2.1 Introduction
2.2 Sorghum
2.3 Pearl Millet
2.4. Groundnut
2.5 Chickpea
2.6 Pigeonpea
2.7 Overall Assessment of Commodity Programmes
ICRISAT serves as a world centre for the improvement of sorghum, millet, chickpea, pigeonpea, and groundnut and acts as world repository for the genetic resources of these crops (See Chapter 3). A large proportion of ICRISAT's budget is devoted to crop improvement. This chapter briefly reviews each of the commodity improvement programmes in light of the major issues confronting the Centre. The evolution of each programmes is described briefly; achievements and impact are noted; future strategy is discussed; and an assessment is provided for each commodity programme. The Chapter concludes with an overall assessment of the entire commodity portfolio.
2.2.1 Evolution
2.2.2 Achievements and Impact
2.2.3 Future Strategy
2.2.4 Assessment
Grown throughout the world between 40° N and S latitudes, sorghum (Sorghum bicolor (L.) Moench) is at home in the SAT. The majority of the cultivated area is in Africa (23.1 M ha) and Asia (14.2 M ha) which combine to produce about 35 M t. Significant areas are also found in Latin America, Australia, and the United States (the world's largest producer). Sorghum ranks fifth in production among the world's cereals and is a staple food crop for millions of people in the SAT. Compared to the cereals that outrank it in global production (wheat, rice, maize, and barley), sorghum is a relatively less developed crop, probably because it is not a food crop in the developed world. Average productivity in the SAT is only around 1.01 ha-1 compared to 3-5 t ha-1 in favourable environments. The biological potential for improving the crop is great as it is endowed with wide genetic variability, adaptation to harsh edaphic and climatic conditions, and is a C4 plant with a very high growth rate.
The limitations to sorghum improvement lie in the physical and socioeconomic environments where it is cultivated. It is hard to overstate the complexity of sorghum production systems in the SAT, particularly in West and Central Africa where so many people subsist on the crop. Over the centuries, yield stability has been the primary selection criterion with adaptation to (and compensation for the variability in) rainfall patterns. Disease, insect and weed pests are balanced in these systems, and the systems may be destabilized by the alteration of any component, particularly the variety. Soil fertility is an overriding constraint in most systems, particularly in Africa. Indeed, it has been pointed out (CCER for WCA, 1996) that improved cultivars may have little or no impact until the fertility problem is addressed in this region.
ICRISAT has been involved in sorghum breeding for more than 20 years, and, in the global research system, bears the leadership for sorghum research especially for the SAT. The other major sorghum research programmes in the world (US, Australia) are oriented towards sorghum production in favourable environments, mainly for feed use.
The Centre has extensive sorghum improvement efforts in Asia, West and Central Africa, and Southern and Eastern Africa, targeting the unique requirements of the diverse array of production systems in the SAT. At present, the research efforts in sorghum are focused on thirteen research themes considered to be of global importance. Attention is also given to complementary themes that recognize specific requirements of different regions. ICRISAT's sorghum research is currently organized and operated as five projects: SG1, SG2, SG3, SG4, and SG5, targeted toward low rainfall, medium rainfall, high rainfall, high altitude/low temperature areas, and post-rainy production, respectively. Commencing in January, 1997, all sorghum research activities will be consolidated under one project.
The US has some international participation in the global effort through the sorghum-millet Cooperative Research Support Project (INTSORMIL) while France has provided major support to sorghum improvement in West Africa through CIRAD/ICRISAT collaboration in Mali. Funding for both French and US participation is tenuous. CIRAD is not expected to provide significant support for the programmes in Mali beyond 1997. ICRISAT is considering plans to pick up the population improvement component of the programme and to adjust staffing to deal with Striga, the most limiting factor to sorghum production in the area. With the closure of the CIRAD programme, an effective sorghum programme may no longer operate in West and Central Africa, the centre of diversity for the crop which provides subsistence for millions of people.
Significant advancements were made by the sorghum programme especially during the period under review. Numerous cultivars developed at ICRISAT and/or in partnership with NARS have been released in several countries in the SAT, and elite breeding lines are in various stages of on-farm and pre-release testing.
Improved sources of resistance to yield- and quality-limiting factors have been identified, and screening methodologies and techniques developed at ICRISAT are now widely used by NARS scientists, including screening methods for various biotic stresses (e.g. grain mold, downy mildew, ergot, shoot fly, stem borer, Striga, etc.), and screening for tolerance to drought. In addition, breeding strategies and concepts have drawn on genetic resources to develop, among others, hybrids with grain mold resistance, tall male-sterile lines for forage and post-rainy season sorghums, and male-sterile resistant lines. Studies on the response of sorghum genotypes to terminal drought, temperature, and photoperiod have provided valuable information that led to better understanding of crop phenology and its implications on adaptability to diverse agroecological regions. Advances were also made on the development of molecular marker and transformation technologies for application to sorghum improvement.
Noteworthy among the recent achievements is ICRISAT's success in identifying grain mold resistance in white-colored sorghums, a development that would have tremendous potential in mitigating this major disease problem, particularly in early maturing cultivars grown in intermediate rainfall areas. Superior hybrids with yield gains of over 40% compared to traditional cultivars were also identified for West Africa. Landrace-based sorghum hybrids with acceptable grain quality and adaptability have been developed for post-rainy season cultivation in India.
