bluuebunny/crossref_metadata_2025 huggingface dataset:
Agronomic and physiological assessments of genotypic variation for drought resistance in sorghum
Authors: Blum A , Mayer J , Golan G
Published: November 2005

This study was designed to assess genotypic variability for drought resistance in sorghum (Sorghum bicolor [L.] Moench) and to conclude on the possible physiological differences between drought resistant and drought susceptible genotypes.Grain yield under drought stress ranged from 184 to 943 g m-2 and relative yield ranged from 35.8 to 103.5% among genotypes. Yield (but not relative yield) under stress was decreased (r= -0.89**) with a longer growth duration of gentoypes. Both stover yield and total biomass under stress increased (r = 0.69** and r = 0.72**, respectively), while harvest index decreased (r = 0.80**) with longer growth duration. Genotypes differed significantly in leaf water potential (LWP), canopy temperature, leaf rolling, leaf carbon exchange rate (CER), stomatal conductance and osmotic adjustment. These data were averaged for the four best ('drought resistant'-R) and the two poorest ('drought susceptible'-S) genotypes in terms of their absolute and relative yields under stress. Compared with S, the R genotypes were earlier in heading and had higher LWP, lower canopy temperature and higher stomatal conductance. While leaf rolling was similar in R and S genotypes, it was found to increase as LWP decreased across all genotypes. Under these stress conditions variations in CER among genotypes on given dates appeared to be affected more by phenology than by plant water status.
The effect of flood irrigation and nitrogen source on the fate of nitrogen fertilizer applied to pasture
Authors: Mundy GN , Mason WK
Published: November 2005

The effects of flood irrigation on soil inorganic nitrogen (N) and on the recovery of 15N from 15N-labelled fertilizers were studied in two pasture experiments. In the first, changes in soil inorganic N were measured during a flood irrigation cycle after fertilization with 0 or 100 kg N ha-1 as ammonium nitrate (NH4NO3). In the second experiment, the recovery of 15N from 15N -labelled fertilizers (50 kg N ha-1 as NH4NO3, urea or urea plus nitrapyrin) was determined in field microplots under three irrigation regimes (0, 6 and 24 h ponding).Soil inorganic N in the unfertilized pasture remained relatively low (< 12 kg N ha-') during the irrigation cycle with ammonium (NH4+) the dominant form of inorganic N. In pasture fertilized with NH4N03 there was a rapid decline in both NH4+ and nitrate (NO3-) in the soil during the 48 h period after the first irrigation. The decline in NH4+ was less rapid than that of NO3-. Presumably immobilization, nitrification and pasture uptake contributed to the disappearance of NH4+ from the soil.In the second experiment total recovery of applied 15N ranged from 65 to 91%, with about half recovered from the pasture and half from the soil plus roots. The lowest recoveries of applied N occurred with NH4NO3with 24 h ponding.Recovery of the urea nitrogen was unaffected by ponding time, making it a more efficient form of N to apply to irrigated pastures.
Yields and nitrogen uptake of grain sorghum in various rotations, including lucerne, annual legume and long fallow
Authors: Holford ICR
Published: November 2005

Long-term yields, nitrogen uptake and responsiveness of grain sorghum following three lucerne rotations, an annual legume rotation, long fallowing, and continuous wheat growing were measured on a black earth and red clay in northern New South Wales. The three lucerne rotations compared two methods of lucerne establishment (with or without a cover crop) and two methods of grazing management (short or extended grazing).There were large beneficial effects of lucerne leys on the first grain sorghum crop, whether they were measured as grain yield, nitrogen content of the foliage and grain, or nitrogen uptake. The effect was much smaller in the second year but it increased in the third and fourth years, in direct relation to the rainfall during the sorghum flowering period. The effect was larger on the black earth than on the red clay, reflecting the much higher lucerne yields on the former soil. Evidence indicated that the nitrogen contribution from lucerne after the first year was no greater than the nitrogen accumulated by long fallowing, and this was attributed to very low rainfall and lucerne yields during the four year ley period.The annual legume rotation suffered from drought and insect damage in most years, and following sorghum yields tended to be lower than those achieved by long fallowing.Differences in the effects of establishment method and grazing management on total lucerne yields were reflected in the differences in subsequent grain sorghum yields. Largest differences were on the black earth where extended grazing lowered the total yields of lucerne and subsequent grain sorghum. Sowing lucerne under wheat had little effect on total yields of lucerne or sorghum.
Dry matter digestibility in vitro of leaf and stem of buffel grass (Cenchrus ciliaris) and related species and its relation to plant morphology and anatomy
Authors: Wilson JR , Anderson KL , Hacker JB
Published: November 2005

