Ashutosh Sarker

Screening techniques and sources of resistance to abiotic stresses in cool-season food legumes

SummaryThe adaptability and productivity of cool-season food legumes (chickpea, faba bean, lentil, pea) are limited by major abiotic stresses including drought, heat, frost, chilling, waterlogging, salinity and mineral toxicities. The severity of these stresses is unpredictable in field experiments, so field trials are increasingly supplemented with controlled-environment testing and physiological screening. For drought testing, irrigation is used in dry fields and rain-out shelters in damp ones. Carbon isotope discrimination (Δ13C) is a well-established screen for drought tolerance in C3 cereal crops which is now being validated for use in grain legumes, but it is relatively expensive per sample and more economical methods include stomatal conductance and canopy temperature. Chickpea lines ICC4958 and FLIP87-59C and faba bean line ILB938 have demonstrated good drought tolerance parameters in different experiments. For frost tolerance, an efficient controlled-environment procedure involves exposing hardened pot-grown plants to sub-zero temperatures. Faba beans Cote d’Or and BPL4628 as well as lentil ILL5865 have demonstrated good freezing tolerance in such tests. Chilling-tolerance tests are more commonly conducted in the field and lentil line ILL1878 as well as derivatives of interspecific crosses between chickpea and its wild relatives have repeatedly shown good results. The timing of chilling is particularly important as temperatures which are not lethal to the plant can greatly disrupt fertilization of flowers. Salinity response can be determined using hydroponic methods with a sand or gravel substrate and rapid, efficient scoring is based on leaf symptoms. Many lines of chickpea, faba bean and lentil have shown good salinity tolerance in a single article but none has become a benchmark. Waterlogging tolerance can be evaluated using paired hydroponic systems, one oxygenated and the other de-oxygenated. The development of lysigenous cavities or aerenchyma in roots, common in warm-season legumes, is reported in pea and lentil but is not well established in chickpea or faba bean. Many stresses are associated with oxidative damage leading to changes in chlorophyll fluorescence, membrane stability and peroxidase levels. An additional factor relevant to the legumes is the response of the symbiotic nitrogen-fixing bacteria to the stress.

Lentils (Lens culinaris Medikus subspecies culinaris): a whole food for increased iron and zinc intake.

Micronutrient malnutrition, the hidden hunger, affects more than 40% of the worlds population, and a majority of them are in South and South East Asia and Africa. This study was carried out to determine the potential for iron (Fe) and zinc (Zn) biofortification of lentils ( Lens culinaris Medikus subsp. culinaris ) to improve human nutrition. Lentils are a common and quick-cooking nutritious staple pulse in many developing countries. We analyzed the total Fe and Zn concentrations of 19 lentil genotypes grown at eight locations for 2 years in Saskatchewan, Canada. It was observed that some genetic variation exists for Fe and Zn concentrations among the lentil lines tested. The total Fe and Zn concentrations ranged from 73 to 90 mg of Fe kg(-1) and from 44 to 54 mg of Zn kg(-1). The calculated percentages of the recommended daily allowance (RDA) for Fe and Zn were within the RDA ranges from a 100 g serving of dry lentils. Broad-sense heritability estimates for Fe and Zn concentrations in lentil seed were 64 and 68%, respectively. It was concluded that lentils have great potential as a whole food source of Fe and Zn for people affected by these nutrient deficiencies. This is the first report on the genetic basis for Fe and Zn micronutrient content in lentils. These results provide some understanding of the genetic basis of Fe and Zn concentrations and will allow for the development of potential strategies for genetic biofortification.

