A series of trials investigated the response of a range of groundnut genotypes to varied levels of competition from millet in intercrop situations in both the Sahelian and Sudanian agro-climatic zones. No genotype interactions were observed in response to different millet population levels. Introducing millet into groundnut cultivation provided considerable benefits to the farmer, particularly at the less dense millet populations, but the introduction of groundnut into millet cropping consistently reduced the yield of millet, with little gain in groundnut yields.

Simple, partial and multiple correlations, as well as regression coefficients, were worked out for 14 quantitative characters in a collection of 42 sesame varieties grown for two consecutive seasons. Total number of seeds per plant, number of pods per plant, plant height, height to the first pod and days to flowering and maturity, gave positive and highly significant correlation coefficients with yield and with one another. Partial regression and partial correlations indicated that the number of pods per plant and plant height are important yield-contributing characters.

A field experiment was conducted on sandy loam soil at Hisar, India during the autumn seasons 1984–85 and 1985–86 to study root characters, evapotranspiration, water use efficiency, moisture extraction pattern and plant water relations of rape genotypes under varying irrigation schedules. Root volume and dry weight increased, while tap root and lateral root lengths decreased with irrigation. Increased irrigation frequency increased evapotranspiration but decreased water use efficiency. The relative water content and osmotic potential of the leaves increased with more frequent irrigation, but plant water retention capacity decreased. There were genotypic differences between the characters examined.

Understanding the genetic variability, heritability and genetic advance (GA) of traits in any plant population is an important pre-requisite for variety development. The objectives of the study were to assess the level of genetic variability among vegetative growth traits and yield, assess the relationship among the growth traits and yield and predict GA for the most heritable traits among Robusta coffee full-sib families. The trial was established in June 2009 at the experimental fields of the Cocoa Research Institute of Ghana with 62 full-sib families planted in a randomized complete block design with six replications. Significant (p < 0.05) variation was observed among the full-sib families evaluated for all traits, except for span (canopy diameter). Span and number of laterals were genetically correlated (p < 0.001) with cumulative yield (2013–2017), with span being the vegetative growth trait most strongly related to cumulative yield (rg = 0.60, p < 0.001). The most heritable vegetative growth and yield traits were, respectively, number of laterals (H2 = 0.59) and cumulative yield (H2 = 0.41). The top 10 families (BP40, BP41, BP9, BP36, BP34, BP28, BP37, BP14, BP4 and BP10) in terms of cumulative yield are proposed for multi-location evaluation and possible release as hybrids for coffee farmers in Ghana.

Sustaining productivity of the rice-based cropping systems in the Eastern Indo-Gangetic Plain (EIGP) requires practices to reverse declining soil fertility resulting from excessive tillage and crop residue removal, while decreasing production costs and increasing farm profits. We hypothesize that the adoption of conservation agriculture (CA), involving minimum tillage, crop residue retention and crop rotation, can address most of these challenges. Therefore, the effects of crop establishment methods – strip planting (SP), bed planting (BP) and conventional tillage (CT); and levels of crop residue retention – high residue (HR) and low residue (LR) on individual crop yield, system yield and profitability were evaluated in a split-plot design over three cropping seasons in two field experiments (Alipur and Digram sites) with contrasting crops and soil types in the EIGP. The SP and BP of non-rice crops were rotated with non-puddled rice establishment; CT of non-rice crops was rotated with puddled transplanted rice. In the legume-dominated system (rice-lentil-mung bean), lentil yields were similar in SP and CT, while lower in BP in crop season 1. A positive effect of high residue over low residue was apparent by crop season 2 and persisted in crop season 3. In crop season 3, the lentil yield increased by 18–23% in SP and BP compared to CT. In the cereal-dominated system (rice-wheat-mung bean), significant yield increases of wheat in SP and BP (7–10%) over CT, and of HR (1–3%) over LR, were detected by crop season 3 but not before. Rice yields under CA practices (non-puddled and HR) were comparable with CT (puddled and LR) in both systems. Improved yield of lentil and wheat with CA was correlated with higher soil water content. The net income of SP increased by 25–28% for dry season crops as compared to CT and was equal with CT for rice cropping systems. Conservation agriculture practices provide opportunities for enhancing crop yield and profitability in intensive rice-based systems of the EIGP of Bangladesh.

