SEED AND PLANT PRODUCTION JOURNAL
Year:2011 | Volume:27-2 | Issue:3|Papers Count:9

To study of the effect of transplanting date on seed yield and its components in four rapeseed cultivars this research was carried out in paddy fields of Rice Research Institute of Iran, Rasht, Iran, in three successive cropping seasons (2004-2007)- Using split plot arranagements in randomized complete block design with three replications. Five transplanting dates, October 23 (Mean air temp. 17.3oC), November 06 (Mean air temp. 16.8oC) and 22 (Mean air temp. 15oC), December 06 (Mean air temp. 10.1oC) and 21 (Mean air temp. 8.3oC) were assigned to main plots, and four rapeseed cultivars, Hayola 401, Hayda 308, RG 003 and Sarigol were randomized in sub-plots. Transplanting was done by hand at 5-6 leaf stage with row spacing of 25 cm and between plant distance 8 cm. Combined analysis of variance showed that the effect of year, transplanting date and cultivar was significant on the majority of traits. Second transplanting date with 2740 kgha-1 and Hayola 401 with 2851 kgha-1 produced the highest average seed yield. Hayola 401 in the second transplanting date had the highest average seed yield (3247 kgha-1). Hayola 308 in fifth transplanting date completed its life cycle (151 days) earlier than the other cultivars. The highest oil harvest index (15.25%) also belonged to Hayola 401. In conclusion, transplanting can be successfully practiced for these four rapeseed cultivars from 23 October (Mean air temp. 17.3oC) to 22 November (Mean air temp. 15oC) with the highest seed yield in the early November in Rasht region.

Suitable planting date, with providing essential growth rate, in oilseed rape leads to higher seed yield by decreasing cold damages. A field experiment was conducted in factorial arrangment with two factors including: four planting date (12 and 23 September and 2 and 12 October) and five cultivars (Modena, Licord, Okapi, Opera and Zarfam) using randomized complete block design with three replications in Khosrosharh field station, Tabriz, Iran, in 2008 to 2010 croppping seasons. Results showed that cultivars in late planting date (12 Oct.), in comparison with suitable planting date (11 Sep.), had significantly less leaves and crown diameter when approaching average air temperature below base temperature (5oC) for oilseed rape and showed significantly higher cold damage (%). Pod number per plant and seed yield decreased in delayed planting. It was concluded that 11-23 Sep. is the suitable planting period in Tabriz plain and areas with similar climatic conditions. Correlation coefficients between leaf no. per plant, crown diameter and cold damage with each other and with seed yield were significant. Therefore, oilseed rape plants with at least 5 leaves and 6 mm crown diameter before occurence of freezing temperatures showed less damage from cold and freezing stresses and were able to produce higher seed yield. Pod number per plant had positive significant correlation with 1000 seed weight and seed yield. These oilseed rape cultivars showed suitable for being grown in Tabriz plain and areas with similar climatic conditions.

To study the effect of sowing date on grain yield and yield components of bread wheat, a field experiment was conducted in Gorgan Agricultural Research Station in two cropping seasons (2005-2006 and 2006-2007). Experimental design was Split-plot arrangements in randomized complete block design with three replications. Main plots were assigned to 4 levels of sowing date: 01 December, 21 December, 10 January and 30 January. Two bread wheat cultivars Moghan 3 and Arta were randomized in sub-plots. The average soil temperature at these sowing dates were 14oC, 11oC, 6oC and 4oC respectively. Results showed that there were significant differences between two years for biological yield, number of spike per m2, days to heading, days to maturity and GDD to heading. All traits except number of grains per spike were significantly affected by sowing date (different GDD). The highest biological yield (14415 Kg ha-1) was obtained in sowing date 01 December (with 14oC soil temperature and GDD=2247oCd). The highest grain yield (4480 kgha-1) was also produced in 1st sowing date (01 December). In the late sowing date, grain yield decreased, because of heat stress at the end of season and low soil temperature average at planting date. There were also significant differences between wheat cultivars for grain yield and biological yield. Moghan 3 had higher grain yield (average of 4324 kg/ha) and significantly differed from Arta. In conclusion, suitable sowing date was 01 December with 14oC soil temperature and GDD=2247oCd.

To determine the in vitro propagation protocol for two pear clonal rootstocks, OH×F333 and OH×F69 four separate experiments were conducted. In the first experiment, effect of MS, QL and modified QL basal media on the vegetative characteristics including length and proliferation rate of shootlets, leaf number and expansion, inter-node length and necrosis of in vitro tips were measured and recorded. Modified QL had the highest proliferation and shoot length among tested media. In the other two experiments, effects of 2iP and BAP in two separate experiments were evaluated on pear rootstocks in 0, 0.5, 1 and 2 mg/l for 2iP, while for BAP due to its importance in media 0 mg/l was excluded. Results of these experiments indicated the appropriateness of 0.5 mg/l 2iP and 1 mg/l BAP on shootlets number and quality. In the forth experiment, the suitable rooting condition was assessed by long and short period exposure of in vitro micro-cutting to IBA. Results demonstrated higher rooting in short-period treated micro-cuttings as compared to the longer periods. The highest rooting rate, leaf expansion, root length and quality were also observed in 2 mg/l IBA. In conclusion, to micropropagate and to facilitate appropriate in vitro survival of these pear rootstocks a growth media containing modified QL enriched with 0.5 mg/l of 2iP and 1 mg/l of BAP are recommended. A short-phase treatment of micro-cuttings with 2 mg/l of IBA for root induction is also recommended.

