (
The lateral shoot length of the second node below TFB was measured at 0, 3, 6, and 9 days after the treatments.
2.2. Effects of pinching treatment (shoot removal) on plant growth, flowering, and yield in determinate tomato
2.2.1. Experimental site, plant materials, growing conditions, and treatments
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 to analyze the mineral nutrient contents.
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 coder (Sumigraph NC-22F, Sumitomo Chemical Analysis Center Corp., Tokyo). The phosphorus (P) contents were measured by vanadomolybdate absorption spectrometry. The potassium (K), calcium (Ca), and magnesium (Mg) contents were measured by an atomic absorption spectrophotometer (AA-630, Shimadzu, Kyoto, Japan). The contents of mineral nutrient in each organ of plant were calculated from dry weight and mineral nutrient concentrations. The first flowering dates of the main stem and the lateral shoots were recorded, and the numbers of flowers, and the number of secondary and higher lateral shoots per primary lateral shoot were counted. Full ripe fruits were harvested twice per week during 6 weeks, and the number of fruits, fruit weight, and the number of marketable fruits were recorded. The soluble solids content (SSC) values of 20 marketable fruits were evaluated using a digital refractometer (APAL-1; AS ONE Corp., Osaka, Japan) to measure the Brix values of fresh juice samples.
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.
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 (C1) growth at the second node below TFB was analyzed in indeterminate-type cultivars in the presence of either TFB (A1) or AB (B1). The growth of C1 was suppressed in the presence of only B1, and the growth of C1 did not change even if both A1 and B1 were removed. Therefore, the presence of A1 promoted the growth of C1 in indeterminate-type cultivars. On the contrary, when the growth of lateral shoot (C2) was analyzed in determinate-type cultivars in the presence of either TFB (A2) or AB (B2), the growth of C2 in the presence of only B2 did not change (growth was suppressed). However, the growth of C2 was accelerated if both A2 and B2 were removed. Thus, the presence A2 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 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 six-true-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 six-true-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 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.
|A × B||NS||NS||NS||NS||NS|
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 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.
|Treatment||Number of flowers per whole plant||Number of flowered lateral shoots per whole plant||Number of flowers per lateral shoot||Number of secondary and higher lateral shoots per primary lateral shoot|
|Total||Primary||Secondary and higher|
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-true-leaf 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 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.
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 , the effect of TFB on lateral shoot growth might be stronger than that on AB in both types of cultivars.
In relation to the inner plant growth regulators, auxin is produced in the apical bud and young expanding leaves in
In the pinching treatments (shoot removal), the growth of lateral shoots, especially in the three-true-leaf pinching treatment, was greater compared with that in the control (Table 1), which would be due to the increase of mineral nutrients uptake since the distribution of some mineral nutrient elements was changed by the pinching treatment. The differences in lateral shoot lengths in the plants by the pinching treatment at four to six true leaves were larger than in the plants by the pinching treatment at zero to three true leaves in the determinate-type tomato “Wase Daruma” . Almost the same result was obtained in regard to the lateral shoot lengths in the different pinching treatments in the present study. The shoot lengths of 3-scaffold shoots by pinching treatment were longer than those of 6-scaffold shoots because the nutrient competition among the remaining shoots reduced in watermelon (
Since the flowering period in the three-true-leaf pinching treatment was significantly shorter than those in the other treatments, the decrease of fruit set ratio that could occur during periods of high air temperatures (over 35°C) might have been avoided by pinching treatment . Although the number of flowers in the three-true-leaf pinching treatment was significantly decreased compared with the other treatments (Table 2), there was no difference in the total fruit yield among all the treatments because the fruit set ratio in the three-true-leaf pinching treatment was higher than that in the other treatments. The harvest term in the pinching treatments was shortened until 3 WAH compared with that in the control until 4 WAH (Figure 7). These findings are in agreement with those of earlier studies [26, 27, 41]. The possibility for both shortening the harvest term and increasing the early yield was recognized in the three-true-leaf pinching treatment. In particular, shortening of the harvest term would permit mechanical harvesting and save labor cost, as described previously [12, 42, 43, 44].
