Bibliography: leaves 182-217. / xx, 217, [18] leaves, [17] leaves of plates : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This study was conducted to determine the etiology of a blight disease of chickpea in south-eastern Australia and the factors affecting disease development. The disease had previously been identified as phoma blight. Pathogenicity testing revealed two isolates subsequently identified as Asochyta rabiei, the first conclusive identification in the southern hemisphere. Greenhouse screening of chickpea varieties identified types resistant to ascochyta blight. The effects of plant age and environmental conditions on disease development were investigated under controlled conditions in growth rooms. Seedlings were more susceptible than older plants. The optimum conditions for ascochyta blight were 20C and a 48-96 h period of leaf wetness. Through field trials it was found that disease intensity increased over time, especially in cv. Desavic. The means of penetration of the chickpea host was established in histological studies. This study provided advance warning of this disease for the expanding chickpea industry, and has allowed the implementation of appropriate disease management strategies. It is recommended that cv. Desavic should not be grown where ascochyta blight is likely to be a problem. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied and Molecular Ecology, 1999

Thesis (Ph.D.)--University of Western Australia, 2008.

No description available.

To increase the global acceptability of chickpea by improving its nutritional quality, seed RFO (Raffinose Family Oligosaccharides) concentration needs to be reduced without affecting their role during seed development and positive impact on human health. To achieve this objective, the key regulating step(s) of RFO biosynthesis needs to be identified. The three main objectives of the thesis were: (1) to optimize an analytical method to determine soluble sugars concentration in chickpea seeds including RFO, (2) to determine chickpea genotypes with contrasting seed RFO concentration, and (3) to optimize and validate RFO biosynthetic enzyme activity assays. These three objectives of the thesis provided basis of the fourth objective. For the first objective, a modified HPAEC-PAD (High performance anion exchange chromatography with pulsed amperometric detector) based gradient approach was optimized to study the concentration and composition of soluble sugars in chickpea seeds. The optimized method separated all the soluble sugars within 20 min of run time with higher accuracy, sensitivity and precision compared to previously reported methods. Therefore, the optimized method was utilized to study the natural variation in RFO concentration of 171 chickpea genotypes. Sucrose (0.60 - 3.59 g/100 g) and stachyose (0.18 − 2.38 g/100 g) were predominant among soluble sugars and RFO, respectively. Analysis of variance revealed a significant impact (P ≤ 0.001) of genotype (G), environment (E), and their interaction (G×E) on seed RFO concentration in chickpea. A significant positive correlation was observed between substrate and product concentration in RFO biosynthesis. Raffinose, stachyose and verbascose showed moderate broad sense heritability (0.25 − 0.56) suggesting the quantitative nature of the RFO trait in chickpea seeds. Desi (ICC 1163, ICC 1471, ICC 9562, ICCV 07115, ICCV 07116 and ICCV 07117) and kabuli (ICC 5270, ICC 10674, ICC 16216, ICC 16528, ICCV 3 and ICCV 91302) chickpea genotypes with high and low RFO concentrations (high RFO genotypes are underlined) were identified. RFO biosynthetic enzymes activities were optimized for substrate and protein concentration, temperature (25 °C), time (10 min for galactinol synthase and 60 min for other biosynthetic enzymes) and pH (7.0). These assays were validated at different seed developmental stages of two released varieties: CDC Vanguard and CDC Frontier. Simultaneously, RFO accumulation at different seed developmental stages was also studied. During 18 - 38 DAF (days after flowering), about a 75 % decrease in seed moisture was observed coinciding with the accumulation of RFO providing desiccation tolerance to maturing seeds. The initial substrates viz. myo-inositol and sucrose were observed throughout seed development process having maximum accumulation at 18 - 20 (0.50 – 0.57 g/100 g) and 20 - 22 (9.94 - 11.17 g/100 g) DAF that decreased afterwards supporting the biosynthesis of galactinol and raffinose, respectively. Galactinol is considered as the universal galactosyl donor, it showed the highest concentration at 30 DAF and this was later utilized for increased RFO accumulation till 36 DAF. Activity of RFO biosynthetic enzymes was observed 2 - 6 days prior to first detection of their corresponding products whereas the highest activities were determined 2 - 4 days prior to maximum accumulation of RFO. However, maximum GS (galactinol synthase) activity was observed at 36 DAF but this did not correspond to amount of galactinol accumulation in seeds. This indicated that galactinol was synthesized in higher amount even after 30 DAF but directed towards RFO biosynthesis thus could not necessarily accumulate in seeds. A galactinol independent pathway was also found operative in chickpea seeds. These results suggested that substrate concentration and GS activity might be the possible factors regulating seed RFO concentration in chickpea. The fourth objective utilized the information, material and methods from the previous three objectives. Chickpea genotypes with contrasting RFO concentration were compared for seed size and weight, germination capacity and RFO biosynthesis (accumulation and biosynthetic enzymes activities during seed development). Sucrose concentration showed a significant positive (r = 0.728, P ≤ 0.05) correlation with seed size/weight. RFO concentration was a facilitator of seed germination rather than regulating factor. Higher accumulation of myo-inositol and sucrose in high RFO genotypes during early seed developmental stages suggested that initial substrates concentrations may influence seed RFO concentration. High RFO genotypes expressed about 2 - 3 fold higher activity for all RFO biosynthetic enzymes compared to those with low RFO concentration. The enzyme activity data corresponded with the accumulation of individual RFO during chickpea seed development. In conclusion, regulating galactinol synthase activity is a potential strategy to reduce seed RFO concentration in chickpea. The present study can be extended to study RFO biosynthesis at the transcript level and the influence of RFO biosynthetic enzymes on seed size and weight, germination, RFO concentration, yield, and stress tolerance.

