bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses of Young Tea (Camellia sinensis) Clones to Drought and Temperature. II. Dry Matter Production and Partitioning
Authors: Burgess P. J. , Carr M. K. V. 
Published: October 2008

SUMMARYThe physiological basis for differences in yields from well-watered and draughted plants of four contrasting clones of tea was studied in terms of light interception, dry matter production and partitioning at a high altitude site in Southern Tanzania where there are marked seasonal variations in rainfall and temperature. The plant dry weights, including roots, were measured eight months after field planting and subsequently at intervals of three to four months, corresponding to the different seasons, during the following two years. Fully irrigated plants of one clone (S15/10) were also harvested after four years in the field. Clones differed in the rates of canopy spread and hence in their capacity to intercept solar radiation. The ‘radiation use efficiency’ (the net total dry matter production per unit of intercepted short-wave radiation) was similar for the four well-watered clones and ranged from 0.40 to 0.66 g MJ−1, which corresponds closely to values reported for other woody tropical plants. A 16-week drought treatment imposed two years after planting reduced the mean light interception of the four clones by about 25% and the mean radiation use efficiency by 78% to 0.09 g MJ−1. Clone S15/10, a cultivar from Kenya which produces large yields, partitioned a greater proportion of dry matter to leaves and harvested shoots than the other clones, and correspondingly less to large structural roots. This resulted in a maximum harvest index of 24%, substantially greater than other values reported in the literature. There were seasonal differences in partitioning, with more dry matter being diverted to roots and less to shoots during the cool season. Although the drought treatments had no significant effect on root growth, the amount of dry matter partitioned to leaves, stems and harvested shoots declined by 80–95%. The roots of all four clones extended in depth at similar rates (about 2 mm d−1), those of Clone S15/10 reaching 2.8m after four years. The results are discussed in terms of appropriate field cultural practices and possible selection criteria for high yielding clones.
Farmer Participatory Crop Improvement. I. Varietal Selection and Breeding Methods and Their Impact on Biodiversity
Authors: Witcombe J. R. , Joshi A. , Joshi K. D. , Sthapit B. R. 
Published: October 2008

SUMMARYFarmer participatory approaches for the identification or breeding of improved crop cultivars can be usefully categorized into participatory varietal selection (PVS) and participatory plant breeding (PPB). Various PVS and PPB methods are reviewed. PVS is a more rapid and cost-effective way of identifying farmer-preferred cultivars if a suitable choice of cultivars exists. If this is impossible, then the more resource-consuming PPB is required. PPB can use, as parents, cultivars that were identified in successful PVS programmes. Compared with conventional plant breeding, PPB is more likely to produce farmer-acceptable products, particularly for marginal environments. The impact of farmer participatory research on biodiversity is considered. The long-term effect of PVS is to increase biodiversity, but where indigenous variability is high it can also reduce it. PPB has a greater effect on increasing biodiversity although its impact may be limited to smaller areas. PPB can be a dynamic form of in situ genetic conservation.
Farmer Participatory Crop Improvement. II. Participatory Varietal Selection, a Case Study in India
Authors: Joshi A. , Witcombe J. R. 
Published: October 2008

SUMMARYFarmer participatory varietal selection (PVS) was used to identify farmer-acceptable cultivars of rice and chickpea. Farmers' requirements in new crop cultivars (varieties) were determined, a search was carried out for released and non-released cultivars that matched these needs, and they were tested in farmer-managed, participatory trials. Farmer-acceptable cultivars were found amongst released material, but not among the recommended material for the area. Lack of adoption is, therefore, because resource-poor farmers have not been recommended or exposed to the most appropriate cultivars under the existing system of varietal identification and popularization. Adoption rates of cultivars would be improved by increased farmer participation, the systematic testing in zonal trials of locally popular cultivars to define their domains properly, a more liberal release system, and a more open system of providing seeds of new cultivars to farmers.
Farmer Participatory Crop Improvement. III. Participatory Plant Breeding, a Case Study for Rice in Nepal
Authors: Sthapit B. R. , Joshi K. D. , Witcombe J. R. 
Published: October 2008

