bluuebunny/crossref_metadata_2025 huggingface dataset:
Genotype (G), Environment (E) and GE Components of Crop Yields
Authors: Simmonds N. W.
Published: October 2008

Genotype-environment (GE) interactions as a component of historically rising crop yields are reviewed. For various cereals (both temperate and tropical), past selection has seemingly evoked responsive varieties, and GE effects constitute about one third of the total estimated yield increase due to G + E + GE. In potatoes and sugarcanes, more stable (less responsive) varieties, less dependent upon good environments to do well, have been prominent. Historically, responses have been largely due to unconscious selection, but GE effects could be deliberately manipulated by breeding if it were desirable to do so, for example, to produce varieties adapted to low-input agriculture (already an object of breeding research in a few crops).
The Social-Scientist's Role in Generating Innovations for Small Farmers: Maize in Nigeria
Authors: Bartlett C. D. S. , Fajemisin J. M.
Published: October 2008

In recent years many economists have been posted to agricultural research stations in Africa but their roles and methodologies have not been clearly defined. Maize research in Nigeria has an exceptionally good structure, good facilities and highly trained manpower, yet the innovations recommended to farmers are not entirely satisfactory. Deficiencies are the result of inadequate attention to the way innovations fit into the farm-household system, identification of farmer's objectives, the uses made of maize and problems of resource shortage. Pilot studies demonstrated how these deficiencies may be rectified by an economist, and suggest changed production recommendations and research priorities.
Effects of Population and Inter-Row Spacing on Yields of Maize and Control of Weeds with Herbicides in the Irrigated Savanna
Authors: Choudhary A. H.
Published: October 2008

In field trials a population of 61,700 maize plants/ha produced higher total dry matter and grain yields than the conventional 36,000 plants/ha. There was no difference in yields with inter-row spacings of 45, 60 or 90 cm, regardless of population levels. Weed suppression was increased by the higher population even though the entire experimental area was treated with herbicides. In one of three years perennial sedge and annual weed growth started 4–5 weeks after herbicide application, under which conditions row spacing had a greater effect and weed growth was significantly less with 45 or 60 cm maize rows than at 90 cm.
Intercropping Morphologically Different Types of Maize with Cowpeas: LER and Growth Attributes of Associated Cowpeas
Authors: Wahua T. A. T. , Babalola O. , Aken'ova M. E.
Published: October 2008

Land Equivalent Ratio (LER) and cowpea growth attributes were used to evaluate three different maize cultivars for intercropping with cowpea, a low canopy crop. The relatively short maize cultivar (Kewesoke) with erect upper leaves transmitted the most light to cowpeas, followed by a liguleless erect-leaf type and then a floppy-leaf type. The more the transmitted light, the greater were the growth and yields of associated cowpeas.
Effects of Parasitic and Non-Parasitic Weeds on Sorghum
Authors: Bebawi F. F. , Farah A. F.
Published: October 2008

The parasitic weed striga had significantly greater effects on sorghum yield components than non-parasitic weeds. Grain reduction caused by striga amounted to 65% compared with 32% reduction caused by non-parasitic weeds. Comparable reductions were also manifest in straw yield, grains/head and plant height of sorghum. Early removal of striga (a week after its emergence), and thereafter at regular weekly intervals, may help to improve crop yields.
Intraspecific Physiological Variants of Striga hermonthica
Authors: Bebawi F. F.
Published: October 2008

Preliminary evidence is presented in this study for the existence of (1) intraspecific physiological variants of Striga hermonthica, with Gabob population as the most responsive strain to a range of Sorghum bicolor cultivars, and (2) a local Sudanese sorghum cultivar called Tetron with broad-spectrum resistance to striga. Thus Tetron may be recommended as another standard resistant cultivar with reference to Framida of East Africa.
Mixed cropping in Northern Nigeria IV. Extended Trials with Cereals and Groundnuts
Authors: Baker E. F. I.
Published: October 2008

Trials carried out at a range of locations in northern Nigeria showed that gross cash returns from mixtures were never less than those from sole groundnuts, confirming results from the main research station at Samaru. In many cases they were considerably higher and in the Northern Guinea Savanna, where the system is most widely practised, showed a high probability of returns greater than the sole crop median. Increasing attention is being paid to haulm yield and the possibility that sole groundnut may be more profitable near large towns because of haulm value.
Yield Stability Studies in Soyabeans (Glycine Max)
Authors: Funnah S. M. , Mak C.
Published: October 2008

Regression analysis, stability variance method, and the genotype-grouping technique were used to investigate the relative yield stability of 20 soyabean genotypes, grown in 12 diverse environments in Malaysia in 1978. With the regression analysis, four genotypes were observed to be unstable for grain yield; however, for the remaining 16 genotypes with non-significant regression coefficients, a substantial proportion of the g × e interaction was non-linearly related to the environmental indices. With the second and third methods less than half of the genotypes turned out to be stable for grain yield. Generally, for some genotypes, the stability classification was the same for all three methods.
Comparisons of the Yields of Four Potato Varieties in Trials and in Agriculture
Authors: Simmonds N. W.
Published: October 2008

