Introduction
Species and family
Chickpea is a legume that is found in Australia, Canada and several parts of Asia and the Middle East. Chickpea belongs to the Cicer arietinum species and the Fabaceae family. The legume is further sub-classified into Faboideae subfamily. Chickpea has different common names which are influenced by the regions of origin. It is known as garbanzo bean, the Egyptian pea, Cece or Ceci. Chickpea was the first legume to be planted during the agrarian revolution era in the Middle East. It has high levels of plant proteins, and this explains its popularity in most parts of the world (Yadav et al. 2007, pp218).
Brief overview: economic importance
Chickpea has various economic uses which depend on the region and the tradition of origin. For example, chickpeas are used for making cold salads in the United States while other countries in the Middle East use chickpeas together with other starch-based foods. This demonstrates the popularity of chickpea and its application in various areas of the economy. Within different regions of the world, chickpea is used to make salad, rice stew or turned into baking flour. The Portuguese use chickpeas in the manufacture of Rancho which can be served with other meals. In other countries such as Spain, chickpea is used in making other common dishes such as bacalhau and tapas salad (Yadav et al. 2007, p217).
Young chickpea plant can also be harvested as fresh and green pods and eaten in the same way as spinach. In turkey, chickpea is used for production of fermented foods and drinks. Chickpea is also used as animal food in some parts of the world such as the United States. Other uses of chickpea include the manufacture of non-water resistant adhesives and plywood. Acid exudates from chickpea plant have medicinal value. Chilean use cooked chickpea and milk as infant food to support growth and development.
Focus area of this report
The popularity of chickpea has grown significantly, and this has led to its demand in different parts of the world. However, the production level has remained minimal with traditional producers being at the forefront. In this report, an in-depth description of chickpea will be provided to highlight its domestication history, role in human nutrition and emerging biotechnology and genetic manipulations to the plant.
Domestication and history of chickpea
Domestication of chickpea
The wild strain of chickpea is found within the remote parts of turkey and modern day Syria. As a result, archeologists have argued that chickpea may have been domesticated from this region over 11,000 years ago. During the pre-pottery Neolithic era, chickpea was one of the plants that contributed to the development of farming in various regions. The domestication of chickpea (garbanzo beans) may have occurred in two groups also known as the Desi and Kabuli. Over 20 different colors and shapes of chickpea were identified which indicate that other sources may exist (Yadav et al. 2007, p220).
A number of publications have suggested that Desi was the pioneer chickpea variant to be domesticated. This is due to its small, angular and variegated nature. Desi is believed to have originated from turkey, a country where the indigenous strain of the crop is found. From Turkey, it spread to other countries in Asia especially India where the Kabuli strains are common. The wild chicken pea strain can only be harvested during winter and this limits its commercial use. The domesticated form of the chickpea also has a high concentration of tryptophan amino acid (Abo and Judith 2003, pp440-448).
Archeological evidence
Archeological evidence of the domestication of chickpea has been found in different parts of the world. For example, archeological evidence was extracted from the ceramic levels of Jericho and the Cayonu in turkey. Neolithic evidence has also been collected in different parts of the world including the Hacilar in turkey. Carbon dating of the pottery and remains found indicate that the domestication may have occurred 3500 BC. Other archeological evidences have been found in different parts of the world including southern France within the L’Abeurador caves (Abo and Judith 2003, pp440-448).
Genetic evidence
The two original strains, Desi, and Kabuli, were sequenced to identify the level of variation as a way of tracing the domestication process. The sequenced genome showed a high level of genetic variation within the Desi strain as compared to Kabuli. This supported the notion that Desi may have emerged earlier as compared to Kabuli.
Karyotypes
Karyotype analysis is essential in the identification of sub-species of a crop that is believed to share a common origin. It is essential in the identification of interspecific relationships and provides the basis for the comparison of the wild and domesticated strain. Based on karyotype studies conducted by different groups, the five species of chickpea have a number of similarities.
Hybridization between domesticated and wild-type
Hybridization is an essential tool that is used to develope a more vibrant and resistant chickpea strain. Wild and domesticated chickpea have different properties that enable them to survive in different environments. The level of tryptophan amino acid in the wild and domesticated strain varies significantly. This information has been used to improve the domesticated chickpea strain. Hybridization presents an opportunity for improving the level of tryptophan and the disease resistance of the domesticated strain. Three species of chickpea have successfully been hybridized and cultivated. Hybridization is possible within a species, and this was conduted to improve the performance of the legume. However, intraspecific hybridization resulted into sterile hybrids that could not be cultivated (Abo and Judith 2003, pp440-448).
