Study of selected quality and agronomic characteristics and their interrelationship in Kabuli-type chickpea genotypes (Cicer arietinum L.)

Abstract

Impact of genotype on quality, agronomic characteristics and their interrelationship in Kabuli-type chickpea was investigated to provide significant feedback to breeder for selection/evolution of the most suitable varieties. Seven genotypes were studied for seventeen physical, chemical and agronomic characteristics. The effect of Kabuli-type chickpea genotype on the physicochemical parameters, cooking time and agronomic characteristics were significant. Maximum seed size and volume were recorded for CC98/99 (0.32 g and 0.26 mL seed⁻¹, respectively), density and swelling index for the genotype FLIP97-179C (having minimum seed size and volume), while the rest of the genotypes were statistically the same. Weight, volume after hydration, hydration capacity and swelling capacity followed the same pattern. Maximum moisture, protein and mineral concentration were noted in CC98/99. Seed protein concentration for the remaining genotypes was statistically non-significant from one another. Longer period was taken by CM 2000 for flowering and maturity (130 and 181 days, respectively). Minimum time to flowering and maturity was taken by CC98/99. Genotype CC 98/99 outyielded all other genotypes (2107 kg ha⁻¹). Seed size and seed volume were strongly and positively correlated with protein content, weight after hydration, volume after hydration, hydration and swelling capacities (r = 0.83–1.0). Strong correlation was also noted among different agronomic characters.

Introduction

Chickpea (Cicer arietinum L.) is an ancient crop and is grown in tropical, subtropical and temperate regions. Major producers of chickpea include India, Pakistan and Mexico. In India and Pakistan, chickpeas are consumed locally, and about 56% of the crop is retained by growers. Turkey, Mexico, Iran, Australia and Canada are the main exporters. Chickpea is valued for its nutritive seeds with high-protein content, 17–22% and 25.3–28.9%, before and after dehulling, respectively (Hulse, 1991; Badshah et al., 2003). Chickpea seeds are eaten fresh as green vegetables, parched, fried, roasted and boiled; as snack food, sweet and condiments; seeds are ground and the flour can be used as soup, dhal and to make bread; prepared with pepper, salt and lemon it is served as a side dish. Dhal is the split chickpea without its seed coat, dried and cooked into a thick soup or ground into flour for snacks and sweetmeats (Hulse, 1991). Sprouted seeds are eaten as a vegetable or added to salads. Young plants and green pods are eaten like spinach. A small proportion of canned chickpea is also used in Turkey and Latin America and to produce fermented food. Animal feed is another use of chickpea in many developing countries. An adhesive may also be prepared; although not water resistant, it is suitable for plywood. Gram husks and green or dried stems and leaves are used for stock feed; whole seeds may be milled directly for feed. Leaves are said to yield an indigo-like dye. Acid exudates from the leaves can be applied medicinally or used as vinegar.

Greater and more stable yields are the major goals of plant-breeding programs. Chickpea yields usually an average of 400–600 kg ha⁻¹ but can surpass 2000 kg ha⁻¹, and in experiments have attained 5200 kg ha⁻¹. Yields from irrigated crops are 20–28% higher than yields from rain fed crops. Chickpea production increased from 1980 to 1990 by about a million tons (at 1.8% annually), and there was a 5.6% increase in yield over the decade (Oram & Agacoili, 1994). Further increases in yield could be attained from the use of germplasm/wild relatives, for identification of new genes, and from new combinations of favourable genes already existing.

This paper reports the study of the effect of genotype on economically important quality and agronomic traits of different Kabuli-type chickpea genotype.

Materials and methods

Field experiment was conducted at the experimental farm of Nuclear Institute of Food and Agriculture Tarnab, Pakistan. The chickpea varieties were obtained from National Uniform Chickpea Yield Trail. Type of soil was clay loam. Seven chickpea genotypes were used in the present study. Nitrogen and phosphorus were incorporated in the soil during seedbed preparation at a rate of 45 and 60 kg ha⁻¹. First irrigation was applied when the germination was completed (after 3 weeks). No irrigation/fertilizers were applied thereafter till harvest. Randomised complete block design with three replications was used. Plot size was 7.2 m² with a plant-to-plant distance of 10 cm and row-to-row distance of 40 cm and was seeded with a small plot drill. Established plots were trimmed to a uniform length.

