bluuebunny/crossref_metadata_2025 huggingface dataset:
Population dynamics of Rhizobium japonicum strains used to inoculate three successive crops of soybean
Authors: Brockwell J , Roughley RJ , Herridge DF
Published: November 2004

Three closely related strains of Rhizobium japonicum, equally effective in N2 fixation, were used to inoculate each of three successive crops of soybeans [Glycine rnax (L.) Merr. cv. Bragg] grown on the same block of land. The soil was a vertisol previously free of R. japonicum, and inoculant was applied at different rates by spraying a suspension of peat culture into the seed bed at time of sowing the seed. The populations of rhizobia that developed in rhizosphere and soil were counted at intervals during crop growth and in the fallow period between crops. There was usually a substantial decline in recovery of inoculant strains immediately after sowing. In soil initially devoid of R. japonicum, populations in the rhizospheres of young seedlings were related to rates of inoculation, but differences disappeared as the plants aged. Shortly after harvest, the soil contained large populations of rhizobia which increased up to 200 times during the fallow period between crops, probably due to release of bacteria from disintegrating nodules. The size of these populations was maintained up to the time of sowing the following crop. Although strains used for second- and third-year crops were dominated by already established rhizobia in rhizosphere colonization and nodule formation, the magnitude of the domination could be reduced by increased rates of inoculation. In soil already containing R. japonicum, the proportion of nodules formed by inoculant strains was greater than the relative number of inoculant rhizobia in the soil or the rhizosphere; this was ascribed to an advantage of specific placement of the inocula in that zone of the soil where infection foci first formed. The results are explicable in numerical terms and are discussed in relation to an inoculation strategy for maximum nodulation by applied inoculant in competition with rhizobia already established in soil.
Salt tolerance in the genus Lolium (ryegrass) during germination and growth
Authors: Marcar NE
Published: November 2004

Two studies were undertaken, one to evaluate the degree of genotypic variation for salt tolerance within the Lolium (ryegrass) genus, and the other to compare the responses of three representative ryegrass species (Wimmera (L. rigidum), Italian (L. muttiforum) and perennial (L. perenne) ryegrass) with those of two known salt-tolerant grasses, tall wheat grass (Elytrigia pontica) and saltmarsh grass (Puccinellia ciliafa). Both germination and growth responses to increasing concentrations of NaCl were assessed under controlled environment conditions: seeds were germinated in petri dishes, and plants were grown in pots containing coarse river sand. In the first study, significant intra- and inter-specific variation for salt tolerance was demonstrated, particularly during germination. However, there was no apparent adaptation for salt tolerance in field collected accessions from saline sites. In the second study, all species were shown to be relatively insensitive to NaCl up to 200 mol m-3 during germination, but higher concentrations were tolerated only by saltmarsh grass, tall wheat grass and Italian ryegrass. Only the latter two grasses maintained their high tolerance during vegetative growth, whereas the ryegrasses were moderately tolerant. It was clear from both studies that relative salt tolerance ranking differed for germination and growth phases. Shoot concentrations of Na, Cl and K did not relate to the degree of salt tolerance.
Effects of soil pasteurization on root rot, seedling survival and plant dry weight of subterranean clover inoculated with six fungal root pathogens
Authors: Barbetti MJ , Sivasithamparam K
Published: November 2004

Subterranean clover was exposed to two levels of inoculum of millet seed colonized by Fusarium avenaceum, Fusarium oxysporum, Phoma medicaginis, Phytophthora clandestina, Pythium irregulare, or Rhizoctonia solani within pasteurized and unpasteurized field soil from sites with (root rot site) and without (virgin site) a history of subterranean clover root rot at Augusta, W.A., with the aim of establishing their pathogenicity in the presence of other soil organisms including resident pathogens. Introduction of F. avenaceum (2.5% w/w), P. clandestina (0.5 and 2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) increased damage to tap and lateral roots of subterranean clover in pasteurized and unpasteurized root rot and virgin soils. All fungi tested, with the exception of P. medicaginis (2.0 and 10.0%) or P. medicaginis (2.0 and 10.0%) and F. oxysporum (0.5 and 2.50%), caused reduction of seedling survival in pasteurized root rot and virgin soils respectively. When the soil was unpasteurized, all fungi except F. oxysporum (2.5%) and P. medicaginis (2.0 and 10*0%) in virgin soil, but only P. irregulare (2.5%) or R. solani (0.2 and 1.0%) in root rot soil, reduced seedling survival. In unpasteurized soils plant dry weight was reduced by P. clandestina (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2 and 1.0%) in root rot and virgin soils, but F. oxysporum (0.5%) reduced plant size only in the root rot soil. Within pasteurized soil all fungi, with the exception of P. medicaginis (2.0 and 10.0%) in virgin soil and F. avenaceum (2.5%), P. irregulare (0.5 and 2.5%), or R. solani (0.2%) in root rot soil, caused reduction in plant size. P. clandestina, P. irregulare or R. solani, in particular, and to a lesser extent, P. avenaceum, are capable of causing serious damage to subterranean clover in natural soil.
Fungicidal control of rust of French prune caused by Tranzschelia discolor
Authors: Kable PF , Bambach RW , Ellison PJ , Watson A , Kaldor CJ
Published: November 2004

