An agro-ecological analysis of the maize component of an agroforestry system in the eastern mid-hills of Nepal was conducted in 1999. The aim of the study was to understand farmers' current maize cultivation practices as a prerequisite to development of maize varieties that are better adapted to local conditions than the improved varieties currently on offer from conventional maize breeding programmes in Nepal. Practices of 50 smallholder farmers were surveyed in three villages, and the response of the maize crop was recorded. The study revealed great variability in agronomic practices, and in particular, farmers' maize husbandry differed markedly from national recommendations for plant population, agronomic inputs and genotypes used. Farmers regularly employed practices that were not even officially recognised by the national research and extension services, such as thinning of maize for livestock fodder, growing the crop in association with trees for fodder, and relay cropping with finger millet, their priority being to optimize overall output of the farming system rather than maximizing maize productivity. Reasons for deviations from recommended practices are analysed and implications for maize crop improvement for heterogeneous conditions are discussed.

Institutional changes in Benin have brought to light farmers' demand for varieties better suited to local growing conditions than existing ones. In response, we initiated a participatory cotton breeding experiment in 1996 to evaluate the relevance of such a methodology for the improvement of a commercial crop grown under rain-fed, semi-intensive cropping systems. This paper compares the performance of the first four mass-selection cycles, implemented by three farmer-breeders (F-B) and one formal breeder, with the original population and two commercial controls over three sites and two years. First results show that genetic changes occurred in all the F-B populations. The highest yielding F-B population (Savalou) was also more exuberant and later maturing than the others. Within the relatively narrow range of environments considered in the trial, there is no evidence that decentralized breeding results in better local adaptation. In Benin, participatory cotton breeding may be considered as complementary to formal on-station breeding and useful for enlarging the genetic variability offered to the farmers. Although the farmers want the approach to be scaled-up, its sustainability relies on a formal partnership between research and farmers institutions.

Different fruit thinning methods were tested on ‘Sensation’ mango trees over two seasons in a trial conducted in Northern Province, South Africa. The objective of the study was to select the best thinning intensity and method based on different parameters. Thinning was carried out in October prior to the occurrence of excessive natural fruit drop. When fruits were thinned to one and two fruits per panicle, fruit number, weight and yield per tree at harvest were all increased. When 50% of the panicles were thinned there was an increase in the fruit retention potential of the trees as well as in the size and quality of the fruit produced. Large fruits were, however, prone to certain physiological problems. Chemical thinning with Corasil.E produced very small fruits with an increased percentage of ‘mules’ (fruit without seed). Trees subjected to severe thinning intensities showed earlier recovery of starch reserves and better vegetative growth than the control.

Twelve seedling cocoa families were evaluated as rootstocks in Sabah, Malaysia using three commercial cocoa clones as scions. The average yield was about 3 t dry cocoa beans ha−1. Yields on pure Scavina rootstock were about 10% above average and those on pure West African Amelonado about 10% below average. However, the effects of rootstock on yield were correlated with those on vigour and there was no effect on the ratio of yield to continuing vegetative growth. Rootstock did not influence bean weight or number of beans per pod or the uniformity of the trees. There was no indication of an interaction between rootstock and scion for any of the traits that were studied. The rootstock effect is considered large enough to warrant its control in critical work, especially field experiments with budded cocoa, but development of high performance scions is a higher priority in cocoa than intensive work with rootstocks.

The objective of the research was to test whether safflower (Carthamus tinctorius) could be grown successfully and profitably as a rain-fed, winter, oil-seed crop at a high-elevation site in a semi-arid area. A three-year field experiment was conducted in the Bekaa Valley of Lebanon at a site 995 m asl with a mean annual precipitation of 518 mm. Two safflower lines, Syrian Hama Local and PI301055, selected from earlier screenings, were compared with barley and lentil, the two dominant rain-fed crops, together with chickpea. Safflower flowered and matured more than a month later than the other three crops, and gave the highest dry matter at flowering. Safflower yielded more than chickpea and lentil, and there were no significant differences in yields between the safflower lines and barley, which is the highest yielding winter crop in semi-arid northern Bekaa. The straw yield of safflower was higher than that of barley, which was in turn higher than those of chickpea and lentil. According to calculations based on seed yield, safflower gave the highest net revenue of $191 ha−1, followed by lentils ($160 ha−1), chickpea ($97 ha−1), and then barley ($27 ha−1). Farmers in the semi-arid Bekaa Valley of Lebanon and in other areas with similar conditions are recommended to plant safflower to meet a regional vegetable oil deficit and to diversify cropping systems.

A three-year trial was conducted on a degraded soil in the moist Guinea savanna of northern Nigeria to assess the possibility of improving productivity and economic viability of maize-based systems by incorporating short-season legumes and green manure crops into the cropping pattern. Treatments included double cropping legume-maize systems, full-season sole maize receiving various amounts of nitrogen, green manure crop mucuna (Mucuna pruriens var. utilis) followed by sole maize and a legume-maize system receiving additional rice mill waste. In comparison with full-season maize, the use of early-season cowpea followed by maize improved productivity as well as economic returns of the cropping system, while the use of mucuna, grown as an early-season crop or full-season crop, resulted in poor overall productivity of the system. The addition of rice mill waste as a soil amendment in cowpea–maize systems stimulated maize yields and rice mill waste can form a cheap source of organic inputs for farmers living nearby rice mills. Given the limited growing season of the northern Guinea savanna, it is concluded that timing of field operations is crucial for the successful application of double cropping systems. In addition, high labour requirements are a serious constraint for wide-scale adoption of double cropping systems by small-scale farmers, stressing the need to reduce soil cultivation operations, for example by maintaining a uniform ridge distance for all crops in the rotation.

In general, olive trees are self-compatible, but under some climatic conditions a number of cultivars have demonstrated problems with pollination and fruit set. The Manzanillo cultivar is usually self-pollinating, but under hot conditions its pollen develops slowly, resulting in little or no fertilization. Trials were carried out in two hot, arid ecosystems (Arid Chaco in La Rioja, Argentina and Sonoran Desert in Arizona, USA) to determine if supplemental pollination of a Manzanillo cultivar has the potential to increase yields, and to assess the effectiveness of three different cultivars as sources of pollen. Branches that received supplemental pollination produced 21% more total olives than the control. In Arizona, total olive and shotberry (unpollinated olive) production were significantly different between treatments. Branches that received supplemental pollination produced 98% more olives, and had 58% fewer shotberries than did branches in the control rows. Significantly more olives were produced on branches pollinated with Sevillano and Arbequina pollen, compared with those pollinated with Ascolano pollen and with the control.