Response to nitrogen fertilization and irrigation management of common bean cultivars in central Chile

ABSTRACT

Four of the most frequently grown varieties of common bean cultivated in Chile were evaluated in a Mediterranean zone of central Chile. The primary objective was to investigate yield potential and morphological and nutritional characteristics through agronomic management improvement programs, including irrigation and nitrogen (N) fertilization. For this purpose, in 2018/19, an experiment was arranged in a randomized complete block split-split plot design with two irrigation treatments, two fertilization rates, and four varieties. The Zorzal variety obtained the highest grain yield (GY) (4.7 Mg ha^–1) when applying 5,400 m³ ha^–1 of water and 120 kg N ha^–1. However, the N doses did not produce differences in GY. In 2019/20, a demonstration plot (DP) was established to compare the best agronomic management derived from the first experiment with the current practices of four farmers. In the DP, GY reached 4 Mg ha^–1 with an N dose of 90 kg ha^–1, while the highest GY (5.4 Mg ha^–1) was obtained by Farmer 1 using an N dose of 130 kg ha^–1 and 9,000 m³ ha^–1 of water. The irrigation, N dose, and cultivars affected the length and width of grains, while the 100-grains weight was affected by N dose and cultivars. Although Zorzal and Torcaza cultivars did not achieve the highest mineral contents, they have high yield potential and higher protein and mineral by sown surface. Finally, the DP demonstrated that reducing the amount of water and N commonly applied by producers in central Chile produces yields similar to those of the most productive farms.

Keywords:
Andean gene pool; Mediterranean zone; race Chile; agronomic management; nutritional composition

Introduction

Common bean (Phaseolus vulgaris L.) is the most important legume for direct human consumption in the world, and it represents the primary source of proteins and nutrients in the diets of developing countries (Broughton et al., 2003). The protein content in common bean seeds typically ranges from 20 % to 25 % (Broughton et al., 2003), and they are a good source of dietary fiber and, to a lesser extent, vitamins and minerals (Broughton et al., 2003). Chile is ranked ninth in the production of common beans in South America, but first in grain yield (GY) reaching 1.71 Mg ha^–1 (FAO, 2023). Common bean is grown mainly in central Chile from the Valparaíso to Araucanía Regions, with a total planted area of 5.874 ha in the 2023-24 season, where the Maule Region is the most important, concentrating around 35 % of national production (Díaz et al., 2021). The most widely cultivated and consumed commercial grain classes are the Tórtola and Coscorrón types, consumed as dry and green shelled beans, respectively (Pinheiro et al., 2018). Both originate from the Andean gene pool and belong to the Chilean race (Arriagada et al., 2024). This race is considered the oldest repository of the Andean common bean pool, rendering this germplasm an indispensable genetic resource (Arriagada et al., 2024; Trucchi et al., 2021).

Agronomically, Tórtola types have been observed to exhibit swift adaptation to water stress compared to other Chilean commercial classes. Cultivars that exhibit strong adaptation to drought conditions have demonstrated a remarkable reduction of up to 50 % in their hydric requirements when cultivated in suitable soil conditions without significantly altering their productive capacity (Satriani et al., 2015). Nitrogen (N) fertilization is also a crucial agronomic practice for achieving high yields. However, in central Chile, overfertilization with N is a common agronomic practice, resulting in the risk of nitrate leaching and groundwater and aquifers contamination (González-Miranda et al., 2021), as well as a decrease in GY and loss of nutritional quality (Albornoz, 2016).

Therefore, we hypothesized that reducing irrigation and N fertilization affects neither the yield nor the nutritional composition of the most cultivated common bean varieties in central Chile. Thus, the primary objective was to evaluate the yield potential of four common bean cultivars in the Maule Region, focusing on agronomic management strategies, particularly the reduction in N fertilization and the overall quantity of water applied throughout the growing season.

Materials and Methods

Plant material

Four Chilean common bean cultivars were used. Curi; a black-colored bean [selection from advanced line Bat 1554 and introduced to Chile from Centro de Agricultura Tropical (CIAT)], Blanco Español; a white colored grain bean type [selection from Mussolini cv.], and two Tórtola classes of grey grains (Torcaza [line Ta8 × Blanco Español] and Zorzal [Blanco Español × Advanced line from Torcaza × Amanda]). The grain of the different cultivars used is shown in Figure 1. As regards its agronomic behavior, the Curi and Blanco Español cultivars have a type I growth habit and take 115 – 120 and 117 – 140 days to harvest (DTH), respectively. Torcaza has a type II-III growth habit and takes 114 – 120 DTH, while Zorzal has a type III growth habit and takes 100 – 105 DTH.

Figure 1

Photograph of the grain of the four cultivars evaluated in this study.

Experimental design and treatments

A first experiment was conducted to evaluate the agronomic performance of the four Chilean common beans cultivars. This was established in the spring and summer seasons of 2018/19 (2018 experiment) in Curepto (34°59’30" S, 72°01’0" W, altitude 16 m), Maule Region, Mediterranean area of central Chile. The average monthly rainfall from June to Oct 2018 was 40.9 mm. The monthly rainfall of the zone was 9.5 mm in summer 2018 (Nov and Dec), 0 mm in summer 2019 (Jan and Feb), and ∼240 mm in winter 2019 (May and June), while the minimal and maximal average daily temperature of the period were ∼8 and ∼20 °C, respectively. The soil was classified as a Udertic Haplustept (Soil Survey Staff, 2022). The main chemical characteristics of the soil were: pH of 6.4 (pHw 1:2.5), 15, 13, and 238 mg kg^–1 of available N, P, and K, respectively, and 1.0 % of soil organic matter (SOM). Before sowing, the experimental site was prepared with a basal fertilization incorporating 200 kg ha⁻¹ of potassium chloride (∼50 % K or ∼60 % K₂O) and 300 kg ha⁻¹ of triple super phosphate (∼20 % P or ∼46 % P₂O₅) with a disc harrow. Weed control was achieved through the simultaneous, pre-emergence application of trifluralin (480 mL a.i. ha⁻¹) and S-metolachlor (2880 mL a.i. ha⁻¹), and post-emergence manual control.