The whole genome short gun for chickpea has been completed, and the result published in various journal databases. The Canadian and Indian Kabuli were sequenced and specific gene loci which are critical in various metabolites identified. Using tandem repeat finder, over 127,000 tandem repeats were identified. Half of the chickpea genome is made up of transposable elements and tandem repeats. In the genome, the 163bp, 100bp and 74bp are the most common tandem repeats in the genome (Upadhyaya et al. 2012, pp51-56).
The disease resistance genes are also present in the genome of the chickpea plant. The presence of these genes enhances disease and pest resistance in chickpea. Based on this genome sequence project, over 187 disease resistance gene homologs were identified. However, this number is low as compared to the number of disease resistance gene homologs in other legumes whose genomes have been sequenced previously. Chickpea genome has over 80,000 simple sequence repeats (SSR) and the SNP markers. These markers are significant targets for polymerase based analysis of chickpea legume such as polymerase chain reaction processes (Upadhyaya et al. 2012, pp51-56).
Genotypic and phenotypic differences between wild and domesticated chickpea
Genotypic diversity in chickpea
Various studies have been conducted on the genotypic and phenotypic variations of the wild and domesticated strains of chickpea. Different techniques such as RAPD and ISSR markers have been used to show the genotypic variations between the two categories of chickpea. Polymorphism identification is essential in showing the genetic diversity between the wild and domesticated strains. This narrow variation can be used for mapping studies on Cicer and the identification of interspecific hybridization.
Phenotypic diversity in chickpea
Domesticated chickpea is indeterminate and has multiple branches that enable it to inhabit different environments. Domesticated chickpea can either be found spreading out or as standing plants with stronger stems. Leaves of domesticated and wild-type chickpea are hairy with multiple stomata on the lower end as compared to the upper surface of the leaf. The seed pods of wild and domestic chickpeas produce the major secondary metabolites which is acidic in nature. The color of the leaves vary, with most domesticated strains possessing dark green or bluish green color.
The shapes of the leaves also differ depending on the species of the chickpea and immediate habitat. The Kabuli chickpea is considered as one of the indigenous crops from which most domesticated strains have emerged. Seed pods of the chickpea developed from the top portion of the plant following self-pollination. The color of the pods also differs, a trait that is attributed to independent allelic assortment during meiosis. The white colored pod is the dominant color allele while purple is the recessive allele.
Nutritional and health benefits of chickpeas
The popularity of chickpeas in different parts of the globe has been attributed to its nutritional and health benefits. Chickpeas or garbanzo have high fiber content, presence of tryptophan amino acids and other trace elements which have various nutritional and health implications. In this section of the paper, the nutritional benefits of chickpeas will be provided to demonstrate its economic importance. Chickpeas also provide an alternative and healthy source of proteins and fatty acids which lowers the cholesterol levels within the blood.
High animal protein intake increases the level of low-density lipoproteins that are used in the synthesis of cholesterol. However, the breakdown of high fiber chickpeas leads to the production of short chain fatty acids which are healthy plant-based lipids. Apart from the nutritional and health benefits, chickpeas have also been processed into cosmetic products. Wrinkles on the skin can be reduced through the application of chickpeas-based manganese. High levels of manganese improve skin cells metabolism, and this reduces the concentration of free radicals in the blood (Jukanti et al. 2012, pp19-23).
Nutritional benefits of chickpeas
Just like other members of the family, chickpeas has nutritional and health benefits. The health implications of legumes have led to their popularity as compared to other foods with high saturated fatty acids. According to Linus Pauling Institute, legumes such as chickpeas reduce chances of heart-related complications. Chickpeas have high content vegetarian-friendly protein which is essential for cell and tissues growth.
A cup of garbanzo beans has over 12 grams of protein that provides 25% of the daily protein consumption needs. Proteins are critical in muscle buildup, repair of damaged tissues and enhancement of the immune system. Chickpeas have the highest concentration of tryptophan as compared to other legumes. Tryptophan increases the concentration of serotonin in the brain, a chemical that boost the concentration rate in human beings. Chickpeas are, therefore, used as a primary source of nutritional boosters in children under the age of ten (Jukanti et al. 2012, pp19-23).
Chickpeas have a high concentration of fiber that has various nutritional benefits. Fiber enhances digestion, reduce the level of blood sugars and eliminate the production of reactive oxygen species in human beings. Chickpeas with high fiber content reduce health challenges such as constipation and other health complication like colon cancer. Fibers soften the stool, and this eliminates constipation and the stool retention in the colon.
Presence of heavy metals and metabolites in stool increase the incidence of colon cancer due to increased stool retention in the colon. Fiber is essential in maintaining healthy sugar levels especially in diabetic patients. With high fiber content in the blood, the rate of food breakdown is reduced. This allows sugar to be absorbed at a low rate into the blood. A cup of chickpeas provide more than 12.5 grams of fiber and is the recommended diet for expectant mothers (Jukanti et al. 2012, pp19-23).
