Pulse Crops: Biotechnological Strategies to Enhance Abiotic Stress Tolerance

Pulse crops are leguminous plants whose grains are used exclusively for food. In Asia, Africa, and many developing countries, pulses constitute a major source of dietary protein and extensive efforts are being undertaken to improve pulse production. However, due to global climate change, abiotic stresses are increasingly impeding crop production. Conventional plant breeding has contributed tremendously to the development of improved crop varieties, but other biotechnological tools are needed to complement breeding efforts to accelerate development of pulse crop varieties tolerant to abiotic stresses such as drought, salinity, and high and low temperatures. Genomics resources such as molecular markers have started to expedite marker-assisted breeding and quantitative trait loci (QTL) introgression in chickpea for drought tolerance. Similarly, transcriptomic resources such as expressed sequence tags and expression profiling such as microarrays also contribute to further understand abiotic stress tolerance in pulses and for the development of genic markers. In pulse crops, development of in vitro regeneration techniques and transgenics has been slow and more resources need to be allocated to expedite their development. In vitro regeneration techniques are also useful for embryo rescue of wide hybrids. Transgenics, although controversial, offer a faster means to develop abiotic stress-tolerant pulse crops. While enhancement of abiotic stress tolerance in pulse crops implies higher returns in the developed countries, in developing countries it will contribute to food and nutritional security and sustainable production. It is therefore encouraging that ICARDA, ICRISAT, and CGIAR (Generation Challenge Programme) invest extensively into using new technologies for improvement of pulse crops in these regions of low-input farming

Achievements and challenges in improving nutritional quality of chickpea

Chickpea (Cicer arietinum L.) grains are an excellent source of protein, carbohydrates, minerals, vitamins, dietary fibre, folate, β-carotene and health promoting fatty acids. Their consumption provides consumers with a variety of nutritional and health benefits. Limited breeding efforts have been made on nutritional quality traits of chickpea. Potential exists for further enhancing contents of protein, minerals (iron and zinc), folate and β-carotene and reducing the contents of flatulence causing raffinose family of oligosaccharides (RFOs). The desi types account for about 80% to 85% of the global chickpea area and largely grown in South Asia, Eastern Africa, and Australia and mainly consumed in South Asia. Though the total chickpea area under kabuli type is less (15 to 20%), the production and consumption of kabuli type is globally more wide spread than the desi types. Chickpeas are mainly used for human consumption and a very small proportion as animal feed. The dry chickpea grains are used whole (after soaking and/or cooking, roasting or parching) or dehulled to make splits (dal) or ground to produce flour (besan). The soaked/cooked chickpea grains are used in salads, making vegetable curries (Chhole) and several other preparations, such as falafel (deep fried balls or patties) and hummus (chickpea dip or spread). The chickpea flour is used in making a wide variety of snack foods, soups, sweets, and condiments besides being mixed with wheat flour to make Indian bread (roti or chapati). Invariably, splits (dal) and flour are made from desi type, while hummus is made from kabuli type. Chickpea leaves are used as leafy vegetable and immature green grains are eaten raw or after roasting and also used as vegetable

Chickpea – nutritional quality and role in alleviation of global malnourishment

Chickpea (Cicer arietinum L.) constitute a well-balanced source of carbohydrates, proteins, vitamins and minerals essential to combat malnourishment in human populations. The various seed constituents show large variations in abundance between genotypes, which allow selection of lines for both calorie-rich and calorie-reduced diets. Chickpea with a high protein content combined with high digestibility is preferred in diets where food is scarce. In diets of affluent cultures, chickpeas with good vitamin, fatty acid and mineral balance combined with low digestibility would have a preference. The major challenges in chickpea improvement are development of region-specific genotypes with reduced content of anti-nutritional constituents such as the raffinose family of oligosaccharides. This improvement would encourage a wider use of chickpea-based diets around the world

Variation in Seed-Quality Traits of Chickpea and Their Correlation to Raffinose Family Oligosaccharides Concentrations

Genetic resources with desired seed composition are needed to improve nutritional quality of chickpea (Cicer arietinum L.) seeds. A germplasm collection of 171 chickpea genotypes (desi and kabuli types) was characterized for selected seed quality traits (thousand-seed weight [TSW], starch, protein, and amylose) in one greenhouse and two field trials. Kabuli-type chickpea genotypes (115.7 to 537.4 g and 36.2 to 49.0%) had higher TSW and starch concentrations than desi types (114.6 to 332.4 g and 32.4 to 42.9%), respectively. Desi type chickpea genotypes (16.7 to 27.5%) showed a higher range for protein concentration than kabuli types (17.1 to 24.8%). However, amylose concentration did not vary significantly between desi (29.7 to 34.4%) and kabuli (29.2 to 35.0%) type chickpea genotypes. Genotype, environment, and their interaction showed a significant impact on selected seed-quality traits. Among the chickpea seed-quality traits studied, seed weight was the most heritable trait, and it showed significant positive correlation with starch concentration. Protein, amylose, and total raffinose family oligosaccharides (RFO) had significant negative correlation with TSW. However, total RFO concentration showed significant positive correlation to both starch and protein concentrations. The identified desi and kabuli genotypes can be used as new genetic resources in chickpea improvement programs to develop chickpea varieties with enhanced nutritional composition

Co-localization of genomic regions associated with seed morphology and composition in a desi chickpea (Cicer arietinum L.) population varying in seed protein concentration