MSCAGR (Plant Production) / Department of Plant Production / Soil infertility, water scarcity, and availability of high yielding and drought tolerant crop genotypes remain major constraints for agricultural production in semi-arid regions. These constraints are major threats to sustainable crop production and food security. Management practices in such areas should always be geared towards improving productivity at a low cost while sustaining soil fertility. Preliminary studies showed the huge potential of chickpea in the dry environments of the North Eastern South Africa. However, lack of nodulation in chickpea has been reported in these regions probably due to low soil pH, insufficient rhizobial populations or total lack of infective native rhizobia. Therefore this study assessed the effect of biochar and rhizobium inoculation on soil pH, nodulation, growth, yield and chlorophyll content of chickpea in Mpumalanga (Nelspruit) and Limpopo (Thohoyandou) Provinces, South Africa. Two field experiments were planted during winter 2015 and 2016. Treatments consisted of three levels of biochar (0, 10 and 20 t ha-1), two Rhizobium inoculation levels (with and without Rhizobium inoculation) and three chickpea genotypes (ACC #4, ACC #5, and ACC #6) in a factorial combination arranged in randomized complete block design replicated three times. Crop phenology (days to 50% emergence, flowering, podding, and physiological maturity), crop growth (plant height, canopy cover, number of primary and secondary branches), nodulation (number of nodules per plant and nodule dry weight), yield and yield components (number of pods per plant, number of seeds per pod and 100 seed weight [100-SW]), and chlorophyll content were determined at various crop growth stages. Identification and isolation of native rhizobia from soils was done using standard protocols. Data obtained were subjected to analyses of variance using the general linear model of Genstat software version 17. Significant differences between the treatments means were compared using the standard error of difference (SED) of the means at 5% level. Correlation analyses were performed to assess the relationship between parameters. Molecular data was subjected to BLASTn in National Centre for Biotechnology Information (NCBI) searches for identification of isolated strains Application of biochar at 10 and 20 t ha-1 increased soil pH by 0.7 pH units in Thohoyandou (clay soil) in 2015 and 2016, respectively. Soil pH increased by 0.77 pH units at 10 t ha-1 and 1.2 pH units at 20 t ha-1 in Nelspruit (loamy sand) in 2015 and 2016, respectively. Similarly, rhizobium inoculation increased soil pH by 0.2 (Thohoyandou) and 0.5 (Nelspruit) pH units in 2015 and 2016, respectively. There was a 100% increase in nodulation in inoculated compared to uninoculated treatments. There was no effect of biochar and rhizobium inoculation on number of days to 50% flowering, podding, v physiological maturity and on plant height. However, plant height varied with genotypes. Biochar application increased above ground biomass by 17% (10 t ha-1) and 12% (20 t ha-1), and 100 seed weight by 9% (10 t ha-1) and 7% (20 t ha-1) in Thohoyandou in 2015. Rhizobium inoculation increased yield and yield components in Thohoyandou in both seasons; biomass was greater by (31 and 23%), grain yield (26 and 24%), number of pods per plant (18 and 31%), and 100-SW (10 and 13%) in 2015 and 2016, respectively. Similarly, rhizobium inoculation increased biomass (53.4%), grain yield (81%), number of pods per plant (54%) and number of seeds per pod (89%) in Nelspruit in 2015. Genotype did not affect yield and yield components in Nelspruit. In contrast, genotype affected above ground biomass, grain yield, harvest index, number of pods per plant, and number of seeds per pod in 2015 in Thohoyandou with ACC #6 producing greater yield compared to ACC #4 and 5. The analysis for native rhizobia showed that agricultural fields in Nelspruit and Thohoyandou lack effective strains of rhizobium. The identified strains according to 16s gene region were Klebsiella variicola, Burkholderia cenocepacia, Bacillus subtilis and Ochrobactrum spp. The effects of biochar and rhizobium inoculation were more pronounced in Thohoyandou compared to Nelspruit. Therefore biochar and rhizobium inoculation may improve chickpea productivity in Limpopo and Mpumalanga Provinces through improved soil pH, nodulation, growth, yield and yield components. / NRF