ICRISAT's research has made significant impact on sorghum production in some regions, particularly in India where the area devoted to the crop has declined concomitant with increases in productivity. On the other hand, and notwithstanding the numerous germplasm releases, evidence is still lacking that ICRISAT's sorghum breeding programme has had significant impact in improving sorghum production in the African SAT. There is, however, increasing documentation on the adoption of ICRISAT-developed cultivars. In Zimbabwe, for instance, the cultivar SV 2 which gives an average of 55% yield advantage over local cultivars had already reached 36% adoption in 1994/95. Cultivar S35 reached as high as 49% adoption in parts of Cameroon and 39% in Chad, resulting in yield differential of about 600 kg ha-1 and significant unit cost reduction (see Section 5.3). Private sector interest has also been elicited in Nigeria for seed production of ICSV 400. These, among others, hold open the possibility for future positive impact of the programme in the African SAT.
A strategy document on genetic enhancement was provided to the EPMR panel. It represents a somewhat eclectic presentation of the sorghum programme and its future strategy. It identifies the specific constraints to sorghum production and discusses the research efforts for each constraint. The consolidation of sorghum improvement into one sorghum project in 1997 hopefully will allow for a more coherent presentation.
The main products of sorghum genetic enhancement are improved varieties and hybrids, hybrid parents, and germplasm pools with specific traits. The strategy reflects a well-considered approach to relationships with the various NARS which vary widely in scientific capacity and research infrastructure. In Asia, where NARS and the private sector have well developed research capability, parental materials and improved populations are the primary products. In Africa, on the other hand, efforts are directed toward the development of varieties and hybrids. Emphasis is given on development of pureline varieties, with complementary efforts on hybrid variety development.
ICRISAT's sorghum improvement is targeted at five major production systems in the SAT. While constraints that are of global significance and most common among production systems are given priority attention, adaptation to specific production systems are also emphasized. Thus, a balanced mix of strategic/applied/adaptive research is carried out. Concerted efforts are focused on drought and Striga, the two most challenging constraints to sorghum production in the SAT.
Genetic enhancement activities in Asia, WCA, and SEA are designed to be complementary and synergistic. Moreover, there are intensive efforts to broaden the genetic base of sorghum through development of populations derived from different races to assure long-term genetic improvement for the various growing environments. Diversification and improvement of the male-sterile lines and cytoplasms are also major objectives.
Molecular marker technology for sorghum is being developed and will be utilized for further characterization of the germplasm and for marker-aided selection, especially for Striga resistance. Efforts are also underway to develop genetic transformation techniques for sorghum for eventual use in incorporating foreign genes into the crop.
Relating to sorghum, the CCERs for West and Central Africa and Eastern and Southern Africa were well done. The EPMR Panel concurs with the CCER's assessment on the technical soundness of the sorghum improvement programme and endorses the rather numerous recommendations. However, while the strategy is technically sound, the Panel is of the opinion that it does not adequately articulate a vision for the future that addresses the challenges of the complex production systems of the SAT, and their contribution to future food security.
The Panel specifically endorses the recommendation for a strengthened interdisciplinary effort among breeders, agronomists, physiologists, and soil scientists to identify and exploit physio-genetic systems that increase efficiency of extraction and utilization of plant nutrients (in particular, P and N). The probability is low that improved genetic materials will make a significant difference in productivity unless coupled with increased efficiency in the use of these nutrients. This highlights the need for more complementary research between crop improvement and natural resources management, especially for low-external input production environments.
The Panel is pleased to note that aspects of farmer participation have been incorporated in the breeding strategy, particularly in Africa. In the highly diverse and complex production systems of the SAT, farmer participation in on-station and on-farm selection could be very effective in guiding and validating breeding objectives as well as evaluating variety performance and acceptability.
Sorghum cultivation, particularly in Africa, must reckon with competing crops such as maize in the higher rainfall areas, projected decreased demand for sorghum as food in the urban areas, and projected increased demand as feedgrain. Thus, sorghum improvement should remain focused on production areas, especially in the Sudanian zone, where the crop would have a comparative edge. The Panel also endorses the CCERs' suggestion that quality considerations be given adequate emphasis in sorghum improvement, to cater to food, livestock feed and agro-industrial requirements.
With the evolution of new GIS technologies, molecular-based breeding, and modeling, it should become possible eventually to tailor "niche technologies" for the complex sorghum production systems of the SAT. The Panel suggests that ICRISAT formulate a strategy with other research partners to work toward this goal (see Section 2.7 at the end of this chapter).
Striga is a major constraint in all production systems in West and Central Africa, and is a serious potential threat in other regions. It should be possible to control this pest through genetic resistance without unbalancing the production systems, and host plant resistance should be the primary component strategy for integrated control of Striga. The Panel endorses the full participation of ICRISAT in collaborative effort with other Centres, IITA and CIMMYT, ARIs and NARS to control Striga and other parasitic weeds affecting sorghum and other mandate crops.
Budgetary constraints limit the ability of ICRISAT to support multi-location projects. India is capable of meeting its own needs for sorghum improvement. Research efforts at Patancheru should revolve around germplasm evaluation and enhancement (see also Section 9.1.3). Finally, given the dependence on this crop, the Panel states unequivocally that no long-term hope exists for the improvement of human welfare in West and Central Africa unless a strong sorghum breeding programme is maintained in the region.
