Population dynamics of Heterodera avenae Woll. in South Australia

1991 ◽  
Vol 42 (1) ◽  
pp. 53 ◽  
Author(s):  
JM Fisher ◽  
TW Hancock
Keyword(s):  
Initial Density ◽  
South Australia ◽  
Heterodera Avenae ◽  
Multiplication Rate ◽  
Population Changes ◽  
Experimental Conditions ◽  
Nodal Roots ◽  
Principal Axes ◽  
Equilibrium Level ◽  
Seminal Roots

Population changes of the cereal cyst nematode (Heterodera avenae Woll.) under various rotational regimes in the field were examined. A density of 5 eggs/g soils caused a loss of about 10% in yield of wheat cv. Bayonet under the experimental conditions. Maximum multiplication rate at low initial densities was about l0x, but this rapidly decreased as initial density increased. Equilibrium levels ranged from 15 eggs/g soil up to 40 eggs/g under different conditions. The resistant wheat, Aus 10894, maintained an equilibrium level of about 1 egg/g soil-a level low enough to avoid damage in a following crop. Annual percentage hatch varied from 70-90% with an average of 85%. Presence or absence of plant species had little effect on per cent hatch. About 7.5% of the nematodes successfully penetrated and became established in the root systems of seedlings, invading both seminal and nodal roots, but only about 0.5% became established in the principal axes of the seminal roots. The implications of these data for various rotational practices are discussed.

Crop and pasture rotations at Coonalpyn, South Australia: effects on soil-borne diseases, soil nitrogen and cereal production

1984 ◽  
Vol 24 (127) ◽  
pp. 555 ◽  
Author(s):  
PM King
Keyword(s):  
Dry Matter ◽  
South Australia ◽  
Grain Legumes ◽  
Gaeumannomyces Graminis ◽  
Heterodera Avenae ◽  
Soil Nitrate ◽  
Bare Patch ◽  
Root Diseases ◽  
Nodal Roots ◽  
Seminal Roots

A crop rotation experiment was conducted at Coonalpyn, South Australia from 1976 to 1979 on a deep, red duplex soil. The experiment compared the productivity of grain legumes and of volunteer and sown annual pastures, and assessed their effects on the mineral nitrogen supply for subsequent wheat and barley crops, and their capabilities for preventing the root diseases of wheat cereal cyst nematode (Heterodera avenae), bare patch (Rhizoctonia solani) and Haydie (Gaeumannomyces graminis). Satisfactory legume dominance of the annual pastures was achieved only in 1979, while the grain legumes grew well and produced more dry matter than the pastures in each season. Wheat and barley yields averaged (1977- 1979) 2.0 t/ha after volunteer and sown pastures, and 2.8 t/ha after grain legumes, with the greatest response in 1979. In that year, wheat produced 11 kg grain/mm of growing season rainfall after grain legumes, but only 6 kg after pastures. The numbers of lesions on the nodal roots caused by R. solani and on the seminal roots by G. graminis varied with the season but both were less after grain legumes than after pasture. Gaeumannomyces graminis had the greatest effect on grain yield and, with soil nitrate at seeding, explained up to 68% of the variation in yield in 1979.

Resistance within wheat, barley and oat cultivars to Heterodera avenae in South Australia

1974 ◽  
Vol 14 (68) ◽  
pp. 399 ◽  
Author(s):  
PC O'Brien ◽  
JM Fisher
Keyword(s):  
Initial Density ◽  
South Australia ◽  
Heterodera Avenae ◽  
Good Resistance ◽  
Relative Growth ◽  
Barley Cultivars ◽  
Wide Range ◽  
Oat Cultivars ◽  
Moderate Resistance ◽  
Method Of Assessment

Resistance of 800 wheat, 83 oat, and 36 barley cultivars to the cereal cyst nematode, Heterodera avenae, was tested in South Australia. A wide range of reactions of selected cultivars, assessed by numbers of females produced on the roots, was obtained for each of the cereals with populations of the nematode from two sites. Good resistance was recorded in only two wheat cultivars; Spring wheat (AUS No. 10894) showed moderate resistance in all tests and Loros (AUS No. 90248), although recorded as susceptible in one test, showed moderate resistance in other tests with a different population of the nematode. The importance of method of assessment, initial density of inoculum and relative growth of the cultivars are discussed.