An orchard spray trial indicated that the dithiocarbamates mancozeb and zineb, the latter with or without the addition of white oil as a sticker, gave superior control of prune rust to dithianon, captafol or triforine. Further orchard studies involving artificial inoculation supported this result, with mancozeb and zineb giving 12-13 weeks of complete protection in one instance. In these studies chlorothalonil and bitertanol were also superior to dithianon and captafol, but appeared to be less persistent than the dithiocarbamates. Propiconazole and RH-3866 were relatively ineffective protectants.The efficacies and persistence of fungicides appeared to be less the later they were applied in spring and summer. Rain within a day or two of spraying appeared to reduce fungicide efficacy and persistence, but when it occurred some days or weeks later there was little effect, even a heavy fall (53 mm) not causing an observable reduction in efficacy. The implications of these findings for the development of control strategies is discussed.
The endogenous phosphorus excretion of preruminant lambs
Authors: Walker DM , Al-Ali SJ
Published: November 2004

Twenty-seven preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were used. Three lambs were sacrificed on day 1 and selected bones taken for analysis. Twenty-four lambs, in groups of three, were bottle-fed on low-phosphorus milk replacers in a 2 x 4 factorial experiment. The sole source of protein in the diets was whole beef blood, supplemented with L-isoleucine and DL-methionine, to supply either 10 or 25% of the total dietary energy as protein. At each protein level the diets were supplemented with CaCO3 to provide four ratios of Ca:P (0.5:1, 1:1, 2:1 and 10:1). The daily intake of gross energy was controlled at 880 kJ-0.73. Faeces and urine were collected separately each day and bulked during the last seven days of the experiment for the estimation of N, Ca and P. Serum Ca and P concentrations were determined at weekly intervals. The lambs were sacrificed at the end of the experimental period of 21 days and selected bones were taken for analysis. The concentrations of bone ash, Ca and P all decreased significantly when compared with values determined at the start of the experiment. The lambs given the high-protein diets showed significantly greater losses of bone ash, Ca and P, and had lower serum P, but higher serum Ca concentrations, than lambs fed on the low-protein milk replacers, irrespective of the dietary Ca:P ratios. Phosphorus excretions during the last seven days of the experiment were as follows: faecal P (day-1); low-protein group (n = 12), 3.1 � 0.5 mg kg-1; high-protein group (n = 11) , 4.1 � 0.5 mg kg-1; all lambs (n = 23), 3.6 � 0.3 mg kg-1. Urinary P (day-1): low-protein group (n = 12), 0.92 � 0.22 mg kg-1; high-protein group (n = 11) , 0.61 � 0.03 mg kg-1; all lambs (n = 23), 0.77 � 0.12 mg kg-1. Faecal and urinary P excretion was unaffected by variation in the dietary Ca:P ratio.
An examination of selection criteria for salt tolerance in wheat, barley and triticale genotypes
Authors: Rawson HM , Richards RA , Munns R
Published: November 2004

This study of 20 genotypes of barley, wheat, durum wheat and triticale had three aims: (1) To determine whether simple measurements on plants grown in salinity tanks in a glasshouse would reflect the documented reputations for salinity tolerance of the genotypes; (2) to test whether rapid development, commonly associated with barleys, is linked with salinity tolerance; (3) to assess several types of measurements as screening tools for salinity tolerance. Measurements of whole-plant leaf area expansion rates were well correlated with biomass production and ranked the genotypes largely in accord with their documented reputations. There was no evidence, either from experimental manipulation of rate of development, or from regression analysis amongst genotypes, that rapid development was linked with salinity tolerance. The origins of tolerance were twofold, deriving from (1) a physiological tolerance - this was defined as a small relative reduction in growth due to salinity, and (2) an absolute tolerance - this was shown as an intrinsic high growth rate of the genotype, i.e. apparent both in and out of salinity. A good indicator of high absolute tolerance, and of potential for screening purposes, was large area of seedling leaves. Regression analysis indicated that absolute tolerance contributed more to productivity in saline conditions than physiological tolerance. Indeed, in one study the latter failed to correlate significantly with productivity. Cl- concentration also was a poor general indicator of productivity in salinity, as was extension rate of single leaves during 10 days after NaCl was applied. It is proposed that screening for intrinsic high growth rate and physiological tolerance should go hand in hand, with more emphasis on the former. This is the reverse of the usual situation.
The effect of copper supply on vegetative and seed yield of pasture legumes and the field calibration of a tissue test for detecting copper deficiency. II. Strawberry clover (Trifolium fragiferum L.)
Authors: McFarlane JD
Published: November 2004