2.3.1 Evolution
2.3.2 Achievements and Impact
2.3.3 Future Strategy
2.3.4 Assessment
Pearl millet (Pennisetum glaucum (L.) R. Br.) is grown on about 26 m ha, mostly in India (10m ha) and West Africa (12 m ha). In West Africa, nearly 80% of the area is in the Sahelian zone. Nigeria, Niger, Mali, Burkina Faso and Senegal produce 84% of the millet in the region. In Southern and Eastern Africa, 2.5 m ha are spread over 16 countries, with Sudan accounting for more than half the total. The crop is dual purpose, with the grain mostly used for human consumption, and crop residues constituting a strategic resource for livestock feed. It is the dominant (sometimes the only) cereal crop in the drier zones and an important component of crop/livestock systems. Average productivity in both Asia and Africa is only about 700 kg ha-1.
ICRISAT has been involved in pearl millet research since the inception of the centre, and it has a clear leadership role for improvement of the crop, both in India and Africa. India is the only NARS with substantial research capacity in pearl millet. The US has some international participation in pearl millet improvement through the sorghum-millet cooperative research support project (INTSORMIL), and France has some involvement with the crop in West Africa through a Niger-based ORSTOM team that operates independently but in collaboration with ICRISAT.
ICRISAT's pearl millet research is currently organized and operated under three global projects: PM1, PM2, and PM3, directed at improving productivity and stability in the semi-arid transition, semi-arid tropical, and long-season semi-arid tropical environments, respectively. These are to be consolidated under one project commencing in January, 1997.
Improved grain yield and downy mildew resistance have been the main thrusts of the pearl millet improvement programme. The result in India has been a significant improvement and stability of grain production, resulting in the prestigious King Baudouin Award for 1996. The Panel commends the Centre for this research which has accomplished so much for what some might call, "a crop of the desert fringe".
This major achievement in pearl millets was brought about by a comprehensive strategic research effort employing genetic enhancement and plant breeding to obtain resistance to downy mildew. Two classes of resistance were used; recovery resistance in which pathogens and host co-exist without affecting yield, and complete resistance. These efforts were complemented by molecular mapping to find the genes that contribute to resistance, their patterns in the plant, and specificity for resistance to different pathogen populations.
Numerous pearl millet cultivars have been developed and released by the Centre and its partner NARS. Highly promising hybrids are also in various stages of advanced testing and prerelease. According to the breeding strategies document, however, the impact in Africa "remains to be assessed", but apparently has not been significant (see Section 5.3). As with sorghum improvement in West Africa, the programme continues to hold open the possibility for future impact. Dependence on pearl millet is extensive, particularly in the drier zones, and it is essential that a strong breeding programme be supported for the region. Otherwise, there can be little hope in the long term for the many people dependent on this crop.
Drought is the most serious production constraint in pearl millet. Downy mildew, on the other hand, is widespread both in Asia and Africa and is a serious threat, especially with the large-scale cultivation of single-cross hybrids. Grain yield and stability through resistance to drought and downy mildew will continue to be the focus of crop improvement efforts in all regions. Early maturity coupled with high grain yield potential is considered to be the most effective crop improvement approach for addressing drought. On the other hand, genetic resistance is the only cost-effective way of controlling downy mildew. Addressing constraints other than downy mildew will require the identification of adequate sources of resistance and effective screening techniques.
Striga is the most serious biotic constraint in pearl millet; however, no good sources of resistance have yet been identified. Building the level of resistance through intercrossing of low susceptibles is used as an approach to develop resistant materials useful in breeding. Molecular marker technology is also being considered to increase the efficiency and effectiveness of breeding for Striga resistance.
Millet breeding efforts are geared toward producing intermediate products, such as improved populations, and two types of finished products: open-pollinated varieties (OPVs) and hybrids. In the past, OPVs and improved breeding materials and populations have been the major emphasis. With the growing capability of some partner NARS, notably India, greater emphasis is now placed on hybrid development and continuing population improvement for Asia.
It is anticipated that OPVs will be the only option in Africa for some time to come, while hybrid varieties will become increasingly dominant in India. Plans in India call for greater attention to hybrid parent development and reorientation of population improvement programmes to produce appropriate base materials.
Research is underway to develop a type of topcross hybrid that involves the use of male fertile inbred line as seed parent. This type of hybrid overcomes many of the technical difficulties of hybrid seed production that is based on the male sterile system, and could eventually find wider application in Africa.
Future plans call for increased collaborative research in all three regions (Asia, SEA, WCA), to be conducted and reported in full partnership with the NARS. The Asia centre will shift toward strategic research and full integration in the areas of strategic research and germplasm exchange. Laboratory oriented research requiring advanced technical skills and tools will be conducted in partnership with developed country laboratories and advanced NARS (e.g. ICAR).
In zones with under 600mm of annual rainfall, the CCER for West and Central Africa recommended that research efforts be concentrated on natural resources management. This recommendation was accepted by ICRISAT. The Panel suggests that this might later be reconsidered in the light of the proposed strategic research thrust on germplasm evaluation and enhancement (see Section 9.1.3).
