Palms of the genus Roystonea: palm heart production in high-density planting

Palmeiras do gênero Roystonea: cultivo adensado para produção de palmito

ABSTRACT

Currently, commercial palm heart production is based on intensive cultivation, due to the introduction of new palm species and technological improvements. Thus, the objective was to evaluate the agronomic potential of species of the genus Roystonea in high-density planting for the production of palm heart. The experimental design was randomized block in a 4 x 2 factorial scheme, 4 replications, 30 plants per plot and a useful area of twelve plants. The factors were four species: Roystonea altissima, R. oleracea, R. regia and R. borinqueana and two spacings: 2.0 x 0.75 m and 2.0 x 0.50 m. Growth parameters were evaluated every 3 months and palm heart production at 24 months. The four Roystonea species showed rapid growth with satisfactory palm heart production at 24 months. R. altissima showed the highest values for height and diameter, variables highly correlated with palm heart production. The stem diameter values from 18 months onwards and the decrease in the diameter growth rate suggest that the harvest may be brought forward. Both planting densities promoted satisfactory yields, with higher palm heart production per area at the 2 x 0.50 m spacing.

Keywords:
Roystonea altissima; R. borinqueana; R. regia; R. oleracea; plant spacing

RESUMO

Atualmente a produção comercial de palmito é baseada no cultivo intensivo, graças a introdução de novas espécies de palmeiras e aprimoramento da tecnologia. Desse modo, o objetivo foi avaliar o potencial agronômico de espécies do gênero Roystonea em cultivo adensado para a produção de palmito. O delineamento experimental foi de blocos ao acaso em esquema fatorial 4 x 2, 4 repetições, 30 plantas por parcela e área útil de doze plantas. Os fatores foram quatro espécies: Roystonea altissima, R. oleracea, R. regia e R. borinqueana e dois espaçamentos: 2,0 x 0,75 m e 2,0 x 0,50 m. Foram avaliados parâmetros de crescimento a cada 3 meses e de produção de palmito aos 24 meses. As quatro espécies de Roystonea apresentaram crescimento rápido com produção de palmito satisfatória aos 24 meses. R. altissima apresentou os maiores valores de altura e diâmetro, variáveis altamente correlacionadas com a produção de palmito. Os valores do diâmetro do caule a partir dos 18 meses e a queda na taxa de crescimento em diâmetro sugere que a colheita pode ser antecipada. Ambas as densidades de plantio promoveram rendimentos satisfatórios, com maior produção de palmito por área no espaçamento 2 x 0,50 m.

Palavras-chave:
Roystonea altissima; R. borinqueana; R. regia; R. oleracea; espaçamento

Heart of palm can be obtained from diverse palms and the introduction of different species that can be cultivated has promoted a transformation in the production chain. Previously, production was based exclusively on the exploitation of natural resources, mainly juçara (Euterpe edulis) and açai (Euterpe oleracea), which have a long cycle for palm heart production (over 60 months) and difficulty in high-density planting (Modolo et al., 2019).The introduction of peach palm (Bactris gasipaes) and Australian king palm (Archontophoenix spp.) has promoted a change in the heart of palm production chain. Compared to the juçara palm, the latter two palms have rapid growth, producing palm hearts up to 24 months after planting. High-density planting (5,000 to 10,000 plants/ha) encouraged agricultural cultivation instead of extraction, transforming the palm heart production chain which was previously predatory (Modolo et al., 2013).The state of São Paulo represents around 40% of the area cultivated for palm heart production in relation to the total area cultivated in Brazil (IBGE, 2024), with peach palm being the species predominantly used for planting, due to its precociousness and tillering characteristics. Evaluating the potential of other palm species in a production system can provide other cultivation options, reducing environmental pressure and enabling a portfolio of differentiated products.

Palms of the genus Roystonea are easily seen in the continental and island landscapes of the Caribbean region, with ten species currently described representing this genus (Zona, 1996). Some species are endemic of Caribbean and other, due the elegant size and great landscaping effect (Lorenzi et al., 2004) have spread throughout the world, such as R. regia (royal palm, Cuban imperial palm) and R. oleracea (imperial palm) (Reis, 2006). The royal palm has been planted by some Brazilians producers, in Santa Catarina and São Paulo, due to the characteristics of its heart of palm. These palms have a single stem, fast growth and edible heart of palm (Hodce, 1965; Berbari et al., 2024). The IAC's Ornamental Palm collection has other species of this genus, like R. altissima and R. borinqueana, that could become an option for high-density planting for palm heart production.