Seven rates of copper were applied to the soil prior to the sowing of strawberry clover (Trifolium fragiferumL. cv. Palestine) on an alkaline peat deficient in copper. Symptoms of copper deficiency were evident only on the untreated plots where the clover did not set seed nor persist into the second year.Over five years� production, 1.0 kg Cu/ha continued to provide adequate copper, with regular dressings of superphosphate, for maximum dry matter production and seed yield. It was found that seed yield was more sensitive than vegetative dry matter yield to sub-optimal copper supply. At the lowest rate of applied copper (0.125 kg/ha), the vegetative yield ranged from 53% to 80% of the maximum harvest yield, whereas the seed yield ranged from 15% to 50% of maximum yield.For tissue sampled in the spring, the proposed critical range for copper concentration in the youngest open leaf (YOL) for vegetative dry matter production is 3-35 mg Cu/kg whereas that for seed production is 4.5-5.5 mg Cu/kg. At other times of the year the critical concentrations were higher. It was not clear if this was due to environmental conditions or changing internal requirements for copper.The critical copper concentration range in whole top (WT) tissue of 3.0-4.0 mg/kg for vegetative dry matter production could be applied to all samplings. For seed yield the critical range for copper concentration in WT was 4.0-5.0 mg/kg for the spring harvests. The critical copper concentration in seed for seed production was 5.0-6.0 mg/kg. In the pasture situation a critical concentration of 5.0-6.0 mg Cu/kg in the WT should be adopted when the animal requirement is considered.
Early generation selection in wheat. I. Yield potential
Authors: Quail KJ , Fischer RA , Wood JT
Published: November 2004

F3 single plant traits were tested as possible selection criteria for increasing yield potential. F3 plants were grown spaced in a glasshouse, while yield was measured in southern New South Wales under irrigation and optimum management. Thc population studied comprised 220 F1-derived lines taken at random from a multiple convergent cross amongst 16 parents representing elite CTMMYT germplasm of the mid 1970s but containing diversity for major dwarfing genes, maturity, leaf angle and other traits. More than 50 traits were determined, comprising numerical components of yield, size and morphology, partitioning ratios, development rates and physiological activities. All F3 traits showed significant genotypic variation which was usually greater for progeny lines than for parents although only occasionally significantly so. Broad sense heritability was generally moderate to high.F3 lines were advanced by single seed descent for replicated F7 and F8 yield experiments, two in each of 1982 and 1983. In each experiment 60-68 progeny lines chosen at random were tested; 44 lines were common to all experiments. Plot size was 8 rows X 5 m, and edge rows and plot ends were discarded. Yield levels were high (mean yield 5.9 t h a 1 at 10Yo moisture) and largely free of interference from lodging and disease. The progeny main effect on grain yield was highly significant, but no progeny line significantly outyielded the best parent. Best correlations with progeny grain yield were given by F3 plant height (r= -0.31 to -0.50 across experiments), F3 kernel weight (r= -0.03 to -0.44), F3 harvest index (r = 0.18 to 0.5 l), F3 leaf angle (r = -0.13 to -0.40, erect leaves favouring high yicld) and F3 spike number (r=0.08 to 0.40). Retrospective selection in F3 using these traits singly at a selection intensity of 25% gave increases in population mean yield (0 to + 12%) and in the proportion of high yielding lines (doubled in some cases), but only selection in F3 for reduced stature is considered worthwhile for advancing yield potential. It is suggested that the ineffectiveness of F3 selection is largely due to genotype by environment interaction, along with the complex multigenic nature of grain yicld.
Alternative methods of estimating water deficit stress of wheat grown on undisturbed and repacked soil in drainage lysimeters
Authors: Tan CS , Meyer WS , Smith RCG , Barrs HD
Published: November 2004

The effect of soil modification on changing the availability of water and the onset of crop water deficit stress in wheat was assessed during 2 drying periods. The different methods of determining the onset of stress generally agreed with each other. Differences were either related to the different parts of the canopy measured or to different physiological processes measured. Because foliage temp. was continuously monitored, the dynamic development of stress in relation to increasing soil water deficit and root growth became evident. The allowable soil water deficit at the onset of stress varied widely between soil treatments and the stage of crop growth at which deficit stress occurred. Physically modifying the soil increased plant available water by 80%. This resulted from both changes in amount of soil water stored and through a more uniformly distributed root system. Wheat growing in undisturbed soil was unable to adapt to post-anthesis stress, as frequent irrigations prior to anthesis concentrated root distribution in the upper layers.
The effects of soil moisture and planting depth on emergence and seedling morphology of Astrebla lappacea (Lindl.) Domin
Authors: Lambert FJ , Bower M , Whalley RDB , Andrews AC , Bellotti WD
Published: November 2004

The effect of various wet and dry day sequences on emergence of seedlings of Astrebla lappacea (Mitchell grass) from both spikelets and caryopses was studied in a glasshouse experiment. Three wet days were required to obtain maximum emergence while periods of 2-4 dry days delayed emergence but did not affect final emergence, provided moisture was re-supplied. The soil reached a water potential of -6 MPa after 2 dry days, which was sufficient to prevent the germination processes from proceeding. Maximum emergence was reached in 8 days for the caryopses and 10 days for the spikelets, so long as each wet day in the period was separated by no more than 2 dry days. At least 40% of the A. lappacea caryopses sown emerged as seedlings from a sowing depth of 60 mm in a sand medium, and from a sowing depth of 45 mm in a clay medium. The maximum depth from which seedlings emerged was 60 mm in the clay medium, and from 80 mm in the sand medium. Both media were maintained at 90% of field capacity. The emergence from single caryopses in sand was greater and more rapid than from clay. Planting depth significantly affected the length of the subcoleoptile internode of A. lappacea during a glasshouse experiment. All seedlings initiated their secondary roots at the soil surface irrespective of sowing depth. Increasing sowing depth retarded the early development of the secondary root system, but by week five, there were no significant differences between the dry weights of secondary roots from plants sown at different depths.
Forage tree legumes. III. Release of nitrogen from leaf, faeces and urine derived from Leucaena and Gliricidia leaf
Authors: Catchpoole DW , Catchpoole DW , Blair GJ , Blair GJ
Published: November 2004