The CCER for West and Central Africa found the pearl millet improvement activities of ICRISAT to be very sound . The EPMR endorses that finding and extends it to the other regions as well. Pearl millet improvement is a major success story for ICRISAT, and further gains can be expected. As with sorghum, the programme at the ICRISAT Asia Centre should revolve around germplasm evaluation and enhancement (see recommendation in Section 3.5), providing enhanced germplasm for crop improvement in Africa and for India in a partnership mode.
The Panel was pleased to note that the centre has also initiated participatory breeding in Rajasthan, India, in conjunction with ISP1. This approach, pursued within the context of integrated production systems, could potentially result in a much refined understanding of cultivar adaptation and adoption in this marginal environment. The Panel encourages ICRISAT to pursue this effort further, with the end goal of developing and elaborating the methodology for participatory breeding.
2.4.1 Evolution
2.4.2 Achievements and Impact
2.4.3 Future Strategy
2.4.4 Assessment
Groundnut (Arachis hypogaea) is one of the major oilseeds and a crop of global importance. More than 100 countries grow groundnut, and its aggregate area amounts to more than 20 million ha. Total production in shell is about 28.5 million metric tons, about two-thirds of which is crushed for oil. Asia accounts for about 63% of the hectarage and 70% of total production, while Africa contributes 31% of total area and 18% of total production.
Over the last four decades, average groundnut pod yield ha-1 in the world increased from about 0.8 t ha-1 to about 1.3 t ha-1 at present. Over the same period, average productivity in Asia also increased from ca 0.8 t ha-1 to about 1.4 t ha-1 pod yield. In the whole of Africa, however, productivity has not improved but has remained at the level of about 0.8 t ha-1 pod yield over the same period.
A large gap exists in groundnut between potential and realized yields. A myriad of constraints contribute to low and unstable yields in different growing environments. For instance, drought is a major constraint in the SAT where about 70% of the groundnuts are grown, largely in mixed cropping systems. Likewise, other abiotic and biotic constraints contribute significantly to reduced groundnut yields. Undoubtedly, breeding and improved management practices can help alleviate most of these constraints; however, these should be coupled with effective technology transfer and delivery mechanisms to have appreciable impact on enhancing groundnut productivity.
ICRISAT has the global mandate for groundnut and has had major activities on the crop for the last 20 years. In keeping with its mandate as a world repository of genetic resources, the Arachis germplasm collection in the Centre consists of more than 15,000 accessions, representing a rich and strategic resource for crop improvement.
Research on groundnut started at ICRISAT in 1976, and subsequently was placed in the Legumes Programme together with pigeonpea and chickpea until 1994, when the crops were placed in projects. In the late 1980's, groundnut research was initiated in SEA and WCA. The current groundnut research portfolio consists of three global projects: GN1, GN2 and GN3, which, respectively, aim to improve productivity and stability of medium and long duration, short duration, and irrigated groundnut. GN1 and GN2 focus on rainfed groundnuts which comprise around 70% of total groundnut hectarage, largely at the subsistence level. GN3 is geared towards high-input and intensive groundnut production principally in Asia. Three regional teams - WCA, SEA, and IAC- are jointly responsible for the three projects. All groundnut activities will be consolidated under one Project in January, 1997. Collaboration with NARS and other institutions is the dominant mode of implementation of the groundnut research.
The Panel commends the Centre for the substantive outputs and excellent quality of the scientific work on groundnut. The more than 50 improved cultivars and breeding lines released or under advanced testing by NARS attest to the project's efficiency. Pioneering work on groundnut viruses and other diseases, utilization of wild relatives, genetic resources evaluation and characterization, and basic genetic studies, among others, have contributed substantially in broadening the knowledge base on the crop. New and emerging knowledge and technologies coming from advanced biology, e.g. genetic transformation, hold promise for further gains in groundnut improvement. Extensive collaboration with groundnut scientists worldwide has also helped strengthen national programmes on groundnut improvement.
Notwithstanding the accomplishments, the Panel is concerned about the paucity of documented impacts of improved groundnut technology on groundnut production, particularly in Africa, and was glad to note that groundnut studies will shortly receive priority in the Impact Assessment Project (see Section 5.3). Similar observations were made during the 3rd EPMR in 1990 and were also highlighted by the recent CCERs for WCA and SEA. The latter even raised questions on the need for further breeding work "unless dramatic improvement in farmer uptake can be achieved" and made a strong recommendation for greater efforts to be concentrated on the deployment and diffusion of new cultivars. A Panel commentary is made on this issue in Section 2.4.4 below.
The overall strategy for genetic enhancement is contained in the draft document entitled "Genetic Enhancement Strategy for ICRISAT Mandate Crops" provided to the EPMR. In brief, the main points of the strategy are the following:
· Breeding of groundnuts for subsistence and high-input environments requires different emphases. Improving yield potential per se deserves common and overriding attention, while also tailoring crop growth duration to fit the growing season. For the rainfed subsistence environment, stable performance is crucial and is achieved by incorporating necessary resistance and/or tolerance to various edaphic and biotic constraints such as drought, leaf spots, groundnut rosette, and others. In irrigated or partially irrigated environments, maximizing yield potential and improved product quality are important.· There is need to exploit a wider gene pool for groundnut improvement, particularly against pests and diseases, where limited useful variability occurs in the cultivated species.
· There is need for greater development and use of new non-conventional approaches to groundnut improvement to complement conventional methodologies.