Twenty-one genotypes of buffel grass (Cenchrus ciliaris), and six other genotypes, viz. C. setigerus, C. Pennisetiforrnis and C. ciliaris x C. setigerus hybrids, were examined for dry matter digestibility in vitro (DMD) of recently expanded leaf and stem at anthesis. Differences in DMD were related to morphological and anatomical characteristics of the tissues.Leaf DMD ranged from 64.0 to 73.4%0 and stem DMD (internodes 2-4 from the top) from 47.4 to 61.7%; genotypes of high leaf DMD generally had high stem DMD (r= 0.68). Leaf DMD was negatively correlated with the proportion of thick-walled tissues in leaf cross-section (r= -0.76), leaf dry weight (r= 0.77 ) and specific leaf weight (r= -0.82). Stem DMD was inversely related to the proportion of lignified tissue in stem cross-section (r= -0.55), height of flowering stem (r= -0.51) and total number of vascular bundles in the stem section (r= -0.55). Genotypes with a high DMD tended to have lax leaves and small vegetative tillers.The main commercial cultivars of buffel, viz. American, Biloela and Gayndah, were 4-6% units (leaf) and 2.5-7% units (stem) lower in DMD than the best genotype, indicating potential for improvement of digestibility. Specific leaf weight and numbers of vascular bundles in stem cross-section, which arc easily and quickly measured and have a heritability comparable to that for DMD, could be useful criteria for preliminary assessment of a large breeding population.
The influence of sowing method on perennial grass establishment. I. Dry matter yield and botanical composition
Authors: Bellotti WD , Blair GJ
Published: November 2005

'Demeter' tall fescue (Festuca arundinacea Schreb.) and 'Victorian' perennial ryegrass (Lolium perenne L.) were sown separately into a white clover (Trifolium repens L.) dominant pasture in June 1981. Eight sowing methods were compared to assess the ability of perennial grasses to establish from direct drill sowing methods relative to conventional seedbed and aerial sowing methods. Within direct drill treatments, two drill implements were factorially combined with three herbicide treatments. Pasture production and botanical composition were sampled over a 27 month period following sowing. After a dry summer, 22 months after sowing, sown grasses dominated pasture composition (69-94% of total dry matter yield) in the high yielding treatments. At this time, the successful direct drill treatments were similar in yield to the conventional seedbed treatment. Within direct drill treatments, sowing implement had little effect on yield and composition, whereas herbicide application markedly increased sown grass yield. Pre-sowing blanket application of herbicide in the triple disc treatment increased tall fescue yield from 82 to 1504 kg ha-1 and perennial ryegrass yield from 98 to 807 kg ha-1. An inverse relationship was described between dry matter present at sowing and eventual yield of sown grasses. These perennial grasses can be successfully established by using direct drill sowing methods provided resident vegetation is adequately suppressed.
Comparison between Merino sheep homozygous (WW) or heterozygous (Ww) for white fleece on the incidence of isolated pigmented wool fibres and types of non-fleece pigmentation
Authors: Fleet MR , Smith DH , Stafford JE
Published: November 2005

Merino sheep known to be homozygous (WW) or heterozygous (Ww) for white fleece were examined for isolated pigmented fibres and various types of non-fleece pigmentation on the adult sheep or pigmented halo-hair on the birth coat.There was no significant difference (P>0-05) between WW and Ww sheep in the occurrence of isolated pigmented fibres. Nevertheless, 17% of the fleece samples contained varying concentrations of pigmented fibres; up to 510 per 10 g scoured staples. Of the various types of macroscopic pigmentation recorded, the scores for pigmented halo-hair (lamb) and pigmented fibres on the horn sites (adult) were the most strongly correlated (r= 0.39 and 0.30, respectively; P<0.001) to the concentration of pigmented fibres in fleece samples. Heterozygous sheep had slightly more black/grey pigmentation for bare skin areas on the nose lips and around eyes ( P< 0.001) or under tail (P<0.05) and in the hooves (P<0.05) than WW sheep, but these differences arc unlikely to be of practical relevance.
Corrigenda - Growth, development and light interception of old and modern wheat cultivars in a Mediterranean-type environment
Authors: Siddique KHM , Belford RK , Perry MW , Tennant D
Published: November 2005

A field experiment was conducted at Merredin in the eastern wheat belt of Western Australia, comparing 10 wheat cultivars representing old and modern wheats. The aim of the study was to identify any morphological and physiological characters associated with higher grain yield of modern wheat cultivars.The modern cultivars reached double ridge, terminal spikelet, anthesis and maturity earlier than the old cultivars, but modern cultivars had a longer duration between double ridge and terminal spikelet stage. The number of leaves on the main stem generally decreased from old, Purple Straw (14) to modern cultivars like Kulin (8). The modern cultivars had a shorter phyllochron interval than the old cultivars. The old cultivars also produced more tillers per plant (7.3) and had a lower percentage (35%) of ear bearing tillers, as compared with 3.9 and 51% for modern cultivars.The green area index and ground cover was higher in old than modern cultivars. However, the efficiency of conversion of photosynthetically active radiation to dry matter was slightly greater for modern cultivars. Although dry matter at final harvest was similar between cultivars, there was a trend for higher dry matter production with modern cultivars. The post-anthesis green area duration was longer with modern cultivars and grain yield increased with increase in post-anthesis green area duration.Grain yield and HI increased consistently from old to modern cultivars. The most recent cultivar Kulin had the highest yield and second highest harvest index, which were 63% and 48% respectively higher than the oldest cultivar, Purple Straw. Increases in grain yield in the modern cultivars were associated with increased grains spikelet-1 and grains ear-1. Mean grain weight showed a slight reduction with modern cultivars. The results are discussed in relation to future improvement in yield.
Effect of nitrogen and phosphorus deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici
Authors: Brennan RF
Published: November 2005

