Differences In Dry Matter Yield Research Articles

Field tests for evaluating spotted alfalfa aphid resistance in lucerne cultivars: a comparison with glasshouse studies

Aphid development, dry matter production and seedling and plant survival data were collected for 22 lucerne cultivars growing at Tamworth, New South Wales. These data were used to investigate whether or not the field performance of these cultivars reflected the range of spotted alfalfa aphid (SAA) resistances determined in published reports of percentage seedling survival in glasshouse screening tests. Numbers of SAA were assessed on seedlings and established plants of each cultivar during heavy, natural field infestations (10.6-23.0 SAA/seedling and 4.2-325.3 SAA/stem). Mean total numbers of SAA/seedling did not differ significantly between cultivars, but compared with the two SAA-susceptible cultivars, Hunter River and 77-6-1 545, lower numbers ( P < 0.01) of large nymphs were found on all SAA resistant cultivars except Matador, Resistador II, DeKalb Brand 167, AS 13R, Amador, Mesilla and Falkiner. However, dry matter yields of all cultivars at first flower were not significantly different, although percentage seedling survivals of the two SAA susceptible cultivars were lower (P< 0.01) than those of the SAA resistant cultivars. For established plants, the SAA susceptible cultivars 77-6-1545 and Hunter River had higher total numbers of SAA and SAA large nymphs (P<0.01) than the SAA resistant cultivars. Within the resistant cultivars, Condura 73 Brand, AS 13R, Amador and Falkiner had higher total numbers of SAA (P<0.01) and Condura 73 Brand, AS 13R, Amador, Lahontan, Lahontan Cycle 4 and Falkiner produced more large nymphs ( P< 0.01) than the other cultivars. Despite these differences in aphid numbers, differences in dry matter yields of established plants of SAA resistant cultivars were generally not significant. However, mean yield of SAA susceptible cultivars was 53% lower than that of resistant cultivars, and mean plant survival of SAA susceptible cultivars was 12% compared with 57.6% for resistant cultivars. With the levels of SAA infestations and the temperatures experienced during our field experiments (17�C and 28�C), neither total aphid numbers per seedling nor dry matter yield indicated the range of SAA resistance determined for these cultivars in glasshouse seedling tests. However, rankings of the total number of SAA and SAA large nymphs per stem generally reflected the ranking of SAA resistances found in glasshouse tests and so these may be used to identify SAA resistant and susceptible plants in the field. Overall, glasshouse screening tests were a poor indicator of the yield and survival of seedlings and established plants of the resistant cultivars tested.

Forage Yield, Seed Weight, and Inflorescence Characteristics of Isogenic Pearl Millet Hybrids with Four Different Cytoplasms1

AbstractValuable traits that are present in the cytoplasm can be used to improve plants. Using such traits has been demonstrated with cytoplasmic‐genic male sterility. The purpose of this research was to determine if there were cytoplasmic effects due to the A1, A2, B1, or B2 cytoplasm in near‐isogenic pearl millet, Pennisetum americanum (L.) Leeke, hybrids on dry matter yield, inflorescence characteristics, days to flower, and seed set and weight. Replicated field tests were grown in 1975, 1977, 1978, and 1981 on a Fuquay soil (loamy, siliceous, thermic arenic Plinthic Paleudults). Differences in dry matter yields were non‐significant (P = 0.05). Plants with the B2 cytoplasm had significantly shorter inflorescences. No differences were observed in inflorescence width. The difference in days to flower was significant with 1 days being the maximum difference between cytoplasms which probably is of little economic significance. There were significant differences between cytoplasms for selfed seed set but not for openpollinated seed set indicating that differences in seed set were due to fertility restoration. ‘Tift 239D2B2’ was a better fertility restorer for the A, cytoplasm than ‘Tift 23D2B2’ was for the A2 cytoplasm. Seed weight differences were related to seed set with plants setting fewer seeds producing heavier seeds. No significant maternal or A and B line effects were detected in this study.