The role of tree legume leaf as a green manure in increasing the N status of soils has been widely recognized. An alternative to the direct application of leaf is the feeding of the leaf to animals and using the dung and urine as the N source. This experiment was undertaken to measure the release of N from dried leaf of Leucaena leucocophala cv. Cunningham and Gliricidia sepium and from the dung and urine from goats fed the same leaf. The residue materials were labelled with 15N and either incorporated into the soil or applied onto the surface. ISN released from the residues was measured over a 10-week period by extraction using a grass crop of Panicum maximum cv. Riversdale and measurement of mineral N in the soil. Highest recovery was 89.6% in the leucaena-derived urine incorporated treatment and lowest (< 10%) in the surface-applied faeces treatment of both species. 15N recovery in the grass indicated that leucaena leaf is more resistant to breakdown than gliricidia leaf. These data suggest that careful consideration should be given to the use of leaf litter as an N source. In situations where volatilization of N from excreta can be minimized, such as in cut-and-carry systems, the N economy of the system could be enhanced by including the animal in the N cycle.
The activity of the thyroid glands in relation to genetic differences in wool production
Authors: Williams AJ , Thornberry KJ , Gilmour AR
Published: November 2004

Twelve adult castrate male Merino sheep from each of two flocks, genetically different in their capacity for clean wool production, were allocated to a high (H: 0.81 kg digestible dry matter day-1; 26 g N day-1) or low dietary regime (L: 0.42 kg digestible dry matter day-1; 9.5 g N day-1). The sheep weighed 47 kg (s.e. =0.8) at the start of the experiment, with sheep from the two genetic groups having similar average liveweights. The dietary treatments were imposed for between 4 and 10 weeks before eight samples of venous blood were collected from each sheep during 24 h. Each sheep was then injected with thyroid stimulating hormone (TSH), (1.25 unit/sheep) before seven samples of blood were collected during the following 24 h. The plasma from these blood samples was assayed for total thyroxine (T4) and tri-iodothyronine (T3). There were no significant differences between the flocks in either T3 or T4 before or after the injection of TSH. We concluded that differences in the activity of the thyroid gland were not necessary for the establishment of genetic variation in the rate of wool growth. The circulating levels of both T4 and T3 were greater in the sheep receiving the H dietary regime (T4: 81.4 v. 55.8 nmol L-1; P<0.5 and T3: 1.8 v. 1.0 nmol L-1; P<0.05). These differences were maintained after the injection of TSH, which approximately doubled the pre-injection levels of T4 in plasma 9-10 h after the injection. The levels of T3 also increased after the injection, reaching a maximum which was 2.3 times the average pre-injection concentration after 4-5 h.
Season, age and adiposity influence death rates in sheep exported by sea
Authors: Higgs ARB , Norris RT , Richards RB
Published: November 2004

A study was conducted to determine the role of season, age and adiposity in the cause of sheep deaths during sea transport from Fremantle to the Middle East. Death rates were higher in the second half of the year in 4 of 5 years. Shipboard death rates in hogget wethers were approximately half those of adult wethers in each of three methods of comparison. Sheep condition (adiposity) was positively correlated with the proportion of sheep that did not eat pellets in the feedlot (P < 0.05) and with shipboard mortality (P < 0.01) in two of three voyages. Individual sheep that were identified as fat had approximately twice the risk of death from inanition aboard ship than sheep identified as not fat. Adiposity was identified as a central factor leading to a syndrome of persistent inappetance. The pathogenesis of this syndrome in adult wethers may be linked to interference with the seasonal control of appetite and energy metabolism. The lower death rate in younger wethers was attributed to the overriding demands of tissue growth, ensuring a stronger appetite than that seen in adult animals.
Profitability of increasing lambing percentage in the Western Australian Wheatbelt
Authors: Morrison D , Young J
Published: November 2004

The value of increasing lambing percentage in the eastern wheatbelt of Western Australia was examined using the MIDAS model of an integrated crop-livestock farm for the May lambing currently practised by most of the region's farmers. MIDAS is an optimization model, which allowed the most profitable way of managing the farm at different lambing percentages to be computed. Thus it provides an estimate of the value of higher lambing percentage corresponding to this optimum practice at higher lambing. Increasing lambing percentage was found to be profitable but not highly profitable. Benefits of the order of $1.80 per ewe per 10% increase in lambing are likely to be largely offset by the costs of treatment to achieve this increase. This finding suggests that it is not highly beneficial to conduct research to increase lambing percentage in the eastern wheatbelt unless methods with a very low cost per ewe can be devised.
Fleece rot and body strike in Merino sheep. V. Heritability of liability to body strike in weaner sheep under flywave conditions
Authors: Raadsma HW
Published: November 2004