Wheat was grown in a slightly acid grey sand at six levels of phosphorus and four levels of nitrogen, in the presence and absence of inoculum of Gaeurnannomyces graminis tritici (Ggt) in a glasshouse experiment. Adequate nutrition of N (400 mg/pot) and P (100 mg/pot) for wheat plants was required to overcome take-all of wheat grown for 46 days. Severely N and P deficient plants had 60% of their seminal and nodal roots infected by take-all. As the plants responded to increasing levels of N and P, the percentage of infected nodal and seminal roots steadily declined to 0% and 10% for each root system respectively at luxury levels of P and adequate N. In both the seminal and nodal root system, increasing the N and P supply decreased the length of proximal lesions (closest to seed) and increased the length of the root between the crown and the proximal lesion. The seminal root system was more severely infected with take-all than the nodal root system.
The response of cassava to water deficits at various stages of growth in the subtropics
Authors: Baker GR , Fukai S , Wilson GL
Published: November 2005

Cassava is a potential tuber crop for northern Australia where water stress is likely to occur during some stages of growth. Field and glasshouse experiments were conducted to examine the response of cassava to soil water deficits which developed at various stages. The field experiments, covering 10-month growth durations from planting in spring to harvesting in winter, showed that water stress occurring in summer or winter had small effects, but in autumn severely reduced the final yield. Autumn was the time of maximum bulking of underground storage organs in well-watered plants, and water stress which reduced assimilate production also reduced bulking. Temperature at this time was suboptimal for canopy development, and leaf area which was reduced during the stress did not increase after its relief, affecting further the growth of storage organs. Similarly, in the glasshouse experiment, plants recovered rapidly during early stages of growth, but when stress occurred later leaf area was reduced greatly, and recovery after its termination was poor. In all experiments, water deficits affected yield of storage organs but not the pattern of assimilate distribution, resulting in similar harvest indices among the plants of different watering treatments. It is concluded that the reduction in cassava yield (cv. M Aus 7) is caused by the reduction in total biomass production, and that stress occurring later in the season is most detrimental to yield because of the additional effect of reduced ability of old plants to recover leaf area after the stress is relieved.
Lupin species and peas vary widely in their sensitivity to Fe deficiency
Authors: White PF , Robson AD
Published: November 2005

Variation exists between lupins and peas and between species of lupins in their performance on fine-textured alkaline soils. Two species of lupins (Lupinus angustifolus, L. cosentinii) and peas (Pisum sativum) were grown on a fine-textured alkaline soil under conditions conducive to Fe deficiency to determine whether differences between species could be related to susceptibility to Fe deficiency.Treatments induced severe Fe deficiency and markedly reduced growth of L. angustifolius, had only a moderate effect on L. cosentinii, and had no effect on P. sativum. Poor growth and symptoms were closely related to Fe concentrations within the leaves of plants.Lupins and peas therefore vary markedly in their tolerance to Fe deficiency, which is possibly related to their ability to produce reactions around their roots which make Fe available for uptake.
The influence of weather on the quality of tropical legume pasture during the dry season in northern Australia. IV. Geographic variation in risk of spoilage of standing hay
Authors: Wall BH , McCown RL
Published: November 2005

This paper assesses the geographic variation in northern Australia of the risk of deterioration to the point of 'spoilage', including both the beneficial and the deleterious effects of rain. The procedure is a modified water balance in which leaf shedding is driven by decline in soil water storage, and moulding is governed by the rate of evaporation following a rainfall of 2 mm or more.For 28 stations, from the West Kimberley to Central Queensland, an average of 40 dry seasons have been analysed for the periods when the legume would have been green, dry but unspoilt, and spoilt. A 'dry leaf' nutritional strategy is feasible where the dry seasons are reliably rainless. Even in regions with a high risk of rain, if green leaf is maintained for a considerable time in the dry season there is also a low risk of spoilage, and the use of non-deciduous legume species in these regions and elsewhere is discussed.
The role of stolons and seedlings in the persistence and production of white clover (Trifolium repens L. cv. Huia) in temperate pastures on the Northern Tablelands, New South Wales
Authors: Archer KA , Robinson GG
Published: November 2005

This paper reports the findings of a five-year study on the growth patterns, production and means of persistence of white clover in a cool temperate environment with summer dominant rainfall, on the Northern Tablelands of New South Wales. White clover essentially persisted as a perennial, but large and rapid declines in plant frequency occurred during late summer if soil moisture levels became depleted. The critical combination of conditions at which plant frequency was adversely affected occurred when available soil moisture levels declined below 35 mm and mean weekly maximum temperatures exceeded 20�C; conditions which often occur in late summer in this environment. During one prolonged period of moisture stress in the second spring and summer period of the study, all plants died. Regeneration was due to germination of seeds and seedling establishment, but plants subsequently persisted as perennials. Relationships were developed to predict the probability of survival of white clover over the range of temperatures and soil moistures recorded in these experiments. Germination occurred to a variable extent each year, but was observed only during winter and spring. Seedling establishment was effective in only one year, which followed the death of white clover in summer, 1980-81. The sward was slow to recover after seedling regeneration owing to low winter temperatures and competition from established temperate perennial grasses in spring. Seedlings contributed little to dry matter production in spring. These results indicate that white clover is unlikely to be of value as an annual in temperate pastures. Strategies aimed at improving white clover in cool temperate environments, either by management or selection/breeding programs, should therefore focus upon improving the ability of white clover to persist as a perennial.
Factors limiting the intake of feed by sheep. 14. Comparisons of voluntary feed consumption and various transactions in the alimentary tract between lambs and sheep fed roughage diets
Authors: Weston RH , Lindsay JR , Peter DW , Buscall DJ
Published: November 2005

