SEED CHEMICAL COMPOSITION OF IMPROVED CHICKPEA CULTIVARS GROWN UNDER SEMIARID MEDITERRANEAN CONDITIONS

Abstract

The seed chemical composition and mineral element concentration were investigated in three improved (Jubeiha-1, Jubeiha-2, Jubeiha-3) and a local Jordanian chickpea cultivars. Seed protein, fat, glucose, sucrose, starch, P, Mg, Na, Mn, Fe, Cu, and Zn concentrations varied significantly among cultivars. Higher concentrations of fiber, starch, P, Na, Fe, Cu, and Zn in Jubeiha-1 seeds; while higher concentrations of protein, fat, fructose, K, Mg, and Mn, in Jubeiha-3 seeds in comparison with other cultivars were noted. The concentrations of seed protein, fat, fiber, ash, glucose, fructose, P, Ca, Mg, Na, and Cu were significantly affected by growing season. The cultivar x growing season interaction found to influence significantly all measured traits except seed starch and Na concentrations in the investigated chickpea cultivars. The investigated chickpea cultivars have different genetic backgrounds for almost all the chemical traits tested.

INTRODUCTION

Chickpea (Cicer arietinum L.) is the world's third most important grain legume after beans and peas [9]. It is grown in the Indian subcontinent, the Mediterranean Basin, East Africa, Mexico and Australia [10]. Chickpeas and other food legumes contribute significant amounts of protein, carbohydrate, vitamins, and minerals to the diets of people living in the Mediterranean region [4], [14].

Chickpea (Garbanzo or Bengal gram bean) cultivars are broadly divided into two groups, desi and kabuli. Kabuli seeds are large and light colored beans, and are characterized by larger size, ram-head shape and with low fiber content [15]. In the Mediterranean countries, chickpeas (Kabuli type mostly) is considered a very important legume crop. It is utilized in many forms, such as canned, roasted, boiled, and puffed. Also it is used in meal preparation such as Falafel and Homos biteiheneh, these two meals are very popular and consumed on daily basis.

Environmental conditions exert significant influences on chemical composition of legumes (e.g. peas, Pisum sativum L.) [1]. Significant genetic variations in chemical composition (e.g. protein) of legume seeds have been reported [1], [5], [8]. The breeding programs are carried out in search for high yielding chickpea cultivars to meet the increasing demand for chickpea seeds. The chemical composition and mineral element levels in the improved or released chickpea cultivars is not emphasized. The objective of this study was to characterize the seed chemical composition and mineral concentration of three improved and a local chickpea cultivars grown under semiarid conditions in northern Jordan.

MATERIALS AND METHODS

Plant Material and Cultural Practices

The seeds of three improved (Jubeiha-1, Jubeiha-2 and Jubeiha-3) and one local chickpea cultivars were provided by the National Center for Agricultural Research and Technology Transfer (NCARTT), Amman, Jordan. The seeds were grown under rainfed conditions during 1994/95 and 1995/96 growing seasons at Maru Research Station (northern Jordan) located 34°40′N; 590 m altitude. The soil type is silty clay (fine, montmorillonitic, thermic, Entic Chromoxeret) with low levels of organic matter (1.2%) and pH 7.9. This location has a typical Mediterranean climate. Long term average rainfall is 370 mm. Phosphorus fertilization was applied at the rate of 30 kg P ha⁻¹ at the time of sowing. The experimental design was a randomized complete block with three replications. Plots were 1.4 × 4 m² with 4 rows spaced 0.35 m apart and 10 cm between plants. Weeds were controlled by hand. At maturity, pods from plants in the two middle rows, of each plot were harvested manually, sun dried for two weeks, threshed manually, and were sent to the laboratory for analysis.

Chemical Analysis

Seed samples (100 g) from each replication were ground to pass a 0.5 mm screen using a Cycotec mill and used for chemical analysis. Seed moisture, protein (N × 6.25), crude fat, fiber, and ash contents were determined according to standard procedures [2]. Glucose, sucrose, and fructose contents were determined by using phenol-sulfuric reaction according to the method described previously [6]. Starch was determined by extracting with 80% ethanol, solubilizing with dilute perchloric acid, and then starch was determined using a spectrophotometer [12]. Phosphorus was determined using a spectrophotometer [16]. Concentration of Mn, Fe, Cu, Zn, Na, K, Mg, and Ca were determined using an atomic absorption spectrophotometer (Pye Unicam, Model SP9, UK) after wet digestion with a mixture of nitric, sulfuric, and perchloric acid (10 : 1 : 4) as described previously [7].

Statistical Analysis

Data were subjected to analysis of variance (main effects and interaction) and least significant difference (LSD) values were used to evaluate significance of differences between means. Simple correlations were computed between different chemical composition parameters using SYSTAT program (The system for Statistics, Evanston, IL).