The experiment was arranged in a randomized complete block split-split plot design with four replicates. Two treatments of irrigation frequency were randomly assigned to the main plots, two N fertilization rates to the split plots, and four common bean varieties to the split-split plots. The irrigation-frequency treatments were standard irrigation (SI) and deficit irrigation (DI), which are equivalent to 60 mm ha^–1 for each irrigation applied over nine weeks (5,400 m³ ha^–1) and seven weeks (4,200 m³ ha^–1), respectively. The first irrigation was applied at the beginning of the flowering period using drip irrigation tapes. In each irrigation plot, two N fertilization levels (applied as urea) were established: 90 (90 N) and 120 kg N ha^–1 (120 N). The common bean cultivars (4) were sown on 11 Nov 2018, with 7 cm within row and 75 cm between row spacing, resulting in 180,000 plants per hectare. Each subplot was 4 m in length × 3 m in width and was harvested manually on 5 Mar 2019.

In 2019/20 (2019 experiment), a second experiment was established at the same location (Curepto) to compare the best agronomic management derived from the first experiment (2018 experiment) with the current practices of farmers at the field scale. For this, a demonstration plot (DP) was compared with the practices used by four Farmers located near to the DP (same soil and climatic conditions). Farmers employed different agronomic management practices that varied mainly in the amount of water, the irrigation system, and the dose of N applied throughout season. For the DP an area of 2,500 m² was sown on 28 Oct 2019 with the Zorzal cultivar, fertilized with a dose of 90 kg N ha^–1, and irrigated with 4,800 m³ ha^–1 using drip irrigation tapes. The sowing dose of Farmer 1 was 80 kg of seed ha^–1 applying 9,000 m³ ha^–1 of water by the furrow irrigation system and a total N dose of 130 kg N ha^–1 as urea. Farmer 2 applied 138 kg N ha^–1 and 2,000 m³ ha^–1 with a subsurface drip irrigation (SDI) system. Farmer 3 fertilized with 46 kg N ha^–1 and used a furrow irrigation system, applying 5,000 m³ ha^–1. Finally, Farmer 4 applied 51 kg N ha^–1 and 2,000 m³ ha^–1 of water with a sprinkler irrigation system (SIS) (Table 1). For the DP, the soil preparation, basal P and K fertilization, and weed management were as previously described for the 2018 experiment. Moreover, the soil preparation, basal fertilization, cultivar (only Zorzal), plant density (18 plants m^–2), weed control, and previous crop (wheat in all cases) were similar for all four farmers. The main chemical characteristics of the soils varied from field to field, where the soil of Farmer 4 showed the lowest fertility level (Table 2). The sowing date for the four farmers was on 28 Oct 2019.

Table 1
Nitrogen fertilization and irrigation management used by four farmers relative to the agronomic management proposed in the demonstrative plot in the season 2019/20.

Site	Coordinates	N fertilization	Irrigation system	Total water applied
		kg ha–1		m3 ha–1
DP	34°59’30" S, 72°01’0" W, altitude 15 m	90	Drip tape	4,800
Farmer 1	34°59’30" S, 72°01’0" W, altitude 15 m	130	Furrow	9,000
Farmer 2	35°02’14" S, 72°03’27" W, altitude 25 m	138	Subsurface drip	2,000
Farmer 3	35°02’58" S, 72°04’53" W, altitude 30 m	46	Furrow	5,000
Farmer 4	35°05’10" S, 72°01’24" W, altitude 20 m	51	Sprinkler	2,000

• DP = demonstration plot.

Table 2
Soil chemical characteristics of the experimental sites in Curepto, Maule Region, Chile.

Site	Available			SOM	Exchangeable cations
	N	P	K		pHw 1:2.5	K	Ca	Mg	Na
	mg kg–1			%		------------------------- cmol(+) kg–1 -------------------------
Experiment 2018	15	13	238	1.0	6.4	0.6	6.2	1.5	0.15
DP and Farmer 1	3	40	489	1.5	6.0	1.3	6.9	1.9	0.17
Farmer 2	10	23	188	1.3	5.9	0.5	5.4	1.9	0.15
Farmer 3	8	38	450	2.3	6.1	1.2	8.8	2.9	0.16
Farmer 4	6	7	57	0.9	5.7	0.1	5.1	2.5	0.10

• DP = demonstration plot; SOM = soil organic matter; pHw 1:2.5 = pH determined in water with a soil to solution ratio of 1 to 2.5.

Harvest index (HI) and GY were obtained for the DP and the four farmers by randomly harvesting 12 rows of 1 m in different locations at each site on 15 Feb 2020.

Phenotyping measurements

In the 2018 experiment, the N content in leaves at full flowering, the canopy coverage (CC), normalized differential vegetation index (NDVI), GY, and HI were scored. After harvest, the morphological, nutritional, and mineral composition of the grains were determined. Furthermore, 100-seed weight (100SW) was measured, and the percentage of defective grains (PDG) was accounted visually as shrunk and stained grains. The NDVI was measured using a portable spectroradiometer sensor (GreenSeeker, Trimble) with data collected at 660 nm (red) and 760 nm (near-infrared) wavelengths. Data was collected from the central rows of each experimental plot, from the vegetative to the reproductive stages of the common bean. The resulting NDVI values were plotted as a function of days after sowing (DAS). The CC was estimated from RGB images collected at different dates throughout the growing season using the Sony® model DSC-H300 digital camera. To quantify color-related traits, images from each plot were processed using the CerealScanner plugin (https://gitlab.com/sckefauver/cerealscanner) (Kefauver et al., 2017). Fully expanded leaves (R6 stage) were sampled from four plants per plot and analyzed for total N content using the Kjeldahl method (Sadzawka et al., 2007).

Morphological and physical properties

To determine the average grain size of each cultivar, samples of 56 units were randomly selected and placed vertically and horizontally on a glass slide (Muñoz et al., 2012). Morphological analysis of grains was conducted using a Leica S8 APO stereomicroscope equipped with a high-resolution MC 170 HD digital camera. The images were processed using ImageJ analysis platform (Schneider et al., 2012) to determine the length (L), width (W), thickness (T), geometric diameter (Dg), sphericity (Φ), and surface area (S) of the grains according to Tunde-Akintunde and Akintunde (2004).

