The evolution of the Mediterranean pulses, the common pea (Pisum sativum L.), the faba bean (Vicia faba L.), the grass pea (Lathyrus sativus L.), the lentil (Lens culinaris Medik.) and the chickpea (Cicer arietinum L.), is considered from the points of view of geographic origin and subsequent dissemination. All appear to have originated in the Fertile Crescent, the most significant subsequent spread being to the north of the Mediterranean basin in the case of the common pea and the faba bean and to the east of it in the case of the other three species. The wild progenitor type is known for all species except the faba bean. In the grass pea the extent of divergence between wild and cultivated populations is small, possibly due to its use predominantly for forage and less as a pulse. Considerable divergence has occurred in other species, where use as a pulse is more important.

The Système International d'Unités (SI) provides a consistent and coherent set of units for specifying the magnitude of physical quantities. Use of SI is recommended by most scientific journals and in many, including Experimental Agriculture, it is now mandatory. Multiples and sub-multiples of units should be chosen to minimize the repetition of zeros before or after the decimal point. Several units related to SI (e.g. tonne and hectare) are convenient in speech as well as in writing but should be avoided in analysis to minimize the risk of numerical errors. Units common in agricultural science are discussed with special reference to the need for compromise between consistency and convenience.

Six genotypes of lentil (Lens culinaris) were grown in pots in a glasshouse under natural photo-periods of 10–12 h, extended to an inductive photoperiod of 16 h by supplementary illumination from incandescent lamps. The illuminance of the supplementary light was varied by placing replicate pots at different distances from the lamps; it decreased geometrically with distance (i.e. down an illuminance gradient) from about 2000 lux directly beneath the lamps to about 40 lux at a distance of 6 m from them. All genotypes came into flower progressively later as illuminance decreased; those selected in northern temperate regions were especially sensitive, taking about twice as long to flower at an illuminance of 40 compared with 2000 lux. We suggest, however, that these quantitative responses do not reflect differences in sensitivity to illuminance per se, but are the consequences of genotypic differences in sensitivity to photoperiod. The implications of these data are discussed in terms of adaptation to the aerial environment and strategies for screening germplasm and plant breeding in lentils and other grain legumes.

Factorial treatment structure and, in particular, confounded designs are important methods of using experimental resources efficiently. Confounded experiments are not used, and possibly not understood, by experimenters. However, the construction and analysis of confounded designs is logically extremely simple, and can be expressed in terms of simple principles. Modern computing facilities can make confounded designs even more useful.

Pearl millet (Pennisetum typhoides) was grown on stored water at Niamey, Niger, using three row spacings (38, 75 and 150 cm), to determine the physiological basis of exploitation and conservation of water by crops during drought Between 18 and 32 days after sowing, roots grew rapidly beneath all crops reaching 140 cm in the narrow spacing, but there were differences between crops in the pattern of growth. Soil cores and trench profiles indicated that plants in wider rows had fewer, deeper roots. Substantial differences in both the amount and pattern of shoot growth were recorded in the different populations. Initially growth was fastest at the narrow spacing but stopped by day 45 and eventually the wide spacing produced most dry matter due mainly to greater survival of tillers. The partitioning of above ground dry matter into vegetative and reproductive fractions was similar at all three spacings and was consistent with figures for comparable crops elsewhere. The important role of tillers is discussed in relation to the development and maintenance of a canopy.

A technique to better ensure reliable nodulation of pot-grown, P. vulgaris plants with cultured strains of Rhizobium is described. Nodulation, dinitrogen fixation (acetylene reduction) activity and growth of 28-day-old plants were all stimulated markedly when seeds had been inoculated with cultured Rhizobium phaseoli suspended in alginate gel (Agrigel) rather than in sucrose solution. Nodulation attributes of plants inoculated with R. phaseoli strain RCR 3644 which had been sub-cultured repeatedly on yeast mannitol agar slopes were consistently inferior to those recorded for the same strain but recently cultured from a freeze-dried sample. Some of the potential problems with open pot culture of nodule-dependent legumes are discussed.

