pág. 9
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
Preliminary agronomic evaluation of rice (Oryza sativa L.)
genotypes under saline soil conditions of Yaguachi, Ecuador
Evaluación agronómica preliminar de genotipos de arroz (Oryza sativa L.) en condiciones
de suelo salino de Yaguachi, Ecuador
Reina Medina Litardo
Universidad de Guayaquil, Ecuador
reina.medinal@ug.edu.ec
Manuel Carrillo Zenteno
Instituto Nacional de Investigaciones Agropecuarias, Ecuador
manuel.carrillo@iniap.gob.ec
Luís Acosta Velazco
FRUTADELI S.A., Ecuador
luiguiacosta14@gmail.com
Iris Pérez- Almeida
Universidad Tecnológica ECOTEC, Ecuador
iperez@ecotec.edu.ec
Christian Duran-Mera
Universidad de Guayaquil, Ecuador
christian.duranm@ug.edu.ec
Pedro José García Mendoza
Universidad Nacional Autónoma de Tayacaja Daniel Hernández Morillo, Perú
pedrogarcia@unat.edu.pe
ABSTRACT
Soil salinity is considered one of the main abiotic stresses that affect rice cultivation throughout the world. The main
objective of this study was to carry out the preliminary agronomic evaluation of five commercial rice varieties
(INIAP11, INIAP14, SFL-011, INIAP-FL-Arenillas and Fedearroz-60) under saline soil conditions in Yaguachi,
Guayas, Ecuador.
A completely randomized block design was used to estimate the agronomic response of the materials by quantifying
grain yield t.ha-1 (Yield), number of tillers.m-2 (TN), plant height at harvest (PH), number of panicles.m-2 (NPM),
panicle length (PL), number of grains/panicle (NGP), number of filled grains/panicle (NFG), number of vain grains
(NVG), weight of 1000 grain (P1000) and content of chlorophyll at 30 (C30D) and 60 (C60D) days.
The analysis of variance reflected a high phenotypic diversity among the varieties studied, showing adequate
adaptation to the level of salinity contained in the soil used for the study. The INIAP-FL-Arenillas, INIAP14,
INIAP11 and FEDEARROZ-60 varieties were the genotypes with the best responses under the study conditions,
expressed in higher productivity levels.
The results also suggest the need to continue evaluating these varieties with and without saline stress conditions, to
discriminate the effect of genotype by environment interaction and confirm the level of tolerance to saline stress
present in these genotypes, optimizing the selection of the appropriate germplasm in breeding programs, aiming to
obtaining genotypes tolerant to saline soils.
Keywords: Electrical conductivity, genotypes, salinity, soils, yield.
pág. 10
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
RESUMEN
La salinidad del suelo se considera uno de los principales estreses abióticos que afectan al cultivo del arroz en todo
el mundo. El objetivo principal de este estudio fue realizar la evaluación agronómica preliminar de cinco variedades
comerciales de arroz (INIAP11, INIAP14, SFL-011, INIAP-FL-Arenillas y Fedearroz-60) en condiciones de suelo
salino en Yaguachi, Guayas, Ecuador.
Se utilizó un diseño de bloques completamente al azar para estimar la respuesta agronómica de los materiales
mediante la cuantificación del rendimiento de grano t.ha-1 (Rendimiento), número de macollos.m-2 (TN), altura de
planta a la cosecha (PH), número de panojas.m-2 (NPM), longitud panícula (PL), número de granos/panícula (NGP),
número de granos llenos/panícula (NFG), número de granos vanos (NVG), peso de 1000 granos (P1000) y contenido
de clorofila a los 30 (C30D) y 60 (C60D) días.
El análisis de varianza reflejó una alta diversidad fenotípica entre las variedades estudiadas, mostrando una adecuada
adaptación al nivel de salinidad contenido en el suelo utilizado para el estudio. Las variedades INIAP-FL-Arenillas,
INIAP14, INIA-11 y FEDEARROZ-60 fueron los genotipos con mejores respuestas bajo las condiciones de estudio,
expresadas en mayores niveles de productividad.
Los resultados sugieren la necesidad de continuar evaluando estas variedades en condiciones con y sin estrés salino,
para discriminar el efecto de la interacción genotipo por ambiente y confirmar el nivel de tolerancia al estrés salino
presente en estos genotipos, optimizando la selección del germoplasma apropiado en programas de mejoramiento,
con el objetivo de obtener genotipos tolerantes a suelos salinos.
Palabras clave: Conductividad eléctrica, genotipos, salinidad, suelos, rendimiento.