The prevalence of body strike was monitored in 740 mixed sex weaner progeny from 43 sires, representing 15 different Merino genotypes. A flywave, characterized by a sudden onset in the prevalence of flystrike, occurred over a 2 month period which coincided with unseasonally high rainfall. A total of 190 strikes were treated in 176 sheep representing a strike rate of 25.7 strikes per 100 sheep and a prevalence of 23.8%. The majority of strikes (92.6%) were body strikes with 19.7% of all sheep affected. The heritability of susceptibility to body strike expressed as prevalence was 0.26�0.12 for both least squares (LS) and restricted maximum likelihood (REML) procedures. The heritability of liability to body strike using quasi-maximum likelihood procedures and assuming a continuous underlying scale was 0.53 which agreed well with estimates from the LS and REML analysis after transformation (0.54�0. 25). Predicted genetic progress in the reduction of susceptibility to body strike was calculated for mass selection where the best 5% of rams and 60% of ewes were selected, with a starting prevalence of 20% body strike, assuming (a) an environment exposed to continuous flywaves, and (b) an environment with infrequent flywaves. After 20 years of direct selection the prevalence of body strike would be reduced to 7.2% and 16.1% for the two environments respectively. Indirect selection based on (c) a variable prevalence of fleece rot with a long term average of 30% and (d) fleece rot expressed at 80% would reduce the prevalence of body strike to 6% and less than 2% respectively. Indirect selection based on (e) a hypothetical indicator trait with a continous distribution, a high heritability (0.4) and a moderate genetic correlation with liability to body strike (0.4), would also reduce the prevalence of body strike to less than 2% after 20 years of selection.
The effect of epistasis on chromosome mapping of quantitative characters in wheat. II. Agronomic characters
Authors: Redden R
Published: November 2004

Chromosome mapping of agronomic characters in wheat was attempted using the complete chromosome substitution series for both 'Hope' and 'Kenya Farmer' varieties as donors and 'Chinese Spring' as recipient variety, grown in replicated yield trials at four sites in South Australia. Grain yield, fertile tiller numbers, 1000-grain weight, fertile spikelets per spike, total dry weight, spike length and green tiller number were estimated from plot subsamples. Overall between chromosome interactions were found for all characters except total dry weight at one or more sites. The patterns of substitution line effects were similar for both series and did not correspond to differences between donor and recipient varieties. Within site variation was low relative to treatment effects at two sites. Sixty four significant substitution line effects were detected in the Hope series, and 67 in the Kenya Farmer series. A simple additive model for the effects of substituted chromosomes was inadequate because of epistasis. Overall epistatic effects can be predicted from the selection history and adaptation pattern of the recipient variety. Genes from the donor variety for complex growth characters cannot be satisfactorily mapped by substitution line analysis.
Host range and geographic distribution of pangola stunt virus and its planthopper vectors in Australia
Authors: Teakle DS , Hicks S , Karan M , Hacker JB , Greber RS , Donaldson JF
Published: November 2004

Natural hosts of pangola stunt virus (PaSV) in eastern Austalia were found to be Digitaria eriantha ssp. pentzii (pangola grass), D. ciliaris (summer grass) and D. milanjiana. Transmission tests using the planthopper vector, Sogatella kolophon, showed that D. polevansii, D. eriantha ssp. eriantha, D. swazilandensis and the Australian native, D. divaricatissima were also susceptible, whereas D. didactyla was not infected. In tests of 22 species in 15 other genera, only Urochloa panicoides (annual urochloa grass) was infected. In field surveys, PaSV was commonly found in pangola grass in near-coastal districts from Grafton, N.S.W. to Walkamin, N. Qld and was detected up to 100 km inland at Toowoomba. The virus was not detected in either pangola grass or D. eriantha ssp. eriantha in subhumid areas west of Toowoomba or at Gayndah. Sogatella kolophon was collected from Bamaga, N. Qld to Murwillumbah, N.S.W. It was commonly associated with both PaSV-infected and PaSV-free digitgrass pastures. It is concluded that PaSV poses a threat to many digitgrasses in near-coastal districts of Qld and subtropical N.S.W., but so far is unknown in inland Australia.
Effects of photoperiod on reproductive development of peanut (Arachis hypogaea L.) in a cool subtropical environment. I. Field studies
Authors: Bell MJ , Harch G
Published: November 2004

The effects of photoperiod on reproductive development and yield of two Virginia, one Spanish and one Valencia peanut (Arachis hypogaea L.) cultivar were investigated in the field at Kingaroy, Australia. The objective was to assess the importance of photoperiod as a limitation to post-flowering reproductive development in a cool subtropical environment. A total of five experimental sowings were made between the 1986/87 and 1988/89 growing seasons. Treatments consisted of either natural photoperiods (ranging from 11 to 14 h, depending on sowing date and growth stage) or long (16 h) photoperiods during a range of phenological stages, both pre- and post-flowering. Long photoperiods were achieved by using low intensity light from incandescent bulbs with equal extension periods in both morning and evening. Different sowing dates and seasons were used to produce a range of natural photoperiods, radiation and temperature regimes, while shadecloth was used to alter incident irradiance during the 1988/89 experiments. Photoperiod responses were significant in only one experiment (S2, 1986/87), and were due to effects of treatment during the immediate post-flowering period. Numbers of flowers, pegs and pods were reduced under long photoperiods in cv. Robut 33-1, and to a lesser extent, in cv. White Spanish. The Virginia cv. Uf 781 14-5 was unaffected. The effects of long photoperiods during this 30 day post-flowering treatment were not expressed until after the treatment period. Effects were relatively small and reproductive (pod) yields at maturity were not significantly reduced. The lack of strong photoperiod responses in the reportedly sensitive Valencia cv. NC17090 and the occurrence of the strongest response in the relatively insensitive cv. Robut 33-1 were unexpected. Analysis of climatic data from these experiments, and others reported in the literature, suggested interactions between photoperiod and temperature, with photoperiod effects being only significant at higher temperatures, i.e. in our studies, when mean daily temperature during the treatment period was 26-0�C. This finding is of considerable significance in assessing the importance of photoperiod sensitivity for cultivar adaptation to long day/subtropical environments. A subsequent paper in this series examines photoperiod x temperature interactions more closely under controlled environment conditions.
Effects of photoperiod on reproductive development of peanut (Arachis hypogaea L.) in a cool subtropical environment. II. Temperature interactions
Authors: Bell MJ , Bagnall DJ , Harch G
Published: November 2004