The yields of four potato varieties (two old and two new) in trials and in agriculture were compared. The six possible paired comparisons of means and of variety-on-variety regressions showed genotype–environment interactions. Trials and agricultural data agreed rather poorly as to both means and regressions, suggesting that further studies are desirable, in diverse crops, of the ability of trials to predict agricultural yields.
Variation in Growth of Young Vegetatively Propagated Tea (Camellia sinensis)
Authors: Kathiravetpillai A. , Kulasegaram S.
Published: October 2008

Variation in the growth of young vegetatively-propagated tea in the nursery was studied. Erect shoots grew more vigorously, furnishing cuttings which rooted better and produced stronger plants than those from the weaker, inclined shoots. When erect shoots were artificially inclined they showed reduced terminal bud activity and shoot growth, while inclined shoots artificially erected commenced bud activity and made growth like naturally inclined and erect shoots respectively. Pruning adequately fertilized mature tea bushes at 40 cm above ground level produced vigorous shoots and at 6–8 months furnished more acceptable cuttings that produced better plants, while non-pruned bushes produced less suitable shoots and cuttings. Young unpruned plants produced weak shoots with fewer and poorer cuttings. The practical implications of these findings are discussed.
Performance of Sorghum (Sorghum vulgare) and Maize (Zea mays) as Forages in Irrigated Saline Soils of the Sudan
Authors: El Karouri M. O. H. , Mansi M. G.
Published: October 2008

Trials were made of the performance of batches of forage sorghum and maize, sown at different times of year. The optimum sowing periods of sorghum variety Abu Sabeen and maize variety 113 were found to be February to October and November to January respectively. Of the various climatic factors considered in this study, mean daily temperature was of greatest importance in affecting yield. The overall performance of sorghum was superior to that of maize, probably because of its relatively higher salt tolerance.
Evolution of Grain Legumes. II. Old And New World Pulses of Lesser Economic Importance
Authors: Smartt J.
Published: October 2008

A consideration of the apparent lack of general success of minor pulse crops can lead to a better appreciation of the factors which have made the major pulses successful. The relevant factors are both biological and economic. High productivity based on an efficient physiology, amenability to local agronomic practices and a satisfactory range of ecological tolerance are prime prerequisites for success. Aspects of quality, palatability, lack of toxic factors (or ease of detoxification), ease of preparation and cooking and the more imponderable questions of consumer preference are equally important. If any of these prerequisites are not adequately met success in cultivation is improbable. At the present time the lack of more extensive success of the winged bean appears to be due to some deficiency in ecological tolerance, and of the horse-gram and jack and sword beans to a lack of palatability; the Hausa groundnut (Kersting's groundnut) suffers from a probably inefficient physiology while limited consumer acceptance has possibly restricted production of pigeonpea and hyacinth bean. The rather limited evolutionary advance achieved by this group of pulses is probably directly related to their somewhat restricted production and the relatively low level of selection pressures to which they have been subjected.
Response of Maize to Planting Dates in a Tropical Rainforest Location
Authors: Fakorede M. A. B.
Published: October 2008

Grain yield of maize (Zea mays L.) was decreased by 30, 38 and 34 kg ha−1 for each day by which sowing was delayed after the first planting in March in 1978, 1980 and 1981, respectively. Yield reduction was associated with reduced plant size (plant and ear heights, tassel weight and branch numbers), ear number, ear weight, grain weight, ear length, ear diameter and kernel weight. High yields can thus be obtained by planting with the first rains of the year, especially if a good rate of emergence and seedling vigour under relatively hot, dry soil conditions can be ensured either culturally or genetically.
Weather Factors Affecting the Response of Maize to Planting Dates in a Tropical Rainforest Location
Authors: Fakorede M. A. B. , Opeke B. O.
Published: October 2008

Simple linear correlations, stepwise multiple regressions and path-coefficient analyses were used to determine the relation between grain yield of maize (Zea mays L.) and weather factors in a three year study involving several planting dates within each year. Maximum and minimum relative humidity, which demonstrated negative relationships with yield, were the most reliable factors, both directly and indirectly, for predicting yield. Temperature (including accumulated heat units), sunshine hours and total and effective rainfall generally showed negligible direct effects on yield. Potential evaporation, which showed positive correlation, had a negative direct influence on grain yield. We conclude that, whenever possible, path analysis should be used as well as correlation and regression analyses in explaining the complex multiple interactions of yield and weather factors in crop production.
Genotype Environment Interactions and the Identification of Adaptable Cultivars of Upland Rice (Oryza Sativa) in South-Western Nigeria
Authors: Oyedokun J. B.
Published: October 2008

Twenty improved upland rice cultivars were evaluated in yield trials at three locations for three successive years in south-western Nigeria. Highly significant genotype x environment interactions were observed, indicating that some cultivars yielded better in some locations than others. The use of regression analysis adequately identified the cultivars best suited to each environment. S2d values (measures of stability) for the cultivars ranged from 0.0007 to 0.2196, the cultivars with smaller values being more stable at the respective locations. The more adaptable cultivars have high mean yields and a deviation from regression as small as possible. The cultivar best adapted to good environments was code 3 (an improved selection from the cross Lac 23 x IR 528) with a yield of 3.36 t ha−1, while code 9 (a sister selection from the same cross) was best adapted to poor environments. Code 8 (a selection from the cross IR 154/O.S. 6 and 63–83) showed general adaptability. Once grain quality has been evaluated some of these cultivars might therefore replace code 18, the currently recommended upland rice cultivar, in the rain-forest zone.
The Effect of Pruning at Different Heights on Yields, Dry Matter Production and Partitioning in Clonal Tea (Camellia Sinensis) in Kenya
Authors: Magambo M. J. S. , Waithaka Kimani
Published: October 2008