The potential of winged bean as a multipurpose legume cover crop was shown in field trials by its abundant vegetative growth throughout the growing period of two years. Protein contents of the dry matter of the whole plant, vegetable pods, seeds and tubers were in the range 22–34, 25–30, 32–38 and 16–19%, respectively. In a comparison of two cultivation methods, significantly higher yields were obtained from staked plants than from those grown without supports; protein contents, however, remained constant.

The Land Equivalent Ratio (LER) concept is presented and interpreted. Several different intercropping systems are considered and the need for methods to evaluate them is discussed. A general form of the LER is proposed for the evaluation, in particular, of a system that combines two intercrops having different yield proportions. Appropriate LER curves, obtained by varying the yield proportions, are used to compare different intercropping systems, and the importance of this approach is discussed.

Pearl millet was grown on stored water at Niamey, Niger, using three row spacings. Water extraction based on neutron probe readings was compared with crop transpiration using a porometer and allied measurements. Between 23 and 52 days after sowing, plants at the narrow and medium spacings used about 77 and 100 mm of water, respectively, and those at the wide spacing used between 59 and 75 mm. Estimates of seasonal crop evaporation from leaf resistances and from the green leaf area index (GLAI) of the crops were 103, 130 and 123 mm for the narrow, medium and wide spacings, respectively. The water use per unit of dry weight produced was similar for both narrow and medium spacings but water was used more efficiently in the wide spacing. Dry weight increased in proportion to intercepted radiation with the same efficiency (1·3 g MJ−1) irrespective of spacing.

Objectives of different intercrop experiments need to be kept in view while analysing the data from them. There is no single straightforward way of analysing the data and certain situations require innovative approaches. Types of situations that are encountered in dryland agricultural research are exemplified and methods of meaningful analysis and interpretation of data from them are indicated here. Agronomically-sound meanings are imputed for different ways of calculating LER. Use of the concept ‘Staple Land Equivalent Ratio’ for assessing intercrop systems in particular situations is illustrated.

Twenty one genotypes belonging to Spanish, Valencia and Virginia groups of groundnut were studied at Patancheru and a further seventeen at Delhi. Their relative performance based on a large number of characters spanning the entire growth phase was assessed. Nitrogenase activity and nodule mass were measured at three stages of crop growth starting from first flowering, and these two characters alone when measured at 30 days after flowering closely matched the measure of relative performance based on the entire set of characters.

Weekly measurements were made of the seed oil concentration (% dry weight) in five sesame genotypes (Sesamum indicum) from flowering to maturity. During early but not late development the oil concentration of main shoot capsules was less variable than that in capsules taken from branches. The oil concentration of seeds from capsules at different nodes decreased from 67 to 22% between the lowest (oldest) capsule at node 8 and the youngest one at the uppermost node (25) in 1976, and from 65 to 19% for the same nodes in 1977. Variations in oil accumulation in relation to capsule age revealed that oil formation begins within 5 days after fertilization and maximum accumulation (52% oil) was achieved after 30 days. The implications of these findings for the assessment of oil yield potential are discussed.

Rice varieties were compared for their response to infestation by the stalk-eyed fly, Diopsis thoracica (West), both when a choice of varieties was available to the pest and when there was no choice. The fly significantly decreased the number of panicles produced (both total and mature), the percentage of tillers with panicles, grain weight and total yield of unprotected plants, and increased the number of immature panicles and time to 50% flowering. Reductions in grain yield of between 2 and 97% were recorded but these losses were unrelated to the percentage of damaged tillers. Production of new tillers did not fully compensate for damaged ones in most varieties. However, photoperiod-sensitive rice varieties were better able to compen- sate for pest damage than most.