Introduction
The problem of salinity affects an area between 900
and 1060,1 million ha worldwide (FAO and ITPS
2015). Ivushkin et al. (2019) placed the global
distribution of soils affected by salinity at 1000 million
ha; in Latin America 31 million ha have this problem
(FAO & ITPS 2015).
On the Ecuadorian coast there are saline soils with a
dS.m-1 > 4, PSI < 15 and pH < 8.5, where the
condition of water deficit favors the edaphic
concentration of basic cations and anions in toxic
degrees for plants. Some 337,613 ha (8.01 %) of
Manabí, Guayas and El Oro show salinity problems,
in several degrees: light (175,107 ha); average (59,247
ha); high (72,806 ha) and very high (30,453 ha) (Pozo
et al. 2010).
Rice (Oryza sativa L.) is the second most cultivated
cereal worldwide, with economic, environmental, and
social importance in Ecuador. It is located mostly in
the coastal region, with the highest production (90,59
%) in Guayas and Los Ríos (INEC 2022b). The most
obvious effects of salinity are poorly developed,
chlorotic, poorly tillered plants. The first symptom of
salinity stress in rice in the vegetative stage is the
white tip of the leaf; in flowering high infertility and
poor grain filling are observed, generating negative
effects directly on crop yield (Dobermann & Fairhurst
2012; Cobos et al. 2021). High salinity eventually
leads to plant death.
The region of Guayas represents about 40 % of the
irrigation areas in Ecuador, which are characterized by
being made up of vertisol soils, with accumulation of
salts on the surface, possibly due to the use of water
for irrigation with the presence of salts and aggravated
by drainage deficiencies in the soils.
In the dry season of 2019, an experiment was planned
under saline soil conditions in that region, with the
main objective of carrying out the preliminary
agronomic evaluation of rice genotypes, to contribute
to the identification of cultivars with satisfactory
adaptation to saline soil conditions, which may in the
future be recommended to rice producers in those
areas with similar soil conditions to where the study
was carried out (Yaguachi area, Ecuador), as well as
to identify genotypes that could be used as references
in subsequent studies where the tolerance of
commercial rice varieties to saline soil conditions is
evaluated.
Materials and methods
Experimental material: In this study, five
commercial rice varieties (INIAP-FL-Arenillas,
SFL011, INIAP14, INIAP11 and FEDEARROZ-60)
were evaluated, these are used by farmers in the region
where the study was carried out. The varieties INIAP-
FL-Arenillas, SFL011 and FEDEARROZ-60 are
genotypes that have their origin in the program of the
Latin American Fund for Irrigated Rice (FLAR), being
pág. 11
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
FEDEARROZ-60 produced by the National
Federation of Rice Growers of Colombia, while
INIAP11 and INIAP14 were originated by the
National Institute of Agricultural Research (INIAP) of
Ecuador. These are varieties widely tested by farmers
but have not been evaluated under saline soil
conditions.
Location of the trial: The research was conducted on
a farm of the Guajala Association, San Jacinto de
Yaguachi canton, Ecuador, during the dry season from
August to December 2019 (Medina et al. 2022).
Test soil characteristics: The soil is a vertisol, with
an electrical conductivity (EC) of 7.44 dS m-1 and pH
of 6.79, whose texture, and other physical and
chemical characteristics were previously reported in
Medina et al. (2022). These chemical characteristics of
EC and pH allow classifying this soil as a saline soil
(USSLS 1954, Shaygan & Baumgartl 2022)
Agronomic management: Fertilization was based on
the results of soil analysis and the demand for the
varieties used in the study (Medina et al. 2022).
Irrigation management, weed control, insect pests and
diseases were previously specified by Medina et al.
(2022).
Evaluated variables: Information was registered
about yield (t.ha-1) (Yield); number of tillers.m-2
(TN); plant height at harvest (cm) (PH); number of
panicles.m-2 (NPM); panicle length (cm) (PL);
number of grains per panicle (NGP); number of filled
grains (NFG), number of vain grains (NVG), weight
of 1000 grains (g) (P1000); chlorophyll content at 30
(C30D) and 60 (C60D) ddt (%), based on the Standard
Evaluation System for rice (SES) (IRRI 2002), as
described by Medina et al. (2022).
Experimental design and statistical analysis: a
random complete blocks design was used, with five
treatments (varieties), four replications, and
experimental units of 6 m2.
For the analysis of the variables, the average obtained
per variable in each experimental unit was used,
according to the established experimental design. For
the separation of the values, Duncan's mean test was
used at 5 % probability. To aid in the separation of
means between the productivity levels of the varieties,
orthogonal contrasts were applied. In addition to mean
tests, confidential intervals were constructed for the
population mean, according to Walpole et al. (2012).