Elemental and protein composition

Elemental grain composition was determined according to Sadzawka et al. (2007). Briefly, common bean grains were dried in an oven at 65 °C and milled. Then, the samples were digested with HNO₃ to measure the Ca, K, Mg, Mn, Zn, Cu, and Fe content by AAS (Agilent® 280FS AA). Total N was determined by an elemental analyzer (TruSpec Leco®). The B and P contents were determined by colorimetry (Agilent® Cary 8454 UV-Vis spectrophotometer) following the vanadate molybdate method and the azomethine-H method, respectively. The protein content (PC) was estimated by multiplying the N content by a factor of 6.25 (MacLean et al., 2003).

Data analysis

In the 2018 experiment, partial least squares discriminant analysis (PLS-DA) and variable importance in the projection (VIP) were determined and plotted using the online MetaboAnalyst 5.0 software (https://www.metaboanalyst.ca/). A multivariate analysis of variance (MANOVA) was carried out to evaluate the effects of irrigation, N dose, and cultivars on the traits evaluated. The Tukey test (p < 0.05) was carried out to determine significant differences between the means. In the 2019 experiment, the farmer was considered the only factor and was analyzed accordingly using one-way ANOVA. Statistical analyses were carried out using StatPlus® Software, and graphics were drawn in GraphPad Prism® v10.

Results

For the 2018 experiment, PLS-DA revealed that irrigation discriminated against cultivars only partially (Figure 2A) and that the N dose was unable to differentiate cultivars under the distinct water regimes evaluated (Figure 2B). However, PLS-DA revealed clear separation between the common bean cultivars under study (Figure 2C), with components 1 and 2 explaining 27.8 % and 30.8 % of the observed variability, respectively. Based on a VIP score of discriminant analysis comparing cultivars, the 15 most important variables in component 1 were P, GY, sphericity, Mn, Ca, length, Zn, Fe, N, PC, stained grains, Cu, shrunk grains, K and 100SW (Figure 2D).

Figure 2

Partial least squares discriminant analysis (PLS-DA) for common bean cultivars: Zorzal, Torcaza, Blanco Español (BE), and Curi. PLS-DA: A) for irrigation (SI = standard irrigation and DI = deficit irrigation); B) for N dose (120 N = 120 kg N ha^–1 and 90 N = 90 kg ha^–1); C) for cultivars; and D) variable importance in the projection (VIP) plot for common beans cultivars, red and blue colors indicate an increase or decrease in the variable evaluated, respectively.

The morphological and agronomic traits were affected by the different treatments and their interaction (Table 3). The average GY ranged from 0.9 to 4.2 Mg ha^–1 in the Curi and Zorzal cultivars, respectively (Figure 3A). The highest GY (4.7 Mg ha^–1) was achieved with the Zorzal cultivar applying SI and 120 kg N ha^–1. However, both nitrogen doses tested (90 and 120 kg N ha^–1) resulted in similar GY for the common bean cultivars evaluated. The high GY was also related to the grain weight, which was ∼50 g per 100 grains for Torcaza, Zorzal, and Blanco Español, whereas Curi produced smaller grains of ∼20 g per 100 grains (Figure 3B; Table 3). Moreover, the Torcaza and Zorzal cultivars had the longest seeds with ∼12 mm, while Curi had the shortest with 9 mm. The Blanco Español had the widest seeds (8.4 mm) and sphericity (Φ = 0.79 %), followed by the Zorzal (7.8 mm, Φ = 0.71 %), Torcaza (7.6 mm, Φ = 0.69 %), and Curi (6.1 mm, Φ = 0.70 %). The number of defective grains was 4.9 % (9.3 kg ha^–1), 3.5 % (26.1 kg ha^–1), 2.0 % (38.5 kg ha^–1), and 1.3 % (27.8 kg ha^–1) in Curi, Blanco Español, Torcaza, and Zorzal, respectively (Figure 3C).

Table 3
Morphological and agronomical properties of grains of Phaseolus vulgaris L. grown under different water and N management in Curepto, Maule Region, Chile.

Treatment	Cultivars	Morphologic						Agronomic
		Length	Width	Thickness	Dg	Φ	S	GY	100SW
		------------------------------------------------ mm -----------------------------------------------						Mg ha–1	g
SI + 90 N	Curi	8.9	5.9	4.4	6.4	0.7	117.6	0.60	20.2
	BE	11.0	8.4	7.2	8.9	0.8	240.4	1.52	47.8
	Torcaza	11.9	7.4	6.3	8.5	0.7	211.8	3.59	52.8
	Zorzal	12.0	7.5	6.3	8.6	0.7	216.2	4.25	51.3
SI + 120 N	Curi	9.2	6.3	4.9	6.8	0.7	133.6	1.18	20.9
	BE	10.7	8.1	7.2	8.7	0.8	229.5	1.24	51.2
	Torcaza	12.3	7.7	6.6	8.9	0.7	228.5	3.80	52.4
	Zorzal	12.1	7.7	6.6	8.8	0.7	226.5	4.47	52.1
DI + 90 N	Curi	8.9	6.2	4.5	6.5	0.7	123.9	0.69	20.2
	BE	11.6	8.6	7.6	9.2	0.8	260.1	1.33	49.3
	Torcaza	12.5	7.5	6.6	8.9	0.7	227.5	3.51	53.0
	Zorzal	11.4	7.3	6.4	8.4	0.7	206.0	4.14	51.9
DI + 120 N	Curi	8.9	6.0	4.3	6.4	0.7	116.7	1.17	20.7
	BE	11.4	8.5	7.4	9.1	0.8	251.3	1.72	50.1
	Torcaza	12.2	7.7	6.6	8.8	0.7	228.4	3.71	52.1
	Zorzal	12.8	8.5	7.4	9.6	0.7	271.6	4.27	52.6
Mean Irrigation	Standard	11.0	7.4	6.2	8.2	0.7	200.5	2.58	43.6
	Deficit	11.2	7.5	6.3	8.4	0.7	210.7	2.57	43.7
Mean N dose	90 kg ha–1	11.0	7.4	6.2	8.2	0.7	200.4	2.46	43.3
	120 kg ha–1	11.2	7.6	6.4	8.4	0.7	210.7	2.69	44.0
Mean Cultivars	Curi	9.0	6.1	4.5	6.5	0.7	122.9	0.91	20.5
	BE	11.2	8.4	7.4	9.0	0.8	245.3	1.45	49.6
	Torcaza	12.2	7.6	6.5	8.8	0.7	224.0	3.66	52.6
	Zorzal	12.1	7.8	6.7	8.8	0.7	230.1	4.28	51.9
SoV	Irrigation (I)	*	*	*	*	NS	*	NS	NS
	N dose (N)	*	*	*	*	*	*	NS	*
	Cultivars (C)	*	*	*	NS	*	*	*	*
	I × N	NS	NS	NS	NS	NS	NS	NS	NS
	I × C	*	NS	*	*	*	*	NS	NS
	N × C	*	*	*	*	NS	*	NS	*
	I × N × C	*	*	*	*	*	*	NS	NS