Comparisons were made of the voluntary intake and digestion of diets based on chopped straw, chopped lucerne and ground lucerne by lambs (c. 23 kg body weight) and adult sheep (c. 53 kg), and of feed intake and digestion by larger lambs (c. 35 kg) and adult sheep (c. 53 kg) grazing senescent pasture. With both the chopped and ground diets the lambs (i) had digesta of finer texture, (ii) cleared larger particles (>600 �m sieve) more slowly from the rumen, (iii) cleared organic matter more rapidly from the omasum and caecum + proximal colon, and (iv) performed more rumination bites. With the chopped diets, digestibility and feed intake pcr unit metabolic body weight were similar for lambs and adults but the lambs (i) spent more time eating, (ii) had more digesta in the reticulorumen per unit reticulo-rumen digesta free body weight, (iii) clcarcd organic matter from the abomasum more rapidly, and (iv) had less ash in abomasal digesta (straw-based diet only). With the ground lucerne diet the lambs (i) consumed more feed per unit of metabolic body weight, (ii) regurgitated more rumination boluses and (iii) cleared organic matter more rapidly from the reticulorumen. At pasture, it was estimated that the lambs (i) consumed more feed per unit metabolic body weight, (ii) had more digesta in the reticulo-rumen per unit rcticulo-rumen digesta free body weight, (iii) clearcd organic matter more rapidly from the omasum and abomasum, (iv) tended to have digesta of finer texture and (v) had less ash in abomasal digesta (-64%). The differences between the lambs and adults and their possible implications arc discussed, and it is suggested that with lower-quality roughages the smaller lamb may be placed at a disadvantage, relative to the adult, because of an inability to exhibit a higher feed intake commensurate with its higher maintenance energy need.
The effect of timing of shade on development, dry matter production and light-use efficiency in groundnut (Arachis hypogaea L.) under field conditions
Authors: Stirling CM , Williams JH , Black CR , Ong CK
Published: November 2005

During the rainy season in India, bamboo screens intercepting approximately 46% of the incident light were used to simulate the effect of shading by a cereal grown as an intercrop with groundnut (Arachis hypogaea L.). The treatments comprised an unshaded control and two durations of shading extending from peg initiation (T1) and the onset of pod filling (T2) to final harvest. Plant height was greatest in the T1 crop, but the maximum rates of leaf development on the main stem, leaf area expansion and pod production were similar in all crops. Shading appeared to reduce the rate of the linear growth phase because the reduced light interception was not entirely offset by an increase in light-use efficiency. Premature senescence in the shaded crops coincided with the virtual cessation of pod production, although continued allocation of dry matter to reproductive structures in the T1 crop resulted in a greater proportion of pods being filled at final harvest than in the other treatments. The responses of groundnut to timing of shade are discussed in terms of their implications for the selection of improved crop combinations for intercropping.
Tree/pasture interactions at a range of tree densities in an agroforestry experiment. II. Water uptake in relation to rooting patterns
Authors: Eastham J , Rose CW , Cameron DM , Rance SJ , Talsma T , Charles-Edwards DA
Published: November 2005

Patterns of water uptake throughout a drying period of approximately one year were investigated under trees and pasture at three tree densities in an agroforestry experiment, and related to tree and pasture rooting patterns and water use. A greater proportion of soil water was extracted from deep in the soil profile under the densely planted trees, owing to lower soil water contents in upper horizons and deeper and more dense rooting systems than at lower tree densities. As the drought period progressed, the ratios of tree transpiration rate and pasture evaporation rate to equilibrium evaporation rate tended to decrease at each tree density as soil water contents in upper horizons decreased, and an increasing proportion of water was extracted from deeper soil horizons. At each tree density, the rate of water uptake per unit root length was lowest in surface soil horizons and tended to increase with increasing soil depth. The rate of water uptake per unit root length tended to increase with time in deeper, wetter soil horizons and decrease with time in surface soil horizons as soil water content decreased.
Losses of the digestible components of annual ryegrass (Lolium rigidum Gaudin) during senescence
Authors: Ballard RA , Simpson RJ , Pearce GR
Published: November 2005

Changes in the digestibility and chemical composition of a L. rigidum cv. Wimmera sward sown in May, 1985 were measured from 21 d pre-anthesis (9 Oct.) until 69 d after anthesis (7 Jan.) when the plants were dead. Max. yield of 11.7 t DM/ha was reached 8 d pre-anthesis. The in vitro DM digestibility (IVDMD) of whole plants decreased from 58% at anthesis to 36% 69 d after anthesis. This was associated with a decrease in the IVDMD of stem, leaf blades and sheaths. In the 3rd stem internode, which was considered representative of the stem, the loss of digestible yield was due to loss of DM soluble in neutral detergent (NDS). The NDS consisted mainly of non-structural carbohydrates. Similar losses of NDS contributed to loss of digestibility in the uppermost leaf blade and leaf sheath. The digestibility of NDS was generally 80-95% but in the leaf blade this declined to 45% as NDS was mobilized during leaf senescence. NDF digestibility of the stem declined from 35% at anthesis to 19% when dead; corresponding values for the uppermost leaf blade were 83 and 54%, resp., and for the leaf sheath 46 and 37%, resp. These characteristics of a senescing grass sward are discussed in relation to options for improving digestibility of dead grass pastures.
Effect of nutrition on the response in ovulation rate in Merino ewes following short-term lupin supplementation and insulin administration
Authors: Leury BJ , Murray PJ , Rowe JB
Published: November 2005