For a palm species to be competitively integrated into the palm heart production system, it needs cultivation characteristics that facilitate phytotechnical management, such as the possibility of high-density planting and early production. According to Mora-Urpi et al. (1999), the density of plants/ha depends on the type of soil, rainfall distribution, luminosity, temperature, use of irrigation, fertilization and crop variety, which, in the case of palm heart, involves the choice of palm species. In this context, the growth habit of the palm strongly influences the density and spacing between plants, as there are single-stemmed palms (1 plant equals 1 palm heart) and multi-stemmed palms (1 plant with several tillers, producing several palm hearts/clump, with characteristics of perennial cultivation). In Brazil, few studies have been conducted on the spacing of peach palm, a multi-stemmed palm responsible for most of the country's palm heart production, in different regions and climates, requiring or not irrigation. In the São Francisco Valley, northeast region, Flori et al. (2004), evaluating the yield of irrigated peach palm heart as a function of planting density, tiller management, and stem cut-off diameter at harvest, concluded that the recommended technical approach is a spacing of 2 m x 1 m (5,000 plants/ha), management with four tillers, and cut-off diameter of the stem from 10 to 12 cm, at 30 cm from ground level. In the northern region of Amazonas, Yuyama et al. (2005) evaluated three plant densities (10,000, 5,000, and 3,333 plants/ha) and NPK fertilization doses in non-irrigated cultivation. These authors concluded that the average time to harvest the stems was shorter (18.4 months) at a density of 3,333 plants/ha and at the NPK fertilization dose of 225-90-180 (18.1 months). In the state of Paraná, southern Brazil, Neves & Santos (2008) evaluated palm heart production in different densities (3,333; 5,000; 6,666 and 8,000 plants/ha) and plant arrangements (single and double rows) in the cultivation of peach palm without irrigation, and concluded that densities of 5,000 to 6,666 plants/ha promoted the highest palm heart production in successive harvests. For Australian royal palm, a single-stemmed species similar to species of the genus Roystonea, Ruiz Filho et al. (2010) evaluated the growth and nutritional aspects when cultivated without irrigation in Paraná Coast, south region, at densities of 12,500, 13,333, 13,888 and 15,625 plants/ha. These authors found that spacing influenced height growth but not the stem diameter of the palms, with the latter variable showing a high correlation with palm heart production (Clement & Bovi, 2000).

The objective of this study was to evaluate the agronomic potential of four species of palms of this genus for the production of heart of palm in high-density planting.

MATERIAL AND METHODS

The experiment was established in the field in February 2020, using seedlings obtained from seeds, at the Polo APTA Vale do Ribeira, Pariquera-Açu, SP, Brazil (24º36'31"S, 47º53'48"W, 25 m a.s.l.). The region exhibits the climatic types, according to the Köppen classification: Cfa. Soil analysis at the beginning of the experiment showed the following chemical characteristics: pH (CaCl₂) = 4.5; organic matter (g/dm³) = 31.0; CEC (mmol_c/dm³) = 73.1; V (%) = 48; P (mg/dm³) = 6.0; K (mmol_c/dm³) = 1.1; Ca (mmol_c/dm³) = 24; Mg (mmol_c/dm³) = 10; Fe (mg/dm³) = 165; Mn (mg/dm³) = 2.1; Cu (mg/dm³) = 0.9; Zn (mg/dm³) = 1.8; B (mg/dm³) = 0.27; H + Al (mmol_c/dm³) = 38; SB (mmol_c/dm³) = 35.1. Based on the results of the soil analysis and the fertilizer recommendation for the production of peach palm heart (Modolo et al., 2022), liming and fertilization at planting were carried out, using 100 g of thermophosphate/plant and 10 g/plant of potassium chloride, to phosphorus and potassium, respectively. Cover fertilization started in Dec/2020 and ended in Dec/2021, alternating monthly in the summer/autumn months with 25 g of ammonium sulfate and 25 g of the NPK 20-05-20.

The experimental design consisted of randomized blocks, in a 4 x 2 factorial scheme, with four replications, experimental unit consisting of 30 plants and useful plot with twelve plants. The factors were the four species of Roystonea: R. oleracea; R. regia, R. altissima and R. borinqueana and two planting densities: 2 x 0.75 m (6,666 plants/ha) and 2 x 0.50 m (10,000 plants/ha).

Plant growth was evaluated every three months, totaling nine biometric estimates between Mar/2020 and Feb/2022, and palm heart production was evaluated at 24 months, in February/2022. The biometric parameters evaluated, with adaptations (Clement & Bovi, 2000) for peach palm, were: height, diameter at the base of the palm stem and number of leaves. During the harvest (Feb/2022), determinations of the total mass of leaves (leaf biomass) and stem (portion of the palm stem from the ground to the insertion of the youngest leaf) were also included. The absolute growth rate (AGR) was also evaluated by: AGR = (P₂ - P₁) / (t₂ - t₁), where P₂ and P₁ are values of two consecutive samplings, and t₂ and t₁ the number of days between them (Tucci et al., 2007).