The strategy as a whole is sound and well thought out, and takes advantage of the interdisciplinary, scientific strengths of ICRISAT and its rich endowment of groundnut genetic resources. In particular, the Panel is pleased to take note of the increasing emphasis on product quality as a breeding objective, because markets for groundnut - both for food and oil, and for reasons of health and acceptability - have started to place a premium on quality considerations. The Panel suggests that ongoing breeding efforts to improve groundnut quality be further intensified, particularly with regard to reduction or elimination of aflatoxin contamination as well as prolonging shelf-life. As a guide to breeding activities, the Panel likewise endorses the CCER recommendation for ICRISAT to assess critically the market prospects of different groundnut types.
A need exists for parallel breeding activities for resistance to biotic stresses in subsistence and high-input farming, to gain specific adaptation and stable high yield potential for defined growing environments. The Panel is pleased to note the emphasis on broadening the genetic base of resistance against major diseases and on concurrent efforts to incorporate multiple resistance into improved germplasm with specific adaptation.
More intensive groundnut breeding activities are needed in the rainfed, subsistence production system. Consolidation of the work in Africa is needed, in collaboration with NARS, to accelerate the development and deployment of improved groundnut cultivars. The Panel does not agree with the CCER recommendation that breeding activities in Africa be scaled down and more efforts be devoted to technology transfer. On the contrary, the dearth of improved groundnut germplasm adapted to subsistence growing environments provides a powerful argument for intensified research and offers opportunities for technology interventions through genetic enhancement. Low dissemination and adoption of improved cultivars are principally seed-system imposed. This, hopefully, will be addressed by the seed component activities of the new CFC-funded project in the region.
A focus is suggested on important soil-related aspects of breeding for subsistence areas, e.g. nutrient use/water use efficiency. The Panel concurs with earlier suggestions by the CCERs that these aspects are essential in systematic germplasm enhancement for these harsh growing environments, and require a base of strong multidisciplinary science. In this regard the Panel believes ICRISAT can make substantive contributions and suggests the Centre strengthen further its fundamental research in these areas.
The utilization of wild relatives of groundnut is essential for its long-term genetic enhancement, and is a research area where ICRISAT has had distinct comparative advantage. The Panel is concerned that research activities in this area have been substantially scaled down in recent years, and strongly suggests that research on wild species evaluation and utilization in wide crossing be given renewed emphasis.
Accelerating the use of new technologies for groundnut improvement is suggested, particularly for virus resistance and other important objectives such as drought and, perhaps, oil quality modification.
2.5.1 Evolution
2.5.2 Achievements and Impact
2.5.3 Future Strategy
2.5.4 Assessment
Chickpea (Cicer arietinum) is a sub-tropical and tropical cool-season food legume with wide adaptation in areas of latitudes 10-45°N. Of the pulse crops chickpea ranks third in area and production worldwide. Asia is the most important producing continent with about 92% of total hectarage and production, and India is the largest single producer. In the Indian subcontinent, the desi type chickpea accounts for some 90% of total production. This is in contrast to the West Asia-North Africa (WANA) region where the kabuli type chickpea contributes about 90% of the total.
Traditionally grown in rotation with cereals, chickpea is important in maintaining the fertility of the cropping system as it can fix symbiotically as much as 80-120 kg N ha-1 and is also very efficient in mobilizing native soil phosphorus.
Until the 1970's, scattered research efforts were undertaken by several NARS on chickpea. When ICRISAT was founded in 1972, it was given the global mandate on chickpea, and research efforts on the crop began at the Centre at that time. ICARDA began its research on kabuli chickpea in 1977. Subsequently, both Centres began to collaborate in research on the crop.
Until 1994, chickpea research was part of the ICRISAT Legumes Programme. Current chickpea research consists of three projects: CP1, CP2, and CP3, which focus on the dry and hot climates, dry and cool climates, and moderately dry and cool climates, respectively. Starting January, 1997, all chickpea research will be consolidated under one project.
An impressive array of improved germplasm has come out of ICRISAT's chickpea projects. During 1991-95, at least 49 cultivars and breeding lines were released in 22 countries worldwide. A majority of these varieties have high yield potential and resistance to Ascochyta blight. Many are resistant to wilt, while some carry chilling/cold tolerance. Extra-short-duration cultivars were developed which has made possible the extension of chickpea cultivation to low latitude environments. On the other hand, cold tolerant materials with Ascochyta blight resistance has enabled winter sowing in the WANA region.
Advances have been made in identifying genetic sources of chilling tolerance, drought tolerance, resistance to Ascochyta blight, Botrytis gray mold, Fusarium wilt, dry root rot, viruses, Helicoverpa pod borer, nematodes, and other important constraints, and in developing appropriate methodologies for systematic screening and evaluation of chickpea germplasm for these constraints. New information, techniques and germplasm have also been obtained or developed from basic studies on biological nitrogen fixation, wide hybridization, and molecular biology of chickpea viruses.
Genome mapping of chickpea was initiated by ICRISAT in collaboration with the John Innes Centre. The genome map construction is ongoing and still to be completed. Priority traits for mapping are resistance to cold, wilt, dry root rot, and Helicoverpa pod borer. Research on genetic transformation is also underway.
In crop management, the Centre has refined and disseminated technologies on double cropping, irrigation of chickpea in hot and dry environments, and pest management.
