Effect of Paclobutrazol on botanical characters of flowers and fruits in the

emergence of parthenocarpic mango cultivar Ataulfo

Efecto del Paclobutrazol sobre caracteres botánicos de flores y frutos en la aparición de

mango partenocárpicos cultivar Ataúlfo

Danilo Valdez Rivera

Master, Agrarian University of Ecuador.

Faculty of Agrarian Sciences Guayaquil-

Ecuador. dvaldez@uagraria.edu.ec

https://orcid.org/0000-0002-5004-930X

Javier Del Cioppo Morstadt

Master, Agrarian University of Ecuador.

Faculty of Agrarian Sciences, Guayaquil-

Ecuador. jdelcioppo@uagraria.edu.ec

https://orcid.org/0000-0001-5689-5884

Cecilia Aguayo Santistevan

Master, Agrarian University of Ecuador.

Faculty of Agrarian Sciences. Guayaquil-

Ecuador. maguayo@uagraria.edu.ec

https://orcid.org/0000-0002-0200-3788

dvaldez@uagraria.edu.ec

http://centrosuragraria.com/index.php/revista, Published by: Edwards Deming Institute,

Quito - Ecuador, October - December vol. 1. Num. 11 2021, This work is licensed under

a Creative Commons License, Attribution-NonCommercial-ShareAlike 4.0 International.

https://creativecommons.org/licenses/by-nc-sa/4.0/deed.es

Received June 09, 2021

Approved: July 21, 2021

Abstract

The presence of parthenocarpic mangoes in the

Ataulfo cultivar in Ecuador has caused a decrease in

the production. This has led to an annual decrease in

the productive area of this cultivar. The objective of

the research was to evaluate botanical characters of

flowers and fruits in the appearance of parthenocarpic

mango in Ataulfo cultivar, this was carried out in two

mango-producing areas in Palenque-Los Ríos and

Cerecita-Guayas, 50 plants were randomly taken for

each treatment with paclobutrazol (PBZ) and without

(PBZ) in the two zones simultaneously in 2019 and

2020. The variables evaluated were: weekly flowering

behavior, percentage of hermaphrodite and staminate

flowers, number of leaves in the last foliar growth

before flowering, number of panicles per tree,

percentage of mangoes with seeds and

parthenocarpics. Descriptive statistics were obtained

for each variable, including the mean, median, mode,

standard deviation, and variability coefficients. The t-

test method was used between the samples from the

two populations. Flowering with PBZ began in week

22 in Cerecita and in week 27 in Palenque. All the

evaluated variables that had PBZ had statistical

significance except for the number of parthenocarpic

mangoes with and without PBZ in Palenque. In the

areas where PBZ was applied, it was possible to

advances plant flowering by two weeks in the two

study areas and with an increase in the percentage of

female flowers vs. staminate by panicles.

Keywords: Anthesis, Mango Ataúlfo, Paclobutrazol,

Parthenocarpy

Resumen

La presencia de mangos partenocárpicos(mango niño) en la variedad ataúlfo en Ecuador ha hecho que

disminuya la producción de este cultivo. Ello ha incidido en una disminución anual del área productiva

de esta variedad. El objetivo de la investigación fue evaluar caracteres botánicos de flores y frutos en

la aparición de mango partenocárpicos en variedad Ataúlfo, esta se realizó en dos zonas productoras de

mangos en Palenque-Los Ríos y Cerecita-Guayas, se tomaron al azar 50 plantas para cada tratamiento

con paclobutrazol (PBZ) y sin PBZ en las dos zonas de manera simultánea en los años 2019 y 2020.

Las variables evaluadas fueron. Comportamiento semanal de floración, porcentaje de flores

hermafroditas y estaminadas, número de hojas en el último crecimiento foliar antes de floración, número

de panículas por árbol, porcentaje de mangos con semillas y partenocárpicos. Se obtuvo los estadígrafos

descriptivos a cada variable entre los que se encuentran la media, la mediana, la moda, la desviación

estándar y los coeficientes de variabilidad. Se utilizó el método de la prueba de U de Mann-Whitney.

