Expression of quantitative resistance to Colletotrichum gloeosporioides in Stylosanthes scabra at different inoculum concentrations and day-night temperatures

1990 ◽  
Vol 41 (1) ◽  
pp. 89 ◽  
Author(s):  
S Chakraborty
Keyword(s):  
Colletotrichum Gloeosporioides ◽  
Quantitative Resistance ◽  
Controlled Environment ◽  
Post Inoculation ◽  
Inoculum Concentration ◽  
Coefficient Of Concordance ◽  
Uninoculated Control ◽  
Number Of Leaves ◽  
Stylosanthes Scabra ◽  
Pasture Legume

Expression of quantitative resistance to anthracnose was studied following inoculation of accessions of the tropical pasture legume Stylosanthes scabra with five different concentrations of Colletotrichum gloeosporioides conidia and at five day-night temperatures in separate experiments. According to Kendall's coefficient of concordance for rankings of accessions at the various inoculum concentrations, resistance in all six accessions was expressed consistently at 102,103, 104, 105 and 106 conidia/ml for race 3 but not for race 4a. Anthracnose severity did not increase with an increase in the inoculum concentration from l05 to 106 conidia/ml for either of the two races. Height and number of leaves/plant in the uninoculated control increased significantly at 30-25�C when glasshouse-grown seedlings were transferred to four controlled environment cabinets maintained at one of the four day-night temperatures of 30-25,32-22,30-15 or 34-14�C. Accessions were subjected to one of the four day-night temperatures for a 3 week pre- and 2 week post-inoculation exposures was not significant, predisposition of some accessions to anthracnose resulted in a significant accession X exposure interaction.

scholarly journals Canopy Size and Induced Resistance in Stylosanthes scabra Determine Anthracnose Severity at High CO2

2004 ◽  
Vol 94 (3) ◽  
pp. 221-227 ◽  
Author(s):  
I. B. Pangga ◽  
S. Chakraborty ◽  
D. Yates
Keyword(s):  
Induced Resistance ◽  
Plant Disease ◽  
Colletotrichum Gloeosporioides ◽  
Controlled Environment ◽  
Infection Efficiency ◽  
Stylosanthes Scabra ◽  
Field Plots ◽  
Canopy Size ◽  
Repeated Experiment ◽  
Similar Stage

This study examines the relative importance of canopy size and induced resistance to Colletotrichum gloeosporioides at 350- and 700-ppm atmospheric CO2 concentrations on susceptible Stylosanthes scabra ‘Fitzroy’ from two studies in a controlled environment facility (CEF) and in the field. Plants were grown at the two CO2 concentrations in a repeated experiment in the CEF and inoculated at 6, 9, or 12 weeks of age. Although the physiological maturity of plants was at a similar stage for all three ages, the number of lesions per plant increased with increasing plant age at both CO2 concentrations. At 350 ppm, the increase was associated with canopy size and increasing infection efficiency of the pathogen, but at 700 ppm, it was associated only with canopy size, because infection efficiency did not change with increasing age. A level of resistance was induced in plants at 700 ppm CO2. In a second study, plants were raised for 12 to 14 weeks at the two CO2 concentrations in the CEF and exposed to C. gloeosporioides inoculum in replicated field plots under ambient CO2 over three successive years. Fitzroy developed a dense and enlarged canopy, with 28 to 46% more nodes, leaf area, and aboveground biomass at high CO2 than at low CO2. Up to twice as many lesions per plant were produced in the high CO2 plants, because the enlarged canopy trapped many more pathogen spores. The transient induced resistance in high CO2 plants failed to operate when exposed to pathogen inoculum under ambient CO2 in the field. These results highlight the need to consider both canopy size and host resistance in assessing the influence of elevated CO2 on plant disease.

Interaction between Helicoverpa armigera and Colletotrichum gloeosporioides on the tropical pasture legume Stylosanthes scabra

2000 ◽  
Vol 51 (1) ◽  
pp. 107 ◽  
Author(s):  
Peter A. Wilson ◽  
Peter M. Room ◽  
Myron P. Zalucki ◽  
Sukumar Chakraborty
Keyword(s):  
Host Plant ◽  
Adult Female ◽  
Helicoverpa Armigera ◽  
Colletotrichum Gloeosporioides ◽  
Life Stages ◽  
Tropical Pasture ◽  
Helicoverpa Armígera ◽  
Stylosanthes Scabra ◽  
Lepidoptera Noctuidae ◽  
Pasture Legume

Glasshouse experiments determined effects of a moth, Helicoverpa armigera (Lepidoptera: Noctuidae), and the anthracnose pathogen, Colletotrichum gloeosporioides (Penz.) Penz. and Sacc., on each other when attacking the same host plant, Stylosanthes scabra (Vog.) (Leguminosae) cv. Fitzroy. The host was treated with both organisms in 2 ways of succession and at 2 different life stages each. Larvae of the moth preferred to feed on healthy plants rather than plants recently infected with C. gloeosporioides, and preferred such newly infected plants to severely diseased ones. Adult female moths laid more eggs on healthy and recently infected plants than on diseased plants, when given a choice of all 3 plant types. Severity of anthracnose disease was neither promoted nor retarded by damage to leaves caused by larvae of the moth.