• Dg = geometric diameter; Φ = sphericity; S = surface area; GY = grain yield; 100SW = 100-seed weight; SI = standard irrigation; DI = deficit irrigation; 90 N = 90 kg N ha^–1; 120 N = 120 kg N ha^–1; BE = Blanco Español; SoV = source of variation;
• ^*
  Significant at p < 0.05; NS = Not significant.

Figure 3

A) Grain yields, (B) weight of 100 grains, (C) protein content of seeds, and (D) total of defective grains of the four Phaseolus vulgaris L. cultivars grown under two water supply regimes and two N levels. Dots (in A, B, and C) represent the values obtained in each plot. The average of all treatments was calculated. Statistical differences are shown after an ANOVA analysis; different letters indicate differences between treatments after the Tukey test (p < 0.05). BE = Blanco Español.

The amount of water applied (p < 0.05) and the cultivars (p < 0.05) affected the elemental and PC of grains (Table 4). Overall, the Blanco Español and Curi have a higher elemental composition than the cultivars of the Tórtola type. The Blanco Español has the highest content in N (36.9 g kg^–1), P (5.3 g kg^–1), Ca (1.6 g kg^–1), Mg (16.3 mg kg^–1), and Zn (42.7 mg kg^–1), and the lowest contents in K (17.9 g kg^–1) and Cu (10.4 mg kg^–1). The Tórtola type had high contents only in K (18.9 g kg^–1 in Zorzal) and Cu (11.2 and 12.0 mg kg^–1 in Zorzal and Torcaza, respectively). Interestingly, the content of all elements and PC increased with the DI treatment, except for the B content which decreased. The average PC for each cultivar ranged between 22.7 % and 24.9 % for Zorzal and Blanco Español, respectively (Figure 3D). The highest PC was obtained in the cultivar Blanco Español (26.0 g 100 g^–1) with DI and 120 kg N ha^–1, while the lowest PC was obtained in the cultivar Zorzal (21.2 g 100 g^–1) with SI and 120 kg N ha^–1.

Table 4
Elemental composition and protein content (PC) of grains of Phaseolus vulgaris L. grown in the 2018 experiment under different water and N management.

Treatment	Cultivars	Elemental composition										PC
		N	P	K	Ca	Mg	Mn	Zn	Cu	Fe	B
		-------------------------- g kg–1 ---------------------------					------------------------- mg kg–1 -------------------------					g 100 g–1
SI + 90 N	Curi	34.1	5.2	18.7	1.5	2.0	15.0	35.3	10.2	69.2	14.3	23.0
	BE	35.6	5.3	17.5	1.4	1.7	16.7	41.0	10.4	73.9	12.7	24.0
	Torcaza	33.0	4.2	18.1	0.7	1.7	13.7	36.1	11.8	68.1	12.3	22.2
	Zorzal	31.8	4.2	18.4	1.5	1.8	12.3	35.9	10.7	66.3	15.7	21.5
SI +120 N	Curi	34.3	4.9	17.6	1.4	1.9	15.3	34.1	10.4	79.1	14.4	23.1
	BE	35.7	5.1	17.4	1.3	1.7	16.9	41.0	10.3	72.5	12.6	24.0
	Torcaza	34.7	4.2	18.1	0.7	1.6	14.5	36.2	11.9	68.1	11.1	23.4
	Zorzal	31.5	4.3	18.8	1.3	1.8	12.8	35.7	11.0	65.8	14.4	21.2
DI + 90 N	Curi	37.4	5.1	19.3	1.5	2.1	17.6	38.1	10.3	75.2	12.2	25.2
	BE	37.9	5.4	18.2	1.8	1.9	14.9	44.4	11.1	75.2	11.2	25.6
	Torcaza	38.2	4.7	18.3	1.0	1.8	12.7	40.9	12.0	69.9	11.6	25.8
	Zorzal	34.7	4.3	19.1	1.0	1.8	15.2	38.2	11.4	68.2	11.2	23.4
DI + 120 N	Curi	37.5	5.1	19.0	1.4	2.0	16.8	38.5	11.3	73.9	13.4	25.3
	BE	38.6	5.5	18.4	1.7	1.9	16.1	44.0	10.0	72.9	10.6	26.0
	Torcaza	37.7	4.6	18.1	1.2	1.9	13.0	39.6	12.0	71.1	11.6	25.4
	Zorzal	36.8	4.5	19.2	0.8	1.8	15.3	40.0	11.5	70.5	11.6	24.8
Mean Irrigation	Standard	33.8	4.7	18.1	1.3	1.8	14.7	36.9	10.9	70.4	13.4	22.81
	Deficit	37.3	4.9	18.7	1.3	1.9	15.2	40.5	11.2	72.1	11.6	25.17
Mean Cultivars	Curi	35.8	5.0	18.6	1.4	2.0	16.1	36.4	10.5	74.4	13.5	24.13
	BE	36.9	5.3	17.9	1.6	1.8	16.3	42.7	10.4	73.6	11.7	24.91
	Torcaza	35.9	4.4	18.1	0.9	1.8	13.5	38.2	12.0	69.3	11.6	24.21
	Zorzal	33.7	4.3	18.9	1.2	1.8	13.8	37.4	11.2	67.8	13.3	22.73
SoV	Irrigation (I)	*	*	*	NS	*	NS	*	NS	NS	*	*
	N dose (N)	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
	Cultivars (C)	*	*	*	*	*	*	*	*	*	*	*
	I × N	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
	I × C	NS	NS	NS	*	*	*	*	NS	NS	*	NS
	N × C	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS
	I × N × C	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS	NS

• SI = standard irrigation; DI = deficit irrigation; 90 N = 90 kg N ha^–1; 120 N = 120 kg N ha^–1; BE = Blanco Español; SoV = source of variation.
• ^*
  Significant at p < 0.05; NS = Not significant.