It is worth mentioning that these are different species of palms and not cultivars, variability in growth between plants is expected and therefore there may also be variability in the size of the plants at the time of harvest. Considering that precocity is an essential characteristic in the cultivation of palms for the production of palm heart, the harvest was carried out at 24 months (740 days). After resting for one day following harvest, the crude stems were peeled to obtain the heart of palm and yield evaluation, obtaining the following variables of the comprising portions of the heart of palm (Modolo et al., 2020): 1) Fresh mass of the soft stipe, tender stem or basal part (g): portion of the stipe immediately below the meristem, still soft and suitable for consumption; 2) Fresh mass (g), length (cm) and average diameter, calculated from the initial and final diameter (cm) of the first-rate heart of palm, measured at the basal and terminal ends of the stalk; 3) Fresh mass of tender leaf (g): apical portion still soft, but not surrounded by the leaf sheath; 4) Total fresh mass (g): sum of the masses of the portions that make up the heart of palm (first-rate palm heart, apical and basal portions).

Plant growth and palm heart production data were submitted to analysis of variance and when significant differences were detected, mean values were compared by the Student-Newman-Keuls test, at 5% probability. In all statistical analyses, the Statgraphics 4.1 program was used.

RESULTS AND DICUSSION

Analysis of growth data for palms of the genus Roystonea (Table 1), considering each evaluation date, showed test Anova, no interaction between the factors (species x spacing) (p>0.05). In the first evaluation (March 2020), one month after seedlings transplanting, there were significant differences among the four species, with height and diameter in the following descending order: R. oleracea (10.5 and 0.70 cm), R. regia (6.2 and 0.60 cm), R. borinqueana (5.0 and 0.50 cm) and R. altissima (3.9 and 0.40 cm). There were no differences in the number of leaves. In subsequent evaluations (June, September, and December 2020), a reduction in these differences was observed, both for stem height and diameter. After one year of planting (fifth and sixth evaluations), there were no differences in height and diameter between the species. In the seventh evaluation (September 2021), R. altissima began to show greater height (97.0 cm) and the same diameter (11.0 cm) as the other species. Twenty months after transplanting (eighth evaluation), there were differences in all three variables, with R. altissima being taller than all other species, larger than R. oleracea in diameter, and equal to R. regia only in number of leaves. At harvest time, 24 months after planting, R. altissima was superior to the other three species in all growth variables (Table 2). In the state of Santa Catarina, the royal palm (R. oleracea) is among the recommended palm heart producing species for planting, noting that its cycle varies from 2 to 3 years and that not all plants in the plantation develop at the same rate (Zambonin et al., 2018).

Table 1
Mean values of pant growth variables of the species Roystonea oleracea, R. regia, R. altissima and R. borinqueana, cultivated in two planting densities, in spacing of 2 x 0.75 (6,666 plants/ha) and 2 x 0.50 (10,000 plants/ha). Campinas, Instituto Agronômico, 2022.