The effects of temperature on the response to photoperiod by peanut (Arachis hypogaea L.) cultivars were examined under glasshouse and phytotron conditions at two locations (Kingaroy and Canberra). Two Virginia cultivars (Early Bunch and Robut 33-l), two Spanish cultivars (White Spanish and TMV-2) and a single Valencia (NC 17090) cultivar were grown in the experiments. White Spanish was common to both studies. Strong photoperiodxtemperature interactions were shown for all cultivars in both experiments, with the sensitivity of peg number to photoperiod increasing at higher temperatures. Photoperiod responses were all indicative of short-day (SD) response types, and were always expressed in post-flowering reproductive development. No effects of photoperiod on time to first flower were evident, but numbers of pegs and pods and total pod weight per plant were reduced in long (16 or 17 h) photoperiods. Data from field experiments at Kingaroy were pooled with those from the glasshouse and controlled environment studies to estimate the critical temperatures above which photoperiod sensitivity became significant. Hourly temperature readings were used to calculate a daily heat sum (�C h) above a base temperature of 10�C for each experiment. This index of the temperature condition proved satisfactory as a possible discriminatory method to describe environments based on likely photoperiod response. Environments where daily heat unit accumulations greater than 340-350�C h were recorded during the treatment period showed significant photoperiod responses. The possibility of minimum temperature being the predominant component of the temperaturexphotoperiod interaction is also discussed. This proved less effective in discriminating between environments for photoperiod response, but data were insufficient to discount this possibility and further studies are needed. Results question the relevance of photoperiod as a factor limiting reproductive development of peanuts in cooler, subtropical environments.
Pollen vectors and pollination of faba beans in southern Australia
Authors: Stoddard FL
Published: November 2004

Commercial crops of faba beans (Vicia faba L.) in South Australia and western Victoria were surveyed for flower visitors and incidence of pollination. Honeybees were the only pollen vectors. The incidence of pollination was never less than 50% and averaged 80%. The effectiveness of honeybees as pollen vectors contrasts with their ineffectiveness in colder climates, partly because in the Mediterranean climate beans flower in late winter and early spring when bees are in search of pollen. It is unlikely that growers of faba beans in Australia will need to provide supplementary hives to ensure adequate pollination.
Sulfur supplementaion and the use of flavomycin with lupin grain for sheep
Authors: Murray PJ , Rowe JB , Speijers EJ
Published: November 2004

Two experiments were undertaken to determine the effectiveness of different S sources, in combination with flavomycin, fed with a lupin supplement, to increase wool growth and liveweight gain in 16-month-old Merino sheep fed wheat chaff. In the first experiment, ewes were fed wheat chaff (600 g/sheep) every day and the equivalent of 250 g/day of lupin grain twice weekly. An initial period of 7 weeks was used to quantify differences in wool growth and liveweight gain between individual sheep. Different S sources [2% gypsum, 12% fishmeal, 1.2% DL-methionine or 1.2% hydroxymethyl-methionine (Mepron)] were then added to the lupin grain with or without the addition of flavomycin and fed to sheep for a further period of 7 weeks. Wool growth was significantly increased (P < 0.05) only in the sheep fed lupin grain with the addition of fishmeal and fishmeal with flavomycin. Wool growth was significantly decreased (P<0.05) in the sheep fed lupin grain with the addition of gypsum or Mepron (+flavomycin). Liveweight gain was significantly increased (P < 0.05) in the sheep given methionine, Mepron or fishmeal. In the second experiment, ewes were offered wheat chaff ad libitum every day and the equivalent of 250 g/day of lupin grain twice weekly. After an introductory period of 2 weeks, different S sources (2% gypsum or 1.2% DL-methionine) were added to the lupin grain with or without the addition of flavomycin and fed to sheep for a period of 8 weeks. Wool growth was only increased (P < 0.08) in the sheep fed lupin grain with the addition of methionine with flavomycin. This treatment also resulted in a change in the pattern of chaff consumption. Liveweight gain was increased significantly (P < 0.05) in the sheep given gypsum, methionine or flavomycin. Poor quality feed supplemented with lupin grain appears to have sufficient N and S for wool growth. When sheep fed restricted amounts of poor quality feed are supplemented with lupins, increases in liveweight gain can be achieved with the addition of flavomycin, with or without S, to the lupins.
Production of summer crops in northern New South Wales. II. Effects of tillage and crop rotation on yields of sorghum
Authors: Holland JF , Herridge DF
Published: November 2004