Dormancy of six varieties of paddy, of three maturity groups, was studied under six seed-treatments. One type showed no dormancy but others showed dormancy in varying degrees 15 days after harvest. Dormancy was completely broken either by removing the kernels from the glumes, or by puncturing the glumes, or by putting acid-treated seeds in an atmosphere saturated with oxygen. The germination percentages were also significantly increased when seeds were treated with N/10 sulphuric acid solution for four hours, or when seeds were put in atmospheres saturated with oxygen. Speed of germination did not improve, as in the case of seeds germinated after four months of harvest, except in cases where the kernels were removed from the glumes or the glumes were punctured. The causes of dormancy of rice seeds were assumed to reside in the flowing glumes (lemma and palea), and different seed-treatments improved the germination of rice seeds by increasing the permeability of the glumes to oxygen and/or reducing the resistance of the tough glume covers over the germinating embryos. The magnitude of the treatment effects differed with variety. These studies suggest methods of improving germination.

Experiments conducted on saline-sodic soils during 1972 and 1973 showed that delay in transplanting medium-duration dwarf high-yielding varieties like Jaya beyond 20 July caused substantial reductions in grain yield, but there was no depression in yield of such varieties even if 55 day old seedlings were used for transplanting at normal times. Older seedlings gave very high yields compared with younger counterparts at late transplantings. Fifty-five day old seedlings took about two weeks less to mature compared with ones planted when 25 days old.

Linear regression of grain and straw yield of dwarf wheats on level of fertilizer nitrogen was significant, but the efficiency of fertilizer nitrogen was determined by the time and method of its application. A single application as a basal dressing was the least productive for grain yield, while split fertilization at sowing and at first irrigation increased the efficiency of applied nitrogen. Further splitting in three doses did not benefit wheat. Foliar application of nitrogen to replace top dressing at the heading stage was of no advantage while replacement of a top dressing at first irrigation by urea spray at heading was definitely deleterious.

This study presents farmers’ evaluations of the performance of winter-sown chickpea technology developed by ICARDA relative to traditional spring planting, and assesses impacts of this technology on farmers’ livelihoods in Syria. Ascochyta blight, insects and weeds were the most important factors affecting productivity of winter-sown chickpea, according to 480 farmers. Among package components, crop varieties were widely adopted and most farmers adopted other components. The winter-sown chickpea area is expanding, particularly in drier regions that do not traditionally grow chickpea. Adoption was higher for better-off farmers – poorer farmers generally prefer to see positive effects first. Adoption over time is accelerating, with obvious benefits: yields have increased by 18% in drier areas and 32% elsewhere in Syria. Winter-sown chickpea technology increased incomes for all adopting households with greatest impact among poorer farmers. All gains are important because chickpea contributes 22% of total household income and should increase with further increases in package adoption.

A previously undescribed mosaic disease was observed on groundnut plants in several districts of West Malaysia. The virus was transmissible through sap, grafting and the aphids Aphis craccivora, A. gossypi, Myzus persicae, Rhopalosiphum maidis and Toxoptera citricidus. A. craccivora, the principal vector, shows dual transmission. The host range of the virus included mostly leguminous plants such as Glycine max, Cassia occidentalis, Crotalaria anagyroides, Indigofera hirsuta, Stylosanthes gracilis and Phaseolus vulgaris, and a non-leguminous host Chenopodium amaranticolor. The longevity in vitro of the virus was between 40–48 hours, its thermal end-point between 63° and 65°C and the dilution end-point 10−4.

Soil erosion and the productivity of cassava (Manihot esculenta Crantz) cropping systems, including forage legume intercropping, were monitored under natural rainfall conditions on Inceptisols in southwest Colombia. Trials were conducted over two cropping periods on moderate slopes. The best erosion control and cassava fresh root yields were achieved by sole cropping on contour ridges. Erosion was greater with forage legume intercropping than with cassava sole cropping in the first cropping period but once well established and uniformly distributed, undersown legumes controlled erosion effectively, though yields of cassava were depressed by 40% or more. Dense stands of grass contour barriers decreased erosion to tolerable levels. Lower cassava yields due to reduced cropping area and competition from the grasses could be compensated for by the production of valuable forage and by increasing cassava planting density.