A noteworthy achievement has been chickpea cultivation in Bangladesh's Barind region, a large tract of land that is largely left fallow during the post-rainy season. ICRISAT's research, in concert with the NARS and with Canadian support, led to the release of adapted chickpea varieties. From a negligible hectarage in 1984/85, chickpea cultivation in the Barind has reached an estimated 10,000 ha (about 1% of the Barind) producing around 8,500 mt. It is projected that this expansion will continue, and if chickpea cultivation eventually covers only 10% of the Barind, total chickpea production in Bangladesh would double.
There are also indications of widescale adoption of ICRISAT-developed or provided chickpea cultivars in India, Myanmar, Pakistan, the WANA region, and Australia. During the last decade in the Indian State of Andhra Pradesh, chickpea cultivation increased at an annual rate of more than 20%; gains were attributed to suitable cultivars that can escape drought, are high-yielding, and are resistant to wilt. In Australia, chickpea cultivation has gone from a few thousand hectares to more than 150,000 ha during the last decade. Two ICRISAT cultivars were directly released there by the Australian NARS.
The genetic enhancement strategy for chickpea is presented in the document provided to the Panel entitled. Genetic Enhancement Strategies for ICRISAT Mandate Crops. The salient points of the strategy are mentioned below.
As more than 90% of the area grown to chickpea is rainfed, ICRISAT concentrates on developing cultivars that can escape or mitigate the effects of low soil moisture. Both extra-earliness and drought tolerance have been found in the germplasm, and intensive breeding efforts are underway to incorporate these traits into high-yielding genetic backgrounds. A major effort attempts to match crop phenology to different drought regimes.
Chilling is a major constraint in the higher latitudes (25-30°) such as are found in Northern India, Pakistan, Nepal, and Myanmar, and efforts are underway to incorporate chilling tolerance with earliness to develop cultivars for these environments . Freezing injury, on the other hand, is a serious constraint in the WANA region. Hence, to enable widescale winter-planting of chickpea in the region, freezing tolerance is being sought in the wild species, Cicer reticulatum and Cicer echinospermum. The winter-planting technology, based on freezing-cold tolerance and Ascochyta blight resistance, can result in potential yield gains of 60-80%.
As a major part of the genetic enhancement strategy, intensive efforts are made to identify and utilize sources of resistance to major biotic stresses such as Ascochyta blight, Fusarium wilt, Botrytis gray mold, root rots, Helicoverpa pod borer, and nematodes. Broad-based resistance to Ascochyta and Fusarium is sought to cope with changing pathotypes. Pyramiding genes for multiple resistance is a major breeding objective.
In Asia, three zones of chickpea adaptation have been identified. Breeding for higher yield potential and adaptation is pursued using the so-called polygon method. This approach involves evaluating segregating populations and selections across locations, and enables the identification of genotypes with wide adaptability and resistance to the principal constraints in various growing environments. This approach is expected to accelerate the development of improved chickpea cultivars with wide adaptation.
Development of molecular markers in chickpea is in the offing to hasten chickpea improvement though pyramiding of resistance genes to major biotic and abiotic constraints, and enable a more systematic evaluation of Cicer germplasm. Genetic transformation technologies are also being developed, with a prime objective of resistance to the Helicoverpa pod borer, utilizing Bt transformation technology.
The Panel finds the genetic enhancement strategy for chickpea to be sound. Breeding objectives are clear and focused; assessment of constraints, opportunities, and priorities are well thought out; and methodological approaches are appropriate.
The Panel is pleased with the achievements made by ICRISAT's chickpea research. In particular, the development of extra-early, wilt resistant, and drought tolerant chickpeas is highly significant, as it has made possible the expansion of chickpea cultivation into low latitude environments where chickpea cultivation has shown the highest rates of expansion. Indeed, this research has resulted in the creation of a new niche for chickpea cultivation worldwide.
Research on chilling-cold/freezing-cold genotypes offers tremendous opportunities for major increases in productivity in high-latitude areas, by using wide hybridization, genome mapping, and basic physiology studies. The Panel strongly suggests that, in concert with ICARDA, the Centre intensify its efforts on germplasm enhancement for cold tolerance.
The Panel commends the excellent inter-Centre collaboration in chickpea between ICRISAT and ICARDA. ICARDA has made major strides in the areas of freezing/cold tolerance and blight resistance, and this work has resulted in significant spillover to ICRISAT's work in low-latitude areas. ICRISAT's advances in breeding of extra-early materials have major potential applications in drought-prone spring plantings in the WANA region. The Panel endorses the ICRISAT/ICARDA collaboration, as it highlights the synergy and complementarity of ecoregional and global approaches on chickpea research. The Panel suggests ICRISAT (and ICARDA as well) further develop this partnership, particularly with regard to germplasm enhancement activities.
2.6.1 Evolution
2.6.2 Achievements and Impact
2.6.3 Future Strategy
2.6.4 Assessment
Pigeonpea is grown on an estimated 4.5 million ha, an area increase of 25 percent above the 3.5 million ha grown just ten years ago. About 90 percent of world production is in India, where pigeonpea is the second most important grain legume. About 0.5 million ha is grown in Africa, mostly in the Eastern and Southern regions, although available statistics underestimate the production outside India. The crop has multiple uses - as food, fodder and fuelwood, as well as for soil conservation and soil fertility enhancement. In particular, pigeonpea is both a crop and a food of the poor, and plays an important role in food security and nutrition for some of the world's most disadvantaged people.