The number of flowers per primary lateral shoot was not different in all treatments, whereas the numbers of flowers per secondary and higher lateral shoots in the both pinching treatments were significantly higher compared with that in the control (Table 2). The flower numbers on the longer lateral shoots could be increased in processing tomato plants . In eggplants, the flower numbers on pinched plants were higher than those on no pinched plants because the number of lateral shoots would be increased on the former . Therefore, in this experiment, the increases in both the number of flowers and the number of secondary and higher lateral shoots in the both pinching treatments compared with the control might be due to the release of apical dominance in plants because of the extension of lateral shoots in the previous reports [17, 19, 20, 47].
Pinching (shoot removal) releases apical dominance and removes a metabolic sink in plants . This results in decreased auxin production in the apical bud and increased nutrient distribution into and growth of the lateral shoots [48, 49]. The levels and distribution of N, P, and K were increased in the lateral shoots of bean plants in relation to apical dominance . Ca, a structural component of the cell wall and membranes, is needed for tomato plant growth at early growth stages , and its uptake under high-growth conditions was increased in tomato shoots [52, 53]. Fukui et al.  also reported that increased the number of flowers were due to the relatively greater availability of photosynthetic products in tomato cultivars with large leaf areas. The number of flowers in tomato plants is also increased by higher contents of N and P . Decoteau  reported that topping enhanced axillary leaf development in processing tomato cultivars. Thus, pinching treatments likely increase the photosynthetic products and mineral nutrient uptake by increasing the leaf areas of lateral shoots, and also likely lead to increased numbers of flowers. Therefore, it was revealed that the numbers of dropped flowers in the control and six-true-leaf pinching treatments were greater than in the three-true-leaf pinching treatment because of the excessive number of flowers per plant.
In tomato plants, flower bud or shoot removal (pinching treatment) affected the branch formation and fruit yield. The emergence of TFB affected the growth of lateral shoots in indeterminate-type cultivar, whereas it did not affect the growth of lateral shoots in determinate-type cultivar. Therefore, it is suggested that the appropriate management of the lateral shoots would be necessary for improve fruit yield or fruit quality, and it would be different between indeterminate and determinate-type cultivars. In indeterminate-type cultivars, it would be important to consider both the position and timing of shoot pinching and the timing of lateral shoot removal. In determinate-type cultivars, it might be necessary to study the number of lateral shoots or the training direction of the vines in order to avoid plant diseases during the periods of high temperature and/or humidity conditions. The shortening of harvest term and increase of initial fruit production in the three-true-leaf pinching treatment would be due to elongated lateral shoots and shortening of the flowering periods per plant. Thus, the pinching treatment could permit machine harvesting and save labor costs for determinate tomato cultivation. From these results, further studies should be undertaken to elucidate the relationships among shoot growth of plant, number of flowers, and physiological factors such as the sink strength in each organ, the distribution of photosynthetic products, and the changes of nutritional status and some plant growth substances in plants after flower bud or shoot removal (pinching treatment).