In experiment 1, groups of Merino ewes, 4-6 years old, were given daily wheat chaff 500 g plus vitamin and mineral supplements, or wheat chaff 800 g and pelleted feed containing lucerne, lupin and barley 350 g plus mineral and vitamin supplements. Diets provided 0.5 and 1.2 times maintenance requirements. On each plane of nutrition, lupins 750 g were given or not given 10 days before oestrus. In experiment 2, the same planes of nutrition were used and sheep were injected daily with insulin 15 IU, or left untreated. Ovulation rate increased in response to lupin feeding at both planes of nutrition. Exogenous insulin, given as a daily single injection did not increase ovulation rate.
The effect of species of grass, stage of maturity and level of intake on the degradation of protein and organic matter in the rumen of steers
Authors: Hart FJ , Leibholz J
Published: November 2005

Six Friesian steers (300 kg liveweight) were prepared with rumen and abomasal cannulae, and fed three artificially dried grasses at three levels of organic matter (OM) intake and at two stages of maturity. The grasses were paspalum (Paspalum dilatatum), oats (Avena sativa) and kikuyu (Pennisetum clandestinum). The apparent digestion of organic matter (OM) in the whole tract decreased with increasing maturity for all grasses. The proportion of OM digested in the rumen was greater for paspalum and kikuyu than oats, and increased with advancing maturity for paspalum and kikuyu. Microbial nitrogen flow from the rumen was 26 and 25 g/kg of OM apparently digested in the rumen for paspalum, 32 and 36 for oats and 25 and 14 for the early and late maturity kikuyu. The true degradation of grass protein in the rumen was between 0.70 and 0.80 for all three grasses, at all three feed intakes and for both stages of maturity of the grasses. Total rumen pool size was less for oats than paspalum or kikuyu. The retention time of particles and fluid in the rumen increased with decreasing feed intake for oats.
The contribution of pod numbers to field pea (Pisum sativum L.) yields in a short growing-season environment
Authors: French RJ
Published: November 2005

Field pea yields in three sowing-time experiments in 1985, and two experiments in 1986, were split into the following components: pods m-2, seeds pod-1 and average seed size. In both years pods m-2 was the component most strongly correlated with yield, but the others were also positively correlated with yield. Multivariate analysis of variance showed that pods m-2 contributed more than the other components to the site and sowing-time main effects in both years. Seeds pod-1 made no contribution in either year, but average seed size contributed to the site main effect in 1985 and to the sowing time and cultivar main effects in 1986. These results identify pods m-2 as the most responsive component to environmental effects on field pea yield. Pods m-2 was split into stems m-2 and pods stem-1, or into the rate of pod formation and the duration of pod formation. Variation in both stems m-2 and pods stem-1 contributed to differences in pods m-2 in the 1986 experiments. In a comparison of two Derrimut pea crops grown at Merredin in 1984 and 1985, the duration of pod formation and the rate of pod formation both varied. Variation in the rate of pod formation was due to differences in stems m-2 rather than in rates of pod formation stem-1. Pods formed early in the reproductive phase contributed much more to total seed yield than those formed later. This was due to later-formed pods containing fewer seeds and being more likely than early-formed pods to abscise before reaching maturity. The proportion of total seed yield carried on the first three reproductive nodes varied from 64.3% to 94.2%. This proportion was higher in harsher environments. It is suggested that in short growing-season environments increased pod formation rates are desirable to allow compression of the pod formation period, so that fewer pods will be formed late in the reproductive phase when the environment is most limiting.
Soil and plant factors relating to the poor growth of Lupinus species on fine-textured, alkaline soils - a review
Authors: White PF
Published: November 2005

Soil type is an important factor affecting the growth of lupins. Successful lupin cultivation is generally restricted to deep, acid to neutral, coarse-textured soils. Very little is known about the factors affecting the performance of lupins on other soil types. This review attempts to define the major factors controlling the growth of lupins of fine-textured, alkaline soils, with a view to providing a focus for future research. Wild populations of the genus, as a whole, occupy soils of a wide pH and textural range (pH 4-8.5, texture ranging from coarse sands to fine clays), although the majority of populations are found on light soils of sandy loam or loamy sand texture with pH values between 5.5 and 7. Species within the genus have distinct preferences for soils of a narrower range than the genus as a whole. Commercially cultivated species appear to be adapted to a narrower range of soil types than the wild species. Iron nutrition, seedling emergence, and rooting pattern and phenology are the major factors influencing the performance of lupins on fine-textured, alkaline soils. Lupins appear to possess some mechanisms thought to enhance the availability of Fe, nevertheless they suffer severely from Fe deficiency. Conditions prevailing on fine-textured, alkaline soils (poor drainage and aeration, CaCO3) are frequently conducive to Fe deficiency. The epigeal pattern of emergence of lupins is unsuitable to fine-textured soils, particularly if crust formation occurs. The rooting pattern and phenology of lupins is better suited to deep sandy soils than shallow, fine-textured soils, and this exacerbates late-season water stress. A better understanding of these factors may allow breeding and management strategies to be developed which will extend lupin cultivation to a wider range of soils.
The effect of temperature on the hardseed content of some annual legumes grown on the northern slopes of New South Wales
Authors: Lodge GM , Murison RD , Heap EW
Published: November 2005