SUMMARYA participatory plant breeding (PPB) programme was conducted for the high altitude areas of Nepal. The aim was to breed acceptable varieties with minimum use of resources and to utilize farmers' knowledge in the PPB programme. Farmer participation began at the F5 stage and progress was followed over two seasons in two villages. Farmers proved to be willing participants and made selections in the segregating material, often with great success. Large differences in farmers' preferences between the F5 bulks were found and the most preferred were adopted rapidly. The most adopted variety, Machhapuchhre-3, performed well in the formal trials system, and much better than the products from conventional centralized breeding. The PPB programme increased biodiversity in the two participating villages.
Nitrogen Fixing Capacity of Mucuna untilis
Authors: Oke O. L. 
Published: October 2008

SummaryThe fixation of nitrogen in root nodules of Mucuna untilis was studied, and its transfer to other parts of the plant. Fixation reached a maximum of 6 mg. per day per plant, and the rate of transfer of nitrogen from the nodules increased gradually until it almost equalled the rate of fixation. Older plants seem to be more efficient fixers of nitrogen than younger ones.
Factors which affect the Germination of Seeds of Six Common East African Weeds
Authors: Huxley Peter A. , Turk Alexander 
Published: October 2008

SummaryInternal and external factors affecting the germination of seeds of six common East African weeds were studied by sowing the seeds in each of 13 different treatments chosen to provide a wide range of different germination environments. The results indicate how germination is regulated in each of these species and provide the basic information necessary for further field studies.
Studies on Browse Plants in Ghana
Authors: Mabey G. L. , Innes R. Rose 
Published: October 2008

SummaryDigestibility of the herbage of the indigenous tree Antiaris africana was investigated. Digestion coefficients (%) were—organic matter 67, dry matter 64, crude protein 78, crude fibre 39, nitrogen-free extract 74, ether extract 36 and ash 36. Calculated nutritive values were—starch equivalent 23·2 and digestible crude protein 3·7, giving a nutritive ratio of about 1 : 6. The herbage was young and its palatability high.
Fertilizer Responses in Swamp Rice (Oryza sativa L.) in Northern Nigeria
Authors: Bredero Th. Y. 
Published: October 2008

SummaryA series of N × P field experiments with irrigated rice, conducted over the period 1958–1962 on the same plots on alluvial soils considered representative for most of the bottom ‘fadama’ land in Niger and Ilorin Provinces, Northern Nigeria, showed small increases with medium dressings of P2O5 and large responses with high dressings of N. The N responses showed considerable variation between soil types and years. The variation between soil types was attributed to different cation exchange capacities, which resulted in NH4′ leaching from the root zone at different rates. The variation in N responses between years was probably due to different physiological timings of the top dressings. Results of chemical analyses of straw and grain samples of the 1961 crop were used to estimate the percentage of N and P2O5 recovered by the crop with the various treatments over the untreated plots in the previous years of the experiments on two soil types. The recovery percentages for the different levels of N on the clay ‘basin’ soils were moderate, about 18 per cent, whereas those for the sandy ‘levee’ soils were lower, averaging only 9 per cent. Recovery of P2O5 varied from good at medium N levels (14 per cent) to moderate at high N levels (9 per cent) on the basin soils. Recovery of P2O5 on the levee soils was poor. The utilisation of the recovered N (75 lb paddy/lb N) and P2O5 (42 lb paddy/lb P2O5) was very good for N and fair for P2O5.
Maize Growing in Nyasaland (Malawi) II. Fertilizer Requirements
Authors: Brown P. 
Published: October 2008

SummaryThe main nutrient deficiency in Malawi is a chronic lack of nitrogen, which is found on all but a few soils. Phosphorus also becomes limiting quite rapidly on certain soil types as a result of permanent cultivation, but there has so far been little response to potash or lime. Incipient sulphur shortage is automatically corrected by the use of sulphate of ammonia and single superphosphate to correct the major deficiencies. Trace elements have not been widely tested. Samples of organic manure vary widely in moisture and nutrient content, and their nitrogen status is frequently low, so it is safest to consider manure as primarily a source of P, K and minor nutrients, and to supplement it with fertilizer nitrogen. It should be possible, with good cultivation of synthetic varieties and improved selections, to obtain maize yields of 15–20 bags/acre with fertilizer dressings of up to 80 lb/acre of the limiting nutrients.
Stimulation of Latex Flow in Hevea brasiliensis
Authors: Abraham P. D. , Tayler R. S. 
Published: October 2008

