It was previously shown that pearl millet genotypes carrying a terminal drought tolerance quantitative trait locus (QTL) had a lower transpiration rate (Tr; g cm−2 d−1) under well-watered conditions than sensitive lines. Here experiments were carried out to test whether this relates to leaf abscisic acid (ABA) and Tr concentration at high vapour pressure deficit (VPD), and whether that leads to transpiration efficiency (TE) differences. These traits were measured in tolerant/sensitive pearl millet genotypes, including near-isogenic lines introgressed with a terminal drought tolerance QTL (NIL-QTLs). Most genotypic differences were found under well-watered conditions. ABA levels under well-watered conditions were higher in tolerant genotypes, including NIL-QTLs, than in sensitive genotypes, and ABA did not increase under water stress. Well-watered Tr was lower in tolerant than in sensitive genotypes at all VPD levels. Except for one line, Tr slowed down in tolerant lines above a breakpoint at 1.40–1.90 kPa, with the slope decreasing >50%, whereas sensitive lines showed no change in that Tr response across the whole VPD range. It is concluded that two water-saving (avoidance) mechanisms may operate under well-watered conditions in tolerant pearl millet: (i) a low Tr even at low VPD conditions, which may relate to leaf ABA; and (ii) a sensitivity to higher VPD that further restricts Tr, which suggests the involvement of hydraulic signals. Both traits, which did not lead to TE differences, could contribute to absolute water saving seen in part due to dry weight increase differences. This water saved would become critical for grain filling and deserves consideration in the breeding of terminal drought-tolerant lines.

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Physiological, biochemical, metabolite changes, and gene expression analysis of greenhouse tomato (Solanum lycopersicum L.) were investigated in two grafting combinations (self-grafted ‘Ikram’ and ‘Ikram’ grafted onto interspecific hybrid rootstock `Maxifort'), with and without arbuscular mycorrhizal (AM), exposed to 0 and 25 μM Cd. Tomato plants responded to moderate Cadmium (Cd) concentration by decreasing yield and crop growth parameters due to the accumulation of Cd in leaf tissue, inhibition of the PS II activity, reduced nutrients translocation, and also to the oxidative stress as evidenced by enhanced hydrogen peroxide (H2O2) generation, ion leakage, and lipid peroxidation. AM inoculation significantly enhanced the metal concentration in shoots and reduced growth and yield. The Ikram/Maxifort combination induced higher antioxidant enzymes, higher accumulation of proline and reduction of lipid peroxidation products. This suggests that the use of Maxifort rootstock in tomato has a high reactive oxygen species scavenging activity since lower H2O2 concentrations were observed in the presence of Cd. The higher crop performance of Ikram/Maxifort in comparison to Ikram/Ikram combination was also due to the improved nutritional status (higher P, K, Ca, Fe, Mn, and Zn) and increased availability of metabolites involved in cadmium tolerance (phytochelatin PC2, fructans, and inulins). The up-regulation of LeNRAMP3 gene in leaf of Ikram/Maxifort could explain the better nutritional status of interspecific grafting combination (higher Fe, Mn, and Zn).

Grafting of vegetable seedlings is a unique horticultural technology practiced for many years in East Asia to overcome issues associated with intensive cultivation using limited arable land. This technology was introduced to Europe and other countries in the late 20th century along with improved grafting methods suitable for commercial production of grafted vegetable seedlings. Tomato grafting is becoming a well-developed practice worldwide with many horticultural advantages. The primary motivation for grafting tomato has been to prevent the damage caused by soilborne pathogens under intensive production system. However, recent reports suggest that grafting onto suitable rootstocks can also alleviate the adverse effects of abiotic stresses such as salinity, water, temperature, and heavy metals besides enhancing the efficiency of water and nutrient use of tomato plants. This review gives an overview of the scientific literatures on the various aspects of tomato grafting including important steps of grafting, grafting methods, scion–rootstock interaction, and rootstock-derived changes in vegetative growth, fruit yield, and quality in grafted plants under different growing conditions. This review also highlights the economic significance of grafted tomato cultivation and offers discussion on the future thrust and technical issues that need to be addressed for the effective adoption of grafting.

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.

Soil contamination by heavy metals negatively affects crop productivity, besides representing serious threat to human health. Grafting tomato onto appropriate rootstocks may raise Ni tolerance through limiting heavy metal uptake by roots and/or its translocation to the shoot and by detoxification. A greenhouse experiment was conducted to determine the influence of long-term Ni exposure (0, 25, or 50 μM) on crop productivity, fruit quality, leaf chlorophyll content, fluorescence, electrolyte leakage, catalase (CAT), ascorbate peroxidase (APX), and guaiacol peroxidase (GPX) activities in leaf, proline content, membrane lipid peroxidation, and mineral composition of tomato plants cv. Ikram, either self-grafted or grafted onto three rootstocks: Black Beauty, Unifort, and Maxifort. Significant reduction in yield was observed in response to an increase in Ni concentration with more detrimental effects at 50 μM Ni. The fruit dry matter and total soluble solids content increased under severe Ni stress. The depression of crop performance under Ni toxicity was attributed to a decrease in leaf pigments (SPAD index), efficiency of PSII, macroand microelements, and increase in lipid peroxidation and membrane damage. Plants grafted onto tomato rootstocks Maxifort and Unifort exhibited higher chlorophyll content, photochemical activity of PSII, antioxidant activity of APX and GPX, lower accumulation of MDA, and a better nutritional status (higher Ca and Fe, and lower Ni) in the leaf tissues in comparison with selfgrafted plants and those grafted onto Black Beauty. Plants grafted onto tomato rootstocks Unifort and especially Maxifort could minimize the nickel toxicity by improving nutritional status and detoxification processes.

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.

A greenhouse experiment was conducted to determine the influence of long-term cadmium (Cd) exposure (0, 25, or 50 µm of Cd) on crop productivity, fruit quality, leaf chlorophyll content, fluorescence, and mineral composition in plants of tomato (Solanum lycopersicum L. cv. Ikram), either nongrafted, self-grafted, or grafted onto rootstocks of tomato (Maxifort or Unifort) and eggplant (Black Beauty). Both moderate (25 µm) and high (50 µm) concentration of Cd in root environment considerably decreased the fruit yield and fruit number in response to Cd levels, whereas mean fruit weight decreased but was similar to both Cd supply levels. The fruit yield, shoot and root biomass, and leaf area (LA) were higher in plants grafted onto tomato rootstocks and especially onto Maxifort in comparison with nongrafted or self-grafted plants and especially grafted onto Black Beauty. The higher plant performance of tomato rootstock–grafted plants were related to higher chlorophyll fluorescence and photosynthetic pigments concentration in leaves associated with better nutrient translocation and availability (higher Ca, Mg, Fe, Mn, and Cu) in leaves. The content of Cd was also lower in leaves and fruits of Maxifort-grafted plants. Concerning fruit quality, especially peel color, toxicity symptoms, and Cd concentration, Black Beauty followed by Maxifort-grafted plants were better than the other grafting combinations. However, plants grafted onto Black Beauty rootstock resulted in lowest fruit yield and plant growth attributes due to lower nutrient uptake and translocation indicating some incompatibility reaction between Black Beauty rootstock and Ikram scion.