La floración con PBZ inicia en la semana 22 en Cerecita y en la semana 27 en Palenque. Todas las

variables evaluadas que tenían PBZ tuvieron significancia estadística a excepción del número de

mangos niños con y sin PBZ en Palenque. Las áreas que tenían PBZ, logró adelantar dos semanas la

floración en las dos zonas de estudio y con un aumento en el porcentaje de flores femeninas vs

estaminadas por panículas.

Palabras claves: Antesis, Mango Ataúlfo, Paclobutrazol, Partenocarpia

Introduction

The Ataúlfo mango is a cultivar of Mexican origin with more acceptance in international

markets. Although its genealogy is uncertain, since its progenitors are unknown, it has been

mentioned that it possibly comes from a mutation or is the product of natural hybridization

(Infante et al., 2011, p. 32).

Currently, the use of growth regulators is essential for the success of mango growers in Brazil,

playing an important role in flower induction, allowing staggering production throughout the

year and obtaining good quality fruit Oliveira (2020). In our country the use of growth

regulators has been normalized, almost all mango export plantations use them in their crop

management programs, to advance flowering and be the first to start harvesting to gain better

prices in the international market and in local sales.

Perez et al. (2011) in research conducted in Nayarit, Mexico, with the manila mango variety

and paclobutrazol (PBZ), flowering was stimulated and harvest was advanced from 15 to 23

days. Moreira et al. (2018) in applications of PBZ on tommy atkins mango variety, advanced

flowering by 30 days.

Leyva et al. (2016) in Mexico, deduced that, in areas producing this variety of mango with

technological development of the crop, the presence of baby mango increases significantly

compared to other plantations with less technical development. In research by Ramirez and

Davenport, (2010, cited in Ferreira, 2020, p. 12), it is stated that "The use of PBZ in mango

promotes the regulation of vegetative growth of plants, stimulating flowering and fruiting".

Ferreira et al, (2020)

Valdez et al.

October - December vol. 1. Num. 10 2021

The Ataulfo mango variety is along with the varieties: Haden, Kent and Tommy Atkins one of

the most cultivated Lucero, (2011). In recent years in Ecuador its productivity has fallen

sharply because a large part of the fruit does not reach the commercial category as is the case

of the so-called child mangoes and parthenocarpic mangoes, a phenomenon whose cause is

supported by some not very clear hypotheses where they determine that extreme temperatures

(≤15 and ≥35 °C) in flowering and fruit development are promoters of child mangoes. Perez et

al (2019) where they establish that edaphic applications of boron of 50 and 100 gr. decreased

the presence of seedless mangoes (p. 276).

Materials and methods

This research was carried out in two mango producing areas, in Cerecita parish, Guayaquil

canton, and in Palenque canton, Los Ríos province. With the following geographical

coordinates 583887, 9736736.98 and 17M 637149, 9839706.98 UTM projection, zone 17S,

datum WGS84, Cerecita and Palenque respectively. The data obtained in this research

correspond to the year 2019 and 2020.

Plants were used in full production of mango variety ataulfo, with a spacing of 7x7 in Palenque

and 7x5 in Cerecita, 50 plants were taken at random for each treatment with paclobutrazol

(PBZ) and without PBZ in the two areas simultaneously in 2019 and 2020. In Palenque there

were marked differences in climate with rains in January, February, March, April and sporadic

rains in May. In Cerecita, the rainy season begins in January, February, March and April with

less incidence than in Palenque.

In the two mango producing zones, 100 mango trees were selected in areas with PBZ and

without PBZ (50 trees per year and per area) to evaluate panicles, number of parthenocarpic

mangoes and mangoes with seed or commercial mango per plant and number of leaves of the

last growth. From this population, 50 mango panicles were randomly selected each year and

the percentages of hermaphrodite and staminate anthesis were determined.