Dry matter production and partitioning in old clonal tea bushes pruned and maintained at different heights were investigated. New tissues (leaves, new branches and small roots) consti- tuted a small fraction of the total dry matter in all bushes pruned and initially maintained at 70, 40, 25 and 10 cm high, 36 months after pruning. Leaf/frame dry matter ratio was larger and the shoot/root and frame/root ratios were smaller in the bushes initially maintained at 10 cm than in the bushes maintained at other heights. Yields per unit area of the plucking surface were greatest in the smallest bushes initially maintained at 10 cm in 42 months of recording but on the basis of the available space they were greatest in the large bushes initially maintained at 70 cm.
An Agronomic and Economic Study of Intercropping Brussels Sprouts and Summer Cabbage
Authors: Salter P. J. , Akehurst Jayne M. , Morris G. E. L.
Published: October 2008

Intercropping Brussels sprouts with cabbage was studied in two experiments comparing four different intercropping systems with sole crop production. Intercropping presented no agronomic or management problems because both crops had compatible cultural and crop protection requirements. Analysis of Land Equivalent Ratios and Relative Value Totals showed that the four intercropping systems gave consistently larger yields than the sole crops. In one experiment profitability, measured by the gross margin, was higher from all of the intercropping systems and costs per unit of produce were reduced. Similar results were obtained with one intercropping system in the other experiment. Alternative methods of evaluating the results in economic terms are discussed, together with the implications of intercropping in high-input systems of vegetable production.
On the Use of Stigter's Ratio in Expressing the Thermal Efficiency of Grass Mulches
Authors: Othieno C. O. , Stigter C. J. , Mwampaja A. R.
Published: October 2008

Data from mulched tea show that an earlier defined ratio of temperature fluctuations in thermally homogeneous soil can be successfully used in rating the thermal efficiency of artificial grass mulches. The efficiency of a natural mulch of growing grass is also determined for comparison. It is demonstrated that the use of the ratio is more precise than using average temperatures in assessing the effects of the mulches.
Response of Pearl Millet Cultivars to Inoculation with Nitrogen-fixing Bacteria
Authors: Wani S. P. , Chandrapalaiah S. , Dart P. J.
Published: October 2008

The results of field experiments conducted with millet cultivars inoculated with different nitrogen-fixing bacteria at the ICRISAT Centre, Hyderabad, India are described. Significant interactions were observed between host cultivars and bacterial strains, but some cultivars showed consistently increased grain and dry matter yields, suggesting the possibility of exploiting suitable plant and nitrogen-fixing bacterial associations for increasing grain yield. Inoculation also resulted in increased nitrogen uptake up to 14.9 kg ha−1, and larger grain nitrogen contents.
Stomatal Responses to Environmental Variables in Shade and Sun Grown Coffee Plants in Mexico
Authors: Fanjul Luis , Arreola-Rodriguez R. , Mendez-Castrejon M. P.
Published: October 2008

The influence of air temperature (T), vapour pressure deficit (vpd), irradiance (Q) and leaf water potential (ψ) on diurnal stomatal movement of coffee plants was examined under field and controlled environmental conditions. Leaves of plants grown under shade had larger stomatal conductance (g) values than plants grown in open sun. Stomatal responses to vpd under constant temperature conditions were very strong, indicating that ambient humidity could play a major role in controlling stomatal aperture. Changes in g as vpd increased probably contributed to observed reductions in the rate of net photosynthesis (Pn), though the effect of vpd on Pn was smaller.
Response of Cowpea (Vigna unguiculata) to Spacing in the Savanna and Rainforest Zones of Nigeria
Authors: Kayode G. O. , Odulaja A.
Published: October 2008

A two year field study designed to investigate the effect of spacing on yield of two cowpea cultivars in the savanna and forest zones of Nigeria showed that cowpea yields were larger in the savanna than in the forest zone at all spacings employed. Inter-row spacing wider than 60 cm and intra-row spacing closer than 10 cm could be used for improved seed yield in the savanna zone, while 60 × 20 cm (83 333 plants ha−1) would be optimum for cowpea production in the forest zone.
Development of Mixed Tree and Food Crop Systems in the Humid Tropics: A Response to Population Pressure and De-forestation
Authors: Watson G. A.
Published: October 2008

Mixed tree and food crop farming systems are being developed in the humid tropics. They offer one solution to the problems caused by population pressure and de-forestation, since they can provide a satisfactory income to the subsistence farmer, while adequately protecting the environment In seeking to develop optimal systems, examples and information can be drawn from traditional mixed cropping systems, from taungya systems of forestation, and from other systems developed within the commodity cropping sector. However, the full potential of mixtures involving perennials and food crops can only be realised within the limitations of local socio-economic and political circumstances.
Effects of Maturation Environment on Seed Size and Subsequent Plant Growth in Peas (Pisum sativum)
Authors: Kant K. , Sharma B. , Tyagi M. C.
Published: October 2008