Chickpeas have vitamins and minerals which are essential for improving the level of manganese and folate absorption. Presence of adequate levels of manganese enhances bone development and wound healing. Cell growth and intracellular communication are improved in the presence of vitamin B9. Chickpeas have high levels of iron that is an essential component of hemoglobin and red blood cells. Lactating and pregnant women should have daily intake of chickpeas to boost their iron levels. Iron lost during the menses cycle can also be replaced through daily intake of chickpeas (Jukanti et al. 2012, pp19-23).
Health benefits of chickpeas
Apart from the direct nutritional benefits discussed, chickpeas improve the health status of users in a number of ways. The high presence of fibers in garbanzo offers significant support to the digestive tract. More than 60% of the fiber in chickpeas is insoluble thus provides beneficial support to the digestive tract. Insoluble fiber passes through the digestive system unchanged and is acted upon by bacteria present within the large intestines or colon (Rachwat & Budryn 2001, pp321-323).
Bacterial breakdown produces short chain fatty acids from insoluble colon that are absorbed directly by the colonic cells. Colon cells derive their energy from butyric acid, a product of fiber breakdown. Healthy colon lowers the risk of a number of medical conditions. For example, colon cancer is a common cancer in the developed countries and has been attributed to low fiber processed foods. In Turkey, chickpea is used for production of fermented foods and drinks. Chickpea is also used as animal food in some parts of the world such as the United States. Other uses of chickpea include the manufacture of non-water resistant adhesives and plywood. Acid exudates from chickpea plant have medicinal value.
High level of reactive oxygen species increases the development of cancer cells in human beings. Such species are produced by the body systems such as the lungs, the nervous system, and the kidney. Chickpeas provide an adequate level of antioxidants that converts reactive oxygen species to non-harmful water and oxygen. Antioxidants in chickpeas include vitamin C, vitamin E, and beta-carotene.
Chickpeas also contain high levels of phytonutrients that are secondary metabolites. Such phytonutrients include quercetin, kaempferol among other essential compounds. Controlled clinical and preclinical studies have showed that chickpeas can be used to reduce incidences of cardiac complications in human beings (Rachwat & Budryn 2001, pp321-323).
Chickpeas also improve blood sugar levels in normal and diabetic people. Fibers are the essential macronutrients in the control of sugar levels due to their ability to lower the level of food breakdown. The stabilization of food flow within the gastrointestinal tract leads to an impulsive release of glucose into the blood stream. Chickpeas also provide an alternative and healthy source of proteins and fatty acids which lowers the cholesterol levels in blood (Rachwat & Budryn 2001, pp321-323).
High level of animal protein intake increases the level of low-density lipoproteins that are used in the synthesis of cholesterol. However, the breakdown of high fiber chickpeas leads to the production of short chain fatty acids which are healthy plant-based lipids.
Apart from the nutritional and health benefits, chickpeas have also been processed into cosmetic products. Wrinkles on the skin can be reduced through the application of chickpeas-based manganese. High levels of manganese improve skin cells metabolism, and this reduces the concentration of free radicals in the blood. Folate also nourishes the skin due to its ability to reduce the level of harmful toxins on the skin. Conditions such as leucoderma have been treated using chickpea-based combination therapies. Chickpeas have also been used for the treatment of jaundice and other color related skin complications (Rachwat & Budryn 2001, pp321-323).
Improving nutritional value of chickpeas through biotechnology
International crops research institute for the semi-arid tropics (ICRISAT) have initiated a number of research projects aimed at improving the nutritional value of chickpea. ICRISAT has developed a number of genes that are used to enhance the nutritional content of legumes including the chickpea. Apart from introducing Helicoverpa resistance genes, ICRISAT has adopted BT based technology aimed at improving the level of tryptophan in chickpea. Genes from pigeon pea have been used to improve the genetic composition of chickpeas (Gupta et al. 2010, p9030).
Previous studies on the domestication of chickpeas have also revealed that wild strains have low levels of tryptophan as compared to the domesticated strain. Genetic breeding techniques were applied to improve the level of tryptophan in the domesticated strain. Similar techniques have also been applied in the enhancement of chickpea to improve the level of antioxidants, fiber and other secondary metabolites (Gupta et al. 2010, p9030).
Chickpea pathology and disease management
The identification and management of chickpea diseases is critical in improving yield volume and legume nutritional content. The presence and severity of the diseases that have so far been identified depend on the weather, crop rotation and the planting season. These factors are beyond the control of chickpea farmers but can be managed if their implications on plant health are identified. In this section, the pathology of chickpea will be described to highlight some of the common diseases and the management approaches that have been developed this far. Chickpea is affected by bacterial, viral, fungal and parasitic infectious agents that reduce the volume of crop yield.