An investigation was undertaken on the relative tolerance to salinity of the olive varieties Manzanillo, Souri and Sigoise in the arid zone of Israel (Negev), in an experimental grove of the Jewish National Fund, using 11-year-old trees that were grown on saline and non-saline soils under irrigation with sewage water. Manzanillo was the most sensitive to salinity, yields and development of trunk, crown and root system all being adversely affected. Sigoise was the most tolerant to salinity and vegetative development was not impaired at all. Souri was intermediate in sensitivity to salinity. In spite of the susceptibility of Manzanillo it is preferred because of its high yield, which was greater even on a saline soil than yields of the other two varieties on non-saline soil.

The pressure chamber method for measuring leaf water potential in peanuts was compared with the thermocouple psychrometer technique. The pressure chamber over-estimated leaf water potential by an average of 0.4 MPa over the range −0.5 to −5.0 MPa. It is suggested that the pressure chamber technique may be appropriate in comparative studies of peanut water stress. However, where absolute measurements are required, as in the calculation of leaf turgor potential, either a correction factor should be applied or, preferably, the thermocouple psychrometer technique used. If no account is taken of the discrepancy between techniques, erroneously large negative turgor potentials will result.

Soil and nutrients losses due to soil erosion are detrimental to crop production, especially in the hilly terrains. An experiment was carried out in three consecutive cropping seasons (2012–2015) with four treatments: sole maize; sole maize with plastic mulch; maize and cowpea under plastic mulching; and maize and soybean under plastic mulching in randomized block design (RBD) to assess their impact on productivity, profitability, and resource (rainwater, soil, and NPK nutrients) conservation in the Indian sub-Himalayan region. The plot size was 9 × 8.1 m with 2% slope, and runoff and soil loss were measured using a multi-slot devisor. The results showed that mean runoff decreased from 356 mm in sole maize with plastic mulch plots to 229 mm in maize + cowpea intercropping with plastic mulch, representing a reduction of 36% and corresponding soil loss reduction was 41% (from 9.4 to 5.5 t ha−1). The eroded soil exported a considerable amount of nitrogen (N) (13.2–31.4 kg ha−1), phosphorous (P) (0.5–1.7 kg ha−1), and potassium (K) (9.9–15.6 kg ha−1) and was consistently lower in maize + cowpea intercropping. The maize equivalent yield (MEY) was significantly higher in maize + cowpea with plastic mulch intercropping than the other treatments. These results justify the need to adopt maize with alternate legume intercrops and plastic mulch. This strategy must be done in a way guaranteeing high yield stability to the smallholder farmers of the Indian sub-Himalayan region.

Crop bioengineering provides unique and dramatic opportunities for international agricultural development. However, we consider the technology not as a ‘silver bullet’ or panacea for crop improvement in the developing world but as an increasingly important tool that can be used to complement conventional methods of crop improvement. The number of bioengineered crops ready for commercial release in developing countries is expected to expand considerably in the next few years. But the multi-national life sciences companies that are leading the research, development and commercialization of bioengineered crops focus primarily on major crops that have high commercial value and extensive international markets. These companies also hold proprietary gene technology for many other crops of extreme importance to subsistence and resource-poor farmers but do not pursue product development and commercialization because of low anticipated returns. Such crops have traditionally been overlooked and are sometimes referred to as ‘orphan crops’ because of the relative lack of research and development applied to them. We propose a strategy for the development and delivery of bioengineered crops, including orphan crops, for developing countries. Consulting local public and private sector stakeholders to determine their highest priority needs for agricultural products is the first step. This ensures local stakeholder buy-in and that we do not invest in technology that is unlikely to be adopted. Next, the feasibility of developing and delivering the product is assessed. If the result is positive, the work is organized into ‘product commercialization packages’ (PCPs) that integrate all elements of the research, development and commercialization processes. The main elements of each PCP include (i) technology development; (ii) policy-related issues such as intellectual property and licensing, as well as gaining regulatory approval by the relevant national authorities; (iii) providing public information to producers and consumers about the benefits, risks and correct management of these new products; and (iv) establishing, or verifying, the existence of marketing and distribution mechanisms to provide farmers access to planting material. Our strategy involves integration of needs-based capacity building, socio-economic impact studies and product stewardship into each PCP. Whenever appropriate, opportunities are sought to create public–private partnerships to help leverage public funds, help absorb development costs and provide a broader distribution channel. To illustrate how our strategy is being translated into action we include, as a case study, examples of work by the US Agency for International Development-funded, Cornell University-led Agricultural Biotechnology Support Project II on the research, development and delivery of bioengineered fruit and shoot-borer-resistant eggplant varieties (Solanum melanogena) for South and Southeast Asia.