Maturation of peas in cool temperatures (mean 17.5°C) at Dalang Maidan, Lahaul (in the Himalayas) led to the development of larger seeds in comparison to those of the same varieties which had matured in warmer temperatures (mean 24.5°C) at Delhi, India. The larger seeds from Lahaul, when sown at Delhi, gave rise to taller plants which came into flower earlier compared with those from the seeds matured at Delhi. Significant location ′ variety interactions were recorded for germination and plant height. Inherent variation in days to flowering could have been a major factor in these interactions. These data are of direct importance to breeders using seeds developed at more than a single location if environmental conditions differ appreciably.
Effects of Cropping Seasons and Temperatures on the Dormancy of Rice (Oryza sativa) Seeds
Authors: Sikder H. P.
Published: October 2008

The Boro (dry) and Kharif (wet) seasons of West Bengal differ appreciably in respect of atmospheric temperature, relative humidity and hours of bright sunshine each day. Post-harvest hot temperature (31°C) either in controlled conditions (in the Kharif season) or in natural (31.5°C) conditions (in the Boro season) had a more significant effect than post-harvest cool air temperature (20.4°C) in the Kharif season on the early breaking of dormancy of paddy rice seeds. However, the pre-harvest hot air temperature (31.4°C) of the Boro season was no more effective in breaking dormancy than the pre-harvest cool air temperature (20.9°C) of the Kharif season. With a mean air temperature of 20.4°C the post-harvest exposure of the seeds to the sun from sunrise to sunset during the Kharif season was much more effective in breaking dormancy than the post-harvest mean air temperature of 31.5°C during the Boro season.
Weather, Physiology and Seasonality of Tea (Camellia sinensis) Yields in Malawi
Authors: Squire G. R.
Published: October 2008

Field measurements with a pressure chamber showed that the water potential of tea shoots was more closely related to the atmospheric saturation deficit than to the amount of water in the soil. Records for shoot growth and weather then revealed that, within a narrow range of mean temperature, the weekly rate of shoot extension was inversely related to mean saturation deficit measured at 1400 h. During periods when saturation deficit did not rise above 20 mbar, the rate of shoot extension varied linearly with mean temperature above a base temperature of 12.5–13.0°C. These correlations suggested that seasonality of shoot growth in tea can be explained largely by the independent effects of temperature and humidity. The effect of mean air temperature on the rate of shoot extension was confirmed in a glasshouse built over an established crop.
Factors Affecting Yields of Dark Fire-cured Tobacco in Malawi
Authors: Tanton T. W. , Abington J. B.
Published: October 2008

The yield data from a series of fire-cured variety × fertilizer trials in Malawi are presented. Variety was not important in determining total yields though it was in influencing the distribution of grades. Fertilizer had a large effect upon yields, particularly upon the Cutter and Leaf grades, but environment had by far the greatest influence. High levels of applied fertilizer could not be relied upon to replenish a depleted soil so that it produced yields comparable to those from a soil with well-maintained fertility. Application of fertilizer produced a beneficial change in the grade distribution within the crop.
Measuring Leaf-water Potential in Chickpea with a Pressure Chamber
Authors: Sivakumar M. V. K. , Virmani S. M.
Published: October 2008

The pressure-chamber technique has been used for the first time to measure leaf-water potentials in chickpea under field conditions. Available soil-water contents at different depths for irrigated and non-irrigated crops are presented along with the diurnal variation in leaf-water status, to show that pressure-chamber measurements correspond closely with available soil water. Leaf-water potential has also shown differences in leaf-water status among different cultivars. The rapidity and ease with which measurements can be made in the field make the technique suitable for quick measurements of leaf-water status for chickpea.
Seed Characters and Germination in Soyabean
Authors: Nangju D.
Published: October 2008

Twenty-five cultivars of soyabean (Glycine max (L.) Merr.), differing in their origin, crop duration and seed size, were planted four times at bi-weekly intervals during the major rainy season at Ibadan, Nigeria and harvested at optimum maturity or two weeks later. Delayed harvest and intense rainfall during pod maturation were essential for selecting for resistance to field weathering, but 2 weeks' delay enabled susceptible and resistant cultivars to be identified. Percentage of infected seed had the highest correlation with potential germination at harvest (r=−0·869**) but may not be a suitable criterion for use in a screening programme. An alternative would be to screen cultivars for resistance to weathering on the basis of seed size and the proportion of smooth and clean seed, since these characters were highly correlated to potential germination (r=−0·562** and 0·632** respectively).
Estimation of Hydrogen Cyanide Released from Cassava by Organic Solvents
Authors: Williams Hugh J.
Published: October 2008

Methods are described for releasing HCN from cassava leaves and tubers by organic solvents and its spectrophotometric estimation as the red complex formed with alkaline picrate. Chloroform was the most efficient solvent, with toluene an acceptable alternative, using enough solvent to wet samples thoroughly to maximize cyanide yield. Cyanide content was concentrated in the veins and towards the base of leaves and declined linearly with leaf age. Release of HCN with solvent compared favourably with traditional homogenization/steam distillation with leaves and parenchymal tissue, but was unsatisfactory for tuber peel. The effective removal of HCN from cooked cassava leaves depends chiefly on release of enzymes by efficiently chopping them before boiling, which only slowly destroyed potential cyanide content of unchopped leaves.
Short Day Induction of Flowering in Pearl Millet (Pennisetum typhoides) and its Effect on Plant Morphology
Authors: Ong C. K. , Everard A.
Published: October 2008