Saito T. Chap. 2. Flower bud differentiation and development of fruit vegetables. Section 1 flowering habit, Section 2 Differentiation process of flower bud. In: Vegetable crop Science. Vegetables. Tokyo: Rural Culture Association; 1982. p. 64-87 (in Japanese)
Tabuchi T. 1. General properties, 2. Flowering habit, and 3. Differentiation and development of flower bud. In: Kanahama K, editor. Vegetable Crop Science. Tokyo: Buneido Press; 2007. p. 21-33 (in Japanese)
Yeager AF. Determinate growth in the tomato. Journal of Heredity. 1927; 18:263-265
Abe I, Kamimura S, Seyama N. Studies on the unstaked culture for processing tomatoes. Some experiments on the direct seeding. Bulletin of the National Institution of Horticulture, Series C. 1965; 3:73-87 (in Japanese with English summary)
Ohta K. Pattern of lateral shoot elongation and the lateral shoot elongation of two nodes immediately below flower truss in tomato plants. Horticultural Research (Japan). 2012; 11(Supplement 1):382 (in Japanese)
Shishido Y, Hori Y. The role of leaf as affected by phyllotaxis and leaf histology on the development of the fruit in tomato. Journal of the Japanese Society for Horticultural Science. 1991; 60:319-327. DOI: 10.2503/jjshs.60.319 (in Japanese with English summary)
Heuvelink E. Chap. 3. Developmental process. In: Heuvelink E, editor. Tomatoes. London, CABI; 2005. p. 53-84
Fukuchi N, Motoori S, Udagawa Y. Effects of fruit thinning and training on tomato yield and fruit soluble solids content. Horticultural Research (Japan). 2004; 3:277-281. DOI: 10.2503/hrj.3.277 (in Japanese with English summary)
Kusakawa T, Fukuchi N, Inoue M. Relationship between leaf weight on lateral shoots below the tomato truss and fruit soluble solids content. Bulletin of Chiba-Ken Agricultural Forestry Research Center. 2013; 5:93-99 (in Japanese with English summary)
Saito T, Fukuda N, Nishimura S. Effects of salinity, planting density and lateral shoot leaves under truss on yield and total soluble solids of tomato fruits grown in hydroponics. Horticultural Research (Japan). 2006; 5:415-419. DOI: 10.2503/hrj.5.415 (in Japanese with English summary)
Sasaki H, Kawasaki Y, Yasuba K, Suzuki K, Takaichi M. Effect of retaining basal lateral shoot on total soluble solids and yield in tomato trained on a high wire system. Bulletin of the National Institute of Vegetable and Tea Science. 2013; 12:1-6 (in Japanese with English summary)
Arima H, Nakamura H. Studies on the laborsaving culture of processing tomato. Journal of the Faculty of Agriculture, Shinshu University. 1969; 2:83-99 (in Japanese with English summary)
Fukui H, Iguchi H, Nakamura M. Characteristics of determinate type tomatoes. Research Bulletin of the Faculty of Agriculture, Gifu University. 1990; 55:125-135 (in Japanese with English summary)
Ito K. A study on the establishment of breeding technology for labor-saving harvest facing breeding in the processing tomatoes [thesis]. Sendai, Japan: Tohoku University; 1992 (in Japanese)
Yanokuchi Y. Basic edition. Tomato. Cultivation system, cropping type, and cultivation point. Cultivation of the processing tomatoes. Compendium of agricultural technology. In: Vegetables 2 Tomato. Tokyo: Rural Culture Association; 1997. p. 607-613 (in Japanese)
McSteen P, Leyser O. Shoot branching. Annual Review of Plant Biology. 2005; 56:353-374. DOI: 10.1146/annurev.arplant.56.032604.144122
Brenner ML, Wolly DJ, Sjut V, Salerno D. Analysis of apical dominance in relation to IAA transport. HortScience. 1987; 22:833-835
Cline MG. Apical dominance. The Botanical Review. 1991; 57:318-358. DOI: 10.1007/BF02858771
Tucker DJ. Hormonal regulation of lateral bud outgrowth in the tomato. Plant Science Letters. 1977; 8:105-111. DOI: 10.1016/0304-4211(77)90019-0
