نتایج جستجو برای: breeding periods
تعداد نتایج: 171368 فیلتر نتایج به سال:
Alleles at the Gli-A3 locus in groups of ukrainian winter common wheat cultivars of different origin
Aim. The aim of the study was to analyze diversity and frequencies alleles at minor gliadin locus Gli-A3 in groups common winter wheat cultivars developed different breeding institutions Ukraine periods time. Methods. Acid polyacrylamide gel electrophoresis gliadins carried out. To identify allele cultivar Myronivska storichna, segregation a sample F2 seeds from crossing with Bezosta 1 analyzed...
BACKGROUND AND AIMS Short life cycles and trade-offs linked to breeding systems make bryophytes good models for the study of plant reproductive strategies. Our aim was to test if differences in sexual reproductive performance of bryophytes in tropical rainforests are driven by the breeding system of the species (monoicous or dioicous) or are mainly affected by the habitat. METHODOLOGY The rep...
In many animals, an individual’s social environment and status can change quickly and unpredictably, suggesting an advantage for signals capable of responding to these changes. However, many signaling traits are fixed for relatively long periods. In birds, for example, most plumage-based signals are constrained by molt and unable to respond to sudden changes in social environment. Soft parts, c...
Plasma levels of luteinizing hormone, prolactin, testosterone, and progesterone were measured throughout breeding in masked boobies, red-footed boobies, and red-tailed tropicbirds at Europa and Tromelin Islands (Indian Ocean). LH secretion showed a dampened pattern in the three species, particularly in tropicbirds. Such specific differences may be related to the less elaborate courtship display...
Seasonal breeding in the temperate zone is a dramatic example of a naturally occurring change in physiology and behaviour. Cues that predict periods of environmental amelioration favourable for breeding must be processed by the brain so that the appropriate responses in reproductive physiology can be implemented. The neural integration of several environmental cues converges on discrete hypotha...
Changes in diet and trophic position of a top predator 10 years after a mass mortality of a key prey
After the disappearance of primary prey, seabirds exhibit gradually decreased breeding performance, and eventually the population size drops. Results are presented of an investigation into the diet of little penguins (Eudyptula minor) at Phillip Island, Australia, during a period when their key prey, pilchard (Sardinops sagax), declined dramatically. Data from stomach flushing (1982–2006) were ...
Habitat selection during the breeding season has important consequences for reproductive success and, in seasonal and heterogeneous environments, most likely occurs on several temporal and spatial scales. I examined several possible topographical, substrate and vegetation, as well as anthropological effects on snowy plover (Charadrius alexandrinus) habitat selection across pre-breeding and bree...
Combining field and laboratory work, this study investigated the reproductive cycle, aggregative behavior, spawning periodicity, development and early growth of the sea star Henricia lisa living at bathyal depths off eastern Canada. Marked differences were found between individuals from *1,300 and *600 m deep. The former had a male biased sex ratio and an aperiodic reproductive cycle, whereas t...
The predicted effects of recent climate warming on egg size in birds are controversial, as only two long-term studies have been reported, with contrasting results. Long-term data on egg size variation are analyzed in relation to ambient temperatures in a southern European population of pied flycatchers where breeding phenology has not matched the spring advancement in the last decades. Cross-se...
Globally, potato is the third most important food crop after rice and wheat in terms of consumption. It is fast maturing, versatile in use and grows in a wide range of environments from sea level up to about 4700 metres above sea level and from Southern Chile to Greenland. Currently, potato production is rapidly expanding beyond the traditional high potential areas. This is mostly due to expand...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید