bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contributions of shoot categories to growth and yield of winter wheat
Authors: Thorne G. N. , Wood D. W. 
Published: March 2009

SummaryMeasurements were made at intervals during 1983–4 on the main stem and on tillers having defined morphological positions on plants of winter wheat cv. Avalon growing in a multifactorial experiment testing combinations of the following five factors: rotation, sowing date, amount of autumn N, amount of spring N, and timing of spring N. Some observations from similar experiments in the two previous seasons are also reported.The tillers in the axils of the first three leaves (Tp, T2and T3) appeared on most plants. An average of 1·8 other tillers were produced on each plant, including 0·14 at the coleoptile node. When number of shoots was maximal, main stems (M), T1and T2together accounted for 64% of the total number of shoots, 76% of the total green area and 87% of the total above-ground dry weight. More than half of the T1s died before maturity, two thirds of the T2s and almost all of the other tillers. The final population of 566 ears/m2was made up as follows: M 56%, T126%, T216%. The differences between categories in dry weight per shoot at maturity were relatively less than earlier. Contributions to the mean grain yield of 9·9 t/ha were: M 60%, T1, 22%, T214%. M had more grains per ear than T1, or T2which had similar numbers. Dry weight per grain was similar in all three categories.Most of the effects of treatments on dry weight/m2, which have been described previously by Prewet al.(1986), were due to effects on all shoot categories. Several treatments increased the number of shoots/m2by increasing the average number per plant of tiller categories that were produced later. This was always the result of an increase in the proportion of plants having many tillers. Neither the maximum number of tillers found on a plant, nor the duration of tiller production, was affected.Both within and between tiller categories, shoots that were produced last died first. Plants which started tillering late produced fewer, smaller, tillers than average and relatively few of these survived. The standard hierarchical order of tiller production and survival was disrupted when plants were damaged by stem-boring insects and when the period shortly before a tiller category was due to emerge was unusually dull and warm.
Modification of host–parasite interactions through mutagenesis in quantitative resistance of rice to bacterial leaf blight
Authors: Nakai H. , Katsumata K. , Gohda M. , Watanabe J. , Koike K. 
Published: March 2009

SummaryA number of mutant lines showing different levels of improved quantitative resistance to bacterial leaf blight (BLB) were obtained through selection of plants or lines derived from seeds of the rice cultivar Harebare exposed to thermal neutrons and gamma-rays. The selections were made on M2–M4 materials under natural BLB-epidemic conditions and/or by artificial inoculation of one of the BLB isolates. Bacterial isolates predominating under the natural conditions were identified as belonging to the differential BLB isolate group I, and the isolates of this group were used in the artificial inoculation for selection of mutants. The selected M4 mutant lines were tested in M5 for BLB resistance by artificial inoculations of four differential bacterium isolates, groups I, II, III and IV. The M6 mutant lines showed quantitatively elevated resistances to the isolate of bacterium group I and also to the other three differential isolates. Analysis of variance of the data demonstrated that the observed elevated quantitative resistances of the mutants to the isolates I, II, III and IV were isolatespecific. Host-parasite interactions in quantitative resistance to BLB and their modification by induced mutations are discussed.
Relative accuracy of a neighbour method for field trials
Authors: Lill W. J. , Gleeson A. C. , Cullis B. R. 
Published: March 2009

SummaryTwo scries of simulation experiments were used to investigate the accuracy of treatment and variance estimation with a neighbour analysis of field trials proposed by Gleeson & Cullis (1987). The first series examined the accuracy of residual maximum likelihood (REML) estimation of seven theoretical error models applicable to field trials. REML estimation provided accurate estimates of the variance parameters, but the Ftest of treatments was slightly biased upward (to +2·4%) for first differences models and slightly biased downwards (to –1·4%) for second differences models. The second series of simulations, based on 19 uniformity data sets, illustrated that treatment effects were consistently estimated more accurately by the REML neighbour (RN) analysis of Gleeson & Cullis (1987) than by incomplete block (IB) analysis with recovery of interblock information. The relative gain in accuracy of RN over IB depends on the amount of systematic variation or ‘trend’ in the trial, and ranged from 6 to 18% with an average of 12% for a range of trend and error variances commonly encountered in field trials. The predicted average standard errors of pairwise treatment differences from the RN analysis were in close agreement with their empirical estimates, indicating that the predicted average S.E.D. is approximately valid.
The effect of reduced leaf shear strength on the nutritive value of perennial ryegrass
Authors: Mackinnon B. W. , Easton H. S. , Barry T. N. , Sedcole J. R. 
Published: March 2009