The data were organized and tabulated to obtain descriptive statistics for each variable,

including the mean, median, mode, standard deviation and variability coefficients. The Mann-

Whitney U test method was used.

Result

Flowering behavior at Cerecita

In the behavior of weekly flowering during 2020 (Figure 1), it is observed that in week 22

flowering began with 95% and in week 23 with 5%, however, the areas without PBZ had a

delay of two weeks, initiating flowering in week 24 until week 26.

Figure 1. Flowering behavior in Cerecita (2020).

Cerecite, flowering behavior by week year 2019.

Figure 2 shows that flowering began at 95% in week 22 and at 5% in week 23; however, the

areas without PBZ were delayed by two weeks, beginning flowering in week 24, with irregular

behavior, ending flowering in week 35.

Figure 2. Weekly flowering behavior in Cerecita (2019).

22 23 24 25 26

20%

40%

60%

80%

100%

Con PBZ

Sin PBZ

Semana

20 22 24 26 28 30 32 34 36

10%

20%

30%

40%

50%

60%

Con PBZ

Sin PBZ

Semana

Valdez et al.

October - December vol. 1. Num. 10 2021

Palenque, flowering behavior per week year 2020

Figure 3 shows that flowering began in week 27 with 95% and in week 28 with 5%; however,

the areas without PBZ had a delay of five weeks, with flowering beginning in week 33 and

ending in week 38.

Figure 3. Flowering behavior by week year 2020

Palenque, flowering behavior per week year 2019

Figure 4 shows that flowering began at 90% in week 29 and at 10% in week 30; however, in

the areas without PBZ, the onset of anthesis began at the same time as PBZ, possibly due to

the management of the plantation, which was extended until week 33.

Figure 4. Flowering behavior by week in 2019.

Semana

26 28 30 32 34 36 38 40

20%

40%

60%

80%

100%

Con P BZ

Sin PBZ

Semana

28 29 30 31 32 33 34

20%

40%

60%

80%

100%

Con PBZ

Sin PBZ

Percentage of hermaphrodite and staminate flowers in two mango producing locations

year 2020.

In Cerecita, the number of hermaphrodite flowers in the area where PBZ was used represented

33% and staminate anthesis 67%, in contrast to the areas without PBZ where the percentage of

hermaphrodite flowers was 23% per panicle and staminate flowers 77%, which represents the

trend per panicle in terms of hermaphrodite and staminate flowers. In Palenque the amount of

hermaphrodite flowers in the area where PBZ was used represented 30% and staminate anthesis

70%, in contrast to the areas without PBZ where the percentage of hermaphrodite flowers was

24% per panicle and that of staminate flowers 76 %, which represents the trend by panicle in

terms of hermaphrodite and staminate flowers. Figure 5

Percentage of hermaphrodite and staminate flowers in two mango producing locations

year 2019.

In Cerecita, the number of hermaphrodite flowers in the area where PBZ was used represented

33% and staminate anthesis 67%, in contrast to the areas without PBZ where the percentage of

hermaphrodite flowers was 23% per panicle and staminate flowers 77%, which represents the

trend per panicle in terms of hermaphrodite and staminate flowers. In Palenque, the number

of hermaphrodite flowers in the area where PBZ was used represented 30% and staminate

anthesis 70%, in contrast to the areas without PBZ where the percentage of hermaphrodite

flowers was 24% per panicle and that of staminate flowers 76%, which represents the trend per

panicle in terms of hermaphrodite and staminate flowers.

Table 1. Percentage of hermaphrodite and staminate flowers in two mango-producing

localities.

Location

hermaphrodite

flowers year

2019

% of flowers in

the year 2019

hermaphrodite

flowers year

2020

% staminate

flowers year

2020

Cerecite with

(PBZ)

Cerecite without

(PBZ)

Palenque with

(PBZ)

Palenque without

(PBZ)

Valdez et al.