SummaryLatex flow can be stimulated by bark scraping and by the application of vegetable oils, auxins and some other substances to the bark, either above or below the tapping cut. Auxin preparations are now widely used in commercial rubber production, 2,4–D and 2,4–5–T being the most common. The response obtained depends upon the formulation, on the method of application, and on other factors such as the age and condition of the tree and the tapping system employed. The effect of stimulation is considered to be due to a dilution of the latex and an increased rate of flow. A larger area of bark is drained, and the duration of flow is prolonged, because plugging of the latex vessels is delayed. In young trees, the conflict between increased latex production and active tree growth requires the development of different and less intensive techniques.
Responses of Lucerne to Different Soil Moisture Regimes
Authors: Landsberg J. J. 
Published: October 2008

SummaryAn experiment in which irrigation intervals for lucerne were dictated by four factors applied to daily evaporation from a Class A pan has been reported by Landsberg (1966). This paper discusses data from a number of subsidiary measurements made during that experiment. An extensive soil sampling programme yielded data on the effects of treatments on soil moisture content, and plant height and per cent ground cover measurements enabled detailed evaluations to be made of crop responses. Both height and ground cover were decreased by soil moisture stress. Relative turgidity was closely related to soil moisture content in the early morning, dry treatments showing more rapid recovery of turgor than those where water was kept at more adequate levels. Radiation utilization by the crop was affected by soil moisture conditions, and also apparently by temperature.
Responses of Cereals to Fertilizers in Northern Nigeria. I. Sorghum
Authors: Goldsworthy P. R. 
Published: October 2008

SummaryAs part of a programme to improve production of the main food crops of Northern Nigeria, trials were carried out to investigate the effect of nitrogen and phosphate fertilizer on the grain yield of sorghum. Five fertilizer response areas have been defined and estimates have been made of the most profitable combinations and levels of phosphorus and nitrogen to use in each area. Fertilizers produced the greatest increase in yield in the two response areas which cover the north of the country.
Improvement of Permanent Pasture by Overdrilling and Oversowing
Authors: Warboys I. B. 
Published: October 2008

SummaryThe failure of overdrilling techniques to improve poor pasture and the development of the dipyridylium herbicides, particularly paraquat, for controlling grass species, prompted research into oversowing techniques in 1963 and 1964. Rotary cultivation, although giving better establishment than any other oversowing technique, did not always reduce the more persistent weed grasses such as Agrostis spp., and so failed to produce a perennial rye-grass dominant sward. This was believed to be due to various factors such as unsatisfactory herbicide pre-treatments, the interval between spraying and cultivation, the high moisture content of the soil when cultivated, as well as the greater resistance of rhizomatous grass species to paraquat. In the absence of paraquat, rotary cultivation was able to establish a satisfactory number of seedlings. In both experiments, however, the subsequent botanical composition was considerably influenced by pasture management.
Systematic Designs for Spacing Experiments
Authors: Bleasdale J. K. A. 
Published: October 2008

SummaryTwo types of design are described, in which the number of plants per unit area varies systematically within any one plot in the field, the plant arrangement being held constant. Any desired range of spacing can be covered in either design and the calculations necessary to establish specific sets of dimensions are given. In addition descriptions are given of the laying-out, planting (or sowing), management and recording of experiments using these designs.
A Second Stock-Scion Trial with Mango in Israel
Authors: Oppenheimer Ch. 
Published: October 2008