RESULTS AND DISCUSSION

Analysis of variance indicated that the growing season (Y) significantly influenced all the traits except for sucrose, starch, K, Fe, and Zn, levels (Table 1). The cultivar (C) found to have significant effect on all the traits except for ash, fiber, fructose, K, Ca, and Na. However, the cultivar and growing season interaction (Y × C) was found to have a greater significant influence on the investigated traits except starch and Na levels in chickpea seeds.

Table 1. Probabilities of Significance of Mean Square for Seed Chemical Composition Parameters in Chickpea Seeds

Trait	Year (Y)	Cultivar (C)	Y × C
Protein	**	**	**
Fat	**	**	**
Ash	*	NS	*
Fiber	**	NS	**
Glucose	**	**	**
Fructose	**	NS	**
Sucrose	NS	**	**
Starch	NS	*	NS
P	**	**	**
K	NS	NS	**
Ca	**	NS	**
Mg	**	**	**
Na	*	NS	NS
Mn	**	**	**
Fe	NS	**	**
Cu	**	**	*
Zn	NS	*	*

*, ** = Significant at P < 0.05 and 0.01, respectively.

NS = not significant.

The chemical composition of chickpea seeds is presented in Table 2. The data showed that the tested cultivars have similar levels of fiber, ash, and fructose. The cultivar Jubeiha-3 was found to have the highest protein (21.2%), fat (7.09) and fructose (5.53%) contents. The cultivar Jubeiha-1 had the highest fiber content, but it ranked the second in ash, glucose and starch content among tested cultivars. The local cultivar had the highest seed glucose and sucrose contents, but it was the lowest in starch content among all cultivars. The variation in seed chemical composition between cultivars found in the present study could be due to inherited differences. Genotypic variation in chemical composition of chickpea seeds have been reported [3], [10], [13]. Data on the association between the chemical traits are shown in Table 3. Interestingly, protein was highly correlated with fat content (r = 0.85**). These results are consistent with those reported on desi and kabuli chickpeas [10]. Negative correlations between fat and ash (r = −0.43*); fat and starch (r = −0.43*) and between fiber and fructose (r = −0.57**) contents were observed. Results also indicated that ash content was negatively correlated with fiber (r = −0.42*) and fat (r = −0.43*). Fructose was found to have a highly significant negative correlation (r = −0.57*) with fiber and positively correlated (r = 0.56*) with glucose. A high positive correlation (r = 0.75*) was noted between sucrose and glucose. Starch had high negative correlation with protein, fat, glucose and sucrose. (correlation values were −0.60, −0.43, −0.43 and −0.64, respectively).

Table 2. Year, Cultivar, and Year × Cultivar Effects on Seed Chemical Composition in Chickpea Seeds

	Protein (%)	Fat (%)	Fiber (%)	Ash (%)	Glucose (%)	Fructose (%)	Sucrose (%)	Starch (%)
Year
1994/95	18.1	6.6	4.7	3.3	4.1	5.9	3.1	31.4
1995/96	19.6	7.0	5.5	3.1	3.5	4.2	2.9	31.3
SE	0.30	0.14	0.43	0.21	0.32	0.82	NS	NS
Cultivar
Jubeiha-1	17.4	6.6	5.5	3.4	3.8	4.8	2.6	32.3
Jubeiha-2	17.4	6.6	5.1	3.4	3.4	4.4	2.4	32.6
Jubeiha-3	21.2	7.1	4.9	3.1	3.5	5.5	3.1	30.6
Local cultivar	19.4	6.9	5.1	3.0	4.7	5.3	4.1	49.9
LSD (P < 0.05)	0.50	0.22	NS	NS	0.49	NS	0.37	2.0
1994/95
Jubeiha-1	16.7	6.5	6.4	3.2	4.1	5.2	2.6	32.8
Jubeiha-2	18.3	6.5	5.3	3.5	3.8	4.6	2.6	31.8
Jubeiha-3	17.7	6.4	3.7	3.1	3.3	6.0	2.8	31.4
Local cultivar	19.7	6.8	3.6	3.4	5.4	7.9	4.7	29.6
1995/96
Jubeiha-1	18.0	6.7	4.5	3.4	3.5	4.5	2.5	31.8
Jubeiha-2	16.6	6.6	4.9	3.2	2.9	4.3	2.2	33.3
Jubeiha-3	24.7	7.8	6.2	2.9	3.7	5.0	3.4	29.8
Local cultivar	19.0	7.0	6.5	2.7	3.9	2.7	3.5	30.3
LSD P < 0.05	0.7	0.31	0.92	0.43	0.69	1.76	0.52	NS

SE = Standard error.

NS = not significant.

DM = Dry weight basis.