Two laboratory experiments were conducted to assess the effects of constant and fluctuating temperatures on the hardseed content of a range of legume species. In the first experiment the effects of constant (10/10,25/25,40/40�C) and fluctuating temperatures (40/10,40/25�C) on the rate of breakdown of the hardseed of 15 legumes was examined over a 12-month period. The second experiment investigated the hardseed level of seven of these legumes stored at temperatures of 25/25,40/25,60/25�C over 11 months. A method of analysing these data is presented which describes the hardseed profile over time and allows the rates of change to be compared. For seed collected in a summer rainfall environment fluctuating temperatures of 40/10�C significantly reduced the hardseed level of Medicago aculeata Willd. and M. scutellata (L.) Mill, cv. Sava, Trifolium subterraneum ssp. subterraneum Katzn. et Morley cv. Woogenellup and T. subterraneum ssp brachycalycinum Katzn. Et Morley cv. Clare. A 40/25�C regime reduced the hardseededness of M. minima (L.) Bart, M, aculeata, M. truncatula Gaertn. cv. Sephi, T. subterraneum ssp, subterraneum Katzn. et Morley cvv. Nungarin and Woogenellup and cv. Clare. At 60/25�C the hardseed level of all legumes declined over time. Further at 60/25�C hardseed contents declined at a significantly faster rate than for those at 40/25�C. Field observations of the number of seedlings emerging in the summer after seed set followed a similar pattern to that expected from the laboratory studies. From these studies it is proposed that, provided their seed set is adequate, cultivars with comparatively low levels of hardseed may perform better than expected when grown in a summer rainfall environment, particularly when they are either grown in association with native grasses or have a high proportion of buried burrs. Under these conditions temperatures of around 40/25�C could be expected.
A differential response of a two-row barley and a six-row barley to detillering under a restricted watering regime
Authors: McDonald GK
Published: November 2005

The effect of detillering on the growth and yield of a six-row barley (cv. Beecher) and a two-row barley (cv. Schooner) grown under adequate and restricted watering was studied in a glasshouse experiment. The vegetative growth of both varieties responded in a like manner to detillering and reduced watering, but there were significant differences in the grain yield responses. Detillering reduced the grain yield per plant in both the non-stressed and stressed treatments of Schooner and the non-stressed treatment of Beecher, but had no significant effect on the yield of Beecher when watering was restricted. The experiment indicated that there may be genetic differences in response to detillering under some conditions and suggests that some caution needs to be exercised when using detillering experiments to predict the value of genetic uniculms.
Phosphorus efficiency in pasture species. IV. Yield, efficiency parameters and partitioning of P in two white clover accessions under varying levels of P supply in solution culture
Authors: Blair GJ , Wilson EJ
Published: November 2005

An experiment was conducted under controlled environment conditions in nutrient solution over four P levels (1,4, 8, 16 8mol P m-3) to evaluate the yield performance and P uptake of two accessions of white clover (Trifolium repens). The two accessions used were Naturalized, which was grown from a seed collection made from a low P soil on the Northern Tablelands of N.S.W., and cv. Ladino. Nutrient solutions were renewed when the P concentrations fell by a maximum of 10% and were pumped so that there was a flow rate of 4.4 L min-1 over the plant roots. The shoot and root fresh weight yield of Ladino was higher than Naturalized at all P levels. At 16 8mol P m-3 the shoot yield of Ladino was fourfold that of Naturalized; however, the relative yield response of Ladino between 1 and 16 8mol P m-3 was only 20% of the response of that in Naturalized. Phosphorus uptake was highest in Ladino at all P levels. The minimum shoot labile P concentrations recorded in this study were 1.1 and 2.5 8mol P g F.wt-1for Ladino and Naturalized respectively, indicating that Naturalized is capable of maintaining relatively high soluble tissue P levels under low P supply. The generally higher labile, lipid and residue P levels in new leaf, old leaf, stem and root in the Naturalized white clover accession indicate a lower efficiency of nutrient utilization in this collection compared to Ladino. In contrast to Ladino, Naturalized white clover may be able to control its P accumulation at high levels of supply, as toxic levels do not accumulate in old leaf. Ladino was the more efficient accession when P efficiency was defined as shoot yield per unit of P in solution. When P efficiency was defined as shoot or plant yield per unit of P absorbed or as the inverse of P concentration (utilization quotient), Ladino was the more efficient accession at 1 and 4 8mol P m-3, with only small differences between the accessions at 8 and 16 8mol P m-3. The results suggest that Naturalized may be adapted to low P supply through its low inherent growth rate which lowers its demand for exogenous P.
Feed intake and liveweight of cattle on subtropical native pasture hays. 2. The effect of urea and maize flour, or protected-casein
Authors: Hennessy DW , Williamson PJ
Published: November 2005