Two crops of sorghum were grown in successive summer seasons at 3 sites on alkaline, black earth soils near Tamworth, New South Wales following either soyabeans, mungbeans, cowpeas, pigeonpeas, sunflowers or sorghum. Tillage practices were cultivation using a chisel plough and scarifier, and no-tillage using atrazine and glyphosate for weed control. Variation in grain yield (1.0-8.4 t/ha) was largely associated with variation in Dec.-Feb. rainfall (128-475 mm). An average of 15 kg grain/ha was produced for each mm water above the threshold value of 83 mm. At the high (Site A) and low (Site C) N-fertility sites, the rotation effect on sorghum yields was significant for one year, but did not carry over to a second sorghum crop. Cowpeas were the best rotation crop, followed by sunflowers mungbeans and soyabeans. At the low N-fertility site, sorghum following cowpeas outyielded sorghum after sorghum by 47% in the unfertilized plots and by an aExperiments to examine the effects of tillage practice and crop sequence on the production of sorghum grain in northern New South Wales are described. Two crops of sorghum were grown in successive seasons at three sites on alkaline, black earth soils near Tamworth following either soybean, mungbean, cowpea, pigeonpea, sunflower or sorghum. Tillage practices were cultivation using a chisel plough and scarifier, and no-tillage using atrazine and glyphosate for weed control. Variation in grain yield (1.0 to 8.4 t/ha) was largely associated with variation in December-February rainfall (128 to 475 mm). We calculated that an average of 15 kg/ha of grain was produced for each mm water above the threshold value of 83 rnm. At the high (Site A) and low (Site C) N-fertility sites, the rotation effect on sorghum yields was significant for one year, but did not carry over to a second sorghum crop. Cowpea was the best rotation crop, followed by sunflower, mungbean and soybean. At the low N-fertility site, sorghum following cowpea outyielded sorghum after sorghum by 47% in the unfertilized plots and by an average of 27% over all N treatments. It is likely that the increased yields of sorghum in the rotation plots resulted from higher levels of plant available N from both N2 fixation activity (legumes only) and reduced amounts of N removed with the harvested grain (particularly cowpea and sunflower). At the non-responsive, moderate-fertility Site B, water, rather than N, was limiting. Responses to no-tillage were apparent only in the very dry 1984/85 season (December to February rainfall, 42% below average). In the other three seasons, the cultivated crops outyielded the no-tilled crops or the differences between the two practices were not significant.
Contributions of nitrogen in soybean crop residues to subsequent crops and to soils
Authors: Bergersen FJ , Turner GL , Gault RR , Peoples MB , Morthorpe LJ , Brockwell J
Published: November 2004

Dried soybean leaves, stems and roots, containing respectively 1.9, 2.1 and 1.4 atoms % 15N were incorporated (May 1986) into the trash-cleared topsoil of 6 m2, unconfined plots in an irrigated block at Trangie, N.S.W. At intervals over the next year, 15N was determined in succeeding crops of oats (May to October) and soybeans (November to May), in weeds and in the soil. Nitrogen derived from soybean leaf residues contributed 33% of the N of winter oats grown immediately after residue incorporation, but N from roots and stems contributed only 0.6 and 3.5%, respectively, of oat N. The following soybean crop derived most of its N from N2 fixation, but residues (15N stems, 15N leaves and total soybean trash) increased plant N. Thus 13, 60 and 394 mg N m-2 of the crop N was derived from 15N -labelled root, stem and leaf residues, respectively. Weeds had higher atoms % 15N than soybeans, but removed only small proportions of residue N from the soil. In the soil, most 15N from the residues remained in the upper (0-10 cm) level of the profile, but 15N excess was detected to 30 cm in soil treated with 15N -stems and 15N -leaves. Mineral N (NO3- + NH4+ ), extracted from the soil with 2 M KCl, represented 0-5 to 2% of the total N present, being greatest in March and least in May, but 15N excess in these extracts was a greater proportion (1 to 13%) of the total 15N excess present. This indicated that the soybean residue N remained more readily mineralizable than native organic N for at least one year. Losses of 15N from the system are discussed in relation to experimental constraints.
Factors associated with the rate of growth of clean wool on grazing sheep
Authors: Birrell HA
Published: November 2004

In a grazing study that spanned 2.5 years, the rate of clean wool growth (Wi, g/day) in 4 week periods on Corriedale wether sheep was measured on each side of the animal with dyebands that were applied, alternately, at 2 week intervals. The observations (n = 224) on wool growth from 3 contiguous periods Wi = 1, 2 and 3 with the middle overlapping the other two periods, were related to either the daily rate of organic matter intake (OMI, g/day), the digestible organic matter intake (g DOMI/day), the hourly rate of OMI (IR, g OMI/h) or the hourly rate of digestible organic matter intake (DR, g DOMI/h) in linear or quadratic expressions. The intake data were collected every 4 weeks over the 3 days that correspond to days 6 to 8 of W1. The variance accounted for in each of W1, W2 and W3 increased in the order OMI<DOMI<IR<DR. DR accounted for 33.2% of the variance in W1 with a significant quadratic fit (P < 0.01) and 24.3% and 7.8% with linear fits against W2 and W3, respectively. A relationship that comprised five factors and accounted for 68% of the variance in W1 was developed by nonlinear regression. Three factors that were associated with nutritional aspects, the hourly rate of digestible organic matter intake (DR, g DOMI/h), the organic matter digestibility (OMD %) and the average organic matter intake in a grazing period (M, g OMI/grazing period) accounted for 54.9% of the variance in W1 while the other two factors that were associated with the physiological state of the animal, fleece-free liveweight change (C, g/day) and the fleece-free liveweight (L, kg) accounted for a further 13.1% of the variance of W1. The study suggests that factors associated with phenomena within a daily period may have important effects on wool growth. Management aspects are discussed.
Effects of a restricted diet during mid pregnancy of ewes on uterine and fetal growth and lamb birth weight
Authors: Holst PJ , Allan CJ , Gilmour AR
Published: November 2004