Long a traditional rainfed crop in drought-prone areas, pigeonpea is usually grown in mixtures or is intercropped with cereals (e.g. wheat, rice, pearl millet, maize); other legumes (e.g. groundnut, soybean, mung bean, cowpea); and commercial crops (e.g., cotton or castor). Traditional varieties are of long duration (as much as 10 months), of indeterminate growth, and tall.
ICRISAT began research on pigeonpea in 1972. All research on the crop has since evolved into one consolidated project encompassing all activities related to improving its productivity and stability. Current efforts are focused on the development of short duration cultivars; hybrid development through cytoplasmic male sterility; and management of Helicoverpa through host plant resistance and integrated pest management.
In recent years, ICRISAT and its national partners have developed a new type of pigeonpea, shorter in crop duration (as short as 85-90 days) and stature, and determinate in growth. The new plant types fit more flexibly into rotations than traditional varieties, and have spread in both rainfed and irrigated production systems, including irrigated wheat in the Indo-Gangetic Plain, and the central valley of Myanmar. Interest in pigeonpea is also growing in the United States. The spread of the new plant types probably accounts for the 25 percent growth in production area over the past decade.
Average yields in India are about 0.7 mt ha-1, while yield potential is 2 mt ha-1 or more. Determinate short duration varieties appear to have higher yield potential under crop protection. The crop's main problems include sensitivity to photoperiod and temperature, and attack by insects and diseases. ICRISAT and host country research on male sterility has made it possible to produce higher-yielding hybrids and has resulted in private sector investments in hybrid production.
ICRISAT and Indian scientists have made a number of advances in the crop, including development and enhancement of short duration and extra-short duration lines; successful wide crossing with wild relatives (e.g., Cajanus sericeus and C. platycarpus) to obtain desired traits; identification of sources of cytoplasmic male sterility as well as restorers to help make hybrid production successful; development of Fusarium wilt resistant materials; and identification of sources of resistance to several other important diseases.
ICRISAT/NARS' success in pigeonpea shows once again how good research can pay off in crops about which little is known, and is illustrated by the expansion in crop area over the past 10 years. Much of that expansion is believed to be due to the availability of short duration and extra-short duration varieties that fit more flexibly into cropping systems outside traditional producing areas. There is evidence of increasing interest in the crop in East Africa.
The Panel saw promising work on integrated pest management (IPM) in western Andhra Pradesh where poor farmers growing pigeonpea and pearl millet use a virus biocontrol agent and other IPM practices to reduce pest attack. Farmers were very happy with the new varieties and the control practices, stating their yields had increased 400 kg ha-1 over 10 years, an annual yield gain of 40 kg ha-1 yr-1.
One impact of the work is worth recounting. Farmers in southern India who grow rainfed pigeonpea with hybrid sorghum experienced severe attack of Fusarium wilt, causing severe yield losses and even crop failure. There was no alternative to pigeonpea in the harsh environment or the cropping system being used. Despite efforts by government agriculturists to control the disease, no measures were successful. The answer came in a wilt-resistant line developed at ICRISAT. The new variety, Maruthi, was successfully planted and harvests were more than satisfactory. Wide adoption of the resistant variety followed, reaching almost 60% in 1992/93. The fungus, Fusarium udum, is one of the most widespread diseases of pigeonpea in India and Africa (Malawi, Tanzania, Kenya), where annual economic losses due to the disease are estimated at US$ 36 million and US$ 5 million, respectively. ICRISAT's research investment on Fusarium wilt of pigeonpea has an estimated net present value of US$ 75 million with an internal rate of return of 73%.
ICRISAT scientists work closely in partnerships with NARS to alleviate priority constraints to productivity and adaptation of pigeonpea in different production areas, including new areas in which the crop is spreading. Primary emphasis at the Institute is given to extra-short and short duration materials. High priority is also given to development of a stable cytoplasmic-genic, male-sterility system and the identification of restorers. In addition to improvement in yield potential, resistance will be sought to Helicoverpa pod borer, Phytophthora blight, wilt, sterility mosaic, Cercospora leaf spot, and drought in extra-short and short duration materials. Work on medium- and long- duration materials will be phased down, with greater emphasis being given to identification of sources of resistance to biotic and abiotic constraints and to technology exchange with NARS.
The Panel was pleased with the progress shown in pigeonpea. The Panel concluded that the work of ICRISAT and its NARS partners confirms that pigeonpea responds to research, and further, that the partnership with the Indian NARS is paying off. The Panel wishes to emphasize this success because the future of pigeonpea in the CGIAR has been somewhat controversial, as some previous external reviews had recommended work on pigeonpea be phased out.
ICRISAT's and the Indian NARS' efforts in developing short duration (ca 110 days) and extra-short duration (ca. 90 days) materials with hybrid production potential have led to what is essentially a new crop.
The short duration and extra-short duration materials differ from the medium and long duration lines, being much shorter in height and in crop duration. Short and extra-short duration lines fit better into crop rotations with cereals and commercial crops than the tall, indeterminate long duration traditional lines. Enhancement of the short and extra-short duration materials to achieve greater resistance to diseases and pests should receive high priority in the future as ICRISAT moves its emphasis more to strategic germplasm research.