Application of biotechnology in breeding lentil for resistance to biotic and abiotic stress

SummaryLentil is a self-pollinating diploid (2n = 14 chromosomes) annual cool season legume crop that is produced throughout the world and is highly valued as a high protein food. Several abiotic stresses are important to lentil yields world wide and include drought, heat, salt susceptibility and iron deficiency. The biotic stresses are numerous and include: susceptibility to Ascochyta blight, caused by Ascochyta lentis; Anthracnose, caused by Colletotrichum truncatum; Fusarium wilt, caused by Fusarium oxysporum; Sclerotinia white mold, caused by Sclerotinia sclerotiorum; rust, caused by Uromyces fabae; and numerous aphid transmitted viruses. Lentil is also highly susceptible to several species of Orabanche prevalent in the Mediterranean region, for which there does not appear to be much resistance in the germplasm. Plant breeders and geneticists have addressed these stresses by identifying resistant/tolerant germplasm, determining the genetics involved and the genetic map positions of the resistant genes. To this end progress has been made in mapping the lentil genome and several genetic maps are available that eventually will lead to the development of a consensus map for lentil. Marker density has been limited in the published genetic maps and there is a distinct lack of co-dominant markers that would facilitate comparisons of the available genetic maps and efficient identification of markers closely linked to genes of interest. Molecular breeding of lentil for disease resistance genes using marker assisted selection, particularly for resistance to Ascochyta blight and Anthracnose, is underway in Australia and Canada and promising results have been obtained. Comparative genomics and synteny analyses with closely related legumes promises to further advance the knowledge of the lentil genome and provide lentil breeders with additional genes and selectable markers for use in marker assisted selection. Genomic tools such as macro and micro arrays, reverse genetics and genetic transformation are emerging technologies that may eventually be available for use in lentil crop improvement.

SPATIAL VARIABILITY MODELS TO IMPROVE DRYLAND FIELD TRIALS

Spatial variability in field trials is a reality. A proportion of this is accounted for as inter-block variability by using block (complete or incomplete) designs. A large amount of spatial variability still remains unaccounted for, however, and this may lead to erroneous conclusions. To capture this inexplicable variation (which is mainly due to intra-block variation), yield data from a series of variety yield trials, using cereals and legumes, were analysed using various spatial models. The most suitable of these, selected on the basis of the Akaike Information Criterion, were used to assess the relative performance of genotypes. Although incomplete-block designs have been found to be effective in variety trials, spatial models have added considerable value to trials with legumes and cereals. The ‘best’ spatial models gave efficiency values of over 330% in winter-sown chickpea ( Cicer arietinum ), 140% in lentil ( Lens esculenta ), and 150% in barley ( Hordeum spp.) trials. Furthermore, the use of these best models resulted in a change in the ranking of genotypes (on the basis of mean yield), which resulted, therefore, in a different set of genotypes being selected for high yield. It is recommended that: (i) incomplete block designs be used in variety trials; (ii) the Akaike Information Criterion be used to select the best spatial model; and (iii) genotypes be selected after the use of this model. The selected model would account most effectively for spatial variability in the field trials, improve selection of the most desirable genotypes and, therefore, improve the efficiency of breeding programmes.

The lentil: botany, production and uses.

1. Introduction 2. Global Production, Supply and Demand 3. Origin, Phylogeny, Domestication and Spread 4. Plant Morphology, Anatomy and Growth Habit 5. Agro-ecology and Crop Adaptation 6. Genetic Resources 7. Genetics of Economic Traits 8. Genetic Enhancement for Yield and Yield Stability 9. Breeding for Short Season Environments 10. Improvement in Developed Countries 11. Advances in Molecular Research 12. Breeding and Management to Minimize the Effects of Drought and Improve Water Use Efficiency 13. Soil Nutrient Management 14. Cropping Systems and Production Agronomy 15. Biological Nitrogen Fixation and Soil Health Improvement 16. Mechanization 17. Diseases and Their Management 18. Insect Pests and Their Management 19. Virus Diseases and Their Control 20. Weed Management 21. Parasitic Weeds 22. Seed Quality and Alternative Seed Delivery Systems 23. Nutritional and Health-beneficial Quality 24. Post-harvest Processing and Value Addition 25. Food Preparation and Use 26. The Impact of Improvement Research.