Species/Spacing	Height (cm)	Diameter (cm)	Leaf number
1st evaluation (Mar/2020)
R. oleracea	10.5 a	0.7 a	2.5 ns
R. regia	6.2 b	0.6b	2.6
R. altissima	3.9 d	0.4 d	2.5
R. borinqueana	5.0 c	0.5 c	2.5
2 x 0.50 m	6.3 ns	0.5 ns	2.5 ns
2 x 0.75 m	6.5	0.5	2.5
2nd evaluation (June/2020)
R. oleracea	12.9a	1.2 a	3.4ns
R. regia	12.2 a	1.1 b	3.5
R. altissima	8.4 c	0.9 c	3.4
R. borinqueana	10.3 b	1.1 b	3.4
2 x 0.50 m	10.3 b	1.0 b	3.3 ns
2 x 0.75 m	11.6 a	1.1 a	3.4
3rd evaluation (Sep/2020)
R. oleracea	20.4 a	1.8 a	3.5 ns
R. regia	19.6 a	1.6 b	3.7
R. altissima	16.9 b	1.4 c	3.7
R. borinqueana	17.4 b	1.5 b	3.6
2 x 0.50 m	18.1 ns	1.6 ns	3.6 ns
2 x 0.75 m	19.0	1.6	3.6
4th evaluation (Dec/2020)
R. oleracea	27.2 a	3.0 a	3.9 a
R. regia	25.6a	2.6 b	3.7 b
R. altissima	24.5 ab	2.4 b	3.7 b
R. borinqueana	23.8b	2.6 b	3.6 b
2 x 0.50 m	24.8 ns	2.6b	3.7 ns
2 x 0.75 m	25.8	2.7 a	3.7
5th evaluation (Apr/2021)
R. oleracea	54.8 ns	5.7 ns	4.5 a
R. regia	52.5	5.5	4.2 b
R. altissima	52.7	5.7	4.5 a
R. borinqueana	50.9	5.5	4.3 ab
2 x 0.50 m	51.4 b	5.4 b	4.3 ns
2 x 0.75 m	54.2 a	5.7 a	4.4
6th evaluation (June/2021)
R. oleracea	67.1 ns	8.9 ns	4.3 ab
R. regia	66.3	8.8	4.2 b
R. altissima	70.6	9.1	4.5 a
R. borinqueana	64.3	9.0	4.2 ab
2 x 0.50 m	65.4 b	8.7 b	4.3 ns
2 x 0.75 m	68.8 a	9.2 a	4.3
7th evaluation (Sep/2021)
R. oleracea	87.3 b	10.5 ns	4.3 ns
R. regia	87.0 b	10.6	4.3
R. altissima	97.0 a	11.0	4.5
R. borinqueana	84.6 b	10.8	4.3
2 x 0.50 m	86.9 b	10.4 b	4.3 ns
2 x 0.75 m	91.0 a	11.0 a	4.4
8th evaluation (Dec/2021)
R. oleracea	113.1 b	14.0 b	4.2 b
R. regia	111.6 b	14.8 ab	4.6 a
R. altissima	126.4 a	15.3 a	4.7 a
R. borinqueana	111.9 b	15.4 a	4.3 b
2 x 0.50 m	114.0 ns	14.4 b	4.4 ns
2 x 0.75 m	117.5	15.3 a	4.5

• Values followed by different letters in the columns differ among species or between spacings, by the Student-Newman-Keuls test, at 5% probability; ns: not significant.

Regarding planting spacing, in the first year of palm growth, in most evaluations, there was no difference between species regarding the variables height, diameter, and number of leaves, except in the evaluations of June and December 2020 (Table 1). After one year of planting (5^th evaluation), significant differences were observed for height and diameter between the two spacings, and at harvest time, the larger spacing (6,666 plants/ha) provided the highest mean values for all variables (Table 2). Regarding the growth rate, there were no differences between the two planting spacings in the absolute height growth of the plants in the two years (Figure 1B), except in the first determination, immediately after transplanting the seedlings. As for the diameter growth rate, significant differences were observed at two points in the first year of cultivation and between December and February (Figure 1D), the period preceding harvest. The limitation of the area/palm of the Roystonea genus, due to the density of the plants, may already be restricting the growth rate in diameter of the species after two years of planting. When using these palms as ornamentals, owing to their rapid growth and exuberant appearance, spacing of 6 to 10 m between plants is recommended, and the palms can reach a diameter at breast height (DBH) of 37 to 57 cm and a height of 15 to 45 m (Reis, 2006). In this case, with spacing 10 times greater than that used in this study, the diameter can reach 57 cm, demonstrating the growth potential of these palm species. In the production of palm hearts, Ruiz Filho et al. (2010), evaluating the growth of the Australian royal palm, found no differences at 28 months of planting in the diameter of the plants among four spacings (population ranging from 12,500 to 15,625 plants/ha).

Table 2
Mean values of growth variables in stem height and diameter, number and mass of leaves per plant and mass of palm heart stem, after 740 days of planting (Feb/2022), of the species Roystonea oleracea, R. regia, R. altissima and R. borinqueana, cultivated in two planting densities, in spacing of 2 x 0.75 (6,666 plants/ha) and 2 x 0.50 (10,000 plants/ha). Campinas, Instituto Agronômico, 2022.

Species/ Spacing	Height (cm)	Diameter (cm)	Leaf (n°)	Leaf mass (kg)	Stem (kg)
R. oleracea	126.5b	14.8 b	4.1b	2.3 b	4.7 b
R. regia	123.1 b	14.8 b	4.4 b	2.4 b	4.6 b
R. altissima	143.4 a	17.0 a	4.8 a	3.3 a	7.1 a
R. borinqueana	112.0 b	15.4 b	4.4 b	2.5 b	4.8 b
2 x 0.50 m	124.3 b	14.8 b	4.3 b	2.4 b	4.8 b
2 x 0.75 m	132.2 a	16.3 a	4.6 a	2.8 a	5.8 a
Overall mean	128.2	15.5	4.4	2.6	5.3

• Values followed by different letters in the columns differ among species or between spacings, by the Student-Newman-Keuls test, at 5% probability.