Effect of copper deficiency in wheat on the infection of roots by Gaeumannomyces graminis var. tritici

1984 ◽  
Vol 35 (6) ◽  
pp. 735 ◽  
Author(s):  
MJ Wood ◽  
AD Robson
Keyword(s):  
Plant Growth ◽  
Copper Deficiency ◽  
Gaeumannomyces Graminis ◽  
Fresh Weight ◽  
Nodal Roots ◽  
Copper Status ◽  
Seminal Roots ◽  
Effect Of Copper ◽  
Gaeumannomyces Graminis Var Tritici ◽  
Take All

Wheat was grown in a soil at five levels of copper (ranging from levels deficient, to those luxurious, for plant growth), in the presence or absence of introduced take-all inoculum (oat kernels colonized by Gaeumannomyces graminis var. tritica). The incidence and severity of take-all were related to the copper supply and hence the copper status of the wheat. Plants grown without applied copper were more severely infected by take-all than were those grown with an adequate or luxurious supply of copper. The number of lesions per gram fresh weight of roots was reduced from 6.5 to 2.4 by increasing the copper supply from that severely deficient, to that adequate for plant growth. In seminal roots, increasing the copper supply from levels severely deficient to those adequate or luxurious for plant growth, decreased the length of proximal lesions (those closest to the seed). By contrast, in nodal roots, a similar increase in copper supply had no effect on the length of proximal lesions, but increased the length of uninfected root between the crown and proximal lesions. In both seminal and nodal roots, copper supply did not affect the intensity of lesions.

Influence of cereal cyst nematode (Heterodera avenae) on wheat yields in South Australia

1981 ◽  
Vol 21 (112) ◽  
pp. 516 ◽  
Author(s):  
AD Rovira ◽  
PG Brisbane ◽  
A Simon ◽  
DG Whitehead ◽  
RL Correll
Keyword(s):  
Wheat Variety ◽  
South Australia ◽  
Field Trials ◽  
Cyst Nematode ◽  
Analysis Of Covariance ◽  
Cereal Cyst Nematode ◽  
Heterodera Avenae ◽  
Yield Increase ◽  
Significant Yield ◽  
Yield Responses

Significant yield responses of up to 0.9 t/ha were obtained with the nematicides aldicarb and dibromochloropropane in seven of eleven field trials with the wheat variety, Condor. Both nematicides reduced the numbers of white cysts of Heterodera avenae on the roots of wheat. With aldicarb the increase in wheat yields varied directly as the decrease in white cysts: dibromochloropropane gave similar increases in yield as aldicarb with a greater reduction in cyst numbers. There was no yield increase with either nematicide when cereal cyst nematode was not present. An analysis of covariance indicated that over all the sites 64% of the increase in yield due to aldicarb could be explained in terms of cysts of cereal cyst nematode.

Water Stressed Nodal Roots of Wheat: Effects on Leaf Growth

1997 ◽  
Vol 24 (1) ◽  
pp. 49 ◽  
Author(s):  
K. M. Volkmar
Keyword(s):  
Growth Rate ◽  
Water Content ◽  
Relative Water Content ◽  
Leaf Growth ◽  
Seminal Root ◽  
Nodal Roots ◽  
Nodal Root ◽  
Relative Water ◽  
Seminal Roots ◽  
Leaf Relative Water Content

This experiment as undertaken to determine the efects of soil drying around the nodal and/or seminal root systems on the shoot growth of wheat (Triticum aestivum L.). Two split-root experiments were conducted, the first on newly emerged nodal roots of 18-day-old wheat plants, the second on 25-day-old plants. In both experiments, nodal and seminal roots were isolated from one another and water was withheld from either the nodal root chamber, the seminal root chamber, or both, over 6 days. In the first experiment, leaf growth was unaffected by withholding water from very short nodal roots, even though leaf relative water content of the droughted plants decreased. By comparison, both leaf elongation rate and relative water content decreased by withholding water from the seminal roots. On plants that were 1 week older, leaf growth rate and leaf relative water content decreased when nodal roots were drought-stressed. Leaf growth rate of seminal root droughted plants was more impaired than their nodal root counterparts, even though leaf relative water contents of the two treatments were the same. In both experiments, drought stress applied to the nodal root system enhanced nodal root growth more than seminal roots. These results suggest that seminal and nodal roots perceive and respond to drought stress differently with respect to the nature of the message conveyed to the shoots.

