Aflatoxin contamination in groundnut by Aspergillus section Flavi is a major pre- and post-harvest problem causing kernel-quality loss. Post-harvest aflatoxin contamination is caused initially by infestation of aflatoxigenic strains at the pre-harvest stage, resulting in reduced kernel quality after harvest. Improper handling of pods and storage methods after harvest lead to high moisture and ambient temperatures, directly causing aflatoxin contamination. In this review, we report the extent of post-harvest contamination along the groundnut value chain in the Kolokani, Kayes, and Kita districts of Mali in West Africa. Groundnut kernels and paste samples were collected from retailers in selected markets from December 2010 to June 2011, and aflatoxin B1 (AFB1) content was estimated. Aflatoxin was significantly higher in groundnut paste than in kernels. Kolokani recorded the highest toxin levels in both kernels and groundnut paste compared with the other districts. Overall, AFB1 levels in kernels and paste increased during storage at the market level in the three districts and were above permissible levels (≯20 μg/kg). The effect of weather factors on post-harvest contamination and the reasons for aflatoxin build-up in Mali are discussed. This paper also highlights different management tools for reducing post-harvest aflatoxin contamination, such as post-harvest grain handling, post-harvest machinery, physical separation, storage methods and conditions, disinfestation, detoxification, inactivation, filtration, binding agents, and antifungal compounds. Post-harvest management options and enhanced use of good agricultural practices for mitigating this problem in Mali are also presented.

Peanut plays an important role in the livelihoods of poor farmers and in the rural economy of many developing countries. Aflatoxin contamination in peanut seeds, caused by Aspergillus flavus, hampers international trade and adversely affects health of consumers of peanut and its products. It can occur in the field when the crop is growing, during harvesting and curing, and in storage and transportation. Aflatoxin research on peanut at ICRISAT focuses on identification and utilization of genetic resistance to preharvest seed infection and aflatoxin production by A. flavus and pre and post harvest management practices to minimize contamination. Breeding for aflatoxin resistance has been a contentious issue in peanut for nearly four decades since the first report of host resistance to aflatoxin production by A. flavus. Despite global efforts, progress in aflatoxin resistance breeding has been limited due to the low level of resistance to different components of resistance (preharvest seed infection and aflatoxin production, and in vitro seed colonization by A. flavus), their variable performance due to high G 3 E interaction, lack of reliable screening protocols, and limited understanding of genetics of resistance. Efforts to combine the three independently inherited components of resistance did not produce expected results towards improving the host plant resistance to aflatoxin contamination. Although breeding lines have shown better performance for resistance to aflatoxin contamination at ICRISAT, they need wider evaluation under diverse growing conditions. The search for better sources of resistance in the cultivated and wild Arachis germplasm continues, and recent developments in the area of transgenic research through modification of aflatoxin biosynthesis pathway or use of genes with antifungal and anti-aflatoxin properties appear encouraging. Meanwhile, the available improved breeding lines coupled with pre and post harvest aflatoxin management practices can help to significantly reduce aflatoxin contamination in farmers' fields. It is expected that transgenic resistance against fungal infection and aflatoxin production in combination with conventional breeding efforts may lead to the development of agronomically superior peanuts that are free of aflatoxin contamination.

A 5-year study was conducted from 1988 to 1992 at three sites in Niger to determine the effects of crop rotation of a cereal and legumes and nitrogen fertilizer on chemical properties of the soil (0–20 cm) and yield of pearl millet (Pennisetum glaucum (L.) R.BR.), cowpea (Vigna unguiculata (L.) Walp.), and groundnut (Arachis hypogea L.). Four N levels and rotation treatments including continuous fallow were investigated. Soil samples taken from the top 20 cm depth at the end of the experiment from treatments without nitrogen application which included continuous fallow, fallow–millet rotation, groundnut–millet rotation, cowpea–millet rotation, and continuous millet were analysed for soil pH, organic carbon, total nitrogen and exchangeable bases. Fertilizer N significantly increased yield of pearl millet, cowpea and groundnut. Continuous monocropping of pearl millet resulted in lower yields across N levels compared to legume–millet rotations. Legume yields were also consistently lower in monoculture than when rotated with millet. There was a decline in organic matter under continuous millet, cowpea–millet rotation and groundnut–millet rotation. The fallow–millet rotation supplied more mineral N than the legume–millet rotations. Nitrogen availability was greater in cowpea–millet rotation than continuous millet. Crop rotation was more productive than the continuous monoculture but did not differ in maintaining soil organic matter. The legume–millet rotation at 30 kg/ha N appears to be the most viable for millet production. Research should focus on understanding the effect of legume/cereal intercrops and rotations on soil productivity.