In both years of cultivation, a decrease in the absolute growth rate in diameter was observed after winter for all four Roystonea species (Figure 1C). There were differences between the species in terms of height growth rate (Figure 1A), with R. oleracea showing a lower rate than the other species in June 2020, and R. altissima standing out with a higher rate in the following growth period. During the spring/summer periods of the first year of cultivation (from September 2020 to April 2021), there were no differences in height growth rates between the four species. From April 2021 onwards, in the second year, R. altissima stood out with growth rates higher than the others, even during the winter (Figure 1A). Regarding diameter, during the summer periods in both years, R. altissima showed a higher diameter growth rate than the other species (4^th and 8^th points in Figure 1C), with no differences in growth rate during the winter periods (June/September) in both cultivation years (Figure 1C). Lower nighttime temperatures are characteristic of the state of São Paulo, which can promote lower growth rates. In peach palm, Tucci et al. (2007) observed lower growth rates during the colder winter months and higher growth rates in the summer. Furthermore, net CO₂ assimilation was lower in the winter months (Tucci et al., 2010), which the authors attributed to lower nighttime temperatures during this period. Between December and February 2022, the last growing period before harvest, a decrease in the diameter growth rate of all species was observed, even during the summer, which is usually characterized by sharp growth (Figure 1C). The higher growth rate in height of R. altissima (Figure 1A) resulted in greater palm height at 24 months (Table 2), even with the transplanting of smaller seedlings at the beginning of the experiment (Table 1).

Regarding palm heart production, there was also no interaction between species and spacing. R. altissima showed greater total palm heart mass production, due to the greater mass of the first-rate palm hearts, when compared to R. oleracea, although it did not differ from R. regia and R. borinqueana, which showed intermediate values (Table 3). The Australian royal palm has a single stem, resembling palms of the genus Roystonea, with early harvesting of plants between 1.70 and 1.80 m in height and an average production of first-rate palm hearts per stem of 0.150 and 0.350 kg (Bellettini et al., 2008; Modolo & Tucci, 2014). Uzzo et al. (2002), harvesting a 30-month-old Australian royal palm, obtained an average production of 0.198 kg of first-rate heart of palm and a total production of 0.541 kg (first-rate palm heart + basal mass + apical mass) per stem, with an average stalk diameter of 3.24 cm. The overall mean production of first-rate palm hearts per stems of the four Roystonea species, harvested after 24 months, was 0.162 kg, with an average stalk diameter of 3.19 cm and total palm heart production of 0.427 kg (Table 3). The production data for first-rate palm hearts of Australian royal palm and Roystonea are similar, with a gain in total production for Roystonea altissima (0.510 kg) when harvesting palms six months younger. Bovi et al. (2003), harvesting 36-month-old Australian royal palms, found a high average production of the basal portion of the stem, ranging from 0.231 to 0.465 kg/plant, and considered the production of 0.146 to 0.388 kg of first-rate palm heart to be quite satisfactory. The authors above highlighted the marked darkening of the heart of palm, attributed mainly to the presence of oxidizing enzymes. The average production of the basal portion of the stipe of the 4 Roystonea species after 24 months of cultivation was 0.240 kg (Table 3). The absence of darkening of palm hearts in Roystonea species during the evaluations is also an exception, unlike what was reported by Bovi et al. (2003) for Australian royal palm. This characteristic should be further studied, but the absence of darkening highlights the potential of this genus for the consumption of palm hearts also in natura, as occurs with peach palm hearts, and not only industrialized, as occurs with Australian royal palm.

Figure 1
Absolute growth rate in height (A, B) and in diameter (C, D) of the stem (cm) of the species Roystonea oleracea, R. regia, R. altissima and R. borinqueana, cultivated in two planting densities, in spacing of 2 x 0.75 (6,666 plants/ha) and of 2 x 0.50 (10,000 plants/ha) (B, D), from Jun/2020 to Feb/2022. Each point represents the mean value ± standard error; * indicates a statistically significant difference at 5% probability, among species, for the same months. Campinas, Instituto Agronômico, 2023.

The spacing used in palms cultivation for heart of palm production should be based on the species' growth habit, i.e., with or without tillering. For single-stemmed palms, such as Roystonea, where each plant produces one heart of palm, the ideal is a greater number of plants per area, as long as it does not affect production per plant. The 2 x 0.75 m plant spacing provided the highest total yield of first-rate palm hearts due to their larger diameter (Table 3). At the time of harvest, two years after planting, the palms planted at the largest spacing (2 x 0.75 m) presented higher mean values in all growth variables analyzed (Table 2), providing greater production of total mass and first-rate palm heart per plant, regardless of the species (Table 3). However, if we consider production per area, with the wider spacing (6,666 plants/ha) we have a lower production of first-rate palm hearts, 1,200 kg/ha, and a total production of 3,100 kg/ha; in contrast to approximately 1,500 kg/ha and 3,900 kg/ha, respectively, for the narrower spacing (10,000 plants/ha).