At Hyderabad, India, stands of pearl millet were grown after the monsoon (a) with no irrigation after establishment and (b) with irrigation as needed to avoid stress. Increases of dry matter and leaf area were determined by regular harvesting. The interception of radiation by the foliage, uptake of water from the soil and stomatal conductance were monitored. Before anthesis at 42 days after sowing (DAS), the rate of dry matter production and the transpiration rate in the unirrigated stand were about 80% of the corresponding rates for the irrigated control, mainly because of a smaller stomatal conductance from 30 DAS. After anthesis, the unirrigated stand grew little and used only 10% of the water transpired by the control. This large difference was partitioned between loss of leaf area and smaller stomatal conductance in the ratio of approximately 2:1. Radiation intercepted by foliage in the irrigated stand produced 2.0 g of dry matter per MJ compared with 2.5 g MJ−1 for the same variety growing in the monsoon, a difference consistent with a smaller stomatal conductance in drier air.

Eight triticale lines were evaluated in Cyprus during the period 1977–82 and compared with the best other cereal varieties grown locally. One triticale line was selected which outyielded Athenais barley by 8.3% and Pitic 62 aestivum wheat by 11.4% in drylands, and durum and aestivum wheat by 20% in irrigated areas. Regression analysis showed that Athenais was the best yielding crop in the least productive environments while under medium or favourable conditions triticale gave maximum yields. Number of grains per spike, harvest index and the N content of grain were larger but ear number, 1000-grain weight and N content of straw were smaller in triticale than in barley. The yield component most sensitive to drought was 1000-grain weight.

Selected leaves of broad bean on separate plants were supplied with 14CO2, at four stages during development and the distribution of radiocarbon products determined quantitatively 24 h later. These leaves retained substantial amounts of the radiocarbon they fixed initially. In the vegetative phase, basal and middle leaves exported more carbon up than down while the apical leaves exported mainly downwards. During the flowering and pod-setting phase, basal and middle leaves exported carbon equally up and down whereas the apical leaves continued to export mainly downwards. Since assimilates produced by basal, middle and apical leaves at any developmental stage in the life of the broad bean plant were moved both acropetally and basi-petally, it must be concluded that bidirectional transport of assimilates occurred in the stem. During the life of the crop all sources supplied assimilates to all sinks.

Differences in the water and air regime of the germination environment may cause variations of 30% and over in the yield of barley, wheat and oats.

Two relay intercropping systems were investigated on an irrigated clay soil: first, wheat with a self-regenerating summer legume and, secondly, grain sorghum with a winter growing legume. A range of summer and winter legumes were evaluated. Phasey bean (Macroptilium lathyroides), a free seeding annual, regenerated vigorously as the wheat matured in early summer; cut twice after the wheat harvest it yielded (including the wheat stubble) 7.5 t ha−1 dry matter. Low seed production jeopardized the regeneration of other summer legumes. Subterranean clover (Trifolium subterraneum) regenerated under the maturing grain sorghum crop as did snail medic (Medicago scutellata) and woolly, pod vetch (Vicia dasycarpa). Together with the sorghum stubble they yielded 5–6 t ha−1 between sorghum crops. The benefits of including self-regenerating forage legumes in irrigated grain cropping systems is discussed.

Field studies designed to investigate the effects of sett size and spacing on tuber yield of white Guinea yam were conducted in three locations over a two year period in the rainforest and savanna zones of Nigeria. Sett weights larger than 400 g could be used for maximum tuber yields in both forest and savanna zones. Spacing had no significant effects on tuber yield in the savanna zone, but optimum spacing has yet to be identified in the forest zone.

The results of field experiments conducted in the spring seasons (February/March to June) of 1980 and 1981 indicate that grain yields of sorghum increased with increase in frequency of irrigation. Crops sprayed with atrazine or CCC yielded more than the unsprayed control; maximum yields were obtained by the application of atrazine at 200 g ha−1. Water use efficiency decreased with increase in irrigation but increased as a result of spraying crops with either chemical. Irrigation water can be saved by the spraying of atrazine or CCC onto spring-sown sorghum.