A routine test for the relative susceptibility of potato genotypes with resistance to Meloidogyne chitwoodi

Nematology ◽  
2016 ◽  
Vol 18 (9) ◽  
pp. 1079-1094 ◽  
Author(s):  
Misghina G. Teklu ◽  
Corrie H. Schomaker ◽  
Thomas H. Been ◽  
Leendert P.G. Molendijk
Keyword(s):  
Logistic Model ◽  
Multiplication Rate ◽  
Experimental Conditions ◽  
Meloidogyne Chitwoodi ◽  
Second Stage ◽  
Final Population ◽  
Pot Size ◽  
Optimal Protocol ◽  
Dry Soil ◽  
Resistant Genotypes

The population dynamics of Meloidogyne chitwoodi on eight potato genotypes was compared to the susceptible cv. Desiree in four glasshouse experiments. The initial nematode densities consisted of log series 2x, with . Seinhorst’s logistic model was fitted to the final population densities to estimate the parameters maximum multiplication rate (a), maximum population density (M) and the ratios RSa, RSM and . Average RSa and RSM of the seven resistant genotypes were smaller than 0.29%. The ratios on six resistant genotypes and cv. Desiree were the same, 1.3, indicating independence of RS. One genotype stood out with , whereby RSa < RSM. Both RS and were unaffected by pot size or experimental conditions. Screening protocols at second-stage juveniles (g dry soil)−1 in 2 or 3 kg pots were evaluated for distinctiveness between the two genotype groups. Based on the results, an optimal protocol for a routine resistance test is proposed.

Variation in reproductive capacity and virulence on different genotypes and resistance genes of Triticeae, in the cereal cyst nematode species complex

Nematology ◽  
2001 ◽  
Vol 3 (6) ◽  
pp. 581-592 ◽  
Author(s):  
Makram Bel Hadj Fradj ◽  
Joseph Jahier ◽  
Sadia Bekal ◽  
Julie Nicol ◽  
Jean-Pierre Gauthier ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Species Complex ◽  
Triticum Turgidum ◽  
Cyst Nematode ◽  
Reproductive Capacity ◽  
Cereal Cyst Nematode ◽  
Host Responses ◽  
Heterodera Avenae ◽  
Genetic Introgression ◽  
Experimental Conditions

AbstractTwo sets of experiments in 1998 and 1999 studied the (a)virulence status of 14 populations of Heterodera avenae, and two populations each of H. filipjevi and H. latipons towards the resistance genes and genotypes of Triticeae, presently known to be resistant to H. avenae, the main species of the cereal cyst nematode (CCN) species complex. Susceptible controls were Triticum aestivum cv. Arminda and Triticum turgidum cv. Cham1. Even in controlled experimental conditions, host responses differed between replicates in the same test and between consecutive tests for unexplained reasons. In spite of that, it has been confirmed that several of these CCN populations differ in their intrinsic capacity to reproduce, and this has to be taken into account in resistance screening. Consequently, the (a)virulence status of a CCN population is better established by a qualitative demarcation between resistant and susceptible plant genotypes based on an average of one cyst limit per plant. The matrix inferred from such a classification of host responses of pooled 1998 and 1999 data showed a complex distribution of avirulent and virulent phenotypes in these CCN populations which seems to arise from a mosaic-like evolution. The more or less wide virulence spectrum shown by this complex of populations and species is discussed in relation to their phylogenetic relationships. Correspondence factor analysis of the pooled data demonstrated a geographical demarcation between several populations of H. avenae and the representatives of H. filipjevi and H. latipons for their (a)virulence to either Cre1 or Cre3 genes and T. aestivum AUS4930 genotype. This could reveal local or regional selection of new pathotypes, more particularly in H. avenae. Genetic introgression to improve resistance to these nematodes in both bread and durum wheats is discussed for regional and global applications.

Root development in seedlings of ryegrass (Lolium perenne L.) and phalaris (Phalaris aquatica L.) sown onto the soil surface

1982 ◽  
Vol 33 (4) ◽  
pp. 665 ◽  
Author(s):  
PS Cornish
Keyword(s):  
Root Development ◽  
Soil Surface ◽  
Undisturbed Soil ◽  
Growth And Survival ◽  
Small Vessels ◽  
Nodal Roots ◽  
Nodal Root ◽  
Seminal Roots ◽  
Surface Drying ◽  
Axial Resistance

