جستجوی مقالات مرتبط با کلیدواژه « تکثیر رویشی » در نشریات گروه « زراعت »

Cogongrass is one of the most serious weeds in palm groves and sugar cane industry of Khuzestan. Understanding the impact of environmental stresses on the ability of vegetative propagation and rhizome sprouting of this weed can help to control this species. Therefore 5 cm rhizomes with 2-3 mm diameter in two separate tests were conducted based on completely randomized design with 4 replications and 6 drought levels (0, -0.3, -0.6, -0.9, -1.2 and -1.5 MP) using polyethylene glycol 6000 and six salinity levels (0, 3, 6, 9, 12 and 15 dS/m) using sodium chloride at Research Laboratory of the Research Institute for Education Development and Cane Industries of Khuzestan. In this experiment rhizomes were placed in a germinator set at 22/30 ° C and light conditions of 8/16 hours (night / day). The results indicated that increasing drought and salt stresses significantly (p<0.01) decreased the rhizome germination rate and percentage compared to the control treatment. Based on the estimation of 3-Parameter logistic models, the salinity and drought values for 50% reduction in rhizomes germinability were 6.42 dS/m and -0.96 MP, respectively. According to these research findings, cogongrass rhizomes were able to sprout under either salinity or drought stresses, indicating this species is a troublesome noxious weed even under such stresses.

To determine the effect of mother stock vigor and auxin on callusing and rooting ability of walnut four trials were carried out in Kahriz Agricultural Research Station during 2006-2007. In cutting trials, the semi-hardwood or hardwood cuttings from each of three clusters of seedling vigor were collected in late September in 2006 and after treating with IBA were planted under mist and bottom heat condition or reversed silo. The mother stock vigor and hormone was only affected callus formation with no effect on rooting. Treating the base of callused cuttings with reduced concentration of IBA was not effective in stimulating of rooting on callus surface. In response to the modified stool layering with application of lanoline paste containing three auxins (IAA, IBA and NAA), average number of roots per layer and rooting score in low-vigor mother stocks were 7.8 and 4.2 (from 5), respectively and significantly improved compared to high-vigor ones. Improved rooting of low-vigor stocks imply on a substantial structural/and or hormonal differences among mother stocks with different vigor and provides the possibility of selection of easy to root clones in walnut.

To study effects of different times of collection, IBA and NAA concentrations on rooting and related characteristics of hard wood and semi-hard wood cuttings in Gisela6 root stocks two experiments were conducted in green house-using factorial arrangements in completely randomized design with three replications. First experiment included: Two times of cutting collection (January and February), two types of cuttings (basal and terminal) and four concentrations of IBA and NAA (0, 1000 and 2000 and 3000 ppm). The second experiment included: two times of cutting collection (June and July), two types of cuttings (basal and terminal) and three concentrations of IBA and NAA (0, 1000, 1500 ppm). Results showed that times of cutting and hormones significantly (p<0.01) affected rooting (%) in hard wood and semi-hard wood cuttings in Gisela6 cherry rootstock. In semi-hard wood cuttings, the highest rooting (70%) was obtained in terminal type of cutting collected in July and treated by 1000 ppm IBA. However, in hard wood cuttings, the highest rooting (46.6%) was observed in basal type of cuttings collected in January and treated by 3000 ppm IBA. As auxin concentration increased, the number of primary and secondary roots as well as the length of rooting section increased. However, the average length of primary and secondary roots decreased.