SummaryProgeny of perennial ryegrass (PRG) plants selected for low and high leaf shear strength were sown in a spaced-plant field experiment and were shown to differ in leaf strength in the same direction, confirming this to be a heritable trait. Selection for low leaf shear strength also reduced weight per leaf length, but had no effect on dry-matter (D.M.) percentage, growth score, rust score or tendency towards aftermath heading.Rates of D.M. consumption (g D.M./min) and ruminal degradation of D.M. using the polyester bag technique, were then determined with small quantities of the two PRG selection lines, and also white clover, using sheep fed a basal diet of fresh ryegrass/white clover pasture. Selecting PRG for low leaf shear strength slightly reduced concentrations of cellulose and hemicellulose, slightly increased total N concentration and increased rate of D.M. consumption by sheep (17%) but had no effect on rates of ruminal D.M. degradation. The selection thus moved the nutritional characteristics of PRG in the direction of white clover.The first nutritional response to the selection appears to be a faster rate of D.M. consumption, and it is considered that leaf shear strength has potential for selecting PRG with increased rates of voluntary intake by ruminants.
The factorial combination of treatments in rotation experiments
Authors: Patterson H. D. 
Published: March 2009

The paper deals with points arising in the design of factorial schemes for incorporating fertilizer and other treatments in rotation experiments. These schemes make extensive use of fractional replication and confounding, including split-plot confounding. They are complicated by the need to apply some treatments cumulatively and others with levels changed between plots in successive cycles so as to minimize errors due to constant plot differences.Design keys are used to identify the treatment main effects and rotation differences with particular plot contrasts. The keys exhibit the structure of a design more compactly and clearly than a complete enumeration of identities and confounded contrasts and enable treatment combinations to be generated systematically.
Factors affecting the yield of seed produced by different varieties of red clover
Authors: Hawkins R. P. 
Published: March 2009

Yields of varieties of red clover were found to vary from year to year and relative to each other.Apart from losses in harvesting the seed, which were not studied, yields of seed were found to be correlated with seed set, size of seed and numbers of heads in the crop. In 1958 the dominant factor affecting yields was Kabatiella.Because of the value of seed set in indicating potential yield, its relation to other characters was studied. Data are given for length of corolla tube, numbers of positive pollinators and size of head as indicated by the number of florets, and their relationship to seed set and to one another.
Sterile boars with ‘knobbed’ spermatozoa
Authors: Buttle H. R. L. , Hancock J. L. 
Published: March 2009

Investigations have been made of boars yielding spermatozoa with a specific morphological (‘knobbed’) defect of the acrosome.Counts were made of the number of knobbed spermatozoa in pairs of nigrosin eosin smears made from the semen of normal boars, in the semen of two (‘affected’) full brothers with ejaculates known to contain a high proportion of knobbed spermatozoa, and in mixtures of normal and affected ejaculates. Few or no knobbed spermatozoa were recorded in the semen of normal boars. Virtually all spermatozoa from the affected boars were recorded as knobbed. Counts on mixed samples agreed well with expected values.
Relationship between growth stage and digestible organic matter in triticale
Authors: Brignall D. M. , Ward M. R. , Whittington W. J. 
Published: March 2009