The NDVI values did not differ clearly across the four evaluated bean cultivars. This parameter increased rapidly until 50 DAS, reaching a peak value of 0.8 at 75 DAS, then decreased (Figure 4). The CC followed a slightly different response pattern, increasing progressively during the growth period, reaching its maximum value at 75 DAS, followed by a subsequent rapid decline attributed to the senescence process. The CC values showed differences between the cultivars; Torcaza and Zorzal reached a CC of approximately 80 % at 85 DAS, and then declined. The Blanco Español reached 80 % of CC, but it started to decline at 75 DAS. For Curi, the CC had a maximum value of 60 % and started to decrease at 75 DAS (Figure 5). These results indicate that CC failed to achieve full saturation in all cases; therefore, a higher plant density should be used, for instance, using 50 cm of row spacing.

Figure 4

Normalized difference vegetation index (NDVI) of four Phaseolus vulgaris L. cultivars grown under two different water supply regimes and two N levels. Standard irrigation: 5,400 m³ ha^–1 of water; Deficit irrigation: 4,200 m³ ha^–1 of water. Bars represent the standard error of mean (n = 4). BE = Blanco Español.

Figure 5

Canopy coverage of four Phaseolus vulgaris L. cultivars grown under two different water supply regimes and two N levels. Standard irrigation: 5,400 m³ ha^–1 of water; Deficit irrigation: 4,200 m³ ha^–1 of water. Bars represent the standard error of mean (n = 4). BE = Blanco Español.

In the second experiment (2019), the DP was established to compare the GY and HI values against those obtained by the farmers (Figure 6). In the DP, GY reached 4 Mg ha^–1 with an N dose of 90 kg ha^–1, while the highest GY (5.4 Mg ha^–1) was obtained by Farmer 1 using an N dose of 130 kg ha^–1 and almost twice (9,000 m³ ha^–1) the amount of water used in the DP. The GY values obtained by Farmers 3 and 4 were 2.1 and 1.4 Mg ha^–1, respectively. The HI values ranged from 0.4 (Farmer 4) to 0.52 (Farmer 3), while the HI achieved in the DP was 0.43. The nitrogen use efficiency (NUE) was higher in the trial established by Farmer 3 (45.65 kg kg^–1), although it was similar to that of DP (44.44 kg kg^–1). On the other hand, the agronomic management implemented by Farmer 4 resulted in the lowest NUE (27.45 kg kg^–1). As regards water use efficiency (WUE), Farmer 2 had the highest WUE (1.95 kg m^–3), followed by DP (0.83 kg m^–3), and the lowest WUE was by Farmer 3 (0.42 kg m^–3) (Table 5).

Figure 6

Grain yield (GY) and harvest index (HI) for a demonstration plot (DP) at field scale compared with the GY and HI values of four farmers. Statistical differences are indicated after the ANOVA analysis, with different letters denoting significant differences among treatments followed the Tukey test (p < 0.05).

Table 5
Nitrogen use efficiency (NUE) and water use efficiency (WUE) among the four farmers and the demonstration plot (DP).

Site	GY	N fertilization	NUE	Total water applied	WUE
	Mg ha–1	kg ha–1	kg kg–1	m3 ha–1	kg m–3
DP	4.0	90	44.44	4,800	0.83
Farmer 1	5.4	130	41.53	9,000	0.60
Farmer 2	3.9	138	28.26	2,000	1.95
Farmer 3	2.1	46	45.65	5,000	0.42
Farmer 4	1.4	51	27.45	2,000	0.70

• GY = grain yield.

In the 2019 experiment, the N concentration of grains was around 3 % for the DP and Farmers 1, 2 and 3, while 4.4 % was reached by Farmer 4 (Table 6). The P concentration in grains was ∼0.5 % for DP and Farmers 1 and 2, decreasing to 0.4 and 0.3 % in the grains from Farmers 3 and 4, respectively. The K concentration of grains was generally stable (1.6 to 1.7 %) among farmers, except for Farmer 4, who recorded only 1.3 %. Similarly, the concentration of Mg and Ca was conserved for all plots, although the grains from Farmer 4 also had a lower concentration. In general, the nutrient concentration in grains was not affected by the N dose applied by farmers (Table 6).

Table 6
Elemental composition of grains of Phaseolus vulgaris L. cultivated by different farmers using distinct N fertilization and irrigation management in Curepto, Maule Region, Chile.

Field	N	P	K	Ca	Mg	Mn	Zn	Cu	Fe	B
	--------------------------------- g kg–1 ---------------------------------					--------------------------------- mg kg–1 ---------------------------------
DP	30.3 a	4.7 bc	16.2 b	2.0 a	1.8 bc	11.50a	40.75 b	10.50 b	58.25 a	11.00 a
Farmer 1	29.2 a	5.0 ab	16.7 ab	2.1 ab	2.0 ab	12.25 a	38.50 b	11.00 b	59.25 a	17.75 a
Farmer 2	29.4 a	5.3 a	17.3 a	1.9 ab	2.0 a	11.50 ab	48.25 a	14.50 a	53.75 a	8.75 a
Farmer 3	29.6 a	4.3 c	16.4 ab	1.8 ab	1.8 c	9.50 b	40.25 b	10.50 b	64.75 a	14.00 a
Farmer 4	43.9 b	3.1 d	13.3 c	1.5 b	1.6 c	10.25 b	44.50 ab	9.50 b	56.00 a	9.00 a

• DP = demonstration plot. Different letters denote differences between farmers (Tukey, p < 0.05).

Discussion

Results from the 2018 experiment indicate that cultivar, irrigation, and N fertilization affect most parameters evaluated in this study differently. The N fertilization rate marginally affected the morphological and agronomic responses but did not impact grain composition, NDVI, and CC parameters. Irrigation affected the elemental composition and had a marginal impact on morphological and agronomic parameters. Cultivar was the most important factor and affected most of the parameters evaluated. In relation to this the Tórtola cultivars (Torcaza and Zorzal) exhibited the highest GY, which agrees with the literature (Martínez-Barradas et al., 2024). The fact that the GY of the evaluated cultivars reached 4.47 Mg ha^–1 in this experiment is quite remarkable since the average GY in the world and Chile were 0.77 and 1.71 Mg ha^–1 in 2022 (FAO, 2023), respectively. This yield gap may be because in Chile, the common bean is typically grown under irrigation, whereas in many other regions of the world, it is grown under rainfed conditions (Mukeshimana et al., 2014). Additionally, the yields achieved by Farmer 1 (5.4 Mg ha^–1) were quite surprising since they represent more than three to six times the global and Chilean average common bean yield, respectively. Considering that 45 % of Chilean bean production is produced under Mediterranean conditions, the use of Tórtola beans (specifically the Zorzal variety) is an important opportunity for Chilean farmers and those from other Mediterranean regions to achieve higher yields. However, further experimentation is needed to understand how the use of specific genotypes, the environment (temperatures, radiation, soils), and their interactions make this Mediterranean area of Chile a "hotspot" for Tórtola bean production.

Grain morphology-related traits are important to crop production, as they provide information on the harvesting tools to be used, as well as for the selection of appropriate separation and/or classification systems (Razavi et al., 2010; Tunde-Akintunde and Akintunde, 2004). Furthermore, grain morphology influences marketing and consumer acceptance (Affrifah et al., 2023). The seed length, width, and thickness were influenced by the irrigation (I), nitrogen (N) dose, and cultivar (C) treatments and their interaction, except for the I × N interaction. These results agree with those obtained by Sezen et al. (2008), where the seed length, width, and weight of beans were affected by different irrigation frequencies and amounts of water applied.

Nutritionally, common beans are recognized as a good source of protein and other nutrients that are essential to the human diet (Hayat et al., 2013). The irrigation and cultivar treatments influenced the elemental and protein content. DI led to an increase in elemental and protein content, which is typically influenced by genotype/cultivar and growing environment (Hall et al., 2017). Protein is one of the most important nutrients in beans, providing approximately 30 % of the total daily protein intake in developing countries (Labastida et al., 2023). In this study, the protein content ranged from 21.2 to 26 % for the cultivars under different agronomic management, which agrees with the values previously reported for various types of beans (Hall et al., 2017; Hayat et al., 2013). Finally, Tórtola beans demonstrated good nutritional quality, which could be further improved through the appropriate use of water management, resulting in higher yields through more sustainable agronomic practices.

The CC is a vegetation index that is related to N nutrition and the capacity of plants to compete for resources (Jones et al., 2003). In this study, the CC values reached about 80 % at 85 DAS for Torcaza and Zorzal cultivars. Traditionally, in central Chile, common beans are sown at a distance of 75 cm between rows using maize sowing equipment, resulting in a planting density of 180,000 plants ha^–1. Therefore, increasing the planting density to 225,000 plants ha^–1 could reach 100 % of CC and result in higher yields; however, this needs to be validated in future studies. Denser plantings of up to 250,000 plants ha^–1 have resulted in a 30-70 % increase in GY and a reduction in weed biomass (Dusabumuremyi et al., 2014; Merga, 2020).

N nutrition is a key agronomic practice that can increase yields in common beans, since the ability to fix atmospheric N₂ symbiotically is limited. The two N doses tested in the 2018 experiment produced no differences in bean yields. This could probably be attributed to soil N mineralization, which can release around 40 kg N ha^–1 in Mediterranean irrigated sites (Salazar et al., 2020). Based on these results, in the 2019 experiment, a dose of 90 kg N ha^–1 was applied in the DP. Farmer 1 obtained the highest GY (5.4 Mg ha^–1), applying 130 kg N ha^–1 and a total of 9,000 m³ ha^–1 of water. However, the NUE was lower than in DP, where 90 kg N ha^–1 was used. Farmer 2 exhibited the highest NUE, with a N dose of 138 kg N ha^–1, attaining a grain yield similar to that of the DP, while using only half of the irrigation water. Therefore, a positive relationship between the amount of water applied and GY was found, which has been widely documented (Karavidas et al., 2022). On the other hand, the content of nutrients in the grains is not greatly affected by the dose of N applied by the different farmers. The elemental composition in grains of common beans was in the normal range previously reported for Chilean bean cultivars (Paredes et al., 2009).

In addition to the dose of N, the amount of water applied in bean production is a fundamental aspect to consider (Ntatsi et al., 2018). In the 2018 experiment, decreasing the amount of water applied did not affect the GY in any of the common bean cultivars evaluated. Regarding this, our results suggests that a more efficient use of water is possible by introducing drip irrigation systems that are more efficient than gravity-based ones (Sugita et al., 2017). On the other hand, the elemental content of grains was affected by the amount of water applied, which increased the content of several grains. Therefore, the use of an irrigation system that allows for a reduction in the water usage without affecting the GY (Mathobo et al., 2017) and that also increases the nutrient content of beans is highly recommendable.

A GY of 4 Mg ha^–1 was obtained in the DP using 90 kg N ha^–1 and 4,800 m³ ha^–1 of water, while Farmer 1 obtained 5.4 Mg ha^–1 of GY using double the amount of water and a 44 % higher N dose. The effectiveness of reducing the amount of water applied was confirmed by Farmer 2, who obtained a GY of 3.9 Mg ha^–1 by applying 2,000 m³ ha^–1 with an underground drip irrigation system. However, the N supply was 53 % higher than in DP. The incorporation of drip irrigation in Tórtola bean production is highly advisable for dealing with the decreasing rainfalls recorded in the Mediterranean regions of Central Chile in recent seasons (FAO, 2022). For example, using a drip irrigation system combined with manure mulch saved 15 % of the irrigation water applied without reducing the GY in beans (Abd El-Wahed et al., 2017).

This work highlights the scarcity of bean studies in Mediterranean areas and the agronomic and nutritional potential of Tórtola type beans for these areas. Our results indicated that by adjusting agronomic practices such as the N dose to 90 kg ha^–1, the amount of water to 4,800 m³, and implementing a drip irrigation system, it is possible to increase GY and its nutritional content. A more sustainable production system is possible in the Mediterranean regions of central Chile, since the amount of N applied does not have a significant impact on grain yield. Therefore, decreasing the amount of N applied allows for greater economic gains and reduces the amount of N released to surface waters. The Tórtola type beans, specifically the Zorzal variety, are highly recommended for bean production in central Chile. Finally, given the current nutritional requirements of consumers, it is essential to conduct further research to enhance the adaptability of common beans to water scarcity and improve their nutritional quality.