The effects of leaves cut during fibre harvesting of Attalea funifera under contrasting irradiance availability were evaluated, studying defoliation-induced changes in photosynthetic and growth characteristics and fibre production in adult individuals of A. funifera growing under full sun and forest understorey. Fibre harvesting was performed with or without (control plants) leaf removal twice in a 12-month interval. Maximum measured values of net photosynthesis (A), stomatal conductance and transpiration were higher in full sun defoliated palms than in non-defoliated palms in the same environment or in understorey palms of the two treatments. Non-defoliated palms from the two environments emitted more leaves than defoliated palms in the same evaluation period. The increment in the leaf-level rate of carbon assimilation following defoliation did not lead to high production of fibre, suggesting that the photosynthetic compensation for leaf removal was not effective, at least during the period of evaluation. The results indicate that leaf removal during harvesting did not represent an advantage for fibre production and may even lead to decreases in leaf and fibre production.

The area of dry-season rice (Oryza sativa L.) has rapidly increased in Cambodia owing to the large-scale development of irrigation infrastructure. But little is known of potential productivity and adaptive crop management. The objective of our study was to evaluate potential yield and nutrient requirements of dry-season rice in Cambodia, and the economic feasibility of soil-specific management recommended by the government. Field experiments were conducted on four soil types (Bakan, equivalent to Alfisol; Krakor, Inceptisol; Prateah Lang, Plinthustalfs; and Toul Samroung, Endoaqualfs) in four provinces (Battambang, Kampong Thom, Pursat, and Siem Reap) during the 2016 and 2017 dry seasons to compare 14 (2016) and 8 (2017) N-P-K combinations. Grain yield ranged from 1.0 to 5.5 t ha−1 in 2016 and from 1.3 to 6.7 t ha−1 in 2017. Potential yield from the experiments was 6–7 t ha−1 on Toul Samroung soil, 5–6 t ha−1 on Bakan soil, and 3–5 t ha−1 on Prateah Lang and Krakor soils. A rate of 140-60-60 kg ha−1 of N-P2O5-K2O was more than enough to achieve the best yields on any soil group. On the other hand, modest application rates in soil-specific management (44–78 kg ha−1 of N, 23–28 kg ha−1 of P2O5, 0–30 kg ha−1 of K2O) proved reasonable for resource-poor farmers in Cambodia, since the treatment always provided >75 % of the highest economic profit in high-input plots.

The objective of this study was to determine whether salicylic acid, nitric oxide (NO) and/or feeding by nymphs of the spittlebug Mahanarva spectabilis affect the concentration of total phenolic compounds and the dry matter content of different genotypes of elephant grass (Pennisetum purpureum). Four genotypes of elephant grass with varying levels of resistance to insect attack were treated with 4 mL of salicylic acid (1%) or 2 mL of NO per plant in the presence and the absence of nymphs. We determined the concentration of total phenolic compounds and the percentage dry matter of shoots and roots in the plants. We found that salicylic acid, NO and attack by M. spectabilis did not change significantly the total phenolic compounds concentration in any of the genotypes of elephant grass tested. However, we observed variations in the concentration of phenolic compounds produced between the resistant and susceptible genotypes, both in the shoot, when subjected to salicylic acid or nymphs, and in the roots in the presence of nymphs. Furthermore, the inducers resulted in variation in the dry matter content of the shoots and roots for most of the genotypes tested. Therefore, we conclude that chemical inducers and feeding by M. spectabilis nymphs cannot be used to elicit a resistance response in elephant grass by stimulating the production of phenolic compounds.

Eight trials, covering a wide range of conditions in Malawi, have assessed the effect of applying nitrogen (0, 45 and 90 kg. ha.−1), sulphur (0, 22, 45 kg. ha.−1), phosphorus (0, 15 kg. ha.−1) and boron (0, 0·63 kg. ha.−1) on growth and yield of cotton. A nitrogen × sulphur interaction was very highly significant at one site, and good responses to nitrogen were obtained at six sites. Phosphorus and boron gave significant increases at one site. Increased yields of seed cotton indicated that there is an overall need for a compound fertilizer to supply nitrogen, sulphur, boron and in some areas phosphorus.