SUMMARYIn two experiments the yield, digestibility, protein and cell wall contents of several autumn-sown triticale cultivars were compared with rye at defined growth stages. Yields at each growth stage were highest in the triticale cultivars. The content of leaf blade and sheath fell with increased maturity while stem and ear content increased. There were differences between cultivars in the contribution of individual stem internodes. Digestibility also declined with maturity for all plant parts, and differences were apparent between plant parts and between cultivars. Leaf blade showed a slow decline in digestibility whereas stem digestibility showed a rapid reduction so that, at growth stage 43, young stem internodes were of much higher quality than older ones. Spring-type triticales (A208 and A476) had the highest digestibility at stages from flag leaf emergence to anthesis. The relationships between digestibility, plant part contents and cell wall characteristics are discussed.
Effect of preceding fodder crops on the nitrogen requirement of tall wheat
Authors: Narwal S. S. , Malik D. S. 
Published: March 2009

SUMMARYIn a 2-year field study, leguminous fodder crops (cowpea (Vigna unguiculata) and cluster bean (Cyamopsis tetragonoloba)) responded more to P than did nonleguminous fodder crops (maize (Zea mays), sorghum (Sorghum bicolor) and pearl millet (Pennisetum americanum)). The local cultivar of tall wheat, C306, yielded more when sown after fallow or legumes than after nonlegumes. Wheat sown after fallow or legumes produced more ear-bearing tillers and more grains per ear than when sown after nonleǵumes. Wheat sown after fallow or legumes responded to N application of up to 20 kg/ha, while when sown after nonlegumes it responded linearly to the highest rate of 60 kg/ha. Thus, preceding fallow, cowpea and cluster bean reduced the N requirement of wheat by 20–40 kg/ha compared with preceding maize, sorghum and pearl millet. Nitrogen increased grain yields only at applications of up to 40 kg/ha because lodging occurred at the higher rates. A cluster bean-wheat cropping sequence proved the most profitable.
Root and shoot growth and water use of chickpea (Cicer arietinum) grown in dryland conditions: effects of sowing date and genotype
Authors: Brown S. C. , Gregory P. J. , Cooper P. J. M. , Keatinge J. D. H. 
Published: March 2009

SUMMARYGrowth and water use of kabuli-type chickpea was measured during the 1982/83 and 1983/84 growing seasons in northern Syria under rainfed conditions. Winter-sown (November) and springsown (March) crops of cv. ILC 482 were grown in 1982/83 while in 1983/84 spring-sown crops of contrasting genotypes (ILC 482, ILC 1929 and ILC 3279) were compared.In 1982/83, shoot dry matter and seed yields of the winter-sown crop were almost twice those of the spring-sown crop although the water use of both crops was almost the same. Root growth of both crops was most rapid before flowering but continued until maturity (early June) in the winter-sown and until mid to late pod filling (also early June) in the spring-sown crop. Root dry weight (c. 45 g/m2) and length (c. 45 cm/cm2) were similar in both crops during pod filling.In 1983/84, shoot weight, root weight and root length were similar in all genotypes but the later maturity of ILC 3279 resulted in lower seed yield and hence harvest index, and greater water use.The root length density decreased approximately logarithmically with depth in the soil profile although comparison between seasons and with other published results showed that the relations could not be used predictively. Water use efficiency was poorer in the second, drier season and was almost doubled by winter sowing.
Ammonia fluxes from grazed grassland: annual losses from cattle production systems and their relation to nitrogen inputs
Authors: Jarvis S. C. , Hatch D. J. , Lockyer D. R. 
Published: March 2009

SUMMARYLosses of NH3 from a number of swards grazed by cattle were measured through 2 (1986–87) grazing years using a mass balance micrometeorological method. Comparisons were made of grass swards receiving 420 or 210 kg fertilizer N/ha per year and a grass-clover sward (GC) dependent upon fixation under rotational grazing managements. In one year a continuously grazed sward was also examined. Rates of NH3 loss were usually greatest whilst animals were present, especially during early and late season. This was not always the case, however, and losses sometimes continued into the next grazing period; there were also large day-to-day variations in fluxes. Seasonal trends were also not distinct, but losses tended to be lower during early and late grazings.The annual losses from 420 and 210 kg N/ha and GC treatments were 25, 10 and 7 kg N/ha, respectively, and the differences between treatments were still marked when losses were expressed on a per animal basis. Total loss under continuous grazing was 61 % of that under the rotational system. Although the losses represent only 7·8, 5·6 and 3·7% of the inputs to420N, 2 ION and GC treatments, there was a good relationship between inputs and total losses, and also between the concentration of N in the herbage and losses per animal. The effects of the measured rates of loss on the input of NH3 from grazed grassland to the atmosphere are discussed.
Effects of irrigation, N fertilizer, cutting frequency and pesticides on ryegrass, ryegrass–clover mixtures, clover and lucerne grown on heavy and light land
Authors: McEwen J. , Day W. , Henderson I. F. , Johnston A. E. , Plumb R. T. , Poulton P. R. , Spaull A. M. , Stribley D. P. , Todd A. D. , Yeoman D. P. 
Published: March 2009