Moisture, protein and mineral concentrations were determined by the standard methods of AOAC (1984), method numbers 10-231, 10-177 and 14-063, respectively. Physical characteristics and cooking time were determined by methods reported by Badshah et al. (1987, 2003, 2005). A brief account of that is given below.

Plant height (cm)

Average of the ten plants’ height per replication was recorded from the base of the plant to the top peduncle on the main branch.

Days to flower

Days from sowing to the initiation of flowering on 50% plants of a genotype (in a plot) in each replication.

Days to mature

Days from sowing to 90% pods maturity on all plants of a genotype (in a plot) in each replication.

Moisture content (%)

Determined by the oven-drying method (AOAC, 1984).

Grain protein content (%)

Twenty-five grams of grain were ground to 30 mesh and the protein content was determined by micro-Kjeldahl method as outlined in AOAC (1984). The conversion factor used to convert the Kjeldahl nitrogen to per cent protein was 6.25.

Mineral concentration (%)

It was determined after incinerating the whole wheat ground flour samples for 16 h at 575 °C (AOAC, 1984).

Grain yield (kg ha⁻¹)

The seed weight of the middle four harvested rows of a genotype in each replication was recorded in grams and converted to kg ha⁻¹.

Seed size (g seed⁻¹)

Three random samples of 100 seeds from a genotype per replication were weighed and the values converted to g seed⁻¹.

Seed volume (ml seed⁻¹)

Taken as mean volume of three random samples of 100 seeds from a genotype per replication, i.e. 100 seeds were transferred to a 100-mL measuring cylinder, and 50 mL of water were added to it. Seed volume = (total volume − 50)/100.

Density (g ml⁻¹)

It is the ratio between weight and volume of seed (weight of 100 seeds/volume of 100 seeds).

Hydration capacity (g seed⁻¹)

It is the gain in weight of a seed after 24 h soaking (weight of 100 seeds after 24 h soaking – weight of 100 seeds before soaking)/100.

Hydration index

It is the ratio between hydration capacity and average seed weight (hydration capacity/seed size).

Swelling capacity (mL seed⁻¹)

It is the gain in volume of a seed after 24 h soaking (volume of 100 seeds after 24 h soaking − volume of 100 seeds before soaking)/100.

Swelling index

It is the ratio between swelling capacity and volume of the seed (swelling capacity/seed volume).

Cooking time (min)

It was determined by placing 25 g of seed in boiling water. Cooking was checked after 60 min boiling and continued at 5 min interval. Cooking was considered complete when the colour of 80–100% of seeds (cotyledon) changed completely from whitish yellow to yellow because of gelatinisation (visual observation).

Statistical analysis

Statistical analysis was conducted (Steel & Torrie, 1984) for each of the measured traits by analysis of variance (Anova) and the means were separated by Duncan Multiple Range test using Mstat-C software (Michigan State University, East Lansing, MI, USA). Pearson correlation coefficients (r) for the relationships between all properties were calculated.

Results and discussion

Results showing the effect of genotype on seed size, seed volume and density are given in Table 1. Among all the genotypes, the parameters studied varied significantly except density. Significantly highest value for density was recorded in FLIP 97-179C (1.43 g mL⁻¹), while for all other chickpea genotypes, no effect on the values of density was observed. The values of seed size ranged from 0.32 (CC 98/99) to 0.23 g/seed (FLIP 97-179C and CC 94/99). Seed volume followed the similar pattern as the seed size values. The reported values for seed size and seed volume are in agreement with those of Badshah et al. (2003).

Results showing the impact of genotype on hydration and cooking characteristics are summarised in Table 2. All the parameters studied varied significantly except swelling index. Significantly highest swelling index was recorded in FLIP 97-179C (1.49), while the rest of the genotypes did not vary significantly. Maximum weight after hydration was gained by genotype CC 98/99 (0.65), while minimum value was observed by genotype FLIP 97-179C (0.47). Volume after hydration and hydration capacity followed the similar pattern as the weight after hydration. Hydration index ranged from 1.08 (genotype CC 94/99) to 0.98 (genotype NCS2001). Swelling capacity varied significantly among all the genotypes and ranged from 0.32 (genotype CC 98/99) to 0.24 (genotype CC 94/99). Maximum and minimum cooking times were 81.7 and 61.7 min for the genotype CC 94/99, genotype FLIP 97-179C and genotype CM 2000, respectively. The present results are in accordance with those reported earlier by Williams et al. (1983); Singh et al. (1992) and Badshah et al. (1987, 2003).