Responses of Crested Wheatgrass and Russian Wildrye to Water Stress and Defoliation

Responses of Crested Wheatgrass and Russian Wildrye to Water Stress and Defoliation

Herbage Dry Matter Yields of Switchgrass, Big Bluestem, and Indiangrass with N Fertilization1

AbstractHerbage dry matter (DM) yield potential and N requirement of native perennial, warm‐season grasses must be known before these species can be effectively used in forage‐livestock systems. This study was initiated to determine the herbage yield response of ‘Blackwell’ switchgrass (Panicum virgatum L.), ‘Kaw’ big bluestem (Andropogon gerardi Vitman), and ‘Nebraska 54’ indiangrass (Sorghastrum nutans L. Nash) to N fertilization.Four replications of a randomized complete block field experiment were established on a Clarion loam (Typic Hapludoll) soil in 1971. A four‐cut management system was used in 1974; a two‐cut system was used during 1975–1976. Applications of ammonium nitrate (34‐0‐0) were made on 21 May 1974 and 13 May 1975 at 0, 75, and 150 kg N/ha levels. Levels of 0, 75, and 150 kg were applied in 1976 as urea (45‐0‐0) on 22 May and again on 3 July after the first harvest. Two of the four replications received 50 kg P/ha as triple superphosphate (0‐46‐0) and 100 kg K/ha as K2SO4 . MgSO4 (0‐0‐22) on 7 May 1976. The K source included 60 kg Mg/ha and 118 kg S/ha.Switchgrass, big bluestem, and indiangrass produced herbage dry matter (DM) yields of 6.14, 6.29, and 5.59 metric tons/ha, respectively, when averaged over N levels and years. In 1974, big bluestem out‐yielded the rest, and in 2 out of 3 years indiangrass yielded significantly less than one or both of the other species. All species generally responded positively to N through 75, and often through 150 kg N/ha.No herbage yield response was observed in 1976 to applied P and K fertilizers, the latter containing both S and Mg.Herbage DM yields generally increased with each of three successive harvests in 1974, whereas second harvest yields decreased with a two‐cut management system used in 1975 and 1976. Relatively unfavorable July–August precipitation seemed primarily responsible for lower second harvest DM yields.A 5 Oct. 1974 harvest of aftermath herbage cut at a 5‐cm height suggests that 2.2 to 2.4 metric tons/ha of herbage would be available for use by nonlactating beef cows. No species difference in DM yield was observed, suggesting equal carrying capacity/ha, for the aftermath.

Effect of soil water osmotic potential on growth and water relationships in barley during soil water depletion

Barley plants (Hordeum distichum, L., cv. ‘Zita’) grown in a sandy soil in pots were adjusted during a pretreatment period of 5 days to three levels of soil water osmotic potential by percolating 61 of a nutrient solution with additional 0, 22.3 and 44.6 mM KCl. A drying cycle was then started and the plants were harvested when the soil water matric potential had decreased to −1.4 MPa, respectively 6, 7 and 8 days later. No significant differences in dry matter yields, transpiration coefficients and wilting percentages were found between treatments. During the drying cycle leaf water potential (ψ l ) decreased concomitantly with decrease in soil water potential (ψ s ) with almost constant and similar differences (ψ l −ψ s ) for all treatments despite differences in levels of potentials. The concomitant decrease in leaf osmotic potential (π) was due partly to dehydration (58%) and partly to increase in leaf solute content (42%) independent of treatment. The part of total osmotic solutes due to K decreased relatively during the drying cycle. Close relationships were found between π and ψ l as functions of relative water content (RWC). Identical curves for the two levels of salt treatment agree with similar concentrations of K, Cl, and ash found for salt treated plants indicating that maximum uptake of macro nutrients may have been reached. During the main part of the drying cycle the turgor potential as function of RWC was higher and decreased less steeply with decreasing RWC in the salt treated than in the non-salt treated plants. In the beginning of the drying cycle additions of KCI lowered the transpiration rates of the salt treated plants resulting in a slower desiccation of the soil and hence an increased growth period. A delay in uptake from a limited soil water supply may be advantageous during intermittent periods of drought.

Screening for sorghum genotypic differences to iron deficiency

Abstract Sorghum [Sorghum bicolor (L.) Moench] generally is susceptible to iron (Fe) deficiency. Rapid, economical screening methods are essential to screen germplasm in a relatively short time so that genotypes with greater ability to grow on soils with low Fe availability can be developed. Different nutrient solutions were tested to determine which treatments were best suited for screening sorghum genotype tolerance to Fe deficiency conditions. Iron deficiencies were induced by growing seedlings in nutrient solutions with higher than normal levels of phosphorus (P); added calcium carbonate (CaCO3); nitrate (NO‐ 3 ammonium (NH+ 4), and (NO‐+ 3 NH+ 4,) as sources of nitrogen (N); and in Fe deficient, calcareous soils in controlled environmental chambers. Regardless of the screening method, sorghum genotypes differed in their response to Fe deficiency conditions. Larger differences in Fe deficiency were noted among genotypes when NO‐ 3 or high P were used. Differences in dry matter yields were greater when...

The effect of seed weight and coleoptile tiller development on seedling vigour in tall fescue, Festuca arundinaceaSchreb.