SummaryThe effects of irrigation, nitrogen fertilizer, cutting three or six times per year and a combined pesticide treatment that included aldicarb, phorate, benomyl and methiocarb on ryegrass (Lolium perenne) cv. S.23, either alone or in mixtures with white clover (Trifolium repens) cvs S.I00 or Blanca, and on lucerne (Medicago sativa) cv. Vertus grown on a silty clay–loam at Rothamsted and a sandy loam at Woburn were studied in 1977–81.Benefits from irrigation were greater for six-cut than three-cut swards, with pesticides than without, for ryegrass with clover S. 100 than ryegrass with Blanca and at Woburnthan at Rothamsted. Lucerne did not benefit.Responses of ryegrass to fertilizer N were best fitted by the model y = a + b/1+cx+dx2; and those of ryegrass–clover by the model y = a+bx (where y = yield, x = amount of N; a, b, c and d are constants). Without N, yields of ryegrass–Blanca clover mixtures considerably exceeded those of ryegrass–S.100. The former gave yields equivalent to those of ryegrass given 270 kg N/ha at Rothamsted and 330 kg N/ha at Woburn.Lucerne without irrigation, N or pesticides gave yields in excess of all other unirrigated crops, even when these received pesticides and maximum N. Yields from three cuts of ryegrass greatly exceeded those from six cuts but yields of ryegrass–Blanca were greater from the six-cut regime.Pesticides substantially improved the yields of ryegrass and clover, whether grown separately or mixed, but not those of lucerne. Pesticides not only controlled pests and diseases but also increased the incidence of vesicular–arbuscular mycorrhizas. The relative magnitude of yields of the different swards at the two sites differed, depending on treatment with irrigation, N fertilizer and pesticides. Differences between sites were removed or reversed by appropriate combinations of treatments.Ryegrass–Blanca given no N fertilizer and cut six times removed 300 kg N/ha, an amount that was increased by irrigation and decreased by less frequent cutting; ryegrass–S.100 clover contained less N. Removals of P and K. often exceeded 35 and 300 kg/ha, respectively, each year. Herbage containing Blanca clover had much more Ca than that containing S.100 but at comparable yields all swards contained similar amounts of Mg.
The artificial rearing of lambs
Authors: Large R. V. 
Published: March 2009

Artificial rearing involves the replacement of those contributions made by the ewe which are essential to the growth and development of the lamb. This not only includes the supply of food but also the warmth, shelter and ‘mothering’ normally provided by the ewe.Relatively little information is available on the artificial rearing of lambs. The earliest report, perhaps, is that of Mumford (1901) who bottle-fed the milk produced by eight ewes to four lambs. The more practical aspects of rearing orphan lambs have been described by Preston (1958) and Caldwell (1957). More recent reports on the artificial rearing of lambs have been made by the Grassland Research Institute (1959–60, 1960–61), Cunningham, Edwards & Simpson (1961) and Large (1962).
The response of grass-clover and pure-grass leys to irrigation and fertilizer nitrogen treatment. II. Clover and fertilizer nitrogen effects
Authors: Reid D. , Castle M. E. 
Published: March 2009