Tucker DJ. Apical dominance in the ‘Rogue’ tomato. Annals of Botany. 1997;41;181-190. DOI: 10.1093/oxfordjournals.aob.a085266
Ece A, Darakci N. Determination of relationships between number of stem and yield of tomato ( Lycopersicon lycopersicum l.). Asian Journal of Plant Sciences. 2007; 6:802-808
Maboko MM, Du Plooy CP, Chiloane S. Effect of plant population, fruit and stem pruning on yield and quality of hydroponically grown tomato. African Journal of Agricultural Research. 2011; 6:5144-5148. DOI: 10.5897/AJAR11.1316
Xu R, Xu H, Wang T. Effects of removing lower leaves and topping treatment on greenhouse tomatoes. Abstracts of the 215th Meeting of the Crop Science of Japan. 2003; 72(Supplement 1):264-265 (in Japanese)
Kozai S. Effect of pinching and leaf-thinning treatment at seedling stage on development of double cluster and the number of flowers of cherry tomato. Horticultural Research (Japan). 2013; 12(Supplement 1):101 (in Japanese)
Motoki S, Ito M, Yanokuchi S, Okamoto K, Nakamura T. Effect of topping management of cherry tomatoes on the form of flower cluster, characteristic of flowering and fruit ripening, characteristic of fruit quality and fruit yield. Bulletin of the Nagano Chushin Agricultural Experiment Station. 1996; 13:63-74 (in Japanese with English summary)
Knott JE. The effect of apical pruning of tomato seedlings on growth and early yield. Proceedings of the American Society for Horticultural Science. 1927; 24:21-23
Sayre CB. Early and total yields of tomatoes as affected by time of seedling, topping the plants, and space in the flats. Proceedings of the American Society for Horticultural Science. 1948; 51:367-370
Ohta K, Ikeda D. Differences in branch formation in indeterminate and determinate tomato types. Environmental Control in Biology. 2015; 53:189-198. DOI: 10.2525/ecb.53.189
Ohta K, Ikeda D. Effects of pinching treatment on harvest term and plant growth in processing tomato. Canadian Journal of Plant Science. 2017; 97:92-98. DOI: 10.1139/CJPS20160127
Ljung K, Bhalerao PR, Sandberg G. Sites and homeostatic control of auxin biosynthesis in Arabidopsisduring vegetative growth. Plant Journal. 2001; 28:465-474. DOI: 10.1046/j.1365-313X.2001.01173.x
Thomas TH. Effects of decapitation, defoliation and stem girdling on axillary bud development in Brussels sprouts. Scientia Horticuturae. 1983; 20:45-51. DOI: 10.1016/0304-4238(83)90110-3
Tucker DJ. Endogenous growth regulators in relation to side shoot development in the tomato. New Phytologist. 1976; 77:561-568. DOI: 10.1111/j.1469-8137.1976.tb04647.x
Zhu YX, Davis PJ. The control of apical bud growth and senescence by auxin and gibberellin in genetic lines of pea. Plant Physiology. 1997; 113:631-637. DOI: 10.1104/pp.113.2.631
Shimizu-Sato S, Tanaka M, Mori H. Auxin-cytokinin interactions in the control of shoot branching. Plant Molecular Biology. 2009; 69:429-435. DOI: 10.1007/s11103-008-9416-3
Dun EA, Germain AS, Rameau C, Beveridge CA. Antagonistic action of strigolactone and cytokinin in bud outgrowth control. Plant Physiology. 2012; 158:487-498. DOI: 10.1104/pp.111.186783
Koltai H, Lekala AP, Bhattacharya C, Mayzlish-Gati E, Resnick N, Wininger S, Dor E, Yoneyama K, Yoneyama K, Hershenhorn J, Joel DM, Kapulnik Y. A tomato strigolactone-impaired mutant displays aberrant shoot morphology and plant interactions. Journal of Experimental Botany. 2010; 61:1739-1749. DOI: 10.1093/jxb/erq041
Leyser O. The control of shoot branching: An example of plant information processing. Plant, Cell and Environment. 2009; 32:694-703. DOI: 10.1111/j.1365-3040.2009.01930.x
Ongaro V, Leyser O. Hormonal control of shoot branching. Journal of Experimental Botany. 2008; 59:67-74. DOI: 10.1093/jxb/erm134