Twenty-five Hereford cattle, of both sexes and a mean liveweight (� s.e.) of 172 �5.6 kg were allocated randomly from stratified groups to five treatments in which urea (UR), urea plus maize (URM), urea plus maize flour and protected casein (URMFC) or protected casein alone (FC) were offered to individually penned cattle on a basal diet of native pasture hay (8.4 g N/kg dry matter (DM)) over 70 days. Rumen ammonia concentrations were low in cattle on the basal hay diet (mean � s.e.d.) of 17 � 10.0 mg N/L but were significantly increased (P<0.01) by a supplement of 280 g/head.day of protected casein (FC) to 70 mg N/L and increased further (1 68 mg N/L) when urea was included with maize (URM) in the treatment. Volatile fatty acid concentrations in rumen fluid were increased (P<0.05) only by URM which also resulted in higher (P< 0..01) molar proportions of propionic acid. All treatments increased (P< 0.01) the hay intake of cattle during the study with the exception of URM, which was based on a high rate of feeding (400 g/day) of maize flour. Liveweight change of cattle was increased (P<0.01) by urea (UR) and maize flour (URM) to 290 and 340 � 56 g/head.day respectively. Higher (P< 0.01) liveweight gains were recorded when protected casein was included in the diet (URMFC, FC), being 550 and 600 g/head.day respectively. The results are discussed in terms of the scope for improving the efficiency of gain in cattle on a low quality grass hay by including low rumen-degradable proteins as a supplement to grass hays.
Effects of Puccinia menthae on growth and yield of Todd's Mitcham peppermint (Mentha x piperita)
Authors: Edwards J. , Parbery D. G. , Taylor P. A. , Halloran G. M.
Published: November 2005

The peppermint cultivar Todd's Mitcham forms the basis of a newly
established peppermint oil industry in north-eastern Victoria. In this study
the effects of Puccinia menthae on growth and yield
components of Todd's Mitcham peppermint grown in pots were investigated.
Rust infection significantly (P<0.05) reduced oil content, stolon number,
leaf area, and root, stem, and leaf weights per plant, and increased
defoliation by 67%. There was a negative linear relationship between
oil yield and level of defoliation. Relationships between the amount of
disease, measured as incidence and severity, and levels of defoliation were
linear and logarithmic, respectively. The impact of disease on various
components of growth and yield is discussed.
Genetic diversity in sunflower (Helianthus annuus L.) as revealed by random amplified polymorphic DNA analysis
Authors: Lawson WR , Henry RJ , Kochman JK , Kong GA
Published: November 2005

A cross-section of sunflower genotypes grown in Australia including commercial cultivars (Suncross 40R, Hysun 33, Hysun 45CQ, Advance, DK3873), breeding lines (Sunfola, S37- 388, PhRR3, HA-R2, MC29, MC69, S37-388RR), wild sunflower varieties (H. annuus, H. argophyllus), a distantly related species (Tithonia diversifolia), and a hexaploid/diploid cross (H. tuberosus L.x H. annuus L.) were assessed for genetic diversity using RAPD (Random Amplified Polymorphic DNA) analysis. A considerable amount of polymorphism was revealed. Of the total of 158 markers amplified, 133 were polymorphic for at least one pair-wise comparison within the 16 genotypes. Overall, 33% dissimilarity was detected, with an average of 27% dissimilarity revealed among the hybrids and breeding lines, which exhibited 38% dissimilarity to the wild varieties H. annuus and H. tuberosus, and 51% dissimilarity to Tithonia and H. tuberosus x H, annuus. PCR of the 5S ribosomal RNA gene spacer region did not reveal any polymorphisms among the cultivated and breeding lines, but did distinguish between H. tuberosus and the other wild species. This survey of a selection of sunflower genotypes indicates that the genetic base of domesticated sunflower may be quite wide. These results suggest that RAPD methodology will provide an efficient tool for the analysis of the sunflower genome, in particular in breeding programs.
Effect of post-inoculation temperature and light intensity on expression of resistance to stripe rust in some Australian wheat cultivars
Authors: Ash GJ , Rees RG
Published: November 2005

Temperature sensitive resistance to stripe rust in selected Australian wheat cultivars was found to be most strongly expressed at a constant post-inoculation temperature of l9�C and at high light intensities. At 25�C the infection type on the susceptible host was reduced, indicating incompatability, while at the lower temperature of 13�C all cultivars were susceptible to the rust. At low light intensities there was a movement towards low infection types in cultivars possessing this resistance even at low temperatures. This made it essential to use high light intensities to differentiate this resistance to stripe rust. The host-pathogen interaction leading to the low infection types became irreversible after 6 to 7 days' exposure to the higher temperatures. As well as affecting disease progress towards the end of the growing season in the warmer areas of the wheat belt, this resistance could have a marked effect on the ability of Puccinia striiformis fsp. tritici to oversummer in the Australian wheat growing areas.
Factors influencing the establishment of latent infection of narrow-leafed lupins by Diaporthe toxica
Authors: Williamson PM , Sivasithamparam K
Published: November 2005

Inoculation of a susceptible cultivar of lupin (Lupinus angustifolius cultivar Yandee) with pycnidioconidia of Diaporthe toxica was carried out in the glasshouse to evaluate the effects of simulated dew period, inoculum concentration, temperature of incubation and host tissue maturity on infection using the assessment of the latent infection structures as the assay method. Optimum infection occurred after a dew period of 72 h. Infection was highest at inoculum levels between 1 x l05 and 1 x l07 and at 20�C. One-week-old stem tissues were most susceptible to infection with very few infections evident on 10 week old tissues.
A glasshouse evaluation of sulfur fertilizer sources for crops and pastures. II. A comparison of sulfur coated triple superphosphates and gypsum
Authors: Blair GJ , Dana M , Lefroy R
Published: November 2005