Chickpea (Cicer Arietinum) was germinated for different lengths of time to determine the influence of germination on the functional and nutritional properties of this legume. Chemical analysis of the flours showed a very significant increase in vitamin C and in lysine during germination. Vitamin C values ranged from 1.2 to 15.6 mg/100 g and lysine from 10.5 to 13.5 g/100g of protein for the intact and the 48 hr-germinated chickpea, respectively. Starch content decreased 15.5% and soluble sugars increased 20% after only 24 hr of germination. Germination decreased trypsin inhibitor activity by 28%. Chickpea and 24 hr germinated chickpea were used as ingredients in the preparation of several products. Germination increased acceptability in some of these products by modifying their rheological and sensory properties. Seed germination enhanced significantly the nutritional quality of chickpea protein. Protein efficiency ratio associated with the germinated chickpea diets compared favorably to that obtained with the casein diet. Protein digestibility decreased as germination time increased. Essential amino acid availability did not change after 24 hr of germination, but small decreases were observed after 48 hr. Protein and starch were studied separately to determine their influence on the observed modifications. No significant changes were found in the concentration of proteins in germinated chickpea even after 72 hr of germination as indicated by densitometry scans of SDS-PAGE patterns. Starch was isolated from intact and germinated chickpeas and characterized by several of its physicochemical properties and its susceptibility to alpha-amylase hydrolysis. Germination increased substantially starch digestibility and modified some of the physico-chemical properties of starch. Scanning electron microscopy (SEM) showed no apparent differences between starches except for a tendency of the germinated chickpea starch to clump. These results suggest that changes in texture, consistency and other physical parameters observed on the germinated chickpea-based products may be attributed mostly to starch.

Cultivated chickpea (Cicer arietinum) has a narrow genetic base making it difficult for breeders to produce new elite cultivars with durable resistance to major biotic and abiotic stresses. As an alternative to genome mapping, microarrays have recently been applied in crop species to identify and assess the function of putative genes thought to be involved in plant abiotic stress and defence responses. In the present study, a cDNA microarray approach was taken in order to determine if the transcription of genes, from a set of previously identified putative stress-responsive genes from chickpea and its close relative Lathyrus sativus, were altered in chickpea by the three abiotic stresses; drought, cold and high-salinity. For this, chickpea genotypes known to be tolerant and susceptible to each abiotic stress were challenged and gene expression in the leaf, root and/or flower tissues was studied. The transcripts that were differentially expressed among stressed an d unstressed plants in response to the particular stress were analysed in the context of tolerant/susceptible genotypes. The transcriptional change of more than two fold was observed for 109, 210 and 386 genes after drought, cold and high-salinity treatments, respectively. Among these, two, 15 and 30 genes were consensually differentially expressed (DE) between tolerant and susceptible genotypes studied for drought, cold and high-salinity, respectively. The genes that were DE in tolerant and susceptible genotypes under abiotic stresses code for various functional and regulatory proteins. Significant differences in stress responses were observed within and between tolerant and susceptible genotypes highlighting the multiple gene control and complexity of abiotic stress response mechanism in chickpea. The annotation of these genes suggests that they may have a role in abiotic stress response and are potential candidates for tolerance/susceptibility.