October - December vol. 1. Num. 10 2021

Cer con PBZ Cer sin PBZ Pal con PBZ Pal sin PBZ

20%

40%

60%

80%

100%

Flores hermafroditas año 2019

Flores estaminadas año 2019

Flores hermafroditas año 2020

Flores estaminadas año 2020

Figure 5. Percentage of staminate vs. hermaphrodite flowers in two mango producing areas

with PBZ and without PBZ year 2019-2020.

Beginning of flowering in two 2019-2020 production zones.

In Cerecita, flowering begins in week 22 in the areas that have PBZ. One of the reasons for the

earlier flowering than the PBZ application period is the presence of rainfall, which generally

lasts until the month of April. The areas that are not treated with PBZ, flowering begins from

week 24 onwards, this depends a lot on the conditions in which the trees are (last vegetative

growth, mature trees older than 2 months of age, pruning season and beginning of inductions).

In the Palenque locality, flowering begins in week 27 in the areas that have PBZ, one of the

reasons for the delay in flowering, compared to the cerecita locality, is the presence of rain,

where it generally rains until May. The areas that are not treated with PBZ, flowering begins

from week 24 onwards, this depends a lot on the conditions in which the trees are (last

vegetative growth, mature trees older than 2 months of age, pruning season and beginning of

inductions). Unlike the Cerecita zone, the application season for PBZ is not the most optimal

due to the presence of continuous rainfall in February and March.

Number of sheets 2019-2020

In Figure 6, it can be observed that in Cerecita the number of leaves had a mean of 8.21 leaves

in the last leaf growth before panicle in the area with PBZ, in the area without PBZ they had a

mean of 6.44 leaves in the last leaf growth before panicle. In Palenque the number of leaves

had a mean of 7.04 leaves in the last leaf growth before panicle in the area with PBZ, in the

area without PBZ they had a mean of 6.29 leaves in the last leaf growth before panicle.

Cer con (PBZ) Cer sin (PBZ) Pal con (PBZ) Pal sin (PBZ)

100

150

200

250

300

350

Figure 5. Number of leaves in the last flow before panicle 2019-2020

Number of panicles (average) year 2019-2020

Figure 7 shows that in Cerecita, the area with PBZ had an average of 302 panicles, the trees

had an average height of 3.50 meters, while in the area without PBZ, the trees had an average

of 321 panicles and an average height of 4 meters. In Palenque, as for the differences in panicles

per plant, in the area with PBZ they had an average of 220 panicles with an average height of

3 meters, while in the area with PBZ they had an average of 205 panicles and the trees had an

average height of 3 meters.

Figure 6. Number of panicles per plant

Valdez et al.

October - December vol. 1. Num. 10 2021

MSA(CeConPBZ)

MNA (CeConPBZ)

MSAl (CeSinPBZ)

MNA (CeSinPBZ)

MSA (PalConPBZ)

MNA (PalConPBZ)

MSA (PalSinPBZ)

MNA (PalSinPBZ)

20%

40%

60%

80%

100%

Percentage of mangoes with seed and parthenocarpic in two zones year 2019-2020.

Figure 8 shows that in Cerecita the number of mangoes per tree varies, with an average of 32%

of mangoes with seeds and 68% of parthenocarpic mangoes, while in the area without PBZ,

there were fewer mangoes with seeds (28%) and 72% of parthenocarpic mangoes. In Palenque,

the average number of mangoes per tree varied between 21% of mangoes with seeds and 79%

of parthenocarpic mangoes, while in the area without PBZ, there was a lower number of

mangoes, 16% of mangoes with seeds and 84% of parthenocarpic mangoes.

Figure 8. Percentage of mangoes with seeds and parthenocarpic in Cerecita and Palenque in

2019 and 2020.

