Abstract: Grain samples, collected for analysis six dry bean cultivars (Sehirali-90, Karacasehir, Akman-98, Göynük-98, Öncüler-98 and Yunus-90) currently cultivated in Turkey, were analyzed for their thousand seed weight, protein, oil, cellulose, ash potassium, calcium, phosphorous, magnesium, sodium, iron and zinc content. Analyses of variance were important differences amongst the cultivars for all the properties studied and different groups were obtained by LSD range test. The highest protein content (28.78%) was obtained in Karacasehir. The positive correlations were found between protein content and calcium (r = 0.954**), oil (r = 0.840**) and phosphorous content (r = 0.791**), while protein content correlated significant negatively with cellulose (r = -0.807**) and moisture content (r = -0.756**). The findings of this research will be useful for breeders in dry bean.
Introduction
Plants proteins provide 65% of the world protein supply for humans, with 45-50% coming from legumes and cereals, mainly for the populations of developing countries and vegetarians of the industrialized nations (Mahe et al., 1994). Food legumes are characterized by a relatively large content of proteins and carbohydrates. In general, pulses also contain significant amounts of minerals and vitamins and at the same time are poor in fats and sodium (Torija and Diez, 1999). Legumes in general contain appreciable quantities of iron and other minerals. Although legumes are often cited as a complement to cereals in terms of amino acid content, they also make a particularly important contribution to micro nutrient nutrition. The dry bean is most important grain legume for direct human consumption, being especially important in Eastern Africa, Asia and Latin America.
Micronutrients in foodstuffs include vitamins and minerals elements, as components which are found in very small amounts, but with an essential role in the metabolism of human body. Nutritional because trace metals such as Ca, Mg, Zn, Fe, P and K are necessary for maintenance of optimum health. Deficiencies of Fe, Zn, I and vitamin A in human populations are widespread, affecting up to two billion people (Anonymous, 1992).
The amount of nutrient per seed is more important measure of micronutrient supply in grain for human food than the total amount of nutrient per seed (Rengel et al., 1999). As seed develops on the parent plant, concentration of nutrients in seed is dependent on soil type, nutrient availability and crop species and to a lesser extent, season and cultivars (Ascher et al., 1994).
Plant breeders have recognized the importance of considering the quality requirements of end users when developing new varieties of pulse crops. Proteins are major components of grain legumes and their nutritional and functional properties dramatically affect the overall quality of seed (Duranti and Gius, 1997). Breeding a variety rich in protein content will also require consideration of some minerals elements of the grain.
Protein improvement in legumes has been hampered because breeding programmes have produced cultivars primarily for high yield and correlations between yield and seed protein have generally been negative (Henry et al., 1995). Negative correlations between protein content and thousand seed weight, cellulose content, but weak correlations protein content and nitrogen-free extracts, have been reported for dry bean seeds (Önder and Babaoglu, 2001). Environmental conditions exert significant influences on the chemical composition of bean (Beebe et al., 1999) and significant genetic variations in the chemical compositions (e.g., protein and Ca, Mg, Zn, Fe, P) of bean seeds have been (Beebe et al., 1999 and Mubarak, 2005).
The nutritional value of a food given mineral depends on the mineral content. Therefore, this study described here aimed at exploring potentially useful variability in quality characteristics among genetically diverse dry bean genotypes, so as to provide plant breeders with information on potential material for the selection criteria to be used in breeding programmes.
Materials and Methods
The six dry bean cultivars (Şehirali-90, Karacaşehir, Akman-98, Göynük-98, Öncüler-98 and Yunus-90) were taken from Anatolia Agriculture Research Institute. The dry beans were grown during the 2001 summer season in the farm of Cumra Agriculture Collage in Central Anatolia and were used in all laboratory experiments. The soil at the region had a pH 8.20 and soil phosphorous, nitrogen, potassium, calcium and organic matter were 55.9, 1.01, 2.2, 269 kg ha-1 and 1.87%, respectively. The crop in the previous year was a cereal. The fertilizer rate of 30 kg ha nitrogen was applied during sowing as Ammonium sulfate (21: N). Dry bean seeds were taken samples from the experimental. The thousand seed weight was determined by weighing 500 seeds in three replicates. Seeds were cleaned to remove foreign material and broken seeds before analysis. Protein, oil and cellulose contents were determined according to the Kjeldahl, Soxlet and Weender methods, respectively, using ground seeds. Kjeldahl nitrogen values were multiplied by 6.25 to obtain crude protein values. Ash content was measured by burning the ground material at 600°C, while moisture content was determined after placing the ground seeds in an oven at 105°C for 3 h. The 0.5 g ground material was digested with concentrate HNO3 in Microwave system. Potassium, calcium, phosphorous, magnesium, sodium, iron and zinc in extracts were analyzed by ICP-AES (Varian-Vista Model). These values were expressed as mg/kg dry matter.
All data were subjected to a randomized complete blocks model of ANOVA and F-test applied to examine the statistical significance of differences amongst the varieties. Experimental data were analyzed by using TARIST.