SummaryIn a second stock-scion trial with mango in Israel the influence of five rootstocks was investigated. In our first trial, two rootstocks—Sabre and 14·12—had been found suitable and unsuitable respectively. In the second trial, 14·6 and 14·7 were found to be not significantly different from Sabre, 3·2 was found to be somewhat inferior and 14·12 was again unsuitable. The important characters of the 22 varieties grown are described, and an evaluation is attempted of their yield and marketability.
Nodulation of Legumes in the Sudan: Cross-Inoculation Groups and the Associated Rhizobium Strains
Authors: Habish H. A. , Khairi Sh. M. 
Published: October 2008

SummaryCross-inoculation tests, based on nodule formation and nitrogen fixation, were made on 21 species of legumes commonly found in the Sudan. The results showed that they may be grouped according to the accepted system of classification, but there were some important inconsistencies in the cowpea group. For instance,Arachis hypogaeaandAcacia spp.have their own strains of Rhizobium. The cultural and physiological characters of the rhizobia studied were generally similar to those known for other species of the organisms.
Host Preference and Survival of the Dark-Headed Rice Stem Borer Chilotraea polychrysa(Meyr.) in Malaya
Authors: Kok L. T. 
Published: October 2008

SummaryThe polyphagous nature of the dark-headed rice stem borer, Chilotraea polychrysa (Meyr.), may contribute greatly to its ability to survive periods of food shortage when rice plants are scarce. Investigations on the preference and survival of C. polychrysa on seven selected hosts belonging to the Gramineae revealed that it oviposited on all the hosts tested, but showed a marked preference for its normal host, rice (Oryza sativa). Survival rates on rice and the alternate hosts did not differ significantly. The percentage of larvae surviving to the adult stage was generally low because of the high rate of mortality from larval to pupal stage, irrespective of host species. In rice, there was distinct ovipositional preference for plants at the maximum vegetative stage rather than for younger plants. The larval survival rate increased with the age of the host from 35 to 65 days, but dropped sharply when infestation occurred on plants 80 days old, by which time the inflorescence is beginning to emerge.
Screening Fungicides for Control of Coffee Berry Disease in Kenya
Authors: Vermeulen H. 
Published: October 2008

SummaryFourteen out of 43 fungicides were selected, after laboratory screening, for field trials against coffee berry disease. Each fungicide was compared with a commercial cuprous oxide formulation and an unsprayed control, by assessing conidial production of bearing coffee branches and by recording the percentage of healthy ripe berries picked. In assessments of fungicidal efficiency, healthy ripe berry counts gave more consistent results than those obtained by measuring conidial production. The results from berry counts indicate that in these experiments Ortho Difolatan (BSI ‘Captafol’) was equal, but not significantly superior, to the standard formulation used in estate spraying. The annual rhythm of conidial production seems to have changed over the past five years. The significance of this is discussed in relation to the control of coffee berry disease.
The Growth of Four Rice Varieties as Affected by Temperature and Photoperiod with Uniform Daily Periods of Daylight
Authors: Owen P. C. 
Published: October 2008

SummaryThe growth and grain production of four rice varieties were compared under controlled environment conditions at two minimum night temperatures (15 and 23°C) and at two daylengths (11½ and 13 hours) where the period of daylight for active photosynthesis was kept constant at 8 hours. The lower night temperature prevented flowering but at the higher one grain yields were associated with panicle weights rather than panicle numbers, and production of so-called photoperiod-insensitive varieties was affected by photoperiod. Although the periods of natural light were constant, and photoperiods were extended by low intensity incandescent light, in-creased total plant weights, not due to effects on tillering, were observed under longer days.
Uptake of Phosphorus and Other Nutrients by Maize in Western Nigeria
Authors: Bromfield A. R. 
Published: October 2008

SummaryUptake of the major nutrients by maize was determined throughout the growing season. Little phosphorus was accumulated, as reflected in its distribution within the plants, but uptake of labelled phosphorus showed two distinct peaks associated with root development. One fifth of the applied phosphorus was recovered by the plants.
Comparative Potential Yields of Rice Varieties in the Australian Tropics
Authors: Owen P. C. 
Published: October 2008