The effects of surface-sowing on root type, number and xylem radius were studied in relation to the seedling growth and survival of ryegrass and phalaris. Under optimal conditions in a growth cabinet, both species produced primary and lateral seminal roots, nodal roots and, in the absence of light, a subcoleoptile internode (s.c.i.). Phalaris had fewer lateral seminal roots and, in this species, internodal roots occurred along the s.c.i. Surface placement per se had no effect on any of the measured parameters of root development, but surface drying prevented nodal root primordia from extending, even when plants were otherwise supplied with water. This effect of surface drying on nodal root development was confirmed in a glasshouse study using undisturbed soil cores (30 by 60 cm) to simulate field conditions. Phalaris was less likely than ryegrass to produce nodal roots after surface sowing. The effective xylem radius (re) of the primary seminal root was 7.9 �m in ryegrass and 11.6 �m in phalaris. Calculations using the Poiseuille equation indicated that the axial resistance to water flow through these roots would greatly restrict seedling water uptake and growth in the absence of other roots. Lateral seminal roots and internodal roots had small vessels which could not significantly reduce the axial resistance to flow. Good seedling water relations in both species therefore depend on early development of the nodal roots which contain large xylem vessels (re > 16 �m). It was concluded that the effect of soil-surface drying on nodal root development was likely to account for some cases of poor vigour and survival of surface-sown grasses.

A synoptic approach for crop loss assessment used to study wheat. VI. The pathogen data and their relationship to soil and cultural data

1983 ◽  
Vol 34 (2) ◽  
pp. 167 ◽  
Author(s):  
BA Stynes ◽  
LG Veitch
Keyword(s):  
Root Systems ◽  
Cultural Practice ◽  
Heterodera Avenae ◽  
Loss Assessment ◽  
Significant Relationships ◽  
Crop Loss Assessment ◽  
Yorke Peninsula ◽  
Seminal Roots ◽  
Shallow Soils ◽  
Sampling Times

As a part of a general investigation of factors that affect wheat crops on Yorke Peninsula, S. Aust., pathogens were measured at 3 and 8 weeks after emergence of the crop and at anthesis. A first study for regression work showed that, except on the coronal root system at anthesis, the pathogen data were independent of the soil and cultural practice data. Further, it showed that patterning within the pathogens was quite weak and so the value of alternative representations was marginal in this situation. In a second study, significant relationships were found between logarithmically transformed pathogen data, first within the pathogens between sampling times and root systems, and second between the pathogens and the soil and cultural practice data. The former relationships were mostly of the expected type in that high levels of a particular pathogen tended to persist over sampling times and extend over both root systems. The latter relationships were generally weaker, with the two most marked being (i) a tendency in sandy soils for coronal roots at anthesis to have high levels of Rhizoctonia solani, and (ii) for seminal roots at anthesis to have high levels of Heterodera avenae when plants were grown in shallow soils on calcareous rocks, particularly where the farmers applied high levels of superphosphate.

scholarly journals Diallel cross analysis for young plants of brachytic maize (Zea mays L.) varieties

1997 ◽  
Vol 20 (3) ◽  
pp. 453-458
Author(s):  
Ana C. Vello Dantas ◽  
José B. Miranda Filho ◽  
Maria R.B. Alleoni
Keyword(s):  
Zea Mays L ◽  
Correlation Coefficients ◽  
Diallel Cross ◽  
Plant Weight ◽  
Nodal Roots ◽  
Maize Varieties ◽  
Sources Of Variation ◽  
Seminal Roots ◽  
Polygenic System ◽  
Total Plant

Six brachytic maize varieties were crossed in a diallel mating scheme. Both varieties and crosses were grown hydroponically in a greenhouse, in randomized complete blocks with three replications in two seasons. Four brachytic double cross hybrids were used as checks. Twenty-eight days after planting, data for eight traits were taken for weights of the total plant (TPW), top plant (TOW), total roots (TRW), seminal roots (SRW), and nodal roots (NRW) and number of total roots (TRN), seminal roots (SRN), and nodal roots (NRN). Ten plants were measured in each plot and all the analyses were accomplished with plot means. In the diallel cross the top plant contributed 57.6% of the total plant weight, for seminal roots 15.4%, and for nodal roots 27.0%. Root number distribution was 36.7% seminal roots and 63.3% nodal roots. Approximately the same ratios were observed in the checks. The average heterosis effects were nonsignificant for all traits; the other components of heterosis (variety and specific heterosis) also were not important sources of variation in young plants. The overall results suggest that nonadditive gene action is not an important source of variation for the plant and root system of young plants. The positive correlation coefficients for combinations of traits indicated that they are under the control of a polygenic system

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