Four hybrids of pearl millet (Pennisetutn typhoides) were screened for photoperiod sensitivity in a heated temperate glasshouse and the effects of 12 h short day induction on the reproductive development and plant morphology were examined. All the hybrids (BK 560, MBH 104, MBH 110 and ICH 105) responded to 14 short days by a considerable reduction in the time to anthesis, plant height and the final number of leaves produced, without any adverse effect on head development. In another experiment BK 560 required at least four short days for floral initiation and another four for subsequent development. Short day induction had no apparent effect on the rate of leaf appearance. The results were compared to those reported for millets in general and to millets grown in the tropics.
Effects of Maturity on Oil Yield of Brassica juncea
Authors: Gambhir P. N. , Narain A. , Tiwari P. N.
Published: October 2008

The change in seed oil percentage and 100-seed weight of Brassica juncea Varuna was studied as the crop matured during rabi 1977–78. Statistically, the oil percentage reached its highest value at 55 days from flowering, whereas the 100-seed weight was highest about 20 days later, when the pods were fully yellow. Oil yield (the product of oil percentage and seed weight) also reached its highest value when the pods were fully yellow. This information should enable the crop to be harvested at the proper physiological stage (yellow-podded) for maximum oil yield.
Evolution of Grain Legumes. V. The Oilseeds
Authors: Smartt J.
Published: October 2008

Although the groundnut and soyabean are not close taxonomic relatives they have a number of features in common. Both are polyploid (2n= 4x= 40 chromosomes) and have arisen from the domestication of wild polyploids. Polyploidy has occurred independently at least twice in the genusArachis, while inGlycinethe genus includes both tetraploids and octoploids, an unusually high ploidy level in a legume. Both crops are oilseeds although oil content varies widely between the two species, ±50% in groundnut and ±20% in the soyabean. The soyabean produces ±35% protein content of good quality whereas that of the groundnut is ±30% and less well balanced nutritionally. The soyabean originated in the Far East whereas the groundnut originated in the eastern Andes foothills (N.W. Argentina to S. Bolivia). The evolutionary changes under domestication in the soyabean are typical; the cultigen has become a compact, erect, self-supporting plant with reduced pod dehiscence and loss of seed dormancy. The evolutionary response pattern of the groundnut is similar but modified on account of its geocarpy. This necessitates the maintenance of adequate contact between basal branches of the plant and the soil for effective fruiting. Notwithstanding this, strongly ascending growth forms have become established. The greatest contrast between the two species is in photoperiod sensitivity; the groundnut is day-neutral while the soyabean is a short-day plant with genotypes varying widely in the day length tolerated without inhibition of flowering.
Studies on Row Arrangement and Population Densities of Potato Cultivars in a Sugarcane and Potato Intercropping System in North Central India
Authors: Verma R. S. , Chauhan R. S. , Singh R. N.
Published: October 2008

Four plant densities and two genotypes of potato intercropped with sugarcane were examined at Lucknow, India and compared with potato–sugarcane sequential cropping. The best yields and monetary returns were obtained with one sugarcane row to two rows of potato (Kufri Chandramukhi) at 80 × 103 potato plants ha−1; this treatment combination gave virtually a full yield of both potato and cane. Sequential cropping of potato and sugarcane with 80 × 103 potato plants ha−1 in rows 50 cm apart gave better yields than intercropping potato with sugarcane in a 1:1 row arrangement. Kufri Chandramukhi, a short duration variety of potato, was more suitable for intercropping with sugarcane than the long duration Kufri Sindhuri. Growing potato either in sequence or as an intercrop with sugarcane decreased soil bulk density and increased its available nitrogen content.
Effect of Iron Pyrites, Organic Materials and Micronutrients on Yield of Rice and Wheat and on Amelioration of Sodic Soil
Authors: Tiwari K. N. , Kumar Anil
Published: October 2008

The effects of iron pyrites, organic materials and micronutrients on the yield of rice and wheat and on the amelioration of saline sodic soil were studied at Kanpur. The grain yield of the first crop of rice increased from 1.37 to 2.97 t ha−1 following application of pyrites at 50% of the estimated gypsum requirement. The grain yield of succeeding wheat and rice crops also increased significantly with pyrites treatment. These increases were associated with marked decreases in pH, electrical conductivity, exchangeable and soluble sodium content and bulk density of the soil and with an increase in its hydraulic conductivity. The beneficial effect of pyrites was increased with the application of rice straw, Sesbania as green manure and micronutrients, the pyrites plus Sesbania green manure treatment being the most effective.
Harvesting Policies For Tea in Malawi
Authors: Palmer-Jones R. W.
Published: October 2008

The information collected from an experiment on tea, in which two plucking intervals and three plucking standards were imposed, allowed analysis of the effects on the total value of output (Cloughley et al., 1983; Cloughley, 1983). The analysis can be extended and its practical relevance improved by incorporating harvesting and manufacturing costs. Using information collected in another experiment and readily available economic information the effects of incorporating these costs are presented. A method of simultaneously determining optimal plucking interval and standard is described.
Effects of NPK Fertilizer on Tuber Yield, Starch Content and Dry Matter Accumulation of White Guinea Yam (Dioscorea rotundata) in a Forest Alfisol of South Western Nigeria
Authors: Kayode G. O.
Published: October 2008