Intermittent drought is the most important yield limiting factor affecting groundnut (Arachis hypogaea L) production in rain-fed regions of Sub-Saharan Africa and Asia.Improvement of crop adaptation to drought is needed and this starts by having a thorough assessment of a large and representative set of germplasm. In this study, 247 lines belonging to the reference collection of groundnut were assessed under well-watered (WW) and intermittent water stress (WS) conditions in India and Niger for two years, following similar experimental protocols. The WS treatment reduced pod yield (31-46%), haulm yield (8-55%) and the harvest index (1-10%). Besides a strong treatment effect, yield differences within locations and years, were attributed to both genotypic and genotype-by-treatment interactions. Pod yield under WW and WS conditions were closely related in both years (Patancheru, r 2 = 0.42 and r 2 = 0.50; Sadore, r 2 = 0.22 and r 2 = 0.23). By contrast, within location and treatment, pod and haulm yields were affected predominantly by genotype-by-year (G x Y) effects, especially under WS. Within treatment across locations and years, pod and haulm yields were mostly ruled by genotypic effects, which allowed identifying a group of entries with contrasting pod yield across locations under WS. However, genotype and genotype by environment (GGE) biplot analyses distinguished India from Niger, suggesting that the selection remains environment-specific and also revealed dissimilarity between years in Niger. A close relationship was observed between yield and pod growth rate (r 2 = 0.51), and partition (r 2 = 0.33) under WS conditions, whereas no significant relationship was found between yield under WS and SCMR, or specific leaf area (SLA). These results showing a close interaction between the environmental conditions and the genotypic response to intermittent drought shows the necessity to carefully choose environments that truly represent target environments. This is an important result in the current breeding context of marker-assisted recurrent selection or genome-wide selection. This work opens also new ways for the breeding of drought tolerant groundnut, by bringing new highly contrasting lines currently used for crossing and deciphering drought adaptation traits to better understand GxE interactions, while it challenges the relevance of long-time used surrogates such as SCMR or SLA.

Aflatoxins produced by Aspergillus flavus and Aspergillus parasiticus are common contaminants of peanut (Arachis hypogea) and a major threat to consumers, particularly in Sub-Saharan Africa. Aflatoxin contamination is a serious concern given their hepatotoxic properties and their widespread occurrence during cultivation, harvest, drying, storage, transit and distribution. Preharvest infection by A. flavus is the major cause of aflatoxin contamination in peanut. Its prevention is a complicated task that requires a series of intervention strategies to be merged with traditional farming practices. The International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) and its partners have developed an integrated approach to mitigate A. flavus infestation and aflatoxin contamination by combining: (i) host plant resistance, (ii) soil amendments with lime and organic supplements to enhance water holding capacity, plant vigor and seed health, (iii) timely harvesting and postharvest drying methods, (iv) the use of antagonistic biocontrol agents, such as Trichoderma and Pseudomonads, and (v) awareness campaigns and training courses to disseminate technology to the end-users. This approach can successfully reduce aflatoxin contamination in peanuts in West and Central Africa. This approach is simple, economical and suitable for subsistence farming conditions, but also can be scaled up for use on commercial farms in developing countries in Africa and Asia.