1. The effects of irrigation and fertilizer nitrogen treatments on four swards were studied for 3 years in an experiment at the Hannah Institute. This paper describes only the effects of the fertilizer nitrogen treatments and their interactions with the presence or absence of clover in the sward, since those of the irrigation treatments have been reported previously.2. Annual applications of 0, 104, 208 or 312 lb. of fertilizer nitrogen per acre were made on swards of S 23 rye-grass or S 37 cocksfoot with or without S100 white clover.3. The yields of the grass + clover swards exceeded those of the pure-grass swards at all fertilizer nitrogen application rates in the first 2 years and at the 0 and 104 lb./acre rates in the third year.
Irrigation of groundnut (Arachis hypogaea) grown in a Mediterranean environment
Authors: Metochis C. 
Published: March 2009

SUMMARYThe response of groundnut to different amounts of irrigation water and the effect of irrigation on the occurrence of chlorosis during the establishment period of the crop were studied in south-west Cyprus in 1984–88. The irrigation requirement of groundnut for the entire growing season was found to be 480 mm. Under-irrigation resulted in a soil water deficit and reduced production. Application of water in excess of requirement also reduced yield. Daily evapotranspiration under optimum soil moisture conditions increased from 1·5–2·0 mm at the beginning of the growing season to 7·0–7·5 mm at full crop development; it then decreased to 2·0–3·0 mm by the end of the season. In soils of low CaCO3 content, neither frequent water application nor over-irrigation during the crop establishment period caused any chlorotic symptoms or affected yield.
Rainfall and temperature effects on lentil (Lens culinaris) seed yield in Mediterranean environments
Authors: Erskine W. , El Ashkar F. 
Published: March 2009

SUMMARYLentil (Lens culinaris Medikus) is a rain-fed crop in North Africa and West Asia whose yields are limited by the amount and distribution of rainfall and winter cold. This study aimed to quantify the effects of climatic variables on lentil seed yields through the fitting of simple empirical models to trial data of two cultivars sown at six sites, 1983–89, representing 31 environments in Syria. The ranges over environments were 152–527 mm for total season rainfall and 1–52 for the number of frost nights. Overall, the total seasonal rainfall accounted for 40·8% of the variance in mean seed yield (1·27 t//ha, S.D. 0·82) with a response of 5·68 kg/ha/mm. A multiple regression model with monthly rainfall from November to May explained 67·6;0% of the variance in mean seed yield. From November to February the response of seed yield to rain was < 10 kg/ha/mm; rain in March, the period of late vegetative growth, made the most important contribution to seed yield. The response to April rain was negative. At Tel Hadya (the most frequently used site), the total seasonal rainfall accounted for 79·8% of the variance in mean seed yield, and the addition of the number of frost nights to the model improved the fit to 92·7%. Winter cold had a smaller effect on yield than rainfall, with no consistent overall effect, but differences over regions. The cultivars contrasted in their responses to drought (78S26002 was superior to ILL4400 at seasonal rainfall levels down to 134 mm) and the number of frost nights at Breda and Tel Hadya (78S26002 was more susceptible to cold than ILL4400). Thus, despite the predominant influence of rainfall on yield, the genetic variability in response to moisture and cold shows the scope for selection under rainfed Mediterranean environments.
Effects of feed intake and environmental temperature on chick growth and development
Authors: Smith M. O. , Teeter R. G. 
Published: March 2009

SUMMARYBroiler chicks reared under three environmental temperatures (7·2, 23·9 and 35 °C) in the Southeastern United States of America in 1988/89 were precision-fed to levels which were c. 70, 90, 110 and 130% of the consumption observed in ad libitum-fed controls at 23·9°C, in order to examine the limitations imposed by feed intake upon growth rate, feed efficiency and survival. Ad libitum-fed birds that were housed at 7·2, 23·9 and 35 °C consumed feed at 12·1, 9·4 and 8·5% of body weight, respectively. Liveweight gain of birds consuming feed ad libitum was depressed by 26 and 46% in the 7·2 and 35 °C environments respectively. Increasing feed intake by precision feeding exceeded ad libitum consumption in the 23·9 and 35 °C environments, but not at 7·2 °C. Consumption of feed above thermoneutral ad libitum levels failed to increase (p <0·l) liveweight of carcass gain. Ration digestibility and dressing out percentage declined (P < 0·05) at the higher feed intake levels in the 7·2 °C environment.