Two characters, previously shown to influence the rate of seedling growth in tall fescue, were studied in detail in three distinct populations as part of a programme to improve seedling vigour in the species. The effect of seed weight was found to be confined to the very early stages of growth and was apparent in seedling dry matter yield but not in tiller number. The development of a tiller in the axil of the coleoptile, which varied significantly between populations, had a far greater and more permanent effect both in terms of dry matter yield and tiller number. The increase in tiller number attributable to the coleoptile tiller and its derivatives increased geometrically in step with the total tiller number, so that the intitial difference of 28% in the first harvest remained practically unchanged in the subsequent three harvests. Similarly, the percentage difference in dry matter yield between plants with and without a coleoptile tiller remained more or less constant at about 22% from the second harvest onwards.

EFFECT OF COOL SEASON GRAZING ON LUCERNE PRODUCTION AND APHID POPULATIONS

In a P-year Wairau lucerne trial, plots were grazed on a 3- or 6- weekly rotation; Half of each plot was hard grazed in June to control overwintering aphids. In the second year a spring/autumn spraying was applied. June grazing reduced aphid populations in spring from 37 to 3 per stem, and gave no significant difference in dry matter yield. Three-weekly spelling, although reducing aphid numbers, halved plant populations and root weight and markedly decreased dry matter yield. In the second year, 6-weekly spelling yielded 13 120 kg/ha, and 3-weekly only 3 540 kg/ha. Spraying of aphids increased yields, but not significantly. The results show that cheap methods of controlling aphids in lucerne can be developed using grazing management.

Leaf Orientation and Yield of Maize1

The advantage of vertically oriented leaves in crop canopies has been studied with variable results. In many maize (Zea mays L.) populations there is a wide variation of leaf orientations. Nine maize inbreds visually selected for upright, intermediate, and horizontal leaf orientation were grown in 51‐cm rows at three plant densities at Iowa State University. Each inbred was evaluated for 2 years for leaf area index, light extinction coefficient (k), dry‐matter yield, and grain yield, and 1 year for leaf orientation and leaf display. We developed a new leaf orientation parameter, leaf orientation value (LOV), to account for the ability of leaves to maintain the same orientation for their entire length. This parameter was easier to measure than k, is a good indicator of leaf orientation, and could be used as a selection index for leaf orientation. Differences in dry matter yields and grain yields across leaf orientation groups agreed with expectations based on theories involving leaf orientation and leaf area index; i.e., yield advantages for genotypes with upright leaves were observed only at high leaf area indices.

Effects of Genotype and Rainfall on Forage Oats in a Semi-arid Region

SUMMARYThere were significant differences in dry matter yield among five forage oat varieties tested at ten environments during 1970–75. The correlation coefficients between annual rainfall and DM yield varied with variety from 0·69 to 0·88, late varieties tending to give higher yields. Lateness, and high varietal response to annual rainfall and improved environmental conditions, can be used as selection criteria in semi-arid regions. Late varieties had higher DM and lower crude protein contents, and forage produced under lower rainfall conditions tended to have more DM and crude protein.

Symbiotic variability in Vicia faba. 2. genetic variation in Vicia faba

Eight varieties of Vicia faba were examined in association with a standard strain of Rhizobium leguminosarum and also with the application of mineral nitrogen. Large differences in dry matter yield, nitrogen percentage and total nitrogen uptake were apparent between varieties and between rhizobium and mineral nitrogen treatments; the interaction was also significant. Genotypic differences in both the effectiveness of the symbiosis with this strain of rhizobium and the efficiency of utilization of nitrogen were thus demonstrated. The implications of this variability on the assessment of varieties and the possiblity of exploiting it by plant breeding techniques are discussed.

Symbiotic variability in Vicia faba. 1. Genetic variation in the Rhizobium leguminosarum population

Twenty isolates taken at random from indigenous populations of Rhizobium leguminosarum sampled near Aberystwyth were each inoculated into plants of a standard Vicia faba variety grown aseptically under conditions free of combined nitrogen. Plants in association with the individual rhizobium isolates exhibited large differences in dry matter yield, nitrogen content, efficiency of nitrogen utilization and date of first flower. The implications of these differences to the productivity and reliability of varieties of field beans are discussed.

