this experiment was conducted to quantify leaf production and senescence in wheat. the experiment was carried out at research farm of the gorgan university of agricultural sciences and natural resources, gorgan, iran in 2005 using a randomized complete design considering sowing dates as environment. treatments were sowing date (14 december, 20 jan and 21 feb, 2005) and cultivars (aria, atrak, k...

Crop models need accurate simulation of the interdependent processes of crop development and leaf area production. Crop development proceeds according to genotype characteristics and environmental influences, specifically temperature and photoperiod. It can be partly described by thermal requirements for development intervals and coefficients that describe genotype adaptation. The objectives of...

[1] This paper analyses the role of the El Niño–Southern Oscillation (ENSO) on the interannual variability of the leaf appearance dates of boreal forests in the Northern Hemisphere (1982–2004). We find significant negative correlations between the ENSO, quantified by means of the Southern Oscillation Index (SOI), and the leaf appearance dates in central Siberia with up to 9 months lag. The corr...

Predicting the rate of leaf appearance, or phyllochron, aids in understanding and modeling grass development and growth. Nine equations predicting the phyllochron of wheat (Tria'cum aesfivurn L.) were evaluated using field data from a variety of locations, cultivars, and management practices. Each equation is referred to by the last name of the first author; if there is more than one equation b...

the objective of this work was to study the responses of two baby lettuce (lactuca sativa l.) cultivars, namely, green paris island and red sanguine, to different nacl concentrations (0, 5, 10, and 20 mm). the study was conducted in a floating system and plants were harvested at the stage of 5-6 leaves, outside leaf 6-10 cm in length (25 and 31 days after sowing for green and red lettuce, respe...

The duration of pre-anthesis developmental phases is of interest in breeding for improved adaptation and yield potential in temperate cereals. Yet despite numerous studies on the genetic control of anthesis (flowering) time and floral initiation, little is known about the genetic control of other pre-anthesis phases. Furthermore, little is known about the effect that changes in the duration of ...

The prediction of leaf appearance rate (LAR) is an important part of many crop simulation models. Most wheat simulations models assume that LAR is affected by temperature and photoperiod. This assumption ignores the fact that seed reserves contribute to a greater LAR of the first two leaves and that the LAR of subsequent leaves decreases as a result of an increase in the distance that each leaf...