the flowering phase of apple trees is the most critical step in relation with low temperatures and frost events. therefore, forecasting the time of flowering is important. if a model can predict the exact time of flowering, it would be feasible to care for flowers agianst late spring freezing (lsf). in this study, we evaluated three temperature-base chilling models namely: chilling hours (ch), ...

Many fruit and nut trees must fulfill a chilling requirement to break their winter dormancy and resume normal growth in spring. Several models exist for quantifying winter chill, and growers and researchers often tacitly assume that the choice of model is not important and estimates of species chilling requirements are valid across growing regions. To test this assumption, Safe Winter Chill (th...

in this research, chilling and heating requirements of six local cultivars of apricot (jafari, ghavami, jahangiri, khiari, khiveaee and rajabali) were evaluated under field and lab conditions. under lab condition, ‘rajabali’ and in some extent ‘johangiri’ began flowering after 500 hours in 4°c. other cultivars except ‘khiari’ flowered at 750 h. ‘khiari’ flowered at 1000 h. in field, due to litt...

This study was carried out in the biotechnology laboratory of Agricultural Faculty of Ondokuz May s University. The objective of this study was to establish the effects of chilling period and chilling temperature on germination in linseed (Linum usitatissimum L.). Seeds were subjected to six different heat temperatures (0, 2, 4, 6, 8 and 10 C) for 24, 48, 72, 96, and 120 hours. Germination test...

Cottonseed exposed to a temperature of 5 degrees during hydration are killed, or the subsequent germination performance of surviving seed is seriously inhibited. Exposure to chilling for periods as short as 30 minutes reduces germination speed and induces root abnormalities, while chilling for 12 hours may kill all seed. Sensitivity to chilling persists during the initial 2 to 4 hours of hydrat...

The objective of this study was to evaluate the effective temperature for overcoming dormancy ‘Fuyu’ persimmon tree buds. Stem samples were collected three times between 2013 and 2014. Stems maintained in a climate incubator chamber at 3, 6, 9, 12 °C. For each temperature, five numbers additional chilling hours (CH) (0, 240, 384, 528, 672 CH) studied. experimental design completely randomized 5...

Insufficient chilling resulting from rising winter temperatures associated with climate warming has been an area of particular interest in boreal and temperate regions where a period of cool temperatures in fall and winter is required to break plant dormancy. In this study, we examined the budburst and growth of trembling aspen (Populus tremuloides Michx.), balsam poplar (Populus balsamifera L....

The effects of chilling on the photosynthesis of a chilling-resistant species, pea (Pisum sativum L. cv Alaska) and a chilling-sensitive species, cucumber (Cucumis sativus L. cv Ashley) were compared in order to determine the differences in the photosynthetic chilling sensitivity of these two species. For these experiments, plants were chilled (5 degrees C) for different lengths of time in the ...

this research was carried out to determine the chilling and heat requirements of grapevine cultivars(rotabi, siah shiraz and yaguti) and carbohydrate and hormones changes in chilled cuttings. uniform cuttings of above mentioned cultivars were harvested when leaves were abscised in autumn, and then transferred to refrigerator (2˚c). cuttingswere subjected to 0 (unchilled control), 100, 200, 300,...