Design principles in long-enduring institutions of Japanese irrigation common-pool resources

Abstract We examine how Elinor Ostrom’s eight design principles that characterize long-enduring, self-governed common-pool resource (CPR) institutions apply to Japanese irrigation CPR management. The eight design principles are “(1) clearly defined boundaries”, “(2) proportional equivalence between benefits and costs”, “(3) collective-choice arrangements”, “(4) monitoring”, “(5) graduated sanctions”, “(6) conflict resolution mechanism”, “(7) minimal recognition of rights to organize”, and “(8) nested enterprises”. These design principles refer to irrigation case studies in developing countries mainly and this has aroused our curiosity to examine them in Japan, which has a highly developed economy and where irrigators self-govern their irrigation CPRs (and where the irrigation institutions have been long-lasting and stable). The non-coercive strategic presence of an external entity (the central, prefectural and local government), although the external entity has a strong economy and has invested a lot, has significantly contributed to irrigators’ self-governance of their CPRs in Japan. We find that non-coercive characteristic of the external entity, while the irrigators have strong endogenous institutional arrangements, has led us to moderate design principle seven to explain Japan’s case. The design principles of monitoring (appropriators’ behavior) and graduated sanctions are quite implicit rather than explicit — as Ostrom has generally described these two principles — in Japan’s irrigation management. With all these, we have found that Ostrom’s eight design principles are basic, well configured, and unique, and when we moderate principle seven, the eight design principles together can account for the success of Japan’s long-enduring irrigation institutions that the irrigators formulate to self-govern their CPRs.

Genetic improvement of grass pea for low neurotoxin (β-ODAP) content

Grass pea is a promising crop for adaptation under climate change because of its tolerance to drought, water-logging and salinity, and being almost free from insect-pests and diseases. In spite of such virtues, global area under its cultivation has decreased because of ban on its cultivation in many countries. The ban is imposed due to its association with neurolathyrism, a non-reversible neurological disorder in humans and animals due to presence of neurotoxin, β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in its seedlings and seeds. The traditional varieties of grass pea contain 0.5-2.5% β-ODAP. Exploitable genetic variability for β-ODAP has been observed for development of low ODAP varieties, which along with improved agronomic and detoxification practices can help reduce the risk of lathyrism. Collaborative efforts between ICARDA and NARS have resulted in development of improved varieties such as Wasie in Ethiopia, Ratan, Prateek and Mahateora in India, and BARI Khesari-1 and BARI Khesari-2 in Bangladesh with <0.10% β-ODAP. Soil application of 15-20 kg ha(-1) zinc sulphate, early planting, and soaking seeds in water have shown significant effects on β-ODAP. Because of the often cross-pollination nature, the current breeding procedures being followed in grass pea requires paradigm shift in its approach for a possible genetic breakthrough.

Recent progress in the ancient lentil

Lentil ( Lens culinaris Medikus subsp. culinaris ) was among the first crops domesticated and has become an important food legume crop in the farming and food systems of many countries globally. Its seed is a rich source of protein, minerals, and vitamins for human nutrition, and the straw is a valued animal feed. Its ability in nitrogen and carbon sequestration improves soil nutrient status, which in turn provides sustainability in production systems. In the current paper, research progress achieved in lentil improvement at national and international levels is reviewed. Since the late 1970s there have been significant national and international lentil improvement programmes, with the main objectives being to develop phenologically adapted, stress resistant and high-yielding cultivars with improved production packages. Systematic research on lentil started recently, compared to other early-domesticated crops. During the last two and a half decades, research progress has been made in various aspects of the crop. Large numbers of germplasm have been collected, evaluated and preserved at national and international levels, with the International Center for Agricultural Research in the Dry Areas (ICARDA) holding the largest collection of cultivated and wild germplasm accessions. A major effort has been made to study the genetic variation in the world germplasm collection, in order to understand local adaptation and to develop specific research programmes. Genotypes with resistance to various biotic and abiotic stresses, particularly resistance to vascular wilt, rust and Ascochyta blight have been identified, and directly exploited or used in breeding programmes. New genotypes have been bred with good standing ability, suitable for mechanical harvest for West Asia and North Africa. Through introduction and hybridization, the genetic base of lentil has been broadened, most particularly in South Asia, by breaking an ancient genetic bottleneck. Agronomic practices, including seeding time, seed rate, tillage requirements, soil type, and weed control, are optimized locally and improved production packages have been developed to realize higher yield. To date, a total of 91 improved cultivars have been released globally, emanating from genetic material supplied by ICARDA. Due to adoption of improved varieties combined with production technologies, the average global productivity has increased from 611 kg/ha to 966 kg/ha, and total production from 1·3 million tonnes to 3·8 million tonnes in the last three decades. Research at the molecular level, including construction of a lentil genetic linkage map, identification of molecular markers, and genetic transformation, has progressed considerably.