RESULTS
The analysis of variance determined highly significant
(p≤0.01) or at least significant (p≤0.05) differences for
the effect of varieties in all the variables analyzed,
except for the number of vain grains (NVG) (table 1),
suggesting sufficient phenotypic diversity among the
varieties included in the study. The coefficients of
variation (CV) and determination (R2) observed in all
the variables analyzed, can be considered appropriate
for this type of studies, except that observed with the
NVG variable, which obtained a relatively high CV
and an R2 of 0.50, which suggests that about 50 % of
the variability shown by this variable could not be
explained by the model used. However, even when the
data transformation was carried out, achieving a much
smaller CV, no significant differences were detected.
A Friedman test, equivalent to parametric ANOVA for
two factors, was also performed, but no statistically
important differences were detected.
Table 1
Mean squares of the ANOVA of 11 variables evaluated in five rice varieties, under saline soil conditions
Sources of variation
DF
Mean Square
Yield
TN
(x102)
PH
PL
NGP
(x102)
NFG
(x102)
NVG
P1000
C30D
C60D
Blocks
3
0.06
28,02
26,73
3,07
3,63
3,26
0,40
0,06
4,57
3,08
Varieties
4
1.29*
132,01**
111,50**
10,03*
13,08*
12,03*
2,51
6,66**
13,52**
11,64*
FLAR VARIETIES
2
0.737
170.00
60.25*
11.66*
1.50
1.65
0.86
2.23
16.56**
13.91*
INIAP VARIETIES
1
0.001
648.00
4.50
3.78
2.27
2.00
3.00
0.001
1.81
0.01
FLAR vs INIAP
1
3.387**
512.80**
242.00**
15.40*
46.75**
42.05**
7.70*
17.70**
0.001
0.11
Error
12
0.27
14,89
10,07
2,16
2,88
3,09
0,94
0,70
2,16
3,01
Total
19
CV (%)
7,04
9,88
3,36
5,71
13,70
14,65
25,02
3,03
3,15
3,54
pág. 12
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
R2
0,62
0,77
0,81
0,66
0,65
0,61
0,50
0,76
0,72
0,61
Mean
7.438
390,50
94,50
25,74
123,88
120,02
3,88
27,51
46,65
49,01
* and ** indicate significant differences at 5 % and 1 %, respectively. I-FL-A = INIAP-FL-Arenillas. TN, PH, NPM,
PL, NGP, NFG, NVG, P1000, C30D and C60D mean, respectively, number of tillers.m-2, plant height, number of
panicles.m-2, panicle length, number of grains. panicle-1, number of filled grains, number of vain grains, weight of
1000 grains, chlorophyll content at 30 days and chlorophyll content at 60 days.
Source: Authors.
Yield (t. ha-1)
The varieties INIAP-FL-Arenillas, INIAP14 and
INIAP11 achieved the highest levels of average
productivity, significantly surpassing SFL011, which
obtained the lowest average productivity (table 2).
Average levels of productivity analysis between the
cultivars of FLAR origin regarding the local group of
INIAP origin carried out through the means test
showed significant differences between both groups,
as demonstrated by the contrast test (table 1).
Table 2
Average values for grain yield (Yield), number of tillers.m-2 (TN), plant height (PH), number of panicles.m-2 (NPM)
and panicle length (PL) estimated in five rice varieties evaluated in saline soils.
N°
Varieties
Yield.
(t. ha-1)
TN
PH (cm)
NPM
PL (cm)
1
INIAP-FL-Arenillas
7.430 a
353.00 b
95.50 b
339.50 b
28.18 a
2
SFL011
6.589 b
354.00 b
103.00 a
349.75 b
25.85 b
3
INIAP14
7.948 a
443.75 a
91.00 bc
438.25 a
23.80 b
4
INIAP11
7.966 a
461.75 a
89.50 c
455.75 a
25.18 b
5
FEDEARROZ-60
7.257 ab
340.00 b
93.50 bc
337.50 b
25.68 b
FLAR VARIETIES
7.092 b
349.00 b
97.33 a
342.25 b
26.57 a
INIAP VARIETIES
7.957 a
452.75 a
90.25 b
447.00 a
24.49 b
Average:
7.438
390.50
94.50
384.15
25.74
Confidence interval (5%):
6.601; 8.276
310.41; 470.59
87.26; 101.74
304.86; 463.44
23.26; 28.21
LSD
0.807
59.45
4.89
58.33
2.26
Values marked with the same letter in each variable do not differ statistically from each other (Duncan α 0.05); LSD
means least significant difference.