Kaizuka T, Suzuki M. Influence of the different methods of growth and environment training of fruit in small type watermelon. Bulletin of the Horticulture Institute, Ibaraki-Agricultural Center. 2004; 12:1-7 (in Japanese with English summary)
Iwahori S, Sakiyama R, Takahashi K. High temperature injuries in tomatoes. I. Effects of different temperatures on fruit setting and of seedlings treated at different stages of growth. Journal of the Japanese Society for Horticultural Science. 1963; 32:197-204 (in Japanese with English summary). DOI: 10.2503/jjshs.32.197
Ito K, Kamimura S, Kanno K. Effect of topping at seedling stage on the flowering convergence in tomato (Preliminary study). Abstract of Tohoku Branch. Journal of the Japanese Society for Horticultural Science. 1980; 55:59-60 (in Japanese)
Stout BA, Ries SK. Development of a mechanical tomato harvester. Agricultural Engineering. 1960; 41:682-688
Stephenson KQ. Selective fruit separation for mechanical tomato harvester. Agricultural Engineering. 1964; 45:250-253
Arima H, Tsuchiya T, Fukaya K, Nakamura R. Studies on the laborsaving culture of processing tomato. On the trial fruits conveyer and mechanical harvester. Journal of the Faculty of Agriculture, Shinshu University. 1973; 10:75-114 (in Japanese with English summary)
Arima H, Kobayashi T, Murata H. Growing phase of the flowering, fruiting and ripening of processing tomato. Journal of the Faculty of Agriculture, Shinshu University. 1997; 8:11-23 (in Japanese)
Ishida K. Effect of pinching at different stages of growth on flowering and fruit yield of eggplants. The Science Report of the Faculty of Agriculture, Kobe University. 1983; 15:235-240 (in Japanese with English summary)
Cline MG. Exogenous auxin effects on lateral bud outgrowth in decapitated shoots. Annals of Botany. 1996; 78:255-266. DOI: 10.1006/anbo.1996.0119
Hillman JR. Apical dominance. In: Willkins MB, editor. Advanced Plant Physiology. London: Pitman; 1984. p. 127-148
Nakamura E. Studies on the branching in Pisum sativum l. VI. Physiological and anatomical aspects of branch development. Journal of the Japanese Society for Horticultural Science. 1967; 36:217-228. DOI: 10.2503/jjshs.36.217 (in Japanese with English summary)
Phillips IDJ. Nitrogen, phosphorus, and potassium distribution in relation to apical dominance in dwarf bean ( Phaseolus vulgaris, c.v. Canadian Wonder). Journal of Experimental Botany. 1968; 19:617-627. DOI: 10.1093/jxb/19.3.617
Halbrooks MC, Wilcox GE. Tomato plant development and elemental accumulation. Journal of the American Society for Horticultural Science. 1980; 105:826-828
Hawkesford M, Horst W, Kichey T, Lambers H, Schjoerring J, Møller IS, White P. Part I. Nutritional physiology. 6. Functions of macronutrients. In: Marschner P, editor. Marschner’s Mineral Nutrition of Higher Plants. 3rd ed. London: Academic Press; 2012. p. 135-190. DOI: 10.1016/B978-0-12-384905-2.00006-6
Nakano Y, Watanabe S, Kawashima H, Takaichi M. The effect of daily nutrient applications on yield, fruit quality, and nutrient uptake of hydroponically cultivated tomato. Journal of the Japanese Society for Horticultural Science. 2006; 75:421-429. DOI: 10.2503/jjshs.75.421 (in Japanese with English summary)
Saito T, Hatayama T, Ito H. Studies on the growth and fruiting in the tomato. III. Effect of the early environment on the flowering (3) nutrition of nitrogen, phosphorus and potassium. Journal of the Japanese Society for Horticultural Science. 1963; 32:131-142. DOI: 10.2503/jjshs.32.131 (in Japanese with English summary)
Decoteau DR. Tomato leaf development and distribution as influenced by leaf removal and decapitation. HortScience. 1990; 25:681-684