scholarly journals Quantification of incubation, latent and infection periods of Phakopsora pachyrhizi in soybean, according to chronological time and degree-days

2016 ◽  
Vol 42 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Anderson Luiz Durante Danelli ◽  
Erlei Melo Reis
Keyword(s):  
Infection Process ◽  
Growth Chamber ◽  
Phakopsora Pachyrhizi ◽  
Degree Days ◽  
Leaf Infection ◽  
Chronological Time ◽  
Accumulated Degree Days

ABSTRACT In experiments conducted in a growth chamber, the chronological time and the accumulated degree-days were determined for the duration of incubation, latent and infectious periods of Phakopsora pachyrhizi cultivars BRSGO 7560 and BRS 246 RR. Detached soybean leaflets were placed in gerbox-type acrylic boxes and inoculated with 20 x 103 uredospores/mL. The study was conducted at 12-h photoperiod and temperatures of 10ºC, 15ºC, 22ºC, 25ºC and 30°C for 30 days. Lesions and uredia/cm2were evaluated and the number of uredia per lesion was quantified after the beginning of sporulation. The sporulation potential was also quantified for cultivars BRSGO 7560 and BRS 246 RR. The steps of the infection process can be quantified based on both the chronological time and the accumulated heat. The cultivar BRSGO 7560 produced 4,012.8 spores/cm2 and BRS 246 RR, 7,348.4 uredospores/cm2. The largest number of uredia was produced at 25ºC in both cultivars; however, BRS 246 RR presented 372.7 uredia/cm2 and BRSGO 7560, 231.6 uredia/cm2. At 10ºC and 30°C, leaf infection did not occur in both cultivars.

Seeding-date effects on yield, quality and maturity of safflower

1994 ◽  
Vol 74 (2) ◽  
pp. 261-266 ◽  
Author(s):  
H.-H. Mündel ◽  
R. J. Morrison ◽  
R. E. Blackshaw ◽  
T. Entz ◽  
B. T. Roth ◽  
...  
Keyword(s):  
Oil Content ◽  
Carthamus Tinctorius ◽  
Test Weight ◽  
Yield Reduction ◽  
Degree Days ◽  
Seeding Date ◽  
Early Maturing ◽  
Yield Quality ◽  
Maturity Degree ◽  
Accumulated Degree Days

Experiments were conducted for 4 yr at Lethbridge and Brooks, Alberta, and at Morden, Manitoba, to determine the effect of seeding date, cultivar (Saffire, S-208 and Cargill-3) and location on safflower (Carthamus tinctorius L.) yield, oil content, test weight and maturity; and the effect of accumulated degree–days (DD) on yield, oil content and test weight. The early-maturing cultivar, Saffire, produced the least variable yields across seeding dates. For locations and years where fall frosts did not occur before maturity, Cargill-3 produced good yields, even with late seeding; S-208 yielded less in similar situations; however, S-208 generally outyielded Saffire. Highest yields were obtained at Brooks by seeding in late April, at Lethbridge, by seeding in late April or early May. However, at both Alberta locations, Saffire could usually be seeded to mid-May without major yield reduction. At Morden, seeding during the third week of May provided optimum yields. Seeding date had little influence on oil content. Later seeding dates tended to reduce days to maturity and test weight. Safflower matured 3 wk earlier at Morden (earliest site) than at Lethbridge (latest site), with maturity at Brooks averaging 4–8 days earlier than at Lethbridge. Plants required more DD to reach maturity at Morden than at either Alberta location. DD was positively associated with yield of S-208 at both Lethbridge and Morden; for Saffire, only at Lethbridge; and for Cargill-3, only at Morden. DD generally did not significantly affect oil or test weight. Key words: Safflower, Carthamus, agronomy, seeding dates, yield, oil, test weight, maturity, degree–days

scholarly journals THERMAL REQUIREMENTS OF CITRUS FRUITS GRAFTED ONTO ROOTSTOCKS IN THE LOW-MIDDLE REGION OF THE SÃO FRANCISCO RIVER BASIN

2018 ◽  
Vol 31 (2) ◽  
pp. 336-343
Author(s):  
FÁDIA SAMARA SANTOS NASCIMENTO ◽  
VALTEMIR GONÇALVES RIBEIRO ◽  
DÉBORA COSTA BASTOS ◽  
JUCIENY FERREIRA DE SÁ ◽  
PEDRO HENRIQUE DIAS NASCIMENTO
Keyword(s):  
River Basin ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Production Cycle ◽  
Middle Region ◽  
Degree Days ◽  
Sao Francisco River ◽  
São Francisco River ◽  
D 12 ◽  
Accumulated Degree Days