Source: Authors.
Number of tillers.m-2 (TN)
The rice varieties generated by INIAP, presented the
highest number of tillers.m-2, being statistically
superior (p≤0.05) to the varieties of FLAR origin
(table 2). The difference in the tillers number per area
of the varieties of INIAP origin compared to the rest
of the evaluated varieties (more than 100 tillers m-2),
shows that they had better both, establishment and
plants development.
Plant height at harvest (PH)
The SFL011 variety presented the highest average for
this variable (table 2), statistically outstanding the
other varieties; the INIAP11 variety was the lowest
PH, but was statistically equal in PH to the INIAP14
and Fedearroz-60 varieties (table 2). When the PH of
both groups of germplasms is analyzed, the mean test
shows that the lowest materials were the varieties of
INIAP origin. However, regardless of the pH reached
by the evaluated varieties, all of them reached heights
of suitable plants for irrigated rice cultivation (low
growth), since they are less prone to lodging due to
strong winds.
Number of panicles.m-2 (NPM)
The INIAP11 and INIAP14 varieties presented the
highest number of panicles.m-2, statistically
outstanding the other varieties, which is derived from
the highest number of tillers.m-2 obtained by them
(table 2). In this regard, it can be observed that the
evaluated varieties expressed a proportion of effective
tillers (tillers with panicles) equal to or greater than
98%, which implies that the difference between the
cultivars in terms of number of panicles was directly
determined by their establishment and tillering
capacity.
Panicle length (cm) (PL)
Regarding this variable, the variety INIAP-FL-
Arenillas reached the highest PL, being statistically
higher (p≤0.05) than the other varieties included in the
study; the lowest PL corresponded to the INIAP14
pág. 13
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
variety, whose average PL was statistically equal to
that observed in the remaining three varieties (table 2).
Number of grains per panicle (NGP), filled grain
(NFG) and vain grain (NVG)
Regarding the NGP trait, the means test separated the
varieties into four groups, where the Fedearroz-60
variety showed the highest average values, while
INIAP11 obtained the lowest values (table 3). The
varieties of FLAR origin expressed on average longer
panicles and with a greater number of grains,
presenting on average panicles with 136.06 grains,
compared to 105.61 grains per panicle in the local
varieties of INIAP origin, which represented a
superiority of the varieties of FLAR origin of 30.45
grains per panicle.
Table 3
Average values for the N° of grains per panicle (NGP), N° of full grains (NFG), N° of vain grains (NVG), weight of
1000 grains (P1000), chlorophyll content at 30 days (C30D) and at 60 days (C60D) after the transplanting obtained
in the evaluation of five varieties of rice in saline soils.
N°
Varieties
NGP
NFG
NVG
P1000
(g)
C30D
C60D
1
INIAP-FL-Arenillas
134.13 ab
129.38 ab
4.75 a
27.98 b
45.63 b
49.83 a
2
SFL011
128.88 ab
124.20 abc
4.18 a
29.40 a
49.63 a
50.80 a|
3
INIAP14
110.93 bc
107.68 bc
3.83 ab
26.30 c
46.08 b
49.08 a
4
INIAP11
100.28 c
97.68 c
2.60 b
26.33 c
47.03 b
49.13 a
5
FEDEARROZ-60
145.18 a
141.15 a
4.03 ab
27.53 bc
44.88 b
46.23 b
FLAR VARIETIES
136.06 a
131.58 a
4.32 a
28.30 a
46.71 a
48.95 a
INIAP VARIETIES
105.60 b
102.68 b
3.21 b
26.31 b
46.55 a
49.10 a
Average
123,88
120,02
3,88
27,51
46,65
49,01
Confidence interval (5%)
95,71; 152,04
92,26; 147,77
2,52;
5,23
25,82; 29,19
43,89; 49,40
46,28; 51,74
LSD
26,14
27,09
1,49
1,29
2,27
2,67
Values with the same letter in each variable do not differ statistically from each other (Duncan α=0.05). LSD = least
significant difference
Source: Authors.
Weight of 1000 grains (g) (P1000)
The SFL011 variety showed the highest average value
for P1000, statistically outstanding (p≤0.05) the rest of
the evaluated varieties, while the INIAP11 and
INIAP14 varieties resulted in the lightest grains (table
3). For the environmental conditions where the study
was carried out, the group of varieties of FLAR origin
expressed grains with a greater weight (28.30 gr)
compared to the INIAP materials (26.31 gr) (table 3).