The behavior of reproductive variables (Figure 9) shows that the use of PBZ did not make a

difference with respect to panicles per plant, with mango and without mango. However, it did

have an influence on the increase of hermaphrodite flowers, but not on staminate flowers. The

mangoes per panicle were not affected by the use of this product, but the fruits per tree were,

which had an increase of 33.67% with respect to the control. Another variable affected was the

number of parthenocarpic mangoes, which increased by 11.03%.

Figure 9. Behavior of reproductive variables

Regarding anthesis, hermaphrodite vs. staminate flowers with paclobutrazol (PBZ) and without

PBZ, Oliveira et al. (2017) expressed that in research conducted in Brazil on mango cultivar

"uba", noted that there was no increase in the proportion of staminate vs. hermaphrodite

flowers, unlike this research that recorded the increase in the percentage of hermaphrodite

flowers vs. staminate flowers in trees with Paclobutrazol (PBZ) in the two areas studied, hence

the fact of having more hermaphrodite flowers within a panicle, the greater the probability of

fertilization, Gehrke (2008) Gehrke states that the ratio of staminate flowers to perfect flowers

influences fruit set and productivity.

The number of leaves in the last leaf growth before anthesis in the Cerecita and Palenque zones

is higher in areas with PBZ, different to that investigated by Cardenas et al. (2003) where it

was found that the use of paclobutrzol caused a restriction effect on vegetative sprouting. This

could be due to the fact that in areas where paclobutrazol (PBZ) is applied, pruning and

fertilization are usually done in December, so that where PBZ is not applied, pruning and

fertilization are delayed, causing a limitation in leaf density in the vegetative flow.

The number of panicles per plant obtained high results with PBZ, as confirmed by Charnvichit

et al,. (2008) (2008), PBZ applications inhibit the biosynthesis of gibberellins, for the

development of shoot growth, by promoting shoot maturation and consequently favoring

flowering.

In terms of the number of parthenocarpic or child mangoes per tree those with PBZ

outnumbered trees without PBZ, Hernandez et al. says (2015) "Fruit stenospermocarpy is a

rare phenomenon and is the result of partially formed seed fruits that are the result of embryo

abortion after fertilization, which, on certain occasions, can also be the cause of the production

of a seedless fruit." Likewise (Perez, 2019) "studied the behavior of pollen in hermaphrodite

and male flowers. The results showed a similar number of pollen grains per anther and pollen,.

viability and germination between the two forms of mango flower. Pollen germination was also

Panículas por planta

panículas con mango

panículas sin mango

100

150

200

250

300

Con PBZ

Sin PBZ

Mangos por panícula

Mangos por arbol

Mango partenocárpico

100

150

200

250

300

Con PBZ

Sin PBZ

Total herm afródita

Total estam inadas

200

400

600

800

1000

1200

1400

1600

Con PBZ

Sin PBZ

n.s

Valdez et al.

October - December vol. 1. Num. 10 2021

studied under different temperature conditions, and the results showed that the percentage of

pollen germination improved throughout the flowering season with increasing temperatures.

Pollen germination at controlled temperatures slowed down at low temperatures. Differences

were found among genotypes in pollen behavior at different temperatures opening the

possibility of selecting mango genotypes with pollen more adapted to low temperatures,

especially for subtropical conditions. "p. 442

Parthenocarpic mangoes presented varied results with PBZ (Perez et al, 2007), coinciding with

the results of this research where it was observed that there was a large number of

parthenocarpic mangoes in trees where the hormone PBZ was applied, while those that were

not applied with this growth inhibitor did not have a large presence of baby mangoes.

Conclusions

In Ecuador, flowering begins in week 22 of the year in the Cerecita area, Guayas, in the area

with PBZ and in week 24 in the areas without PBZ. In the Palenque area, it begins in week 27

with PBZ and 29 in the area without PBZ. The proportion of hermaphrodite vs. staminate

anthesis, although there are no statistical differences, it can be observed that the mean number

of hermaphrodite flowers is higher than the staminate ones, therefore the probability of

producing mango with seeds is high.