Environmental effects on the short-term response of tropical grasses to nitrogen fertilizer

The short term response of tropical grasses during spring to ammonium nitrate and urea fertilizers (1 12 kg N ha -1) was measured on kikuyu (Pennisetum clandestinum) at one site, and on setaria (Setaria anceps cv. Kazungula) at two sites. Fertilizers were applied at weekly intervals on 16 occasions at each site during the August-December period. Treatments were assessed in terms of the dry matter response (DMR) and apparent recovery of fertilizer nitrogen (NR), where DMR is the differences in dry matter yield of topdressed plots over the control and NR is the corresponding difference in nitrogen yield expressed as a percentage of the amount of nitrogen applied as fertilizer. These responses were measured at four, and sometimes at eight weeks, and were related to environmental variables by regression analysis. The DMR was more responsive than NR to changes in temperature. Both DMR and NR were very sensitive to changes in soil moisture potential, especially on wet soils, and to changes in effective rainfall (rainfall less run-off). If low temperature limited growth during the first four weeks after topdressing, both DMR and NR increased further when growth during 5-8 weeks extended into warmer periods. However, when moisture supply limited the response at four weeks, the NR remained depressed at eight weeks even with an improved moisture supply. Environmental factors influenced the response more than the type of nitrogen fertilizer and at four weeks, the respective overall DMR and NR from urea were 90 and 86 per cent of those from ammonium nitrate.

Effect of maturity of corn silage at harvest on the performance of feeder heifers.

VARIOUS criteria have been used in order to determine the proper time of harvesting corn silage. Maximum yield of dry matter (Johnson et al., 1966) and of digestible energy (Johnson and McClure, 1967) have been reported between the dent and glazed stages. Gay (1966) and Keeney et al. (1967) found that the late dent-hard dough stage gave maximum dry matter yields. However, Pratt, Conrad and Triplett (1964) measured no differences in dry matter yield between the late milk-early dough stage and the well-dented stage. Geasler, Henderson and Hawkins (1967) reported a decrease in dry matter yield with increasing maturity. Noller et al. (1963) found maximum dry matter consumption to occur with the very early dent stage, Huber, Graf and Engel (1963) and Gay (1966) in the hard dough stage, while Geasler et al. (1967), Bryant, Huber and Blaser (1965) and Johnson et al. (1965) showed that it increased with increasing maturity.

Crosses between red clover (Trifolium pratense L.) Varieties to find a suitable combination for reciprocal recurrent selection

As an introduction to a program of reciprocal recurrent selection in red clover crosses of varieties were tested. Five varieties were crossed with Leisi and five with Groninger red clover. Flowering showed that the crosses were successful. Varieties were tested under different conditions. A significant positive difference in dry matter yield between the cross and the better parent of the pair occurred in one of the ten crosses namely Red clover CB × Groninger red clover and under particular conditions. Only a poor comparison was possible in this case because Groninger red clover was attacked by eelworms. It was concluded that none of the tried crosses warranted a program of reciprocal recurrent selection. The data of flowering of the crosses with Leisi showed that in most cases there is intermediate inheritance of the number of flowering heads. In the cross Lembke × Leisi rich flowering was dominant to less rich flowering.

Effects of variation in density and phosphate application on growth and composition of Townsville stylo (Stylosanthes humilis)

Townsville stylo (Stylosanthes humilis) was grown at Brisbane from February to June 1967 at initial densities of 10, 50, 250, 1250, and 6250 plants per m2 in boxes of sand which received basal nutrients and applications of 0, 10, and 50 kg P per hectare as calcium dihydrogen phosphate. Plots were irrigated frequently. Wide differences in dry matter yield between plant densities and a positive density phosphorus yield interaction persisted throughout the experiment. Peak yield was 1050 g per m2 with leaf area index (LAI) of 6.8. Intraspecific plant competition was evident in high densities 35 days after emergence, extending to the lower densities by 58 days. Plant mortality at the highest density was independent of phosphorus treatment. Maximum growth rates were reached earlier at high than at low plant densities ; the subsequent decreases in growth rate were expressed through drifts in both LA1 and NAR and were associated with progressively more unfavourable environmental conditions for growth. Nitrogen and phosphorus concentration of both shoots and roots decreased with increasing density. Phosphorus application did not affect nitrogen concentration. Exploitation of native soil phosphorus and recovery of applied phosphorus was greatest in high density swards. The data illustrate the loss in potential production which may occur in sparse swards of Townsville stylo and the limitations to efficient phosphorus response inherent in low density swards.