Chlorophyll content at 30 and 60 ddt (C30) (C60)
The SFL011 variety presented the highest content of
C30, surpassing the remaining varieties, which
showed statistically equal values. However, the C60
content determined that the varieties INIAP-FL-
Arenillas, SFL011, INIAP14 and INIAP11 obtained
chlorophyll concentrations statistically equal, but
higher than the value observed in the Fedearroz-60
variety (Table 3). No significant differences (p>0.05)
were found between the means of these characters
observed for both groups of genotypes.
DISCUSSION
The orthogonal contrast test determined highly
significant differences (p≤0.01) between the varieties
of FLAR origin and the INIAP varieties, for all studied
variables, except for the chlorophyll content at 30
(C30D) and 60 (C60D) days after transplanting, where
both groups presented statistically equal values
(p>0.05) and for the panicle length (PL) and number
of vain grains (NGV) traits, whose differences
between both groups of genotypes were only
significant (p≤0.05) (table 1). Another important
aspect to highlight was what was observed with the
block effect, which was not significant for all the
variables analyzed. These results suggest a high spatial
uniformity in the conditions of the terrain where the
experiment was carried out, which was most likely
favored by the low number of materials included in the
test and the use of a lot of land with adequate leveling.
Yield (t. ha-1)
pág. 14
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
The varieties INIAP-FL-Arenillas, INIAP14 and
INIAP11 achieved the highest levels of average
productivity, significantly surpassing SFL011, which
obtained the lowest average productivity (table 2).
These results were to be expected, since the local
materials come from the region, which implies that
they must have genetic factors that allow them to adapt
adequately to the environment. This situation is also a
reflection of the complexity of grain yield, influenced
by many environmental, genotypic factors and their
interaction (Hallauer et al. 2010).
Salinity is considered one of the main abiotic factors
that affects different phenological stages of the crop,
reflected in lower productivity (Dobermann &
Fairhurst 2012). Several studies have found significant
reductions in grain yield in rice due to stress generated
by saline soils, which can vary, under conditions of
soils with high levels of salinity and sodicity, between
28 to 97% (Krishnamurthy et al. 2016), variation that
will depend on the genotype and its interaction with
the environment where the crop is grown. Zeng and
Shannon (2000) reported significant effects of salinity
on grain yield, grain/plant weight, grain/panicle
weight, and spikelet/panicle number.
The experimental average productivity was 7.438 t/ha,
which when compared with the productivity of rice
cultivation in Ecuador during 2019, both nationally
(4.274 t/ha), and in Guayas (5.140 t/ha) (INEC 2022a),
it can be inferred that the varieties used in this study
had normal growth and development, despite the soil
salinity conditions; this suggests that they have
suitable adaptation to this type and level of abiotic
stress. On the other hand, despite the good behavior
shown by the varieties, the study shows that there is a
difference according to their origin; in this particular
case, the varieties of the national program (INIAP)
were superior in productivity to those of FLAR origin,
reaching a difference of 0.865 t/ha, which was
statistically significant (p≤0.05), suggesting that this
group has a better adaptation to the particular soil
conditions used in this study. In summary, the higher
productivity of the INIAP-FL-Arenillas, INIAP14 and
INIAP11 varieties could indicate their adequate
adaptation to the soil and climate conditions where the
study was carried out.
Number of tillers.m-2 (TN)
The rice varieties generated by INIAP, presented the
highest number of tillers.m-2, being which is
indicative that the INIAP Ecuador breeding program
for rice cultivation has been efficient in obtaining
varieties with adequate adaptation to abiotic stress
conditions, such as those generated by saline soils,
despite the fact that said program was not focused in
developing materials for saline soils. All this has been
possible because the cultivars are being generated in
the environmental conditions typical of the region of
production.
Plant height at harvest (PH)
Under saline soil conditions, Cristo et al. (2012),
observed a substantial reduction in plant growth,
because of osmotic stress, imbalance of specific ions
and toxic effects caused by excessive accumulation of
ions. Also, Ashraf and Harris (2004), indicated that
salinity in soils produces different types of stresses,
which affect germination, vegetative growth,
flowering, among other phenological processes of the
plant. All of these types of effects could end up
negatively affecting the PH.
Number of panicles.m-2 (NPM)
In this regard, it can be observed that the evaluated
varieties (table 2) expressed a proportion of effective
tillers (tillers with panicles) equal to or greater than
98%, which implies that the difference between the
cultivars in terms of number of panicles was directly
determined by their establishment and tillering
capacity.