• Declaration of use of AI Technologies
  No AI Technologies were used in the writing of this article.

Data availability statement

The data that support the findings of this study are available from the corresponding author on request.

Acknowledgments

The authors would like to thank Instituto de Investigaciones Agropecuarias (INIA Chile) for providing the seeds used in these experiments. This work was part of the Master Thesis in Horticulture of R.A. This research was funded by Agencia Nacional de Investigación y Desarrollo (ANID) FONDECYT Project N° 1201050 and Fortalecimiento Científico de los Centros Regionales ANID, Proyecto R20F0001.

References

• Abd El-Wahed MH, Baker GA, Ali MM, Abd El-Fattah FA. 2017. Effect of drip deficit irrigation and soil mulching on growth of common bean plant, water use efficiency and soil salinity. Scientia Horticulturae 225: 235-242. https://doi.org/10.1016/j.scienta.2017.07.007
  » https://doi.org/10.1016/j.scienta.2017.07.007
• Affrifah NS, Uebersax MA, Amin S. 2023. Nutritional significance, value-added applications, and consumer perceptions of food legumes: a review. Legume Science 5: e192. https://doi.org/10.1002/leg3.192
  » https://doi.org/10.1002/leg3.192
• Albornoz F. 2016. Crop responses to nitrogen overfertilization: a review. Scientia Horticulturae 205: 79-83. https://doi.org/10.1016/j.scienta.2016.04.026
  » https://doi.org/10.1016/j.scienta.2016.04.026
• Arriagada O, Arévalo B, Pacheco I, Schwember AR, Meisel LA, Silva H, et al. 2024. A past genetic bottleneck from Argentine beans and a selective sweep led to the race Chile of the common bean (Phaseolus vulgaris L.). International Journal of Molecular Sciences 25: 4081. https://doi.org/10.3390/ijms25074081
  » https://doi.org/10.3390/ijms25074081
• Broughton WJ, Hernández G, Blair M, Beebe S, Gepts P, Vanderleyden J. 2003. Beans (Phaseolus spp.): model food legumes. Plant and Soil 252: 55-128. https://doi.org/10.1023/A:1024146710611
  » https://doi.org/10.1023/A:1024146710611
• Díaz GA, Cabeza RA, Amigo R, Llancamil E, Montenegro O, González P, et al. 2021. Severe outbreak of Fusarium wilt on common beans (Phaseolus vulgaris caused by Fusarium oxysporum in the Maule Region, central Chile. Plant Disease 105: 2725. https://doi.org/10.1094/PDIS-12-20-2758-PDN
  » https://doi.org/10.1094/PDIS-12-20-2758-PDN
• Dusabumuremyi P, Niyibigira C, Mashingaidze AB. 2014. Narrow row planting increases yield and suppresses weeds in common bean (Phaseolus vulgaris L.) in a semi-arid agro-ecology of Nyagatare, Rwanda. Crop Protection 64: 13-18. https://doi.org/10.1016/j.cropro.2014.05.021
  » https://doi.org/10.1016/j.cropro.2014.05.021
• Food and Agriculture Organization [FAO]. 2022. GIEWS: Global Information and Early Warning System. FAO, Rome, Italy. Available at: https://www.fao.org/giews/countrybrief/country.jsp?code=CHL [Accessed Jan 25, 2023]
  » https://www.fao.org/giews/countrybrief/country.jsp?code=CHL
• Food and Agriculture Organization [FAO]. 2023. Statistical Databases - FAOSTAT. FAO, Rome, Italy. Available at: https://www.fao.org/faostat/en/#data/QCL [Accessed Jan 27, 2024]
  » https://www.fao.org/faostat/en/#data/QCL
• González-Miranda I, Vidal K, Peñaloza P. 2021. Comparing nitrate leaching in lettuce crops cultivated under agroecological, transition, and conventional agricultural management in central Chile. Chilean Journal of Agricultural Research 81: 210-219. https://doi.org/10.4067/S0718-58392021000200210
  » https://doi.org/10.4067/S0718-58392021000200210
• Hall C, Hillen C, Robinson JG 2017. Composition, nutritional value, and health benefits of pulses. Cereal Chemistry 94: 11-31. https://doi.org/10.1094/CCHEM-03-16-0069-FI
  » https://doi.org/10.1094/CCHEM-03-16-0069-FI
• Hayat I, Ahmad A, Masud T, Ahmed A, Bashir S. 2013. Nutritional and health perspectives of beans (Phaseolus vulgaris L.): an overview. Critical Reviews in Food Science and Nutrition 54: 580-592. https://doi.org/10.1080/10408398.2011.596639
  » https://doi.org/10.1080/10408398.2011.596639
• Jones HG, Archer N, Rotenberg E, Casa R. 2003. Radiation measurement for plant ecophysiology. Journal of Experimental Botany 54: 879-889. https://doi.org/10.1093/jxb/erg116
  » https://doi.org/10.1093/jxb/erg116
• Karavidas I, Ntatsi, G, Vougeleka V, Karkanis A, Ntanasi T, Saitanis C, et al. 2022. Agronomic practices to increase the yield and quality of common bean (Phaseolus vulgaris L.): a systematic review. Agronomy 12: 271. https://doi.org/10.3390/agronomy12020271
  » https://doi.org/10.3390/agronomy12020271
• Kefauver SC, Vicente R, Vergara-Díaz O, Fernandez-Gallego JA, Kerfal S, Lopez A, et al. 2017. Comparative UAV and field phenotyping to assess yield and nitrogen use efficiency in hybrid and conventional barley. Frontiers in Plant Science 8: 1733. https://doi.org/10.3389/fpls.2017.01733
  » https://doi.org/10.3389/fpls.2017.01733
• Labastida D, Ingvarsson PK, Rendon-Anaya M. 2023. Dissecting the genetic basis of drought responses in common bean using natural variation. Frontiers in Plant Science 14: 1143873. http://doi.org/10.3389/fpls.2023.1143873
  » http://doi.org/10.3389/fpls.2023.1143873