Variation in shoot and root characteristics and their association with drought tolerance in lentil landraces

Lentil (Lens culinaris Medikus subsp. culinaris), generally grown as a rainfed crop, is often subjected to drought. Drought tolerance is closely related to the distribution of root systems in the soil. We studied seedling shoot and root characters in a set of eight randomly selected lentil genotypes collected from Ethiopia, India, Iran, Syria and ICARDA. Each group of genotypes represents a specific adaptation to the environmental conditions associated with its area of origin. The genotypes were evaluated during two seasons (1997 –1999) under field conditions. Thirty-five-day-old seedlings grown in pots in the open air were assessed for stem length, stem weight, taproot length, lateral root number, total root length and total root weight. Combined analyses over 2 years showed that these characters exhibited significant genotypic variability. Stem length, taproot length and lateral root number were highly correlated, both amongst themselves and with yield. High heritability estimates provided reliability in screening based on these traits. Regression analysis showed that stem length alone accounted for 85% of the variance that occurred in seed yield per plant. Cluster analysis showed that the landraces that originated in Iran and Syria, and the breeding lines developed at ICARDA are distinctly different from the lentil accessions that originated in countries at more southerly latitudes (India and Ethiopia). However, of the total of 40 genotypes, only one line (ILL 6002) was strikingly different from all other test genotypes. This line exhibited significantly superior root and shoot traits and yield, and, therefore, is a valuable germplasm for breeding drought tolerant cultivars.

Genetic Variation in Root Traits and Nutrient Acquisition of Lentil Genotypes

ABSTRACT Lentil (Lens culinaris L.), a pulse crop, is grown in nutrient-poor soils in many developing countries, often with little or no fertilization. Knowledge on root traits of lentil and the assessment of their role in nutrient capture would help to sustain its production in these nutrient-poor soils. Root traits (root length, root hairs, root-induced acidification, and phosphatase enzymes) of 10 lentil genotypes (Barimasur-3, Barimasur-4, PLX-79542, GP-8407-5, GP-8403, BLX-79542, L-5 × 8704(2), L-107 × 87012, L-5 × 87272 and 8406-122) were investigated and then related to the plant uptake of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulphur (S), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), and cobalt (Co) in laboratory and pot experiments. There were significant (p < 0.05) differences in root length (RL) and root-hair density (number mm−1 root) among the genotypes. The genotypes did not differ to induce rhizosphere acidification and acid phosphatase activity (aptase). Uptake of most nutrients differed significantly (p < 0.05) among the genotypes, but root length (RL) was, in general, weakly correlated to the uptake of the most nutrients in the shoot dry matter (DM). The genotypes with prolific root-hair formation (Barimasur-4 and Barimasur-3) were particularly superior in uptake of those nutrients (K, P, Fe, Mn, Cu, Zn, Mo) whose availability in soils is usually low and whose transport to the roots is diffusion limited. The results of this investigation, though based on a small sample of lentil accessions/cultivars, suggest that genetic variation in lentil root traits and nutrient uptake can be pronounced. Screening of a large number of local and exotic cultivars or lines of lentil should be conducted by including more root traits (N2 fixation, organic acids, mycorrhizae) to find nutrient-efficient germplasm to promote lentil production.