Panicle length (cm) (PL)
When the materials are observed according to their
origin (table 2), the varieties of FLAR origin
expressed, under the environmental conditions of the
experiment, a greater panicle length (26.57 cm)
compared to the local varieties of INIAP origin (24.49
cm), representing this an average difference between
both groups of 2.08 cm
Number of grains per panicle (NGP), filled grain
(NFG) and vain grain (NVG)
For the number of filled grains per panicle (NFG), the
behavior of the varieties was similar to that expressed
in the NGP trait, where the variety Fedearroz-60
showed the highest mean values, whereas the variety
INIAP11 resulted with the lower values for this trait.
The FLAR varieties origin expressed an average of
131.58 full grains per panicle in comparison with the
local varieties of INIAP origin that managed to
pág. 15
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
produce, under the experimental conditions, 102.68
full grains per panicle, which meant a difference of 29
GFP between both groups of genotypes.
For the number of vain grains (NVG) no significant
differences were detected between the varieties, which
was due to the great similarity of the values reached
by them, even though in the contrast analysis
differences were detected when comparing the
varieties by their origin (table 1), where the varieties
of FLAR origin surpassed the varieties of INIAP
origin in the NVG (table 3). However, the percentage
of vain grains reached by the varieties was less than
4%, despite the abiotic stress conditions generated by
the saline soil, which suggests that the genotypes had
a normal grain filling process under the environments
conditions where the study was carried out. The results
reveal that these cultivars could have tolerance to the
level of salts contained in the soils where the study was
carried out, since it is known that although rice is
relatively tolerant to salinity in the germination stage,
it is sensitive in the panicle initiation and flowering
stages (Khatun & Flowers 1995; Zeng et al. 2001). In
susceptible rice cultivars, the vanishing of the grains
due to the effect of high concentrations of salts in the
soil is due to the fact that fertilization of the ovule is
not achieved or causes the unviability of the pollen
(Cristo et al. 2012).
Weight of 1000 grains (g) (P1000)
Zeng & Shannon (2000) report that one of the
measurable or visible effects of salinity on plants can
include significant reductions in yield components,
one of them being the weight of 1000 grains; therefore,
the normal filling of grains (table 3) occurred in the
varieties evaluated in this study (values in accordance
with those observed in irrigated rice cultivars),
indicate that they have tolerance in the reproductive
stage to the salinity conditions of the soils used in this
study.
Despite the fact that the varieties of FLAR origin
exceeded the varieties originated by INIAP in the
characters PL, NGP, NFG and P1000, the INIAP
varieties exceeded those of FLAR origin in average
productivity, which was due to the greater capacity of
tillering shown by the INIAP varieties, which allowed
them to reach a greater number of effective panicles
per surface unit. These results demonstrate the
importance, in commercial plantings, to use rice
cultivars that guarantee an optimal capacity for both,
plants establishment and plant development.
Chlorophyll content at 30 and 60 ddt (C30) (C60)
These results seem to indicate that the rice plant is
much more sensitive to the effects of soil salinity in
the early stages of development. Indeed, soil salinity
is considered one of the most important abiotic
stresses, which directly affect plant growth and
development (Arshad et al. 2012), processes closely
linked to photosynthesis. In this sense, Castillejo et al.
(2021) found a reduction in net photosynthesis
associated with a drop in the rate of electron transport
as salinity in the medium increased, a process that
articulates the absorption of light energy and its
conversion into photoassimilates. That explains why,
generally, varieties tolerant to salt stress exhibit a high
percentage of chlorophyll. This variable is directly
related to salinity tolerance, since the decrease in
chlorophyll content affects the process of
photosynthesis, plant growth and development (Khairi
et al. 2015).
Salinization can be understood as a process of
excessive accumulation of soluble salts in soils, by
different sources, generating adverse effects on the
environment where plants develop and therefore on
their productivity (Hussain et al. 2018). Under these
conditions, genotypes with the best agronomic
responses may reflect a higher level of tolerance to
saline soil condition. In this way, INIAP-FL-Arenillas,
INIAP14, INIAP11 and Fedearroz-60 would be the
genotypes that capitalized on the best responses,
observed at higher levels of productivity. However,
the SFL011 variety also presented a favorable
response in plant height, was among the varieties with
the highest NGP, NFG, was the variety with the
highest weight of 1000 grains and highest chlorophyll
content at 30 and 60 days. These results demonstrate
the need to continue evaluating these varieties under
conditions of salt stress, as well as in soil conditions
without this type of stress, in order to determine the
level of tolerance to salt stress present in the genotypes
evaluated, because under the conditions in which they
were evaluated in this study the results only determine
their response to the soil and climate condition where
the study was conducted. Despite being results
obtained in a single environment, due to logistical and
economic limitations that did not allow the placement
of other environments, the study is considered very
useful to justify the investment in research, in order to
continue evaluating these and other varieties of rice
under soil conditions with and without stress
generated by high levels of salts, as well as for the
pág. 16
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
selection of the appropriate germplasm for breeding
programs, aiming at obtaining genotypes tolerant to
saline soils.