Results and Discussion
All variables were significantly differences amongst the varieties (Table 1). TSW of 6 genotypes ranged from 182.21 to 407.44 g. TSW was highest in Göynük 98 (407.44 g) and lowest in Karacasehir (182.21 g) (Table 2). Similar interspecific variations have been reported earlier by Akcin (1974), Akdag (1997) and Önder and Babaoglu (2001). Significant positive genotypic correlations were found between thousand seed weight and cellulose content, zinc content and moisture content, whereas thousand seed weight was negatively correlated with protein content, oil content, calcium content and iron content (Table 3). These results are similar to that reported by Önder and Babaoglu (2001) for thousand seed weight, oil content and protein content.
| Table 1: | Summary of ANOVA for variables examined in various dry bean cultivars |
| p<0.01 | |
| Table 2: | Mean data and statistical groups of various dry bean cultivars with respect to variable analyzed |
| 1Means in the same row different letters are significantly different ( p<0.01) | |
The protein content ranged from 21.46 to 28.78% of seed dry matter. The highest values were found in Karacasehir (28.78%). After Karacaşehir, Yunus-90 (24.58%), Akman-98 (23.49%) and Göynük-98 (23.49%) show the next highest levels of protein content. The remaining cultivars present lower contents: Sehirali-90, 22.26% and Öncüler-98, 21.46%. These results are agreed with the results obtained by Akcin (1974), Kadam et al. (1998), Önder and Babaoglu (2001) and Mubarak (2005). The positive correlations were found between protein content and calcium content, oil content and phosphorous content, while protein content correlated significant negatively with cellulose content and moisture content (Table 3). Önder and Babaoglu (2001) reported interaction with protein content and cellulose content.
The contents of oil found in this study range between 1.51 and 2.47%. The lowest content was found in Yunus-90. Karacaşehir had the highest content in this study. These results coincide with the data represents in the literature, which reveal that oil content represent between 1.44 and 2.84% (Önder and Babaoglu (2001) and Mubarak (2005)). Oil content was highly and positively correlated with calcium content, sodium content and phosphorous content, whereas the negative correlations were found between oil content and zinc content, cellulose content and moisture content (Table 3).
| Table 3: | Correlation coefficients between the grain variables and protein content in various bean cultivars |
| *: p<0.05; **: p<0.01 | |
Bean cultivars analyzed have cellulose contents ranging from 5.57 to 8.87%. The lowest content was found in Karacasehir and the highest in Sehirali-90. Previous finding indicated that bean cellulose content varies from 5.97 to 9.26% (Önder and Babaoglu (2001). The ash contents found range from 3.43 to 3.66%, levels that are similar to those described by other authors (Akçin (1974), Önder and Babaoglu (2001), Sanchez-Mata et al. (2003) and Mubarak (2005)). The moisture contents of cultivars were ranged from 6.10 (Karacasehir) to 7.07% (Sehirali-90). These results agree with the results of Akçin (1974), Önder and Babaoglu (2001) and Mubarak (2005), who found for moisture content in dry bean.
The positive correlations were found between ash content and iron content, between moisture content and zinc content. Cellulose content was negatively correlated with calcium content and phosphorous content. Ash content was most strongly negative associated with magnesium content. Moisture content had also a negative correlation with both calcium content and phosphorous content (Table 3).
Large variations resulted in statistically different groups with respect to potassium content (Şehirali-90, 1873.88 mg/100 g; Akman-98, 2248.34 mg/100 g), calcium content (Öncüler-98, 94.60 mg/100 g; Karacaşehir, 213.32 mg/100 g), phosphorous content (Şehirali-90, 663.66 mg/100 g; Karacaşehir, 770.50 mg/100 g), magnesium content (Göynük-98, 172.75 mg/100 g; Akman-98, 195.42 mg/100 g), sodium content (Akman-98, 43.15 mg/100 g; Karacasehir, 54.65 mg/100 g), iron content (Göynük-98, 6.70 mg/100 g; Öncüler-98, 8.85 mg/100 g) and zinc content (Karacaşehir, 1.85 mg/100 g; Şehirali-90, 2.25 mg/100 g) (Table 2). These results agree with reported by Beebe et al. (1999) and Mubarak (2005). Variations amongst the cultivars in the mineral composition can be attributed to varying genetic constitutions, similarly to previous reports by Beebe et al. (1999). As seed develops on the parent plant, concentration of nutrients in seed is dependent on soil type, nutrient availability and crop species and to a lesser extent, season and cultivars (Ascher et al., 1994).
In this study, potassium content was significantly correlated with magnesium content. Similarly, calcium content had a positive correlation with both phosphorous content and sodium content. However, the negative correlations were found between potassium content and sodium content, between magnesium content and sodium content, between zinc content and calcium content, phosphorous content and sodium content. Other variables were unimportant; it could be positively and negatively correlation. This result is in agreement with reported by Bee et al. (1999), who found similar interrelations in bean.
Conclusions
The detailed descriptions of genotypes will be useful for pulse breeders in dry bean. The large variation observed in most of the properties measured increases their value. The positive correlations were found between protein content and calcium, oil and phosphorous content, while protein content correlated significant negatively with cellulose and moisture content. The findings of this research will be useful for breeders in dry bean