A moderate below maintenance nutritional restriction was applied to pregnant ewes for 4 weeks commencing at either 79, 87 or 95 days post coitus. Measurements were made after slaughter at the end of each restricted period and at Day 144 of pregnancy on the uterus and fetus of restricted and control ewes. Lambs were weighed at birth. Overall there was no significant difference in the response of ewes to timing of restriction but there was a response to restriction. Dietary restriction reduced fetal growth rate, girth size, crown rump length (CRL) and weight of other fetal tissues. Though reduced, girth size and CRL maintained their normal relationship with fetal weight. Growth rates of fetuses on all treatments were similar during refeeding. The largest effect of nutritional restriction on the reproductive tract occurred in lower fetal membrane weights at 144 days of pregnancy (mean of restricted group 595 g v. 761 g controls). At that time, previously restricted ewes also had an increased number of cotyledons but decreased average weight of cotyledons compared to control ewes. Fetal weight at Day 144 was significantly correlated with girth and CRL (P < 0.01) and placental weight (P < 0.05) but not with weight of fetal membrane or cotyledons. Birth weights of single and twin lambs from the restricted ewes were similar to that of the controls and appeared to be unaffected by the restriction. Small differences in the gestation length of ewes bearing twin lambs may have helped to overcome the deficit in fetal weight observed at Day 144 in ewes bearing single lambs. It was concluded that ewes respond to dietary restriction followed by improved forage availability with changes in maternal and fetal growth patterns that presumably interact to produce viable lambs.
Studies on alfalfa mosaic virus infection of burr medic (Medicago polymorpha) swards: seed-borne infection, persistence, spread and effects on productivity
Authors: Jones RAC , Nicholas DA
Published: November 2004

During 1988-90, burr medic (Medicago polymorpha) cvv. Circle Valley, Serena and/or Santiago were grown in field trials in which plots were sown with healthy seed or seed that carried varying levels of infection with alfalfa mosaic virus (AMV). Seed-infected plants were the primary source for subsequent virus spread by aphids. Levels of AMV infection normally reached 80-100% in swards sown with infected seed whether they were mown, grazed or not defoliated, most spread occurring late in the growing season. Infection of harvested seed was often less than in seed sown. However, in self-regenerated grazed swards AMV spread earlier and infection in harvested seed was up to 10 times greater than in seed before regeneration. In two trials sown in 1988, plots were mown or left uncut; AMV infection decreased herbage yields by 13-35% while seed yields were decreased significantly (by 7-30%) in one of the two trails. When one of these trials was cropped with barley in 1989 but allowed to regenerate in 1990 and grazed, herbage yield fell by 5-15% and seed yield by 2-29% due to AMV infection. In a trial sown in 1989 in which some plots were grazed and others not, AMV infection decreased herbage and seed yields by 27-32% and 21-29% respectively. In a similar grazing trial sown in 1990, AMV infection decreased herbage daily growth rates by 16-42% and seed yield sometimes by as much as 32%. Seed harvested from plots sown with infected seed was normally smaller than seed from plots sown with healthy seed. AMV-infected swards were established in 1987, allowed to regenerate in 1988-91 and grazed. With cvv. Circle Valley and Serena, AMV was readily detected each year in foliage and was also found in seeds.
Sodium chloride and soil texture interactions in irrigated field grown sultana grapevines. I. Yield and fruit quality
Authors: Prior LD , Grieve AM , Cullis BR
Published: November 2004

The effects of the salinity of irrigation water on the productivity of mature grapevines was studied. We injected NaCl solutions into River Murray water to generate five salinity levels ranging from 0.37 to 3.47 dS m-l, with sodium adsorption ratios of between 2 and 37. These treatments were applied through a trickle irrigation system for six years to own-rooted sultana grapevines growing in a vineyard at Dareton, N.S.W. The effect of irrigation water salinity was most severe on vines growing in the most heavily textured soil, and increased with time. The yield (y) response was well described by the generalized logistic function: y = D[1+(ECi/ECih)�]-1 where y is yield, ECi is salinity of irrigation water, D is the theoretical yield at ECi=0, Ecih is the half-effect ECi and a: is the shape parameter. Soil texture affected the response via an effect on ECih and, to a lesser extent, on �. These parameters were related to % (silt & clay) in the final model, which was fitted for each of years 2 to 6 and accounted for 76.2% of the variance in yield. The yield response on the lightest soil most closely resembled the Maas-Hoffman 'bent-stick' model, being relatively flat at low levels of ECi and becoming steeper at moderate salinity levels. Yield losses for heavy soils were much greater than predicted by the Maas-Hoffman model. Bunch number was the primary determinant of yield, while a lower berry weight also contributed to the reduction in yield in salinised vines. Effects on dried fruit quality were apparent only when yield was severely reduced.