CONCLUSIONS
The present study showed that the commercial rice
varieties evaluated have adequate adaptation to the
level of salinity contained in the Guayas soils where
the study was carried out, having a normal
development of the crop and obtaining paddy rice
yields that exceeded the average reported for the
region in which they were evaluated by more than 2
t/ha, evidencing that they are useful seed technologies
capable of enabling profitable productions for farmer
rice producer. The INIAP-FL-Arenillas, INIAP-14,
INIAP-11 and Fedearroz-60 varieties were the
genotypes with better responses under the study
conditions, expressed in higher levels of productivity.
Even though the SFL-011 variety presented the
highest chlorophyll content at 30 and 60 days,
influencing a favorable response in plant height and
grain weight, its level of productivity was below that
of the remaining varieties. The results showed that the
FLAR source materials expressed plants with larger
panicles, with a greater number of grains and heavier
grains, however they were not the ones with the
highest yield, due to a deficiency in the number of
panicles per area, which implies less capacity for
establishment and/or tillering. The results demonstrate
the need to continue evaluating these varieties under
conditions of salt stress and without stress, to
determine the level of tolerance to salt stress present
in the genotypes evaluated. All these varieties could
also be used as reference witnesses in future studies
where it is sought to evaluate new genotypes of rice
under conditions with and without salt stress, due to
their adequate agronomic response under the study
conditions.
Acknowledgments
The authors wish to thank the University of Guayaquil
for the availability of time to conduct this research.
Also, to the National Institute of Agricultural Research
(INIAP) for the accompaniment of field work and
interpretation of results. In addition, to the Ecotec
University and the National Autonomous University
of Tayacaja (UNAT) for supporting the research with
their biostatistics and plant breeding teams. The
authors also wish to express their gratitude to Dr. Rosa
María Alvarez (INIA-Venezuela), specialist in rice
plant breeding, for the critical review of the
manuscript and suggestions to improve the content of
the work.
Conflicts of interest
All the authors made equal and significant
contributions to the document and agree with its
publication and state that there are no conflicts of
interest in this study.
REFERENCIAS BIBLIOGRÁFICAS
[1] Arshad, M; Saqib, M; Akhtar, J; Asghar, M. 2012.
Effect of calcium on the salt tolerance of different
wheat (Triticum aestivum L.) genotypes. Pak. J. Agri.
Sci, 49 (4): 497-504.
[2] Ashraf, M; Harris, P. 2004. Potential biochemical
indicators of salinity tolerance in plants. Plant Sci.,
166(1): 3-16.
https://doi.org/10.1016/j.plantsci.2003.10.024.
[3] Castillejo-Morales, A; Jarma-Orozco, A; Pompelli,
MF. 2021. Physiological and morphological features
denote that salt stress in Stevia rebaudiana is based on
nonstomatic instead of stomatic limitation. Revista
Colombiana de Ciencias Hortícolas, 15(3): e12928.
https://doi.org/10.17584/rcch.2021v15i3.12928
[4] Cobos, F; Gómez, L; Reyes, W; Hasang, E; Ruilova,
M; Duran, P. 2021. Effects of salinity levels in Oryza
sativa in different phenological stages under
greenhouse conditions. Revista de la facultad de
Agronomía de la Universidad de Zulia, 39(1):
e223905. Disponible en:
https://produccioncientificaluz.org/index.php/agrono
mia/article/view/37392.
[5] Cristo, E; González, M; Pérez, N. 2012.
Comportamiento de genotipos de arroz (Oryza sativa
L.) promisorios para suelo salino. Cultivos Tropicales,
33(3): 42-46.
[6] Dobermann, A.; Fairhust, T. 2012. Rice: Nutrient
disorders & nutrient management. IPNI. 155-156 pp.
[7] FAO and ITPS (Food and Agriculture Organization of
the United Nations and Intergovernmental Technical
Panel on Soils). 2015. Status of the World’s Soil
Resources (SWSR) – Main Report. Rome, Italy.
[8] Hallauer, A.; Carena, M.; Miranda, J. 2010.