Field trials designed to investigate the effects of nitrogen, phosphorus and potassium on the yield, starch and dry matter content of white guinea yam were conducted over a four year period in south western Nigeria. The optimum level of nitrogen for successful production of white guinea yam was 35 kg ha−1in a forest Alfisol that had been under cultivation for at least two years. Nitrogen, phosphorus and potassium had no significant effect on starch content, but large applications of phosphorus and potassium significantly decreased dry matter accumulation.
Controlled Environments as an Adjunct to Field Research on Lentils (Lens culinaris). II. Research Strategy
Authors: Summerfield R. J. , Muehlbauer F. J.
Published: October 2008

The strategy and associated practical details are described of a research programme which seeks to make effective use of controlled environment facilities in providing information and screening techniques useful to lentil breeders. Two principal objectives were (a) that genotypes grown in artificial climates should respond to whatever factors are being investigated in a manner which reflects their responses and relative sensitivity to different agroclimates in the field, and (b) to deploy controlled environment facilities for the longest period which is feasible during each calendar year and with maximum benefit:cost ratio.
Inducing Orthotropic Shoots in Coffee with the Morphactin Chlorflurenolmethylester
Authors: Stemmer W. P. C. , Van Adrichem J. C. J. , Roorda F. A.
Published: October 2008

The auxin-transport-inhibiting morphactin chlorflurenolmethylester (CFM; Methyl 2-chloro-9-hydroxyfluorene-9-carboxylate) breaks the dormancy of axillary buds in young coffee plants and produces orthotropic shoots. A concentration of CFM as low as 50 mg/litre induced an average of 24 orthotropic shoots per 6-month-old seedling. This approach could provide a fast and inexpensive method of vegetative propagation for raising disease-resistant cultivars if adult clones respond similarly to the seedlings used here and the treatment does not adversely affect the propagation of induced shoots.
Minimizing Nitrate-nitrogen Leaching by Parallel Multiple Cropping in Long-duration Row Crops
Authors: Yadav R. L.
Published: October 2008

The nitrate–N profile of soil was studied in sole and parallel multiple-cropping systems of pigeonpea and maize and of sugarcane and blackgram. In sole cropping there was more nitrate–N in the deeper horizons because of leaching from the inter-row spaces of row crops, whereas the nitrate content was drastically reduced in parallel cropping at more than 30 cm deep as N in the inter-row spaces was better utilized by the crops. The yield of two crops, when combined, was more in parallel cropping than the sum of crops grown separately, and the Land Equivalent Ratio was higher in parallel-cropping systems than in sole cropping.
Effects of Zinc on Yields and Zinc Content of Rice Varieties on Calcareous Soil
Authors: Rai Raman , Singh S. N. , Sinha R. B. , Prasad V.
Published: October 2008

Application of zinc to six high-yielding rice varieties in calcareous soils produced significantly higher grain yield and interactions between varieties and Zn levels were significant. Yields of varieties IR 20, Jaya, Sita and Jayanti at 2.5 and 5.0 ppm Zn were similarly affected, but Archana produced significantly higher grain yield at 5 ppm Zn than at 2.5 ppm. Effects of Zn on straw yield were similar. Zn application invariably resulted in a higher Zn concentration in plants at all stages of growth and in grain in all varieties. Maximum Zn contents were observed at the tillering stage and minimum at harvest.
Setting up and Managing an Experimental Farm for Crop Studies: the First 20 Years' Experience at Broom's Barn
Authors: Cooke D. A. , Jaggard K. W. , Draycott A. P. , Scott R. K. , Webb D. J. , Golding M. J.
Published: October 2008

The objectives and management policy of an experimental farm for studies on the sugar beet crop are described. Farm yields of sugar beet and cereals are discussed in relation to yields in experiments and on a national scale. Some aspects of experimental accuracy and design are considered.
Intercropping Barley and Beans I. Effects of Planting Pattern
Authors: Martin M. P. L. D. , Snaydon R. W.
Published: October 2008

Barley (Hordeum sativum) and field beans (Vicia faba) were grown in pure stands, alternate-row mixtures and within-row mixtures in two field experiments. In both experiments the Land Equivalent Ratio (LER), based on seed yield, was consistently greater than 1.0 only when the crops were grown in alternate rows. The LER was greatest (1.8) when the mixture included more barley than beans. Reasons for the yield advantage of alternate row planting are discussed. Barley was more competitive than beans in mixtures, but this was not significantly affected by planting pattern.
Effects of Planting Schedule and Intercropping on Green Gram (Phaseolus Aureus) and Bulrush Millet (Pennisetum Americanum) in Tanzania
Authors: May K. W.
Published: October 2008

Experiments in Tanzania have shown that green gram planted one week before bulrush millet produced a complimentary protein energy balance optimal for a cereal–legume diet. Grain yields were increased due to additive intercropping (by 13%) and replacement intercropping (27%). Green gram plants were more competitive than bulrush millet plants at the seedling stage but were overpowered in later growth stages.
Effects of Defoliation on Yield and Forage Quality of Some Tropical Grasses, Legumes and their Mixtures
Authors: Osman A. E. , Abu Diek A. A.
Published: October 2008