The use of herbicides in cropping systems is routine in western Canada as is the practice of rotating crops between cereals, oilseeds and pulse crops. Often, herbicides that are appropriate one year in the crop rotation are not compatible with the following crop. Additionally, certain herbicides are designed to target certain enzyme pathways that can interfere with amino acid synthesis. These pathways also exist in the microbial community, including Rhizobium species. Rhizobia have a unique symbiotic relationship with legumes. In return for a carbon source, rhizobia not only fix atmospheric dinitrogen (N2) for the plant, but also can increase soil N reserves for the following year. With herbicides targeting amino acid synthesis in both plants and microbes, there is a possibility that N2 fixation may be inhibited by the application of certain herbicides.<p> This project was designed to examine possible negative effects of herbicide application on N2 fixation in field pea (Pisum sativum L.) and chickpea (Cicer arietinum L.). The study included field, growth chamber and laboratory experiments in which the effects of pre- and post-emergent herbicides, as well as herbicide residues in soil were examined.<p> In the field experiments, some early season measurements suggested that herbicide application had a negative impact on various growth and N2 fixation parameters. However, as the season progressed, plants recovered from early herbicide damage and N2 fixation ultimately was relatively unaffected. Growth chamber experiments similarly revealed that N2 fixation was largely unaffected by herbicide application when the application rates were relatively low (i.e., at rates intended to simulate partial herbicide breakdown, and thus lower than the recommended field rate). Although, N2 fixation was suppressed where high rates of herbicide (i.e., greater than recommended field rate) were applied, the efficiency of the rhizobia to fix N2, (i.e., the amount of N2 fixed per unit nodule mass), was unaffected. This along with a laboratory experiment which monitored growth of rhizobia in vitro, confirmed that rhizobia were not directly affected by the herbicides used in this study and that overall N2 fixation was not inhibited directly by the application of these herbicides. It was concluded that any negative impact on N2 fixation caused by herbicides used in this study, was related to the impact of the herbicide on crop growth, and was not due to any direct effects of the herbicide on the rhizobia.

Chickpea is a food legume crop grown in tropical, sub-tropical and temperate regions. World chickpea production is roughly three times that of lentils. Among pulse crops marketed as human food, world chickpea consumption is second only to dry beans. Turkey, Australia, Syria, Mexico, Argentina and Canada are major chickpea exporters. There are two types of chickpea, namely, the kabuli and the desi. The kabuli type is grown in temperate regions while the desi type chickpea is grown in the semi-arid tropics. Chickpea is valued for its nutritive seeds with high protein and starch content. They are eaten fresh as green vegetables, parched, fried, roasted, and boiled, as snack food, dessert and condiments. The seeds are ground and the flour can be used in soup, dhal and bread. Cooked chickpea is mostly preferred by consumers, especially the kabuli type. In this thesis, the heat and moisture transfer behavior of kabuli chickpea when subjected to cooking at different temperatures was investigated. The thermo-physical properties of chickpea were studied to develop a model to simulate the temperature distribution and moisture absorption in a chickpea seed when cooked in water. The thermo-physical properties determined experimentally were thermal conductivity, specific heat, moisture diffusivity, particle density and moisture content. Thermal diffusivity was calculated using the experimental values of thermal conductivity, specific heat and density. The water absorption in chickpea was determined when the seeds were soaked at different temperatures. It was observed that as the temperature of the soaking medium was increased, the rate of moisture absorption also increased. Soaking was done to enhance the gelatinization process during cooking. Cooking experiments were conducted for boiling temperatures ranging from 70 to 98°C for both soaked and unsoaked seeds. It resulted in the soaked seeds being cooked within 40-50 min, whereas the unsoaked seeds took around 250-300 min to cook. The amount of soluble solids lost during the cooking process is also reported which enables to predict the optimum soaking and cooking temperature. Using linear regression simple models for dependency of thermal conductivity, specific heat, thermal diffusivity and density on temperature and moisture content were developed. The rate of moisture transfer and the center temperature in the seed during cooking was determined experimentally and also simulated with the constant thermal properties found experimentally. The closeness of the simulated and experimental results was proved by appropriate statistical analysis. Based on the results obtained, it can be understood that soaking the chickpea seeds at temperatures ranging from 25 to 40°C for 8 h and cooking it at higher temperatures ranging from 90 to 100°C will improve the quality of the cooked seed with minimum mass loss. This optimum condition saves both energy and time.

The main objective of this research was to investigate possible uses of Western-Canadian grown chickpea (<i>Cicer arietinum</i> L.) in the form of flour, starch and protein isolates in low-fat pork bologna. <p>In the first study, flour, starch and protein isolates from six chickpea cultivars (three Kabuli and three Desi) from two harvests (2005 and 2006) were evaluated for their physico-chemical, functional and thermal properties. Chickpea flour was made by grinding seed to pass through a 0.1mm screen, whereas protein isolates and starch were prepared by a wet milling process. Protein isolates were prepared from chickpea flour (23.2% protein on average) by alkaline extraction (pH 8.0) and isoelectric precipitation (pH 4.3). Protein isolates contained 72.8-85.3% protein; the starch fraction contained 93.0-98.0% starch. On SDS-PAGE, the chickpea flours and protein isolates contained similar polypeptide bands in the range of 30 to 55 kDa, with three major bands at approximately 50-55, 40 and 30 kDa. Least gelation concentration (LGC) for chickpea flours ranged from 6-14%; LGC for chickpea protein isolates ranged from 10-14%. Differential scanning calorimetry (DSC) of chickpea flour slurries revealed two endothermic peaks. One corresponded to starch gelatinization at approximately 64°C, which was slightly higher than for the starch fraction (~60°C). The second broad peak at approximately 96°C corresponded to the denaturation of the globulin protein fraction, which was also slightly higher than for the protein isolates (~91°C). Chickpea flour exhibited nitrogen solubility index values higher than those of chickpea protein isolates and soy and pea protein isolates. Chickpea protein isolates exhibited water holding capacities, oil absorption capacities, emulsion activity indeces and emulsion stability indeces higher than those of the chickpea flours. CDC Xena (Kabuli) and Myles (Desi), in general, most exhibited properties appropriate for meat applications. In the second study, the efficacy of flour, starch and protein from CDC Xena (Kabuli hereafter) and Myles (Desi hereafter) were investigated in low-fat pork bologna (LFPB). Low-fat pork bologna (<5% fat) was prepared by incorporating 2.5 or 5.0% flour, 1.5 or 3.0% protein isolate (protein basis), or 1.0 or 2.0% starch in the formulation. Controls were prepared without any binder, and formulations containing wheat or pea flour, soy or pea protein isolate, potato or pea starch, or extra meat were prepared for comparison. Inclusion of chickpea flour, protein or starch had a positive effect (P<0.05) on the cook yield, expressible moisture and purge of LFPB, and had little effect on colour. Increasing chickpea flour substitution from 2.5 to 5.0% altered the sensory and instrumental textural quality of LFPB significantly (P<0.05). Desi flour at 5.0% showed the highest TPA (texture profile analysis) hardness and chewiness, Allo-Kramer shear values and torsion shear stress. Similarly, LFPB containing chickpea protein isolate (CPI), soy protein isolate (SPI) or pea protein isolate (PPI) (3.0% protein basis) was firmer than either LFPB containing 1.5% protein from CPI, SPI or PPI or the control-I (with the same level of meat protein). Likewise, LFPB formulated with 2.0% Kabuli or Desi starch had higher TPA values than those prepared with pea or potato starch. For most flavour sensory properties, Kabuli and Desi chickpea flour and starch, irrespective of level of incorporation, performed similarly to the control. However, panellists noted more off-flavours with the addition of wheat flour or pea flour at 5.0%. Chickpea protein isolate, SPI or PPI at the 1.5% protein addition level did not alter the flavour properties of LFPB.<p>It was concluded that chickpea flour, starch and protein had potential for utilization as extenders in low-fat meat emulsion systems such as frankfurters and bologna.