Spring planting of KSC704 maize hybrid in temperate areas of Fars province in Iran is usually infected with maize rough dwarf and Iranian maize mosaic viruses. Cold temperatures also affect summer sown maize cv. KSC704 hybrid late in autumn befor harvest. To evaluate effects of planting dates on exotic medium maturity hybrids with European origin and reaction of Chinese hybrids to important maize viruses in Fars province two separate experiments was carried and. These experiments were conducted using randomized complete block designs (split plot arrangement in the first trial) with four replications in Zarghan field station, Shiraz, Iran, in two growing seasons (2006-2007). Results, in first trial, showed that growing season effect on grain yield was not significant. Planting date had significant effect on grain yield and yield components. One month delay in planting date decreased the viral infection in all hybrids. OSSK602 hybrid had the highest grain yield with 10.2 t/ha. However, this hybrid in first planting date had high viral infection, and grain yield of about 6 ton/ha. In second trial, Chinese maize hybrids showed tolerance to either viruses. Although they showed high viral infection symptoms, but produced reasonable grain yield. Therefore, it was concluded that Chinese maize hybrids have sources of resistance or tolerance to these viruses and could be used in the national maize breeding programs for development of resistant/tolerant maize hybrids.

Rotabi and Siah-Samarghandi are two major grape cultivars grown in Fars province, Iran. Post-harvest management is a major concern during transportation and cold storage of fruits of these cultivars mainly berry shattering and decay. This research was carried out to study the effect of grape guard pads on extended storage life of fruits of Rotabi and Siah-Samarghandi grape cultivars. Freshly harvested fruits (based on full coloring of berries) for each cultivar were packed in plastic boxes of 7 kg capacity and enclosed with perforated and imperforated plastic bags including one or two SO2 generating pad (s). These boxes were stored in cold store at 1±1oC and 85-90% relative humidity. Results showed that using two grape guard pads (one below and one over the fruits) enclosed with perforated plastic bag for cv. Siah-e-Samarghandi proved to be effective to maintain stem freshness (95%), berry shattering (0%) and berry decay (0%) as well as other quality attributes by 120 days in cold storage. Flavor of berries of cv. Rotabi was highly affected by SO2, hence, this cultivar is not suitable for being stored in cold storage using grape guard pads. The control boxes (without grape guard pads) could only be stored for 25 days.

Autumn-sown sugar beet is an important strategy to produce sugar to meet domestic demand in Iran. New bolting resistant sugar beet cultivars can facilitate sowing sugar beet in autumn in warm and semi-warm areas in Iran. Therefore, a field experiment was conducted as split plot arrangement in randomized complete block design with four replications in Ardabil Agricultural and Natural Resources Research Center in 2008-2010 cropping seasons. Experimental factors included: three sowing dates (23 September, 12 October and 01 November), four harvest times (22 May, 22 June, 23 July and 23 August) and three cultivars (resistant, moderately resistant and sensitive). Results showed that cultivars were significantly different (P<0.05) for bolting rate. Sensitive cultivar with 89.75% bolting rate was significantly different from moderately resistant (41.78%) and resistant (12.23%) cultivars. Effect of sowing time on root, sugar and white sugar yields was not significant. Harvest time had significant (P<0.05) effect on white sugar yield and sugar content. Shifting of harvest time from 22 May to 22 June significantly increased sugar yield, white sugar and sugar content. Bolting resistant cultivar had higher root, sugar and white sugar yield than the other two cultivars. In conclusion, sowing of bolting resistant sugar beet cultivar in early November and harvesting in late June had the least bolting rate (1.32%), highest root (49.81tha-1), sugar (7.63tha-1) and white sugar (6.26 tha-1) yields in autumn sown sugar beet in Moghan region in Iran.

To evaluate effects of gibberllic acid, gridling, berry and bunch thining and their combination on fruit maturity, berry and bunch characteristics of grape cv. Yaqooti an experiment was carried out using randomized complete block design with three replications in Kavar, Shiraz, Iran, in 2010-2011 growing season. Each experimental plot consisted of three vines. Treatments included: T1: gibberllic acid spry (50 mg/l), T2: girdling, T3: berry thining, T4: bunch thining, T5: girdling+berry thining, T6: girdling+bunch thining, T7: girdling+gibberllic acid spry, T8: girdling+berry thining+bunch thining, T9: gridling+berry thining+gibberllic acid spry, T10: gridling+bunch thining+berry thining+gibberllic acid spry, and T11: control (No treatment). Results showed that gridling promoted fruit maturity (8 days earlier than control) and the largest berries which was significantly (P<0.01) different from other treatments. Therefore, trunk gridling was the most effective treatment to improve berry quality and maturity. Fruit maturity was the latest in gibberllic acid treatment. Hence, due to commercial importance of early fruit maturity of cv. Yagooti, as a novel fruit, gibberllic acid treatment is not useful.