In many parts of the world it has become more economical to use triple superphosphate (TSP) rather than single superphosphate (SSP) as a pasture fertilizer where only P deficiency exists. Coating TSP with elemental S is an attractive alternative to SSP for situations where P and S deficiency exists. A pot experiment was conducted on an S deficient Aquic Haplustalf soil to compare the ability of gypsum (G) and S coated TSP to supply S to a ryegrass/white clover pasture over 14 repeated harvests over a 96 week period. The adhesives used to coat S to TSP were UNE1, UNE3, UNE2 and a commercial product (HF). The reverse dilution 35S technique was used to calculate fertilizer S uptake. Total yields were highest with G and UNE1. Total fertilizer S recovery by the pasture was 64.4% for G and 52.3% and 52.9% for UNEl and UNE3 respectively. These amounts were significantly higher than from UNE2 or HF. The time course of fertilizer S release varied between products and shows that bonding method can affect S availability from S coated TSP products.
Breeding and selection for high early season sugar content in a sugarcane (Saccharum spp. hybrids) improvement program
Authors: Cox MC , Hogarth DM , Hansen PB
Published: November 2005

A recurrent selection program for high early season commercial cane sugar (CCS) in sugarcane (Saccharum spp. hybrids) commenced in 1988. About 20 families (first clonal stage) and their parents are grown in two regions each year. Elite clones with high early CCS are selected and these are recycled into the breeding population with a short generation interval. Estimates of narrow-sense heritability from midparent-offspring regressions were moderate to high (0.6 or greater). Thus breeding for this trait using a large database of information available on early CCS characteristics of parental clones should be effective. Additive genetic variance (=2A) was more important than non-additive genetic variance.
The recovery of 15N from labelled urea fertilizer in crop components of sugarcane and in soil profiles
Authors: Chapman LS , Haysom MBC , Saffigna PG
Published: November 2005

Trash conservation measures associated with burnt and green harvested cane, and minimum tillage, are being adopted by canegrowers. These new management systems pose questions about how to apply N fertilizers. Experiments were conducted to evaluate the efficiency of fertilizer N uptake by the crop. Urea, labelled with 15N , was either broadcast or buried in three trash management systems: with and without trash after harvesting cane burnt, and with trash after harvesting cane green. The proportion of applied fertilizer-N recovered in a cane crop was 33% when labelled urea was buried, and 18% when broadcast. The presence of trash mulches from burnt or green harvested cane had negligible effects on the uptake of fertilizer-N. Of fertilizer-N applied, 25% was detected in soil 12 months after application, and there was no difference between burying and broadcasting urea. The fate of the lost fertilizer-N was not determined. Leaching did not appear to be a significant loss process in this gleyed podzolic soil, but ammonia volatilization probably occurred when urea was broadcast and it is suspected that denitrification accounted for the majority of the fertilizer-N losses.
Temporal response of plasma metabolites to ractopamine treatment in the growing pig
Authors: Dunshea FR , King RH
Published: November 2005

Eight crossbred gilts (73 kg liveweight) were surgically prepared with indwelling venous catheters to examine the temporal pattern of circulating metabolites and hormones during dietary ractopamine (RAC, 0 or 20 mg kg-1) treatment for 24 days. Pigs were bled every 2 h for 24 h on days 1, 2, 8, 22 of treatment and again 5 days after withdrawal of RAC. Dietary RAC increased liveweight daily gain and decreased feed consumption : liveweight gain by 37 and 25%, respectively. There were no differences in growth performance between the two groups of pigs during the week after withdrawal of RAC. Dietary RAC had no acute or chronic effects upon plasma concentrations of non-esterified fatty acids (NEFA) or glucose. Likewise, plasma NEFA and glucose were not different during the withdrawal period. Plasma urea nitrogen began to decrease after 24 h of dietary RAC treatment, and remained lower than for the controls for the duration of RAC treatment. Withdrawal of RAC caused a marked increase (21%) in plasma urea nitrogen. Dietary RAC decreased plasma insulin and negated the normal increase with age in plasma IGF-I. These metabolic data are consistent with increased protein deposition with little change in fat deposition during dietary RAC treatment.
Immunization of lambs against somatotropin release inhibiting factor to improve productivity: comparison of adjuvants
Authors: Westbrook SL , McDowell GH
Published: November 2005

Responses to immunization against somatotropin release inhibiting factor (SRIF) were compared in lambs injected with SRIF plus either Freund's complete adjuvant (FCA), muramyl dipeptide (MDP), Freund's incomplete adjuvant/muramyl dipeptide (FIA/MDP), DEAE-Dextran (DEAE), or Quill A. By comparison with control lambs, immunized lambs grew faster and produced more wool. In lambs immunized with SRIF plus MDP or FIA/MDP, depths of back-fat and of the m. longissirnus dorsi were increased. Anti-SRIF antibody titres were very variable between groups of immunized lambs, with titres being highest for lambs injected with SRIF plus FCA or DEAE. Adverse effects of immunization were observed in lambs given FCA, DEAE and Quill A. It appears from the present study, that MDP alone or in combination with FIA would be suitable for use in commercial vaccines to enhance productivity by immunization against SRIF.