Harvesting begins in Cerecita 16 weeks after the panicles are 10 cm long, while in the Palenque

area 14 weeks, when the panicle is 10 cm long. All the variables evaluated showed statistical

differences between the areas treated with PBZ and without PBZ, however, in Palenque Mango

niño with PBZ vs. without PBZ, did not show statistical differences, this could be due to the

influence of (climate) at the time of anthesis and fertilization.

References

Charnvichit, C., Tongumpai, P., Saguansupyakorn, C., Phavaphutanon, L., &

Subhardrabandhu, S. (2008). Effect of paclobutrazol on the control of board size and

flowering of mango, cv. Nam dok mai twai no. 4, after hard pruning. Acta Horticulturae

291, 60-66.

Ferreira, K., Simões, W., Mouco, M., & Leita da Silva, J. (2020). Efficient management of the

application of paclobutrazol for the production and quality of'Tommy Atkins' mango.

Research, Society and Development, 9(8).

Gehrke, M. (2008). Reflections on problems of reproductive biology of Ataúlfo mango in

Soconusco, Chiapas. Revista Tecnología en Marcha 21(1), 174-183.

Hernández, M., Castillo, A., Pérez, H., Avitia, E., Trejo, I., Alberto, J., & García, R. (2015).

Boron fertilization and its relationship with seedless fruit production in ʻAtaúlfoʼ mango.

Mexican journal of agricultural sciences, 6(8), 175-176. Retrieved from

http://www.scielo.org.mx/scielo.php?pid=S2007-

09342015000801757&script=sci_arttext

Infante, F., J. Quilantán, F. Rocha, H. Esquinca, A. Castillo , Ibarra , G., & Palacio , V. (2011).

Ataulfo Mango: Pride of Chiapas. CONOBIO. BIodiversitas , 1-5.

Leyva , A., Noriega , D., Pérez , M., González, M., & Hernandez , J. (2016). Geographical

distribution of parthenocarpic fruits in mango cv. Ataúlfo in the Coast of Guerrero.

Guerrero Studies Forum Vol. 2 No. 3, 1-5.

Lucero, O. (2011). La producción, comercialización y exportación. delmango en ecuador

período 2007-2009. Guayaquil: Universidad de Guayaquil, Thesis for the degree of:

Economist.

http://repositorio.ug.edu.ec/bitstream/redug/2184/1/Lucero%20Jara%20Olga%20del%2

0Rosario.pdf

Moreira, R., Becerril , A., Tijerina, L., & Cajuste , J. (2018). Effect of flowering promoters on

the nutritional status of mango cv. Tommy atkins. VIII Ecuadorian Congress of Soil

Science. Universidade da Coruña

Oliveira, G., Lopes de Siqueira, D., Chamhum, L., Cecon, P., & Magalhães, D. (2017). Pruning

paclobutrazol and branch tips on flowering induction and fruit quality of mango. Pesqui.

Agropecu. Trop. vol.47 no.1, https://doi.org/10.1590/1983-40632016v4743861.

Pérez , M. H., Tomás , E., Avitia , E., Gutiérrez , M., Santiago, M., Ramírez , H., & Cano , R.

(2019). Calcium prohexadione reduces vegetative growth and increases floral sprouting

in 'Ataulfo' mango. Rev. Mex. Cienc. Agríc vol.7 no.2 Texcoco, 7(2), 263-276.

Pérez, M. H., Osuna, A., Sánchez, R., & Vásquez, V. (2011). Paclobutrazol as a flowering

promoter in 'manila' mango, even without inductive environmental conditions. Chapingo

Journal. Serie horticultura, 47-52.

2Pérez, M. H. (2019). Pollen performance in mango (Mangifera indica L., Anacardiaceae):

Andromonoecy and effect of temperature,. Scientia Horticulturae,, 439-446.