ABSTRACT To understand the production cycle of a particular cultivar in a given region, it is necessary to obtain information related to its phenology and the accumulated degree days. The purpose of this study was to evaluate the phenological cycle of citrus species grafted onto two rootstocks and grown in the Low-Middle Region of the São Francisco River Basin, in particular with respect to accumulated degree days. The experiment was conducted using ‘Rubi’ and ‘Pera D-12’ oranges and ‘Page’ mandarins. Two rootstocks were used, namely ‘Cravo’ and ‘Volkameriano’ lemon species that were drip irrigated in the Campo Experimental de Bebedouro, an experimental field owned by Embrapa Semiárido. ‘Page’ mandarins with ‘Cravo’ or ‘Volkameriano’ rootstocks exhibited a subperiod (0-10) of 183.32 and 181.24 days, respectively. Meanwhile, ‘Pera D-12’ and ‘Rubi’ oranges with ‘Cravo’ rootstocks had values of 249.57 and 178.58 days, respectively, while those with ‘Volkameriano’ rootstocks had values of 226.35 and 200.41 days, respectively. The accumulated degree days were measured from the initial sprouting to harvesting, which took place when the fruits presented a soluble solids/titratable acidity ratio equal to or greater than 12. ‘Page’ mandarins required 2,720 degree days, whereas ‘Pera D-12’ and ‘Rubi’ oranges required approximately 3,390 and 2,280 degree days, respectively. Finally, ‘Pera D-12’ and ‘Rubi’ oranges with either rootstock presented cycles characterized as mid-season and precocious, respectively, while ‘Page’ mandarins had precocious cycles.

BIOLOGY OF AGAPETA ZOEGANA (LEPIDOPTERA: COCHYLIDAE), PROPAGATED FOR THE BIOLOGICAL CONTROL OF KNAPWEEDS (ASTERACEAE)

2000 ◽  
Vol 132 (2) ◽  
pp. 223-230 ◽  
Author(s):  
George W. Powell ◽  
Brian M. Wikeem ◽  
Allen Sturko
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Adult Emergence ◽  
Larval Survival ◽  
Control Agent ◽  
Spotted Knapweed ◽  
Degree Days ◽  
Centaurea Diffusa ◽  
Calendar Date ◽  
Accumulated Degree Days

AbstractWe examined the influence of temperature and release density on the root-boring moth, Agapeta zoegana L., a biological control agent of diffuse knapweed, Centaurea diffusa Lam., and spotted knapweed, Centaurea maculosa Lam. Moths were released at six densities (1, 2, 4, 8, 16, and 32 adult male–female pairs) in each of 2 years (1992 and 1993 cohorts) into outdoor, caged plots containing spotted knapweed. Air temperature, larval establishment and mass, and adult emergence, mass, and body dimensions were measured. Larval production increased linearly with adult release density in both cohorts. Larval survival ranged from 0 to 100% and was not correlated with release density or accumulated degree-days in either year. Date of first emergence occurred earlier as both release density and larvae per plant increased, but only for the 1992 cohort. Declining resources or increased contact among the larvae may induce early pupation. Peak emergence rate increased with release density in both cohorts. First emergence was related more closely to calendar date than accumulated degree-days. In contrast, peak emergence rates were more consistent with degree-day accumulations between cohorts than calendar date. Adult production increased with parental release density in both cohorts. Females were heavier, wider, and longer than males. Optimal A. zoegana production will be achieved with releases of greater than 1.6 male–female adult pairs per spotted knapweed plant.

DIFFERENCES IN POST-DIAPAUSE THERMAL REQUIREMENTS FOR EGGS OF TWO RANGELAND GRASSHOPPERS

1987 ◽  
Vol 119 (7-8) ◽  
pp. 653-661 ◽  
Author(s):  
William P. Kemp ◽  
Norma E. Sánchez
Keyword(s):  
Laboratory Experiments ◽  
Field Observations ◽  
Degree Days ◽  
Egg Hatching ◽  
Grasshopper Species ◽  
Thermal Requirements ◽  
Diapause Development ◽  
Species Specific ◽  
Oviposition Sites ◽  
Accumulated Degree Days

AbstractA study was conducted to examine the springtime hatching characteristics of Melanoplus sanguinipes (F.) and Aulocara elliotti (Thomas) eggs on rangeland. Laboratory experiments showed that eggs of M. sanguinipes required fewer accumulated degree days (DD) to complete post-diapause development than those of A. elliotti at a constant temperature of 23.3°C. Springtime field observations revealed that A. elliotti nymphs emerged prior to or concurrent with M. sanguinipes. Additionally, results suggest that A. elliotti nymphs emerge over a shorter interval than M. sanguinipes. Much of the variation in springtime emergence could be attributed to species-specific oviposition sites, pod depth, and pod orientation that resulted in A. elliotti eggs accumulating heat more rapidly than M. sanguinipes eggs. Results help explain some of the variation found in egg hatching of these two grasshopper species on rangeland.

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