The performance of three tropical grasses and three legumes (buffel grass, rhodes grass, green panic, butterfly pea, phillipesara and alfalfa), grown in pure stand and in legume–grass mixtures, was evaluated over two seasons when cut monthly at 0, 7 or 14 cm high. Harvesting at 7 cm favoured total dry matter and crude protein production in all cases, with highest yields from butterfly pea grown alone. Buffel grass was the best dry matter producer among grasses in pure stand, while rhodes grass–butterfly pea mixture was the best legume–grass mixture. Forage of these low-protein tropical grasses could be significantly improved by growing them in mixture with legumes.
Effects of Irrigation Interval, Urea and Gypsum on N, P and K Uptake by Forage Sorghum on Highly Saline–Sodic Clay
Authors: Magid E. A. Abdel , Mustafa M. A. , Ayed I.
Published: October 2008

The effects of three irrigation intervals (7, 10 and 15 days), four nitrogen levels (0N, 1N, 2N and 3N where 1N = 43.8 kg N/ha), and 0 or 11.9 tons/ha gypsum on leaf N, P and K uptake by forage sorghum grown on a highly saline–sodic clay soil were investigated in two successive seasons. The two seasons' data consistently showed that both leaf-N and leaf-K increased significantly with increasing N-rate and by splitting the same quantity of irrigation water into more frequent irrigations. Gypsum had no consistent effect. The responses of both leaf-N and leaf-K to nitrogen rates were significantly linear and a linear response of dry matter yield to leaf-N was also observed. P uptake was improved by more frequent irrigations in the first cutting of 1978, but was not otherwise affected by treatments.
Diurnal Variations in Soil Temperature under Tea Plants
Authors: Othieno C. O.
Published: October 2008

Diurnal variations in soil temperature were measured under tea plants with different kinds of mulches. During the early years after planting temperatures differed, depending on the type of mulch and its heat absorptivity. Black plastic and stone chippings showed the greatest diurnal variations, but the variations disappeared in all treatments when there was a ≥ 60% canopy. Tea plants themselves modify soil temperatures, which could affect growth and yield in places where soil temperatures are generally lower.
Nodulation in the Hypocotyl Region of Groundnut (Arachis Hypogaea)
Authors: Nambiar P. T. C. , Dart P. J. , Srinivasa Rao B. , Ramanatha Rao V.
Published: October 2008

Different subspecies ofArachis hypogaeashow variation in their ability to nodulate in the hypocotyl region. Some cultivars belonging to subspecieshypogaeanodulate profusely on the hypocotyl, while those offastigiatanodulate rarely in this region. The utilization of this character in breeding for increased nitrogen fixation is discussed.
Analysing Daily Rainfall Measurements to Give Agronomically Useful Results. I. Direct Methods
Authors: Stern R. D. , Dennett M. D. , Dale I. C.
Published: October 2008

Simple methods are described for the analysis of daily rainfall measurements. The distinctive feature is that each year provides one number for any event or characteristic of interest. The resulting observations are then analysed, assuming that they are a simple random sample from a single distribution. An estimate of the probability of an event can be made directly from its relative frequency of occurrence, or alternatively a distribution (such as the normal) can be fitted. The methods are applied to agronomic questions on dry spells, the start, end and length of the growing season, and the distribution of amounts of rainfall through the year. Examples are given from Nigeria and India.
Installation and Evaluation of Permanent Access Pits Which Permit Continuity of Measurement in Cultivated Soils
Authors: Howse K. R. , Goss M. J.
Published: October 2008

We describe the insertion and reinstatement of a simple lined access pit that allows for the permanent installation of tensiometers, piezometers, etc. in soil that is cultivated annually. The presence of the access pit did not affect the hydrology of the soil in its vicinity. We give an example of the application of results from tensiometers permanently installed in this way.
Flowering Pattern and Reproductive Efficiency of Oilseed Sesame
Authors: Saha S. N. , Bhargava S. C.
Published: October 2008

In maximizing productivity levels in oilseed sesame (Sesamum indicum) one of the major constraints is the large-scale shedding of buds, flowers and capsules. The present study examines the reproductive behaviour of five sesame genotypes with a view to ascertaining the extent of production, shedding and retention of different reproductive organs. Sesame genotypes produce 250–350 flower buds per plant but shed most of them at different stages of development. Shedding is thus excessive, and 86–91% of the reproductive potential was not realized in this study, thus limiting yield. Improvement in yield through increased fruit retention is essential.
Effects of Leaf Blight and Rust on Maize in Lowland and Highland Cameroon Environments
Authors: Ayuk-Takem J. A. , Chheda H. R.
Published: October 2008

COCA (highland), TZPB (lowland) and COCA x TZPB maize varieties were tested at Bambui Plain (1330 m) and Ekona (550 m). Leaf blight and rust were controlled chemically with Dithane-M45 and Benlate, and their use significantly increased the yields of COCA when grown in lowland environments, where it does not possess resistance to lowland leaf blight (H. maydis) and rust (P. polysora); yields of TZPB were similarly increased in highland areas, where it is susceptible to highland leaf blight (H. turcicum) and rust (P. sorghi). COCA x TZPB was intermediate in resistance to both diseases at the two locations.
Effects of Planting Dates on Pest Infestation, Yield and Harvest Quality of Cowpea (Vigna unguiculata)
Authors: Ezueh M. I.
Published: October 2008