Fungal chickpea diseases
The prevalence of chickpea disease differs based on regions and the environmental conditions. For example, the South Pole has a high prevalence of Ascochyta blight, Sclerotinia, Phoma blight among other root based diseases. Others include common viruses such as root lesion and Phytophthora root which significantly reduces overall yields. Ascochyta is a fungal blight that invades chickpea plant at any stage of development. The presence of pale and water-soaked spots on leaves of the chickpea plant is the first symptom of this disease. This spot is accelerated by high humidity which leads to the formation of Pycnidia or black sports.
Failure to fumigate the plant on time leads to colonization of the entire plant by the fungi. This reduces the seed set and result into discoloration, loss of yield and nutritional content. Genetic engineering has led to the introduction of Ascochyta resistance seed variety. However, adequate fungi management strategies must be adopted. Strategic fungicide use is the best approach for managing Ascochyta in chickpeas. However, quality seeds, seed variety, and crop management remain the primary approaches used for preventing fungal infection in chickpeas (Department of Agriculture and Food 2005).
Botrytis Grey mold is also common chickpeas and affects the legume at any stage of development. Leaves infected with Grey mold become soft and fluffy, and this affects foliage development and plant maturity. Sowing infected chickpea without adequate fungicide fumigation increases the establishment of seedlings. Proper seed dressing and fumigation is necessary before planting to prevent the spread of these fungi. Ascochyta blight fungicide can also control the emergence of Grey mold in chickpeas (Department of Agriculture and Food 2005).
In Australia, Sclerotinia is the most prevalent chickpeas disease which has led to sporadic yield loss. The disease is prevalent during the wet month of July and symptomized by presence of white mycelial growths. Failure to address this disease at an early stage leads to the development of black spots known as Sclerotia. Crop rotation is the best Sclerotinia management approach as it breaks the growth cycle of the disease. Phoma blight is the final fungal chickpea disease that leads to root rot and the development of black lesions (Department of Agriculture and Food 2005).
The disease-causing fungi can survive within the soil for a long period. Just like other fungal blights, Phoma is common during the wet season. The use of disease-free seeds and crop rotation are the best management approaches identified so far.
Chickpeas bacterial diseases
Apart from the fungal diseases highlighted, other bacterial diseases have been identified which affects the cultivation of chickpea. Xanthomonas campestris is the most prevalent bacterial condition that has been associated with decreased crop yield. Different strains of this condition have so far been identified, and possible control measures developed. The symptoms include presence of black lesions and decay of the seeds. Campestris secretes a number of proteins that initiate a hypersensitive reaction on the surface of the crop. Just like other common fungal infections, campestris is prevalent during the wet season (Department of Agriculture and Food 2005).
Burkholderia andropogonis is the second common bacterial disease in chickpeas. This is a soil based bacteria that infects the leaves, buds and stems of the plants. Though minor in chickpeas, the identification and management of this condition is critical in improving the total yield. Andropogonis is gram negative bacteria that have a protective carbohydrate based sheath. They colonize the leaf and stems of the chickpea plant leading to stunted growth. Plant debris from the previous harvest serves as a reservoir for this bacterium. Management and elimination of the disease is achieved through proper post-harvest practices and adequate soil treatment (Department of Agriculture and Food 2005).
Viral diseases in chickpeas
Research has identified a number of viral diseases that affect chickpeas and significantly reduce the yield level. Alfalfa and cucumber mosaic are common viral diseases which affect the level of yield in chickpeas. The two viruses have been identified in Canada, Australia and other parts of Asia. Viral mosaic has symptoms similar to nutritional deficiency symptoms, and this affects accurate disease identification and management. Chickpea viruses are small pathogenic organisms that need living hosts to survive. They are seed-borne and emerge at an early stage of plant germination and growth. Aphids act as a vector to the virus, spreading it from the plant to plant within the plantation field. Infection by viral mosaic leads to the loss of over 50% of the total yield.
Demographic studies have shown similar impacts in different parts of the world including Australia. Symptom of viral mosaic differs based on the chickpea strain and the geographical location. For example, viral mosaic-infected Desi strain experience leaf tips necrosis. This can spread to other parts of the plant and lead to loss of an entire plantation. In Kabuli strain, the disease is presented by chlorosis and reddening of leaves. Management approaches include the use of whole and fumigated seeds free of mosaic viruses. The seed rate and stubble retention should also be improved to increase the level of seedling performance following growth.
Conclusion
The popularity of chickpea in different parts of the world is as a result of its beneficial and nutritional values. Chickpea is found in different parts of the world and is a priced legume. In this paper, the economic value of the crop has been discussed based on the emerging farming trends and biotechnology applications. The paper has also evaluated some of the diseases which are associated with chickpea and the best management approaches.
References
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