1 groundnut (Arachis hypogaea L.) in Mali, West Africa 2 3 ABSTRACT 13 Groundnut is a major source of livelihood for the rural poor in Mali. However, the crop is 14 prone to pre-and post-harvest aflatoxin contamination caused by Aspergillus flavus and A. 15 parasiticus. Therefore, to minimize health related hazards from exposure to aflatoxin 16 contaminated food, information on the prevalence and distribution of aflatoxins (AFB1) in 17 the groundnut value chain in Mali is needed for timely interventions. To this end, a study was 18 undertaken in three districts (Kayes, Kita and Kolokani) to assess aflatoxin contamination in 19 the field and storage. Ninety pod samples in each district were collected from fields (30 20 villages/district and 3 samples/village) during 2009 and 2010. Pre-harvest contamination was 21 estimated at harvest, whereas samples for post-harvest contamination were collected from 22 granaries of the same farmers at a monthly interval for 3 months. The villages in each district 23 were categorized into safe, acceptable, moderate risk and high risk areas based on pre-harvest 24 AFB1 levels. Kayes recorded more pod samples (77%) within 20 µg/kg of pre-harvest 25 aflatoxins followed by Kolokani (55.6%) and Kita (45.6%) based on 2009 and 2010 mean 26 values. Toxin concentrations at harvest were comparatively less in Kayes during both years. 27 Further, Kayes had more villages under safe and acceptable limits when compared to 28 Kolokani and Kita. Overall, 46 out of 90 villages in the three districts had acceptable pre-29 harvest toxin limits. Further, 12 villages in Kolokani were in the high risk category. An 30 increase in toxin levels was noticed with period of storage during both years. Comparatively, 31 toxin levels after storage were least in Kayes during 2009. Kayes also recorded less AFB1 32 levels in 2010 after Kita. Our results indicate that Kayes is relatively safe over Kita and 33 Kolokani in pre-harvest aflatoxin contamination. The reasons for district-wide variations in 34 pre-harvest contamination; and the reasons for post-harvest flare up of the problem are 35 discussed. Further, proper storage of pods at farmers' granaries in Mali is suggested to 36 overcome the problem from reaching alarming levels. 37 38

SUMMARYThe effects on yield of varying the planting date and planting pattern of morphologically different cowpea cultivars intercropped with pearl millet were studied in two field trials. The interaction between cowpea cultivars and planting date was highly significant. There was a sharp reduction in cowpea yields with late planting. Millet yields were reduced less when sown simultaneously with early cowpea cultivars than when sown with a late maturing local cultivar. Early maturing cowpea cultivars planted in closely spaced hills had less effect on millet yields than a late maturing cultivar sown in widely spaced hills. An appropriate cowpea cultivar for intercropping with peal millet would be one that was weakly competitive and that yielded both grain and fodder. Bonny R. Ntare: Cultivo intercalado de caupt's morfologicamente distintos con mijo perla en un entomo de temporada corta en el SaheL RESUMENSe realizaron dos ensayos de campo para estudiar los efectos sobre el rendimiento al variar la fecha y el patron de plantation de cultivares de caupi' morfologicamente distintos en cultivo intercalado con mijo perla. La interaction entre los cultivares de caupi y la fecha de plantation resulto altamente significante. Hubo una disminucion'acusada en los rendimientos de caupi al plantarse tarde. Las reducciones en los rendimientos de mijo fueron menores al sembrarlo simultaneamente con cultivares tempranos de caupi que al sembrarlo con un cultivar local de maduracion tardi'a. Los cultivares de caupi' de maduracion temprana plantados en grupos de espaciado estrecho tuvieron menor efecto sobre los rendimientos de mijo que un cultivar de maduracion tardi'a sembrado en grupos muy separados. Un cultivar de caupi apropiado para el cultivo intercalado del mijo perla seri'a uno que fuera debilmente competitivo y que rindiera tanto grano como forraje.

Climate change is projected to intensify drought and heat stress in groundnut (Arachis hypogaea L.) crop in rainfed regions. This will require developing high yielding groundnut cultivars that are both drought and heat tolerant. The crop growth simulation model for groundnut (CROPGRO-Groundnut model) was used to quantify the potential benefits of incorporating drought and heat tolerance and yield-enhancing traits into the commonly grown cultivar types at two sites each in India (Anantapur and Junagadh) and West Africa (Samanko, Mali and Sadore, Niger). Increasing crop maturity by 10 % increased yields up to 14 % at Anantapur, 19 % at Samanko and sustained the yields at Sadore. However at Junagadh, the current maturity of the cultivar holds well under future climate. Increasing yield potential of the crop by increasing leaf photosynthesis rate, partitioning to pods and seed-filling duration each by 10 % increased pod yield by 9 to 14 % over the baseline yields across the four sites. Under current climates of Anantapur, Junagadh and Sadore, the yield gains were larger by incorporating drought tolerance than heat tolerance. Under climate change the yield gains from incorporating both drought and heat tolerance increased to 13 % at Anantapur, 12 % at Junagadh and 31 % at Sadore. At the Samanko site, the yield gains from drought or heat tolerance were negligible. It is concluded that different combination of traits will be needed to increase and sustain the productivity of groundnut under climate change at the target sites and the CROPGRO-Groundnut model can be used for evaluating such traits.