Using Lindenmayer systems to model morphogenesis in a tropical pasture legume Stylosanthes scabra

1999 ◽  
Vol 77 (3) ◽  
pp. 394-403 ◽  
Author(s):  
Peter A Wilson ◽  
James S Hanan ◽  
Peter M Room ◽  
Sukumar Chakraborty ◽  
David Doley
Keyword(s):  
Morphological Data ◽  
Growth Data ◽  
Lindenmayer Systems ◽  
Virtual Plant ◽  
Total Leaf ◽  
Systems Modelling ◽  
Plant Form ◽  
Pasture Plant ◽  
Stylosanthes Scabra ◽  
Pasture Legume

This paper summarizes the processes involved in designing a mathematical model of a growing pasture plant, Stylosanthes scabra Vog. cv. Fitzroy. The model is based on the mathematical formalism of Lindenmayer systems and yields realistic computer-generated images of progressive plant geometry through time. The processes involved in attaining growth data, retrieving useful growth rules, and constructing a "virtual plant" model are outlined. Progressive output morphological data proved useful for predicting total leaf area and allowed for easier quantification of plant canopy size in terms of biomass and total leaf area.Key words: Lindenmayer systems, modelling, Stylosanthes, morphogenesis, plant form.

Inheritance of anthracnose resistance in the tropical pasture legume Stylosanthes hamata

1995 ◽  
Vol 46 (7) ◽  
pp. 1353 ◽  
Author(s):  
N Iamsupasit ◽  
DF Cameron ◽  
M Cooper ◽  
S Chakraborty ◽  
LA Edye
Keyword(s):  
Combining Ability ◽  
Colletotrichum Gloeosporioides ◽  
Single Gene ◽  
General Combining Ability ◽  
Tropical Pasture ◽  
Gene Model ◽  
Stylosanthes Hamata ◽  
Moderately Resistant ◽  
Half Diallel ◽  
Pasture Legume

Eight tetraploid accessions of the tropical pasture legume Stylosanthes hamata with varying levels of response to the anthracnose pathogen (Colletotrichum gloeosporioides) were crossed in a half diallel scheme. Based on mean disease severity ratings (MDR), two parents, 55830 and 75164, were grouped as resistant (R), 55828 and 65365 were susceptible (S), and the remaining four, cvv. Verano and Amiga and 65371 and 75162 were moderately resistant (MR). Of these, the two resistant parents appear to carry different genes for resistance. The MDR of 20 of the 28 F2 populations was significantly different from their mid-parent MDR and the expression of resistance, in most cases, was recessive. Only a limited number of the F2 distributions for crosses between RxS, RxMR and MRxS parents conformed to a single gene model. The inheritance patterns observed were considered to be predominantly quantitative. Variation for general combining ability, was as large as or larger than that for specific combining ability suggesting that a large proportion of the genetic differences among the parents was additive. The finding that the resistance is inherited as a quantitative trait is consistent with results on the epidemiology of anthracnose in tetraploid S. hamata.

scholarly journals Reaction of dwarf cashew clones to Colletotrichum gloeosporioides isolates in controlled environment

2010 ◽  
Vol 67 (2) ◽  
pp. 228-235
Author(s):  
Ana Maria Queijeiro López ◽  
John Alexander Lucas
Keyword(s):  
Environmental Conditions ◽  
Host Resistance ◽  
Colletotrichum Gloeosporioides ◽  
Anacardium Occidentale ◽  
Controlled Environment ◽  
Production Loss ◽  
Structural Barriers ◽  
Anthracnose Disease ◽  
Brazilian Northeast ◽  
Significant Production

The cashew (Anacardium occidentale L.) crop is an important source of income for the population of the Brazilian Northeast, and anthracnose disease caused by Colletotrichum gloeosporioides leads to significant production loss. However, there is little information on either the host resistance or the variation in the aggressiveness of the pathogen under controlled environment. The reaction of commercial (CCP-06, CCP-09, CCP-76 and CCP-1001) and one non-commercial (CAP-14) dwarf cashew clones was assessed against 36 isolates of this fungus controlled environmental conditions. All the isolates, including those from hosts other than cashew, were able to cause lesions on leaves and stems of most clones, albeit to different degrees. Clone CCP-06 was the most susceptible, while clone CCP-1001 showed a level of resistance to a number of the isolates, including isolate 905, while isolates 910 and 912 were aggressive to all clones. Injury increased the susceptibility of the clones to all isolates, indicating that resistance also might be associated with structural barriers that hinder penetration. Ripened cashew apples (8-week-old), of commercial clones were susceptible to isolates 905 and 910. Immature pseudo-fruits (2-week-old), with exception of clone CCP-76 which was susceptible to both isolates showed resistance against these isolates, suggesting the presence of structural and chemical barriers. Developed nuts (8-week-old), however, were more resistant than immature nuts (2-week-old) to both isolates, probably due to their thicker exocarp cuticle and reduced number of stomatal pores.