Table 3
Mean values of yield variables of palm heart, after 740 days of planting (Feb/2022 harvest), of the species Roystonea oleracea, R. regia, R. altissima and R. borinqueana, cultivated in two planting densities, in spacing of 2 x 0.75 m (6,666 plants/ha) and of 2 x 0.50 m (10,000 plants/ha^-1). Campinas, Instituto Agronômico, 2022.

Species/ Spacing	Total mass (g)	Basal mass (g)	Apical mass (g)	First-rate palm heart
				Mass (g)	Length (cm)	Diameter (cm)
R. oleracea	369.2 b	209.2ns	27.2ns	135.6 b	22.5 ns	3.0 ns
R. regia	403.9 ab	225.2	23.0	155.7ab	25.0	3.1
R. altissima	510.2 a	291.7	33.6	184.9a	25.1	3.4
R. borinqueana	426.0 ab	232.2	23.3	170.9 ab	24.2	3.3
2 x 0.50 m	389.3 b	220.4 ns	23.9 ns	146.5 b	24.2 ns	3.0 b
2 x 0.75 m	465.4 a	258.8	29.7	177.1 a	24.2	3.4 a
Overall mean	427.4	239.6	26.8	161.8	24.2	3.2

• Values followed by different letters in the columns indicate significant differences by the Student-Newman-Keuls test at 5% probability; ns: not significant.

For the four species of the genus Roystonea, high positive correlations (≥0.7) were observed between plant height or diameter and most heart of palm production variables, except stem length (Table 4), highlighting the correlation between diameter and total heart of palm mass of R. altissima (0.860). In several palm species that produce palm heart, linear measurements, such as height and diameter of the main stem, showed positive and significant correlations with heart of palm production: açaí palm (Bovi et al., 1990), peach palm (Bovi et al., 1992; Clement et al. (1996) and Australian king palm (Bovi et al., 2001). Correlation studies between palm size and heart of palm production should be conducted to determine the ideal time for harvesting Roystonea stems when grown at different spacings. Considering the correlation between diameter and heart of palm production in several species of palms (Clement et al., 1996; Bovi et al., 2001) and that observed in Roystonea (Table 4), the harvest could be brought forward, since there was a drop in the diameter growth rate (Figure 1C) and minimal difference between the diameter of the plants between Dec/21 (Table 1) and Feb/22 (Table 2).

Table 4
Pearson's correlation coefficient between stem height or diameter and palm heart production variables, after 740 days of planting, for the species Roystonea oleracea, R. regia, R. altissima and R. borinqueana. Data from plants grown at both densities, in spacing of 2 x 0.75 m (6,666 plants/ha) and of 2 x 0.50 m (10,000 plants/ha) were analyzed together. Campinas, Instituto Agronômico, 2023.

Species	Variable	Total mass (g)	Basal mass (g)	First-rate palm heart
				Mass (g)	Length (cm)	Diameter (cm)
R. oleracea	Height (cm)	0.832	0.793	0.787	0.562	0.733
	Diameter (cm)	0.837	0.779	0.842	0.633	0.794
R. regia	Height (cm)	0.697	0.627	0.723	0.610	0.782
	Diameter (cm)	0.807	0.764	0.777	0.582	0.808
R. altissima	Height (cm)	0.838	0.792	0.788	0.615	0.825
	Diameter (cm)	0.860	0.824	0.782	0.532	0.805
R. borinqueana	Height (cm)	0.762	0.648	0.798	0.492	0.803
	Diameter (cm)	0.763	0.677	0.765	0.425	0.748

• All coefficients were significant at p<0.001. The total number of variable pairs was 69 for R. oleracea; 66 for R. regia; 63 for R. altissima; 64 for R. borinqueana.

The production of cultivated palm hearts is carried out by planting poorly improved palm species, with uneven growth among plants. Harvesting is done based on stem diameter and is always staggered since the plants do not reach the same size at the same time. For Australian king palms, staggered harvesting is carried out when the plants reach a diameter of 12 to 14 cm (Modolo & Tucci, 2014). In this context, all four Roystonea species exhibit rapid growth, with an average diameter of 11.0 cm at a 2.00 x 0.75 spacing at 18 months (Table 1; 7^th evaluation), indicating that the harvest may be brought forward. The species R. altissima presented the highest values for height (126.4 cm) and diameter (15.3 cm) at 21 months of planting (Table 1; 8^th evaluation), variables that showed a high correlation with palm heart production (Table 4). In terms of total palm heart production, R. altissima (510.2 g) was superior to R. oleracea (369.2 g).

Both planting densities promoted satisfactory heart of palm production for a single-stemmed palm. Production per plant was higher with a spacing of 2 x 0.75 m (6,666 plants/ha), while a spacing of 2 x 0.50 m (10,000 plants/ha) resulted in higher heart of palm production per area. From 14 months after planting, the values for height and stem diameter were lower in the narrower spacing (2 x 0.50 m²), and the decrease in the diameter growth rate in the last two months, in both spacings, suggests increased competition between plants. Given the staggered nature of the harvest, the spacing between plants to be used will depend on harvest management practices.

ACKNOWLEDGMENTS

The authors are grateful for the financial support provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Grant No. FAPESP-2019/03444-3 and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Grant No. 137892/2021-7, for scholarship.

REFERENCES

• BELLETINI, S; CORRÊA JR, C; SANTOS, AF; NEVES, EJM; CHAIMSOHN, FP; RODIGHERI, HR. 2008. Cultivo da palmeira real australiana para a produção de palmito. In: SANTOS, AF; CORRÊA, JR; NEVES, EJM (eds). Palmeiras para a produção de palmito: Juçara, Pupunheira e Palmeira Real Australiana. Colombo, Paraná, BR: Embrapa Floresta p.65-78.
• BERBARI, SA; TOTI, FGP; ERISMANN, NM; MODOLO, VA. 2024. Industrialization potential of palm heart of Roystonea spp palms. Observatório de la Economia Latinoamericana 22: 1-16. https://doi.org/10.55905/oelv22n12-076
  » https://doi.org/10.55905/oelv22n12-076
• BOVI, MLA; GODOY JUNIOR, G; SPIERING, SH; CAMARGO, SB. 1990. Phenotypic relationship between non-destructive traits and palmito yield of assai palms. Bragantia 49: 69-81. https://doi.org/10.1590/S0006-87051990000100006
  » https://doi.org/10.1590/S0006-87051990000100006
• BOVI, MLA; SAES, LA; GODOY G JUNIOR . 1992. Phenotypic correlations between non-destructible characters and heart of palm in peach palm trees. Turrialba 42: 382-390.
• BOVI, MLA; SAES, LA; UZZO, RP; SPIERING, SH. 2001. Adequate timing for heart-of-palm harvesting in King palm. Horticultura Brasileira 19: 135-139. https://doi.org/10.1590/S0102-05362001000200008
  » https://doi.org/10.1590/S0102-05362001000200008
• BOVI, MLA; GODOY , JUNIOR G; CEMBRANELLI, MAR; SPIERING, SH. 2003. Yield and characteristics of heart-of-palm from Australian king palm. Horticultura Brasileira 21: 307-307.
• CLEMENT, CR; BOVI, MLA. 2000.Standardization of growth and yield measurements in pejibaye heart-of-palm experiments. Acta Amazônica 30: 349-362. https://doi.org/10.1590/1809-43922000303362
  » https://doi.org/10.1590/1809-43922000303362
• CLEMENT, CR; MANSHARDT, RM; DEFRANK, J; CAVALETTO, CG; NAGAI, NY. 1996. Introduction of pejibaye for heart-of-palm in Hawaii. HortScience 31: 765-768.
• FLORI, JE; RESENDE, GM; DRUMOND, MA. 2004. Effect of density, cut-off diameter classes and shoot number on production and yield of irrigated plant peach palm at San Francisco River Valley. Ciência Agrotecnologica 28, 70-74. https://doi.org/10.1590/S1413-70542004000100009
  » https://doi.org/10.1590/S1413-70542004000100009
• HODCE, WH. 1965. Palm cabbage. Principes 9: 124-131.
• INSTITUTO BRASILEIRO DE GEOGRAFIA E ESTATÍSTICA - IBGE. 2024 Produção Agrícola Municipal. Rio de Janeiro. Avaiable at: < Avaiable at: http://www.sidra.ibge.gov.br >. Accessed: March 2026.
  » http://www.sidra.ibge.gov.br
• LORENZI, H; SOUZA, HM; CERQUEIRA, LSC; COSTA, JTM; FERREIRA, E. 2004. Palmeiras brasileiras e exóticas cultivadas Nova Odessa, São Paulo, BR: Instituto Plantarum.
• MODOLO, VA; CANTARELLA, H; TRANI, PE. 2022. Palmito Pupunha. In: CANTARELLA, H; QUAGGIO, JA; MATTOS JUNIOR, D; BOARETTO, RM; RAIJ, B (eds). Boletim 100: Recomendação de calagem e adubação para o estado de São Paulo. Instituto Agronômico, Campinas, São Paulo, Brasil. p.471-474.
• MODOLO, VA; FERREIRA, L; SPIERING, SH; ERISMANN, NM. 2020. Spear leaf in determining the harvest timing of peach palm heart. Horticultura Brasileira 38: 356-362. https://doi.org/10.1590/s0102-053620200403
  » https://doi.org/10.1590/s0102-053620200403
• MODOLO, VA; TUCCI, MLS. 2014. Palmito de palmeira real australiana. p. 317-320. In: AGUIAR, ATDE; GONÇALVES, C; PATERNIANI, MEAGZ; TUCCI, MLS; CASTRO, CEFD (eds). Boletim 200: Instruções agrícolas para as principais culturas econômicas. Instituto Agronômico, Campinas, São Paulo Brasil.
• MODOLO, VA; TUCCI, MLS; ANEFALOS, LC. 2013. Cultivo de palmeiras para a produção de palmito. In: SILVA, LD; HIGA, AR (eds). Sustentabilidade de sistemas de produção florestal Curitiba, Paraná, BR: FUPEF. p.237-280
• MODOLO, VA; ANEFALOS, LC; MARTINS, ALMM; BOLLER, PG; VEJA, SMR. 2019. Palmito pupunha: a pesquisa gerando nova opção para o agronegócio. O Agronômico 71: 133-143.
• MORA-URPÍ, J; OQUENDO, CA. 1999. Cosecha. In: MORA-URPÍ, J; GAINZA, EJ (eds). Palmito de pejibaye (Bactris gasipaes Kunth): seu cultivo e industrialização. São José, CR: FUNDEVI. p. 118-122.
• NEVES, EJM; SANTOS, AF. 2008. Production of three cuttings of Bactris gasipaes for heart-of-palm under different plant density in the Paraná State Coastal Region, Brazil. Pesquisa Florestal Brasileira 56: 87-95.
• REIS, R. 2006. O gênero Roystonea e suas espécies. In: OLIVEIRA, AR; TEIXEIRA, MLF; REIS, R (eds). As palmeiras imperiais do Jardim Botânico Jardim Botânico Nacional, Rio de Janeiro, RJ, Brasil. p.14-41.
• RUIZ FILHO, RR; MARQUES, R; ROCHA, AA. 2010. Growth and nutritional aspects of the Australian king palm tree, under different spacing between plants, in the Paraná Coast, Brazil. Scientia Agraria 11: 179-180.
• TUCCI, MLS; BOVI, MLA; MACHADO, EC; SPIERING, SH. 2007. Seasonal variation in growth of peach palms cultivated in containers under subtropical conditions. Scientia Agricola 64: 138-146.https://doi.org/10.1590/S0103-90162007000200006
  » https://doi.org/10.1590/S0103-90162007000200006
• TUCCI, MLS; ERISMANN, NM; MACHADO, EC; RIBEIRO, RV. 2010. Diurnal and seasonal variation in photosynthesis of peach palms grown under subtropical conditions. Photosynthetica 48: 421-429.
• UZZO, RP; BOVI, MLA; SPIERING, SH; SAES, LA. 2002. Phenotypic correlations between vegetative characters and heart-of-palm yield traits of the Australian king palm. Scientia Agricola 59: 505-511.
• YUYAMA, K; CHAVEZ, FWB; PEREIRA, BG; SILVA, IA. 2005. Effect of density and fertilization NPK on heart-of-palm production of peach palm. Revista Brasileira da Ciência do Solo 29: 373-378. https://doi.org/10.1590/S0100-06832005000300007
  » https://doi.org/10.1590/S0100-06832005000300007
• ZAMBONIM, FM; MARIGUELE, KH; BERTOLDI, FC; NORA, I; MASSIGNAN, A; VIANNA, LFN; ZABOT, AO. 2018. Palmeira imperial: aspectos de cultivo para a obtenção de palmito em SC. Santa Catarina, EPAGRI, 8p.
• ZONA, S. 1996. Roystonea (Arecaceae: Arecoideae). Flora Neotropica 71: 1-35.

• Consent for publication:
  All authors give their consent for the publication of the manuscript to HorticulturaBrasileira.
• DATA AVALAIBILITY
  Data will be made available upon request to the corresponding author.
• Declaration of generative AI and AI-assisted technologies in the writing process:
  The authors declare that they did not use artificial intelligence tools.

Edited by

• Responsible editor:
  Francisco Antônio Passos

Data availability

Data will be made available upon request to the corresponding author.

Publication Dates

• Publication in this collection
  29 June 2026
• Date of issue
  2026

History

• Received
  05 Dec 2025
• Accepted
  29 Apr 2026