The chemical characteristics of the studied genotypes are depicted in Table 3. The data revealed that except the genotype CC 98/99, there were no significant differences in protein content of different genotypes with values ranging from 19.22% (genotype CC 98/99) to 18.01% (genotype CM 2000). Moisture and ash content showed significant differences (P < 0.05) among the studied genotypes with values ranging from 9.70% (genotype CM 2000) to 10.31% (genotype CC 98/99) and from 2.94% (CC 98/99) to 2.45% (genotype FLIP 97-172C), respectively. All these values are in agreement with those reported earlier (Williams et al., 1983; Badshah et al., 1987, 2003; Singh et al., 2004).

Data regarding the effect of genotypes on the agronomic characteristics of chickpea is presented in Table 4. Significantly higher number of days to flower was noted for the genotype CM 2000 and lower number of days to flower for CC 98/99. Similar pattern was observed for days to mature. Data revealed that maximum and minimum plant heights were attained by genotype K-990395 (99.0 cm) and CM 2000 (73.67 cm), respectively. The highest yield was recorded for genotype CC 98/99 (2107 kg ha⁻¹) and lowest for genotype CM 2000 (1179 kg ha⁻¹), indicating significant differences (P < 0.05) in yield among different genotypes of Kabuli-type chickpea.

The interrelationship of physical, biochemical and agronomic characteristics in Kabuli chickpea genotypes are summarised in Table 5. The data revealed strong positive correlation between seed size and seed volume, weight after hydration, volume after hydration, hydration capacity, swelling capacity and seed protein content, while the correlation of seed size with seed moisture content was also significantly positive. There was negative correlation (although non-significant) between seed size and density, swelling index and days to mature. Seed volume has strong positive correlation with seed protein (which is contradictory to that observed by Badshah et al., 2003 who reported negative association of protein content with seed size and volume in desi chickpea cultivars, weight after hydration, volume after hydration, hydration capacity and swelling capacity and negative correlation with density and swelling index. This contradiction in correlation might be attributed to genetic/environmental variability in chickpea genotypes used in this experiment. There was very strong positive interrelation of density with swelling index. Chickpea seed protein had strong positive correlation with weight after hydration, volume after hydration, hydration capacity and swelling capacity, while it showed significant negative association with days to mature. Correlation of ash with cooking time was significantly positive while with swelling index it was negative. Weight after hydration and volume after hydration had very strong positive interrelation with each other as well as with hydration capacity and swelling capacity. There was a very strong correlation of hydration capacity with swelling capacity. Hydration index had significantly positive correlation with cooking time. Swelling capacity and moisture were also positively correlated with each other. Days to flower had strong positive correlation with days to mature, while with plant height, yield and cooking time, it had significantly negative interrelation. The correlation of yield with plant height was significantly positive. Swelling index had negative relation with all the parameters studied, except protein and hydration index. Cooking time was positively correlated to ash content and hydration index and negatively to days to flower. The correlation of yield to protein content, ash content and plant height was positive while that with days to flower and days to mature was negative. Moisture content has positive relation with seed size, weight after hydration, volume after hydration and swelling capacity.

Williams et al. (1983) and Singh et al. (1992) have reported a strong positive correlation between seed size and hydration capacity. The present results are in accordance with those reported earlier by Williams et al. (1983); Khairwal et al. (1997) and Singh et al. (1992). As per our results, Singh et al. (2004) reported significant differences in physical, chemical, cooking and textural properties in blackgram varieties. They reported that seed weight and volume correlation well with swelling capacity, swelling index, hydration capacity, cooking time and hardness.

Conclusions

It was interesting to conclude that the genotype CC98/99 has maximum seed size, volume, hydration capacity, swelling capacity, weight and volume after hydration, moisture, protein, mineral concentration and yield. The same genotype took shorter time period to flower and mature and attained statistically significant higher plant height. This genotype is strongly recommended to be a future variety. Among the different chickpea genotype, there were significant differences in physicochemical, cooking and agronomic characteristics. Seed size and seed volume correlated well with density, protein content, weight after hydration, volume after hydration, swelling capacity, swelling index, days to mature, plant height and moisture content. Strong correlation was also noted among agronomic characters, which imply that alteration in one character will modify the other one. Strong association of cooking time with ash, hydration index and days to flower was also observed.

Acknowledgment

The authors are thankful to Director, NIFA, for providing facilities to carry out these studies.

References