Yields and tiller numbers of four perennial ryegrass varieties grown as monocultures and certain mixtures in micro plots

SummaryFour perennial ryegrass varieties, S.24, S.321, S.23 and Vertas Hardgrazing, were grown in micro plots containing 30 plants each at a spacing of 5 cm apart. Monocultures and four of the possible six binary mixtures between the varieties were grown in a randomized block design with four replicates. The data recorded comprised dry-matter yields and tiller numbers, and the components of the mixtures were harvested separately. The data were based on both whole plots, to give total production of mixtures and monocultures, and half plots, to give the contribution of mixture components to total mixture production. Four harvests were obtained during 1968, and the data from these were analysed separately and summed to provide the annual total data.Mixtures and monocultures did not differ significantly for annual total dry-matter yield or for dry-matter yield at the separate harvests. However, differences in drymatter yields between monocultures and between mixtures were detected at some harvests. Within mixtures, significant differences between some of the respective components were found at certain harvests, but these were not obtained for the annual total data.The stability of monocultures and mixtures was investigated by a regression technique and considered in the context of the environments used. This technique revealed that there was a specific mixture effect whereby the mixture (S.24 + S.23) differed significantly from all other treatments.Significant differences between monocultures for fertile and sterile tiller numbers were detected. Between mixtures there were differences for fertile tiller numbers, and within mixtures certain of the components differed for fertile, sterile and total tiller numbers.The relationship between dry-matter yield and tiller numbers was investigated by regression analyses over all treatments and for monocultures and mixtures separately. Significant differences between the slopes of the regression lines and zero and between the slopes of the regression lines themselves were obtained.Possible reasons for the differences recorded both between and within monocultures and mixtures are considered and related to the competitive relations existing in the trial.

EFFECT OF DATES OF CUTTING ON DRY MATTER PRODUCTION AND CHEMICAL CONTENT OF ALFALFA AND BIRDSFOOT TREFOIL

In two experiments, one with alfalfa and the other with birdsfoot trefoil, we have been able to show that a late cut in October does not adversely affect dry matter yield (DAI) of the legumes. Three cuts during a harvesting season ending on September 5 were detrimental to alfalfa, since lower yields were obtained the following year of harvest. Birdsfoot trefoil varieties were affected differentially. Three cuts did not affect the yield of Viking the following year, but did so of Empire. Significant differences in dry matter yields were obtained between DuPuits and Vernal and between Viking and Empire. Protein in the forage followed inversely the same pattern as that of DM yields, that is, where the intervals were shortest, the protein content was highest, and conversely. The total available carbohydrate and the nitrogen content of the roots were lowest following the treatments which had the shortest intervals between them.

Local Effect on Fertility of Urine Voided by Grazing Cattle1

AbstractA trial was conducted in an attempt to determine the local effect of urine deposited by grazing cattle on the fertility of the affected sward. Cattle were permitted to graze an unfertilized, pure stand of tall rescue at three seasons of the year: fall, spring, and summer. A number of urine spots were selected on each occasion for further study. The vegetative growth on each spot and on a comparable check area was harvested at intervals for a period of up to 2 years following deposition. The effect of urine was then measured as the difference in dry matter yield, %N and %K between the urine‐treated and the nontreated vegetation. Since it is only a minor component of urine, no results are reported for the effect of phosphorus.The following conclusions might be drawn from the results of this study: An individual urination affects a roughly circular area with a radius of from 21 to 25 inches. That is, a total of from 9½ to 13 square feet of sward are affected per urination. The effect is not uniform, but decreases in a linear manner from the center to the periphery of the spot. The effect of urine decreases quite rapidly with time after deposition. As a result a urination ceases to be of practical significance within, at most, 10 months following deposition. Both the magnitude of the effect and the rate of decrease of the effect appear to be directly related to the rate of plant growth. Under conditions prevailing in the southeastern United States, and in the other areas where forage growth and mineral depletion are rapid, the urine returned by grazing cattle would appear to contribute little to the fertility of the pasture as a whole.

The effect of chisel ploughing and inter-row cultivation on soil water content and yield of bulrush millet (Pennisetum typhoides) at Katherine, N.T

A multifactorial experiment comprising combinations of three pre-wet-season chisel ploughing treatments, three wet-season chisel ploughing treatments, and three inter-row cultivation treatments was carried out on bulrush millet (Pennisetum typhoides S. & H.) at Katherine, N.T., in 1963-64, and was repeated in 1964-65. Pre-wet-season ploughing throughout the growth of the nitrogen yield of millet when treatments had very little effect on the dry matter or nitrogen yield of millet crop. Increasing the depth of wet-season ploughing increased the dry matter and sampled at 7 and 12 weeks after sowing, but at the final sampling, 18 weeks after sowing, only the differences in dry matter yield were maintained. Responses in dry matter and nitrogen yield were obtained to one inter-row cultivation, but not to a second. Differences in dry matter yield due to wetseason ploughing and inter-row cultivation were associated with differences in soil water content measured in the 1-4 feet profile in 1964-65.