Quantitative genetics in maize breeding. 3rd. Ed.,
London, Springer. 663 p. https://doi.org/10.1007/978-
1-4419-0766-0
[9] Hussain, M; Ahmad, S; Hussain, S; Lal, R; Ul-Allah,
S; Nawaz, A. 2018. Rice in Saline Soils: Physiology,
Biochemistry, Genetics, and Management. Advances
in agronomy, 148: 231-287.
https://doi.org/10.1016/bs.agron.2017.11.002.
pág. 17
Artículo científico
Volumen 6, Número 2, julio - diciembre, 2023
Recibido: 05-06-2023, Aceptado: 03-08-2023
https://doi.org/10.46908/tayacaja.v6i2.209
[10] INEC (Instituto Nacional de Estadística y Censos),
ESPAC (Encuesta de superficie y producción
Agropecuaria Continua) 2021. 2022a. Aspectos
metodológicos, resumen estadístico y resultados.
Available in:
https://www.ecuadorencifras.gob.ec/documentos/web
-inec/Estadisticas_agropecuarias/espac/espac-
2021/Principales%20resultados-ESPAC_2021.pdf
[11] INEC (Instituto Nacional de Estadística y Censos).
2022b. Encuesta de Superficie y Producción
Agropecuaria Continua. Boletín Técnico. Disponible
en:
https://www.ecuadorencifras.gob.ec/documentos/web
-inec/Estadisticas_agropecuarias/espac/espac-
2021/Bolet%C3%ADn%20t%C3%A9cnico.pdf
[12] IRRI (International Rice Research Institute). 2002.
Sistema de Evaluación Estándar para Arroz. Manila,
Filipinas.
http://www.knowledgebank.irri.org/images/docs/rice-
standard-evaluation-system.pdf
[13] Ivushkin, K.; Bartholomeus, H.; Bregt, AK.; Pulatov,
A.; Kempen, B.; De Sousa, L. 2019. Global mapping
of soil salinity change. Remote Sensing of
Environment, 231, [111260].
https://doi.org/10.1016/j.rse.2019.111260
[14] Khairi, M; Nozulaidi, M; Jahan, S. 2015. Effects of
different water levels on physiology and yield of
salinity rice variety. Australian Journal of Basic and
Applied Sciences, 9(2): 339-345. Disponible en:
https://www.researchgate.net/publication/277258267
_Effects_of_different_Water_Levels_on_Physiology
_and_Yield_of_Salinity_Rice_Variety
[15] Khatun, S; Flowers, T. 1995. Effects of salinity on
seed set in rice. Plant Cell Environ, 18: 61-67.
https://doi.org/10.1111/j.1365-3040.1995.tb00544.x
[16] Krishnamurthy, SL; Gautam, RK; Sharma, PC;
Sharma, DK. 2016. Effect of different salt stresses on
agro-morphological traits and utilisation of salt stress
indices for reproductive stage salt tolerance in rice.
Field Crops Research, 190: 26-33.
https://doi.org/10.1016/j.fcr.2016.02.018
[17] Medina, RC; Sady, JG; Carrillo, MD; Pérez-Almeida,
IB; Parismoreno, LL; Lombeida, ED. 2022. Effect of
mineral and organic amendments on rice growth and
yield in saline soils. Journal of the Saudi Society of
Agricultural Sciences, 21(1), 29-37.
https://doi.org/10.1016/j.jssas.2021.06.015
[18] Pozo, W; Sanfeliu, T; Carrera, G. 2010. Variabilidad
Espacial Temporal de la Salinidad del Suelo en los
Humedales de Arroz en la Cuenca Baja del Guayas,
Sudamérica. Revista Tecnológica- ESPOL, 23(1): 73-
79.
[19] Shaygan, M; Baumgartl, T. 2022. Reclamation of Salt-
Affected Land: A Review. Soil Syst. 6, 61: 1 - 17.
https://doi.org/10.3390/soilsystems6030061.
[20] United States Salinity Laboratory Staff. 1954.
Diagnosis and Improvement of Saline and Alkali
Soils; U.S. Department of Agriculture: Washington,
DC, USA. Disponible en:
https://www.ars.usda.gov/ARSUserFiles/20360500/h
b60_pdf/hb60complete.pdf.
[21] Walpole, R.; Myers, R.; Myers, S.; Ye, K. 2012.
Probabilidad y estadística para Ingeniería y Ciencias.
Editorial Pearson.
[22] Zeng, L; Shannon, MC. 2000. Effects of salinity on
grain yield and yield components of rice at different
seeding densities. Agronomy Journal, 92 (3): 418-423.
https://doi.org/10.2134/agronj2000.923418x
[23] Zeng, L; Shannon, M; Lesch, S. 2001. Timing of
salinity stress affects rice growth and yield
components. Agric. Water Manage, 48: 191-206.
https://doi.org/10.1016/S0378-3774(00)00146-3