mohammadali chegini

Sugar beet seed plants about five to six weeks after the formation of a seed stem, flowering started and within two weeks, this stage of plant growth will be completed. A significant negative correlation between the temperature received from flowering to seed maturity and the plant reproductive growth period with grain yield shows that the long plant reproductive growth period, will lead to a decrease in seed yield. With the postponement of phonological stages of sugar beet seed plants the possibility of synchronization of plant reproductive stage, with unfavorable conditions increases which leads to loss of yield. To increase the yield, it is necessary to do research on issues such as seed breeding and farm management reform in the production of sugar beet seed according to variety to be done. In this regard, little research has been done in Iran. Therefore, this study aimed to investigate the occurrence of phonological stages and morphological characteristics and its impact on quantitative and qualitative characteristics of hybrids monogerm sugar beet seeds were. This study was conducted in Ardabil Agricultural Research Station (Alarough) in two years (2011-2012 and based on a Completely Randomized Block Design. The experimental treatments were five promising diploid cytoplasmic male sterile (CMS) lines (7112×SB36, SB37×28874, 7112×436, 419×SB36 and 261×231) of sugar beet. Each plot consists of eight lines planting and hybrid varieties were sown in strips in female: male ratio was 6: 2. Phonological characteristics, including the emergence, bolting and flowering components, during daily visit were recorded at the time specified. For the evaluation of plant morphological characteristics, before harvest, five plants of each plot were randomly selected and evaluated in the laboratory. The results indicated that there were significantly differences among CMS lines in respect to phonological and morphological characteristics and quantity and quality of seed. The maximum number of main branch and auxiliary branch, and plant dry weight was obtained in 7112×SB36 and SB37×28874. But, for line of 261×231, number of main branch and auxiliary branch and plant dry weight was lower than other lines, and the highest crude seed yield was observed in the 7112×SB36 and SB37×28874 and the lowest of crude seed yield was observed in 261×231. These data indicate that there is a positive correlation between phonological and morphological characteristics with the quantity and quality and negative correlation between plant heights with seed yield Considering that there is a positive correlation between phonological and morphological characteristics with the quantity and quality and negative correlation between plant heights with seed yield. Therefore, the sugar beet institutions must, prior to the introduction of CMS lines, assess the CMS lines on the morphological characteristics and do advise in the fields planting density and pruning plant announced. While in Iran (Ardabil), for the production of sugar beet seed, planting operations often regardless of the morphological characteristics of crop varieties, with a density of 50 × 70 doing and plant density and topping of seed plants on seed production in Iran has never been considered.

In this research the effects of size and halving of sugar beet steckling on stem length¡ number of main stem¡ shoot weight and seed yield were investigated. Experiment was conducted in 28 Dec. and 21 Feb. 2014 in field in split split plot design with 10 replications. Treatments were combination of three paternal HM5514¡ S1-24 and SB26 two levels of whole and sliced stecklings and three levels of size of stecklings. Results showed that root size had significant effects on stem length and seed yield. Where¡ the tallest of main stem of stecklings with crown diameter 1.71¡ 1.59¡ 2.29 and 2.44 cm were 60¡ 67¡ 99 and 114 cm¡ respectively. Results also showed that seed yield of of stecklings with crown diameter 3.39¡ 4.80 and 6.28 cm were 15.35¡ 22.64 and 31.13 gr¡ respectively. In addition¡ seed yield was reduced by slicing of steckling. However¡ total seed yield of 2 sliced steckling were significantly more than one whole steckling.

In this research studies the effects of duration of vernalization¡ size and halving of steckling on bolting¡flowering and seed setting of sugar beet were studied by conducting three experiments. First and second experiments were conducted in 28 Dec. and 1st Feb. 2014 in glasshouse. Treatments were stecklings of HM5514¡ two levels of whole and sliced stecklings and four levels of size of stecklings. Experiment was conducted in CRBD. The 3rd experiment was conducted in 28 Dec. and 21 Feb. 2014 in field in split split plot design with 10 replications. Treatments were combination of three paternal HM5514¡ S1-24 and SB26 two levels of whole and sliced stecklings and three levels of size of stecklings. Results of 1st experiment showed that no bolting occurred in even 100 days after stecklings replanting. Bolting occurred in 2ndand 3rd experiments 50 and 29 days after stecklings replanting¡ respectively. In 2nd experiment negative correlation was exist between stecklings size and time to bolting. Where¡ in stecklings with crown diameter 3.13 and 6.24 cm bolting occurred 60 and 50 days after stecklings replanting¡ respectively. In 3rd experiment¡ stecklings with crown diameter 3.4 and 6.3 cm bolting occurred 32 and 29 days after stecklings replanting¡ respectively. So¡ when verbalization requirement were fulfilled¡ there was no correlation between stecklings size and time to bolting. Bolting was postponed by slicing of steckling.

This research was carried at The University of Reading in 1999. The aim was to estimate the effects of 18 hd-1 (long-day, LD) and 12 hd-1 (short-day, SD) light exposure duration of plants before bolting or flowering on time to bolt and flower in two bolting susceptible (BSG, IC1) and bolting resistant (BRG, SAXON) genotypes of sugar beet. So, two experiments were conducted. The experiments were carried in a glasshouse containing two compartments. The photoperiod in compartments one and two was adjusted to 18 hd-1 and 12 hd-1, respectively. In the experiment one, the aim was to determine duration from root replanting to bolting and flowering. So, plants were exchanged from LD to SD and vice versa at 0, 8, 21, 33, 40, and 47 days after root replanting. In the experiment two, the aim was to determine the duration from bolting to flowering. So, at first step we let all the plants bolt in the LD and then they were reciprocally exchanged from LD to SD and vice versa at 0, 8, 16, 24, 40, and 30 days after bolting. Results showed that BSG responded to LD from root replanting whereas BRG had a longer photoperiod-insensitive pre-inductive phase. The resistant genotype plants did not bolt even after 180 days. When BSG plants were exposed to SD after bolting all of them eventually flowered. This results indicated that by the time of bolting, photoperiod requirement for flowering was also fulfilled, whereas BRG needed further inductive photoperiod after bolting to flower. Therefore, bolting and flowering are two independent phenomena and they require different LD cycles. BSG is a quantitative LD plant in which bolting and flowering occur sooner in LD than in SD. However, very resistant genotypes (e.g. Saxon) showed a more or less obligate requirement for LD and did not bolt in 12 h photoperiod within 180 days after root planting. So, it is suggested that sensitivity to day-length seems to be a good selection tool to reduce the tendency for bolting in plant populations.