• MacLean WC, Harnly JM, Chen J, Chevassus-Agnes S, Gilani G, Livesey G, et al. 2003. Food Energy: Methods of Analysis and Conversion Factors. FAO, Rome, Italy. (Food and Nutrition Paper, 77).
• Martínez-Barradas V, Inostroza-Blancheteau C, Tighe-Neira R, Romero-Romero JL, Schwember AR, Arce-Johnson P. 2024. Drought tolerance evaluation of ‘Zorzal,’ the most cultivated common bean in Chile, a country facing desertification. Agricultural Research 13: 41-52. https://doi.org/10.1007/s40003-023-00679-2
  » https://doi.org/10.1007/s40003-023-00679-2
• Mathobo R, Marais D, Steyn JM. 2017. The effect of drought stress on yield, leaf gaseous exchange and chlorophyll fluorescence of dry beans (Phaseolus vulgaris L.). Agricultural Water Management 180: 118-125. https://doi.org/10.1016/j.agwat.2016.11.005
  » https://doi.org/10.1016/j.agwat.2016.11.005
• Merga JT. 2020. Evaluation of common bean varieties (Phaseolus vulgaris L.) to different row-spacing in Jimma, south western Ethiopia. Heliyon 6: e04822. https://doi.org/10.1016/j.heliyon.2020.e04822
  » https://doi.org/10.1016/j.heliyon.2020.e04822
• Mukeshimana G, Lasley AL, Loescher WH, Kelly JD. 2014. Identification of shoot traits related to drought tolerance in common bean seedlings. Journal of the American Society for Horticultural Science 139: 299-309. https://doi.org/10.21273/JASHS.139.3.299
  » https://doi.org/10.21273/JASHS.139.3.299
• Muñoz LA, Cobos A, Diaz O, Aguilera JM. 2012. Chia seeds: microstructure, mucilage extraction and hydration. Journal of Food Engineering 108: 216-224. https://doi.org/10.1016/j.jfoodeng.2011.06.037
  » https://doi.org/10.1016/j.jfoodeng.2011.06.037
• Ntatsi G, Gutiérrez-Cortines ME, Karapanos I, Barros A, Weiss J, Balliu A, et al. 2018. The quality of leguminous vegetables as influenced by preharvest factors. Scientia Horticulturae 232: 191-205. https://doi.org/10.1016/j.scienta.2017.12.058
  » https://doi.org/10.1016/j.scienta.2017.12.058
• Paredes M, Becerra V, Tay J. 2009. Inorganic nutritional composition of common bean (Phaseolus vulgaris L.) genotypes race Chile. Chilean Journal of Agricultural Research 69: 486-495. https://doi.org/10.4067/S0718-58392009000400002
  » https://doi.org/10.4067/S0718-58392009000400002
• Pinheiro A, Ivanovic C, Rodríguez L. 2018. Legume consumption in Chile: perspectives and challenges. Revista Chilena de Nutrición 45: 14-20 (in Spanish, with abstract in English). http://doi.org/10.4067/S0717-75182018000200014
  » http://doi.org/10.4067/S0717-75182018000200014
• Razavi SM, Bostan A, Rezaie M. 2010. Image processing and physico-mechanical properties of basil seed (Ocimum basilicum Journal of Food Process Engineering 33: 51-64. http://doi.org/10.1111/j.1745-4530.2008.00259.x
  » http://doi.org/10.1111/j.1745-4530.2008.00259.x
• Sadzawka A, Carrasco MA, Demanet R, Flores H, Grez R, Mora ML, et al. 2007. Métodos de análisis de tejidos vegetales. 2ed. Instituto de Investigaciones Agropecuarias, Santiago de Chile, Chile. (Serie Actas INIA, 40) (in Spanish).
• Salazar O, Casanova M, Nájera F, Contreras A, Tapia Y. 2020. Net nitrogen mineralization in maize-cover crop rotations in Mediterranean central Chile. Journal of Soil Science and Plant Nutrition 20: 1042-1050. http://doi.org/10.1007/s42729-020-00191-4
  » http://doi.org/10.1007/s42729-020-00191-4
• Satriani A, Loperte A, Soldovieri F. 2015. Integrated geophysical techniques for sustainable management of water resource. A case study of local dry bean versus commercial common bean cultivars. Agricultural Water Management 162: 57-66. http://doi.org/10.1016/j.agwat.2015.08.010
  » http://doi.org/10.1016/j.agwat.2015.08.010
• Schneider CA, Rasband WS, Eliceiri KW. 2012. NIH Image to ImageJ: 25 years of image analysis. Nature Methods 9: 671-675. http://doi.org/10.1038/nmeth.2089
  » http://doi.org/10.1038/nmeth.2089
• Sezen SM, Yazar A, Akyildiz A, Dasgan HY, Gencel B. 2008. Yield and quality response of drip irrigated green beans under full and deficit irrigation. Scientia Horticulturae 117: 95-102. http://doi.org/10.1016/j.scienta.2008.03.032
  » http://doi.org/10.1016/j.scienta.2008.03.032
• Soil Survey Staff. 2022. Keys to Soil Taxonomy. 13ed. USDA-NRCS, Washington, DC, USA.
• Sugita M, Matsuno A, El-Kilani RMM, Abdel-Fattah A, Mahmoud MA. 2017. Crop evapotranspiration in the Nile Delta under different irrigation methods. Hydrological Sciences Journal 62: 1618-1635. http://doi.org/10.1080/02626667.2017.1341631
  » http://doi.org/10.1080/02626667.2017.1341631
• Trucchi E, Benazzo A, Lari M, Iob A, Vai S, Nanni L, et al. 2021. Ancient genomes reveal early Andean farmers selected common beans while preserving diversity. Nature Plants 7: 123-128. http://doi.org/10.1038/s41477-021-00848-7
  » http://doi.org/10.1038/s41477-021-00848-7
• Tunde-Akintunde TY, Akintunde BO. 2004. Some physical properties of sesame seed. Biosystems Engineering 88: 127-129. http://doi.org/10.1016/j.biosystemseng.2004.01.009
  » http://doi.org/10.1016/j.biosystemseng.2004.01.009

Edited by

• Edited by:
  Mário Henrique Murad Leite Andrade

Publication Dates

• Publication in this collection
  21 Nov 2025
• Date of issue
  2025

History

• Received
  09 Oct 2024
• Accepted
  01 July 2025