SummaryDuring the wet summer season of northern tropical Australia higher yields were attained by introduced weakly photoperiod-sensitive short-duration rice varieties than by locally-bred strongly photoperiod-sensitive varieties resembling traditional tropical indicas. There was no clear relationship between growth durations and yields. Dry season yields were lower, associated with shortened durations (especially of the reproductive phase) and lower cumulative radiation totals in the late phases of growth. Dawn, a variety of U.S. origin imported from the Philippines, outyielded all other varieties. In both wet and dry seasons yields depended largely on panicle weights, which in turn depended on high seed numbers per panicle. Individual seed weights were of less importance. The results tended to confirm a prior interpretation of climatic data, i.e. that there is no environmental factor limiting wet season yields in the region to levels below those obtained elsewhere in the tropics, provided the crop receives a high standard of care and attention.
Sulphur Nutrition of Legumes
Authors: Oke O. L. 
Published: October 2008

SummaryApplication of S, alone or in combination with P, significantly increased the number, yield and nitrogen content of root nodules on pigeon pea and guar. Sulphur, applied at different levels with NPK, increased the methionine content and yield of plants significantly but had no significant effect on the N content. Sulphur at 20 p.p.m., alone or in combination with P, increased the methionine content of pigeon pea significantly but the effect decreased at higher levels of S. In general, higher values of methionine were obtained in the presence of S than when it was absent.
Growth and Productivity of Tapioca (Manihot utilissima)—I. Leaf Characteristics and Yield
Authors: Williams C. N. , Ghazali S. M. 
Published: October 2008

SummaryThe shoots of high, medium and low yielding clones of tapioca were examined to see whether yield was associated with morphological characteristics of the foliage and/or with leaf area development. The lowest yielding variety had the highest leaf area per stem, and vice versa, differences in leaf area being mainly due to differences in leaf size. Leaves of the highest yielding variety possessed attenuated lobes, which tended to have a more vertical mid-day orientation, whereas the lowest yielding variety possessed large broad-lobed leaves with more horizontal orientation. The intermediate variety had acutely attenuated lobes and showed a much more vertical day-time orientation. The relationship between the leaf properties and canopy efficiency is discussed.
Water Relations of Beans I. Effects of Water Stress on Growth and Flowering
Authors: Nadi A. H. El 
Published: October 2008

SummaryExperiments were made in glasshouses, growth cabinets and growth rooms to study the differential responses of the broad bean to water stress during the vegetative and flowering phases of growth. Plants in the flowering phase proved to be more sensitive to drought than in the vegetative period, and there were different responses (Relative Growth Rate) to temperature at different stages of plant growth. Day length and temperature influenced the position of the earliest flower initials on the stem, and intensity of flower shedding was aggravated by high temperature.
Effects of Rainfall on Yield of Cocoa in Ghana
Authors: Ali Faisal M. 
Published: October 2008

SummaryEffects of rainfall on yield of cocoa from a large-scale experiment has been investigated at 10 and 12 sites, over seven years, in the Eastern and Ashanti regions of Ghana. There was a positive association between yield and rainfall at certain times of year, but a negative association at other times. Variation due to the regression of yield on monthly rainfall varied up to 23 per cent, while a maximum variation of 31 per cent accounted for the regression of yield on the total rainfall of February to April in the Eastern region.
Effects of Nitrogen Fertilizer on Natural Pastures in Western Tanzania
Authors: Walker B. 
Published: October 2008

SummaryAt Ukiriguru, in Western Tanzania, three levels of sulphate of ammonia were compared on natural pastures on hardpan soils. Yields of dry matter were substantially increased by nitrogen fertilizer and at high stocking rates the growth of cattle on different treatments followed fairly closely the amounts of dry matter available.
Selection of Intercrops for Cotton in India
Authors: Varma Mahendra P. , Kanke M. S. Subba Rao 
Published: October 2008

SummaryResults of an investigation to select intercrops showed that cotton can be grown with more profit with groundnut or gora paddy than when grown alone. Growing food or cash crops along with cotton enables an early crop to be produced and the practice may help to extend cotton cultivation in Chotanagpur and Santhal Parganas, a potential cotton belt of the future.