Time of planting was found to significantly influence insect damage, quality of harvest and yield of cowpea in southern Nigeria. The greatest insect damage occurred on the August planting. Maruca testulalis was the most serious pest on cowpea whilst thrips were the least. Dry grain yield was higher in the early season plantings but quality of harvested crop was better in the late season plantings. These observations were also influenced by cultivar differences.
An Assessment of Pest Damage on Grain Sorghum in Botswana
Authors: Flattery K. E.
Published: October 2008

In trials conducted over five years, data on pest (insect, disease, bird) attack and yield of sorghum cultivar 65D were accumulated. A modified analytical method of damage assessment is described, which includes consideration of all pest occurrences and different levels and timing of pest attack. There was a positive correlation between crop yield and rainfall. The selective infestation of stronger plants, or the ability of those plants to support pest populations, is shown; thus, in most cases, yield reductions are masked. The importance of the tillering habit of 65D on yield, and its ability to compensate for pest damage by further tillering, are shown. A cultivar which does not normally tiller was tested in the final year. Effects on yield of all the pests encountered in the five years are discussed.
A Short Review of Farming Systems Research in the Tropics
Authors: Simmonds N. W.
Published: October 2008

Farming systems research (FSR) has come to prominence as a part of tropical agricultural research in the past decade or so. The main stimulus was the growing realization that small farmers are ‘economically rational’ and agricultural economists have been the leading agents in developing FSR ideas. Three broad aspects are distinguished: (1) FSR sensu stricto, the deep analysis of farming systems as they exist, which is essentially an academic activity, (2) OFR/FSP (‘on farm research with farming systems perspective’), a practical adjunct to research which seeks to test the socio-economic suitability of research ideas on-farm before recommending extension and (3) NFSD (‘new farming systems development’) which seeks to develop complex, radical change rather than the stepwise change characteristic of OFR/FSP. The technical components of NFSD are probably mostly available but the necessary transdisciplinary, synthetic thinking is not. Research on perennial plants in tropical agriculture has been rather neglected but there are signs of growing concern; they must be an important feature of any NFSD for the wetter areas.
Manure for Cropping: A Case Study from Central Nigeria
Authors: Powell J. Mark
Published: October 2008

The traditional management of cattle manure in a cropping system in the savanna zone of central Nigeria is discussed in conjunction with the agronomic benefits and problems of manure use. Nitrogen and phosphorus contents of the manure varied seasonally. On-farm trials showed that maize grain yields were about 1 t ha−1 more and weed growth 90% greater in manured than in non-manured areas. It is important to reduce the competition between crops and weeds if grain crops are to obtain the full benefit of manure in such cropping systems.
Traditional versus Improved Groundnut Production Practices: some Further Evidence from Northern Nigeria
Authors: Abalu G. O. I. , Etuk E. G.
Published: October 2008

Improved groundnut production practices are compared with traditional methods. Improved sole crop production practices show significantly greater net returns per hectare than traditional methods but when other considerations such as the riskiness of the various enterprises are examined, the superiority of the improved sole crop technology becomes less clear-cut. A case is made for designing improved technologies involving crop mixtures.
Evolution of Grain Legumes. VI. The Future – the Exploitation of Evolutionary Knowledge
Authors: Smartt J.
Published: October 2008

The future evolutionary potential of pulses is determined by the nature and extent of the genetic variability in the primary gene pool. This is extensive in the major grain legumes, notably the groundnut, soyabean, Phaseolus and faba beans, and in the cowpea. It is less extensive in the cultivated lupins and this appears to be a serious limitation to their development as useful crops. The considerable development of isolating mechanisms between related species of legumes has restricted the development of the secondary gene pool. This is most developed in the genus Arachis, where section Arachis provides an extensive secondary gene pool for the groundnut. Tertiary gene pools are potentially quite extensive for many grain legumes but since most interspecific hybrids are inviable this resource would be difficult to exploit with present techniques. The development of sophisticated gene transfer techniques for grain legumes is inhibited by their lack of amenability to in vitro culture. The suggestion is made that genetic resources profiles could be constructed on the basis of an expansion of Harlan and de Wet's gene pool system. These could serve as a guide to the present state of germplasm collections, indicating their strengths and weaknesses, which would be useful in formulating future collection and evaluation strategies.

The potential for more intensive exploitation of such legumes as the winged bean and lupins undoubtedly exists. The reasons for past under-exploitation of the winged bean need to be determined.

Grain legumes have an assured future for good economic and nutritional reasons. More attention probably should be devoted to exploiting the legume-Rhizobium symbiosis, fundamental to the development of efficient and economic farming systems in the developing world.
Evaluation of Brassica Carinata as a New Oilseed Crop in India
Authors: Katiyar R. K. , Saran Ganga , Giri G.
Published: October 2008

Brassica carinata (an uncultivated species) was compared with other oilseed species already under cultivation in India, on irrigated and rainfed soils. B. carinata yielded very well in a wide range of environments partly because it had a large number of primary and secondary racemes. It also showed better environmental adaptation and substantial resistance to pests and disease.