Production and dispersal of Colletotrichum gloeosporioides spores on Stylosanthes scabra under elevated CO2

2000 ◽  
Vol 108 (3) ◽  
pp. 381-387 ◽  
Author(s):  
S. Chakraborty ◽  
I.B. Pangga ◽  
J. Lupton ◽  
L. Hart ◽  
P.M. Room ◽  
...  
Keyword(s):  
Elevated Co2 ◽  
Colletotrichum Gloeosporioides ◽  
Stylosanthes Scabra

scholarly journals Temperature and Irradiance Effects on Flowering of Two Species of Leucocoryne

2003 ◽  
Vol 128 (6) ◽  
pp. 809-814 ◽  
Author(s):  
J.L. Catley
Keyword(s):  
Floral Development ◽  
Temperature Drop ◽  
Controlled Environment ◽  
Days To Flowering ◽  
Irradiance Level ◽  
Mean Temperature ◽  
Temperature Regimes ◽  
Flower Stem ◽  
Number Of Leaves

The influences of temperature and irradiance on flowering of two species of Leucocoryne [L. coquimbensis F. Phil and L. ixioides (Hook.) Lindl.] were examined in controlled environment growth rooms. Growing environments had day/night temperatures of 10/5, 15/10, or 20/15 °C, providing mean temperatures of 7.5, 12.5, or 17.5 °C, and photosynthetic photon fluxes (PPF) of 497 or 710 μmol·m-2·s-1. Inflorescence emergence data were recorded up to three times a week, measurements of floral development were made twice weekly and destructive harvests were carried out every 2 weeks. Both species of Leucocoryne flowered most quickly when grown at a mean temperature of 17.5 °C. Leucocoryne coquimbensis flowered first in all temperature regimes (means of 7.5, 12.5, or 17.5 °C), taking an average of 7.1, 5.1, or 4.5 months to flower, whereas plants of L. ixioides took 7.6, 5.4, or 4.7 months to flower. Although taking longer to flower, L. ixioides produced better quality flowers (taller scapes and more florets per inflorescence). Plants of L. coquimbensis grown in the two highest temperature regimes produced up to four inflorescences per bulb. As mean temperature decreased, the number of inflorescences produced by each bulb together with the number of florets in each inflorescence and the number of leaves produced before emergence of the inflorescence decreased. Decreases in these attributes were much greater with a 5 °C mean temperature drop from 12.5 °C, than a drop from 17.5 to 12.5 °C. At least half the florets in an inflorescence opened before the first floret began to senesce. The onset of senescence was delayed as mean temperature decreased. The highest irradiance level promoted development of further inflorescences of L. ixioides at all mean temperatures, and at a mean temperature of 17.5 °C for L. coquimbensis. Flower stem heights of L. coquimbensis increased as mean temperature increased and irradiance level decreased. An increase in irradiance level also promoted scape heights of L. ixioides, although maximum scape heights were attained at a mean temperature of 12.5 °C. Regardless of mean temperature or irradiance level, all cut stems were able to stand without support. These findings suggest days to flowering, inflorescence number and floral quality may be improved by growing these two species of Leucocoryne at mean temperatures greater than 17.5 °C, whereas mean temperatures below 12.5 °C will be detrimental to these floral attributes.

Response of Mitchell grasses (Astrebla F. Muell.) to photoperiod and temperature

1970 ◽  
Vol 21 (3) ◽  
pp. 395 ◽  
Author(s):  
FX Jozwik
Keyword(s):  
Growth And Development ◽  
Effect Of Temperature ◽  
Controlled Environment ◽  
Floral Initiation ◽  
Leaf Production ◽  
Number Of Leaves ◽  
Main Tiller ◽  
Effect On Growth

Controlled environment experiments were carried out to determine the effect of temperature and photoperiod on Astrebla pectinata, A. lappacea, A. elymoides, and A. squarrosa. Photoperiod had little effect on growth and development of tillers and on floral initiation, but did affect numbers of emergent inflorescences. Usually, inflorescence production increased with decreasing photoperiod. Temperature had significant effects on all parameters measured (number of main tillers and emergent inflorescences, elongation of main tillers, and number of leaves and axillary tillers per main tiller). Growth per tiller and leaf production increased with temperature (up to 30/25�C) but for tiller numbers the optimum was about 28/23�, Geographically separated strains of A. pectinata generally exhibited similar responses to photoperiod and temperature while different species from the same location differed in their response.

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