IRANIAN JOURNAL OF HORTICULTURAL SCIENCE AND TECHNOLOGY
Year:2005 | Volume:6 | Issue:1|Papers Count:5

To study the adaptation of ten cultivars of bermudagrass in Isfahan, a field study using a randomized complete block design with three replications was established in Khomeinishahr, Isfahan during 2002-2003. Results showed significant difference among cultivars for measured traits. ‘Tifway’ and ‘Tifgreen’ showed excellent establishment and cover rate. ‘Tifway’, ‘3200w19-9’ and ‘ISF2’, showed highest leaf area, height and dry weight compared to others. Density of ‘ISF2’, ‘Tifgreen’ and ‘Tifway’ was increased by the end of experiment. Evaluation of monthly average color showed that the turfgrass color was the best during July and September and the least during December to February. All cultivars showed unsuitable color in December, January and February. Also evaluation of cultivars average color showed that ‘Tifdwarf’, ‘Tifgreen’ and ‘ISF2’ were the best. However, due to significant interaction between genotypes and time, color of cultivar was depended on month (temperature). Finally, ‘Tifway’, followed by ‘ISF2’, showed most adaptability to Isfahan climate.

In this investigation, proliferation of shoots from seedling nodal sections of two guava cultivars namely ‘Local 1’ from white–fleshed types and ‘Local 2’ from red-fleshed types was attempted. After surface sterilization, the explants were cultured on Murashige and Skoog medium (MS) with 0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.5 and 2.0 mg l-1 BA and 0 and 0.25 mg l –1 NAA and their combinations as well as Barba and Patena (BP) medium with 0 and 1.5 mg l-1 BA. Generally, with increasing BA up to 1.5 mg l-1 the average shoot number was increased, but the shoot length decreased. The best shoot proliferation (5 shoots per explants) was obtained in ‘Local-1’ with 1.25 mg l-1 BA and 0.25 mg l-1 NAA, while increasing NAA in the medium was ineffective for ‘Local 2’. In comparison, MS was superior to BA medium. The best treatment for rooting was 0.5 g l-1 IAA in MS medium which resulted in 4.75 roots per explant.

Several experiments were conducted in Khalatpoushan Station of the University of Tabriz using completely randomized design with three treatments and three replications in order to identify the effects of interrupted and continuous chilling and heating on budbreak rate in ‘Sultana’ grapevines in 2001. The grapevine shoots were removed on the 18th of Oct. in 2001 and 28th of Jan. in 2002. In control treatment, to save the chilling requirements of buds, cuttings were exposed to continuous chilling at 4oC for 9 days (200 hr). In order to interrupt continuous chilling in the other two treatments, after completing one-and two-thirds of chilling requirements of buds at 4oC, cuttings were exposed to 20 and  25oC for 1, 2 and 7 days and then were exposed to 4oC until completion of chilling requirements of the buds. The results indicated that treatment with interrupted chilling at 25oC for 7 days was better than the continuous chilling treatment at 4oC for 9 days in breaking dormancy of grapevine buds. Also, continuous chilling at 20oC for 1 or 2 days after the completion of  two-thirds (6 days) of chilling requirements of buds, caused  reductions in budbreak percentage and budbreak rate as compared to the control treatment (9 days continuous chilling). Therefore, interrupted chilling treatment at 20oC for 1 or 2 days following the completion of one-third (3 days) of chilling requirement of buds was similar to the continuous chilling treatment for budbreak percentage and rate. Also, the results indicated that the effect of high temperature during the chilling period on budbreak rate of grapevines buds depends on the dormancy stage of the buds. Therefore, cuttings on 28th of Jan. 2002, on which buds were finished their dormancy period, high temperature (20oC) for 1 day during the chilling period of 9 days did not affect budbreak rate. In another experiment, to study the effect of low temperature on the heating requirement of buds for budbreak, cuttings were obtained on 12th of Feb. 2002. Analysis of data showed that interrupted heating at 4oC did not affect the amount of heat requirement for the days to 50% budbreak as compared to continuous heating treatment.  It can be concluded that accumulated heat for budbreak is accumulative.

To determine DRIS norms for sweet lime trees in Fars province, yield and leaf analysis data (including N, P, K, Fe, Mn, Zn and Cu) were collected from 399 orchards (located in Jahrom, Darab, Fasa, Kazeroon and Firoozabad) and assessed in a period of four years. The results obtained were entered into a data bank. Nutrient data were expressed in different forms of DRIS norms and based on the yield data, orchards were categorized into low and high yield groups. Mean, coefficient of variation (C.V.) and variance (S) of different forms of nutrient expression were calculated for low and high yield orchards and the ratio of variance of low yield orchards to high yield orchards (SB/SA) was also determined. Those forms of nutrient expression that had highest SB/SA were selected as norms. The norms of leaf nutrients and the ratio between them were obtained for sweet lime as the following: N=2.66%, P=0.13%, K=1.71%, Fe=83.44 mg kg-1, Mn=30.89 mg kg-1, Zn=19.89 mg kg-1, Cu=6.62 mg kg-1, P/N=0.051, N/K=1.675, Fe/N=31.492, N/Mn=0.1, P/K=0.082, Fe/P=643.17, P/Mn=0.005, Fe/K=53.61, Mn/K=18.84, Zn/K=12.09, Fe/Mn=3.083, Fe/Zn=4.922, Fe/Cu=14.96, Zn/Mn=0.745, Cu/Mn=0.246, Zn/N=7.47, N/Cu=0.577, Zn/P=150.068, P/Cu=0.0267, Cu/K=4.32 and Zn/Cu=3.99.

During two successive years, 2000 to 2001, the effect of propagating by stem cutting for eradication of bacterial agents of potato black leg and bacterial wilt diseases were evaluated. Rooting percentage and amount of minitubers production and the efficiency of this method to control bacterial disease were determined. Potato seeds from four cultivars; ‘Agria’, ‘Draga’, ‘Marfona’ and ‘Concord’ were selected. In the first step, the health of tubers was certified by bacterial test. These tubers were inoculated with two bacterial suspensions and then cultivated in factorial design containing 12 treatments, namely, four cultivars and bacterial agent in three levels (two bacterial inoculums and control). Terminal cuttings were prepared as plants attained 15 to 20cm in length. Cuttings were cultured in perlite medium and rooting percentage was accounted. Production of minitubers from each cutting was determined. Samples of explants from stem cuttings and minitubers were taken in successive periods of growing period. The amount of contamination was determined by biochemical and physiological standard tests. Results showed that rooting percentage in different treatments did not significantly different at 5% level. Regarding minituber production, only cultivars had significant effects and ‘Agria’ produced highest minitubers. The data of bacterial tests did not show any bacterial agent in minitubers which means terminal stem cultings in potatoes elimianate these two bacterial diseases.