Table 3. Correlation Coefficients (r) of Chickpea Seed Chemical Composition Parameters (Combined Data, n = 3)

	2	3	4	5	6	7	8
1. Protein	0.85**	0.20	−0.32	0.19	0.12	0.51*	−0.60**
2. Fat		0.37	−0.43*	0.13	0.02	0.41*	−0.43*
3. Fiber			−0.42	−0.14	−0.57**	−0.21	0.03
4. Ash				0.31	−0.17	0.39	0.21
5. Glucose					0.56**	0.75**	−0.43
6. Fructose						0.51*	−0.19
7. Sucrose							−0.64**
8. Starch

*, ** = Significant at P < 0.05 and 0.01, respectively.

The data on seed mineral composition of the investigated chickpea cultivars are shown in Table 4. Mineral levels in the four chickpea seed cultivars varied significantly for Mg, Na, Mn, Fe, Cu, and Zn. Mineral level found to compare very well with those values reported on chickpea cultivars [3]. However, no significant variation due to growing season was observed for K, Fe and Zn. The concentration of minerals in seed of all cultivars showed significant variation and the same is true for the growing season.

Table 4. Year, Cultivar, and Year × Cultivar Effects on Seed Mineral Concentrations in Chickpea Seeds

	P	K	Ca	Mg	Na	Mn	Fe	Cu	Zn
	(mg g^−1 DM)				(μg g^−1 DM)
Year
1994/95	3.7	14.2	2.6	1.9	213	32.5	97	22.0	49.6
1995/96	2.1	12.2	2.3	1.4	269	27.5	90	17.5	44.9
SE	0.2	NS	0.2	0.2	41	2.0	NS	2.0	NS
Cultivar
Jubeiha-1	3.4	11.3	2.5	1.5	270	34.3	133	24.8	52.6
Jubeiha-2	2.9	13.3	2.5	1.8	208	29.6	69	19.8	48.8
Jubeiha-3	3.0	14.2	2.4	1.9	207	36.3	83	17.1	51.1
Local cultivar	2.2	13.6	2.5	1.4	264	20.4	90	17.3	36.4
LSD	0.3	NS	NS	0.2	62	3.0	18	3.0	10.4
1994/95
Jubeiha-1	4.6	11.3	2.1	1.5	256	28.7	126	26.6	60.3
Jubeiha-2	3.3	17.0	3.3	2.2	188	35.2	96	24.5	58.3
Jubeiha-3	3.4	17.6	3.4	2.4	206	48.2	99	20.5	50.0
Local cultivar	3.3	10.4	1.8	1.4	204	18.0	90	16.6	29.8
1995/96
Jubeiha-1	2.2	11.3	2.9	1.6	285	39.8	141	23.1	44.9
Jubeiha-2	2.4	9.6	1.6	1.4	229	24.1	42	15.2	39.4
Jubeiha-3	2.7	10.9	1.4	1.4	209	24.4	68	13.6	52.3
Local cultivar	1.1	16.8	3.2	1.4	232	22.9	111	18.0	42.9
LSD	0.4	0.44	0.4	0.3	88	4.2	26	4.2	14.7

SE = Standard error.

DM = Dry weight basis. All values are average of three replications.

Phosphorus levels ranged from 1.1 (local cultivar) to 4.6 mg g⁻¹ (Jubeiha-1), K concentration varied significantly and ranged from 9.6 (Jubeiha-2) to 17.6 mg g⁻¹ (Jubeiha-3). Calcium also ranged from 1.4 (Jubeiha-3) to 3.4 mg g⁻¹ (Jubeiha-3). Magnesium concentration is considered high and ranged from 1.4 (local cultivar) to 1.9 mg g⁻¹ (Jubeiha-3). Other minerals Mn, Fe, Cu and Zn also varied and their ranges were 18.0 (local cultivar) to 48.2 μg g⁻¹; 42 (Jubeiha-2) to 141 μg g⁻¹ (Jubeiha-1); 13.6 (Jubeiha-3) to 26.6 μg g⁻¹ (Jubeiha-1) and 29.8 (local cultivar) to 60.3 μg g⁻¹ (Jubeiha-1), respectively. The variation in mineral levels might be attributed to cultivar and environmental effects. The concentration of minerals is in agreement with data presented previously [11].

In conclusion, the investigated chickpea cultivars have different genetic backgrounds for almost all the chemical traits tested. Data showed that the chemical composition of the chickpea seeds offer to the nutritionists the possibility of using these cultivars as excellent sources for proteins, fat, fibers, starch, sugars and minerals.

The growing season, cultivar and their interaction had significant influence on the chemical analysis of these seeds. The high positive and significant correlations between protein and fat; glucose and sucrose; glucose and fructose offer to the breeders the possibility of indirect selection for any of these quality characters.

Acknowledgments