As pigeonpea spreads into new areas it will encounter new problems for which genetic resistance or tolerance will be needed. At the same time, areas where pigeonpea is traditionally grown will also require research that helps farmers to deal better with new problems. For such problems, the quest for genetic traits in ICRISAT genebank collections, plus the application of both new and conventional scientific methods in evaluation and enhancement, will prove beneficial.
The Panel commends ICRISAT and its partner NARS for the pigeonpea research effort which is exemplary in terms of using all necessary means in genetic innovation and improvement to create a new crop.
Pigeonpea should no longer be considered a tall, long duration, traditional crop. Rather, it can now be a short season, higher-yielding, hybrid crop with multiple uses in crop rotations or grown as a sole crop. In the meantime, the medium and long duration materials will continue to be used in cropping systems where they fit and are productive, and will also benefit from research to identify pest and disease resistance and higher yield potential.
The Panel agrees with the ICRISAT strategy to concentrate more on enhancement of short and extra-short duration materials, and in particular to find more resistance to pests and diseases. As well, the Panel agrees with the strategy to search the genebank holdings for resistance genes for enhancement of medium and long duration materials. These strategies are fully in line with the recommendations and longer-term vision of the Panel for ICRISAT (see Sections 3.5 and 9.1.3).
In the harsh environments of the SAT, ICRISAT's crop improvement efforts have been a success. Releases of ICRISAT-derived cultivars worldwide rose from 166 in 1992 to 365 in 1996, an increase of about 120% in just four years alone. These include significant achievements such as downy mildew and ergot resistant pearl millet, rosette virus and leaf spot resistant groundnut, short duration and wilt resistant pigeon peas and chickpeas, and high-yielding, grain mold resistant sorghum. Evidence is mounting that these crops are now benefiting farmers in large areas of the SAT, especially in Asia and Africa (see Section 5.3). In many ways, ICRISAT research has in fact succeeded in creating what are essentially new crops and new ecotypes for the varied production systems of the SAT. For these achievements, ICRISAT and its partner NARS fully deserve the Panel's commendation.
Increasingly, farmers have been involved directly in the commodity improvement programmes. This occurs at various points: through participatory "breeding"; farmer evaluation in on-farm assessment of improved cultivars; and in various aspects of assessment of adoption and impact of improved cultivars. In the highly complex growing environment of the SAT, these approaches could be very important in understanding the interactions of bio-physical and socioeconomic factors that collectively define the success (or lack of) of technology intervention. The Panel suggests that in due time, ICRISAT should document and evaluate its experiences and lessons with respect to participatory approaches in breeding and assess its merits relative to conventional approaches. The Panel further suggests that the recommendations arising out of the recent review of the On-Farm Research Sector are accepted and taken into account by the Commodity Programmes in implementing future on-farm trials (see Section 5.5).
Only a small portion of the genetic variation found in nature has been captured in the cultivated varieties of ICRISAT's mandate crops. Major constraints remain that have so far proved intractable to efficient genetic manipulation (e.g. drought, Helicoverpa, among others). The institute is in the unique position of having, in its collection at Patancheru, much of the world's available genetic variation for those crops. Most of these uncultivated types are perhaps agronomically unappealing, but the technology is now evolving that will allow for the assimilation from these accessions desirable genes for yield as well as biotic and abiotic stress tolerance. Recently, for instance, it has been demonstrated that, despite its overall inferior appearance, a wild relative of cultivated rice contains genes that can substantially increase the yield of that crop (Nature 384: 223-224, November 21, 1996). There are indications that similar situations occur in tomato and other crops as well. It seems likely that the same potential exists for the mandate crops of ICRISAT. They simply have not received the same level of systematic and deliberate scrutiny in the past as have other major crops.
The challenge for ICRISAT is to bring to bear the rapidly evolving capacity in molecular biology to help solve the complex production problems of the SAT. This is an urgent need for millions of the world's impoverished people, and no other institution is likely to do it. Unless ICRISAT takes up the challenge, the people of the SAT are unlikely to benefit from the ongoing revolution in biology. As an example of the potential, the previously intractable problem of Striga in Africa which constitutes a major limitation to production might be solved through the application of molecular breeding.
Given the well developed capacity of the Indian NARS, ICRISAT's applied commodity breeding efforts in direct support of the Indian NARS can no longer be justified. The situation in Africa and other less developed countries of Asia and LAC, however, requires that, in the foreseeable future, ICRISAT should continue with germplasm enhancement and applied crop improvement activities that are focused on the highly limiting environments of these regions. These efforts should be directly coupled with research on natural resources management so that these less endowed regions of the SAT may finally reap, in a sustainable manner, the benefits that can be derived from improved genetic materials.
The Panel endorses the pursuit of research on methodologies, such as participatory breeding, that could provide new and powerful tools and approaches toward germplasm evaluation and enhancement, and because of the potential power of molecular biology to address some of the more pressing limitations to crop production in the SAT, the Panel recommends that the present commodity improvement programmes of ICRISAT at Patancheru should evolve into a global germplasm strategic research effort with germplasm evaluation and enhancement components that would provide intermediate products to commodity improvement programmes operated by ICRISAT in Africa and to NARS in all continents in a partnership mode.
