abstract in order to study the effect of density and time of nitrogen application on morphological, phenological characteristics, yield and yield components of black cumin (nigella sativa l) a field experiment was conducted at chenaran in khorasan razavi province in 2005 growing season. three nitrogen fertilizer (urea) application times (1- control 2- at 4-6 leaves stage 3-preblooming 4-complet...

Studying plant phenology is very important to regulate the rangeland utilization. Plant phenology can be determined by Growing Degree Days (GDDs). Since temperature varies yearly, the phenological stages may consequently differ yearly. Determining the base temperature is one of the key steps in the calculation of GDDs. The aim of this study was to calculate the required GDDs for each phenologic...

Studies dedicated to understanding the behavior of pathogens in relation to their hosts are the starting point for any breeding program aimed to develop resistant cultivars. The objective of this study was to analyze the resistance to Septoria tritici Rob in 77 F11 progenies of wheat derived from the three-way cross Tadinia × (Yecora rojo × UC554) in the phenological stages of seedling, tilleri...

the aim of this research was determination of nutritive value of cressa cretica with gas test method, in vivo digestibility and degradability with nylon bag method in three phenological stages. the amount of crude protein decreased significantly in seeding stage. but the amount of ndf and adf increased in seeding stage. the degradability of dry matter and rapid and slowly degradable fractions d...

information on quality characteristics of forage species help the range managers to select a suitable grazing program that minimizes the damages to vegetation. water soluble carbohydrates (wsc) -the main photosynthetic products- are stored in various plant parts and are more likely to be consumed when plants require them. in order to investigate the changes of wsc in distinguishable organs in t...

Information on quality characteristics of forage species help the range managers to select a suitable grazing program that minimizes the damages to vegetation. Water Soluble Carbohydrates (WSC) -the main photosynthetic products- are stored in various plant parts and are more likely to be consumed when plants require them. In order to investigate the changes of WSC in distinguishable organs in t...

The crop coefficient (Kc) is widely used for operational estimation of actual evapotranspiration (ETa) and crop water requirements. The standard method for obtaining Kc is via a lookup table from FAO-56 (Food and Agriculture Organization of the United Nations Irrigation and Drainage Paper No. 56), which broadly treats Kc as a function of four crop-growing stages. However, the distinctive physio...

late spring frost damage is the main factor that limits apricot production in iran.this research was aimed to evaluate the damage of freezing in two apricot cultivarflowers: ʽʽnasiriʼʼ and ʽʽnori-dirrasʼʼ during spring 2011. reproductive organs of thesecultivars at two phenological stages, popcorn and full bloom, were transferred toprogrammable freezer with temperature touch down from 5°c to -1...

This study aimed to evaluate effects of elevation and phenological stage on essential oil components of Teucrium polium L. and Teucrium orientale L. belonging to the Lamiaceae family. The aerial parts of the grown plants in two ranges of elevation including 2000-2500 and 2500-3000 m above sea level were harvested at three time-points, including end of vegetative, flowering, and seed filling sta...

Phenology is increasingly recognized as an important factor structuring communities because it determines when and at what life stage organisms interact. Previous work indicates that changes in first or mean timing of a phenological event can affect populations and communities, but little is known about the consequences of changes in the distribution (e.g., synchrony) of a phenological event. W...