Key message Major QTL on LG 1 and 3 control seed filling and seed coat development, thereby affecting seed shape, size, color, composition and weight, key determinants of crop yield and quality. Abstract A chickpea (Cicer arietinum L.) population consisting of 189 recombinant inbred lines (RILs) derived from a cross between medium-protein ICC 995 and high-protein ICC 5912 genotypes of the desi market class was analyzed for seed properties. Seed from the parental lines and RILs was produced in four different environments for determination of seed shape (SS), 100-seed weight (100-SW), protein (PRO) and starch (STA) concentration. Polymorphic genetic markers for the population were identified by Genotyping by Sequencing and assembled into a 522.5 cM genetic map. Phenotype data from the different growth environments were analyzed by QTL mapping done by single and multi-environment analyses and in addition, single marker association mapping. The analyses identified in total 11 QTL, of which the most significant (P < 0.05) loci were located on LG 1 (q-1.1), LG 2 (q-2.1), LG 3 (q-3.2, q-3.3), LG 4 (q-4.2), and LG 5 (q-5.1). STA was mostly affected by q-1.1, which explained 19.0% of the phenotypic variance for the trait. The largest QTL effects were demonstrated by q-3.2 that explained 52.5% of the phenotypic variances for 100-SW, 44.3% for PRO, and 14.6% for SS. This locus was also highly associated with flower color (COL; 95.2% explained) and showed q-3.2 alleles from the ICC 5912 parent conferred the blue flower color and production of small, round seeds with relatively high protein concentration. Genes affecting seed filling at q-1.1 and seed coat development at q-3.2, respectively, were considered to underlie differences in seed composition and morphology in the RIL population

Nutritional quality and health benefits of chickpea (Cicer arietinum L.): a review

Chickpea (Cicer arietinum L.) is an important pulse crop grown and consumed all over the world, especially in the Afro-Asian countries. It is a good source of carbohydrates and protein, and protein quality is considered to be better than other pulses. Chickpea has significant amounts of all the essential amino acids except sulphur-containing amino acids, which can be complemented by adding cereals to the daily diet. Starch is the major storage carbohydrate followed by dietary fibre, oligosaccharides and simple sugars such as glucose and sucrose. Although lipids are present in low amounts, chickpea is rich in nutritionally important unsaturated fatty acids such as linoleic and oleic acids. b-Sitosterol, campesterol and stigmasterol are important sterols present in chickpea oil. Ca, Mg, P and, especially, K are also present in chickpea seeds. Chickpea is a good source of important vitamins such as riboflavin, niacin, thiamin, folate and the vitamin A precursor b-carotene. As with other pulses, chickpea seeds also contain anti-nutritional factors which can be reduced or eliminated by different cooking techniques. Chickpea has several potential health benefits, and, in combination with other pulses and cereals, it could have beneficial effects on some of the important human diseases such as CVD, type 2 diabetes, digestive diseases and some cancers. Overall, chickpea is an important pulse crop with a diverse array of potential nutritional and health benefits

Factors Governing Pasting Properties of Waxy Wheat Flours

Citation: Purna, S. K. G., Shi, Y. C., Guan, L., Wilson, J. D., & Graybosch, R. A. (2015). Factors Governing Pasting Properties of Waxy Wheat Flours. Cereal Chemistry, 92(5), 529-535. doi:10.1094/cchem-10-14-0209-rWaxy wheat (Triticum aestivum L.) contains endosperm starch lacking in amylose. To realize the full potential of waxy wheat, the pasting properties of hard waxy wheat flours as well as factors governing the pasting properties were investigated and compared with normal and partial waxy wheat flours. Starches isolated from six hard waxy wheat flours had similar pasting properties, yet their corresponding flours had very different pasting properties. The differences in pasting properties were narrowed after endogenous alpha-amylase activity in waxy wheat flours was inhibited by silver nitrate. Upon treatment with protease, the extent of protein digestibility influenced the viscosity profile in waxy wheat flours. Waxy wheat starch granules swelled extensively when heated in water and exhibited a high peak viscosity, but they fragmented at high temperatures, resulting in more rapid breakdown in viscosity. The extensively swelled and fragmented waxy wheat starch granules were more susceptible to a-amylase degradation than normal wheat starch. A combination of endogenous a-amylase activity and protein matrix contributed to a large variation in pasting properties of waxy wheat flours

Identification of genomic regions determining the phenological development leading to floral transition in wheat (Triticum aestivum L.)

Autumn-seeded winter cereals acquire tolerance to freezing temperatures and become vernalized by exposure to low temperature (LT). The level of accumulated LT tolerance depends on the cold acclimation rate and factors controlling timing of floral transition at the shoot apical meristem. In this study, genomic loci controlling the floral transition time were mapped in a winter wheat (T. aestivum L.) doubled haploid (DH) mapping population segregating for LT tolerance and rate of phenological development. The final leaf number (FLN), days to FLN, and days to anthesis were determined for 142 DH lines grown with and without vernalization in controlled environments. Analysis of trait data by composite interval mapping (CIM) identified 11 genomic regions that carried quantitative trait loci (QTLs) for the developmental traits studied. CIM analysis showed that the time for floral transition in both vernalized and non-vernalized plants was controlled by common QTL regions on chromosomes 1B, 2A, 2B, 6A and 7A. A QTL identified on chromosome 4A influenced floral transition time only in vernalized plants. Alleles of the LT-tolerant parent, Norstar, delayed floral transition at all QTLs except at the 2A locus. Some of the QTL alleles delaying floral transition also increased the length of vegetative growth and delayed flowering time. The genes underlying the QTLs identified in this study encode factors involved in regional adaptation of cold hardy winter wheat