محسن آقایی زاده

Sugar beet is one of the root knot nematode (Meloidogyne spp.) hosts and destructive virus (Beet necrotic yellow vein virus, BNYVV) which is the cause of rhizomania disease. The use of resistant cultivars is the simplest and most efficient method of managing plant diseases. Based on this, to develop a cultivar resistant to rhizomania and root knot nematode in sugar beet, two populations carrying resistance genes to the above-mentioned diseases were identified and selected. From the target population, 10 half-sib families were developed and crossed with single cross monogerm 7112*SB36 and 10 monogerm hybrids were developed. Evaluation of hybrids in terms of quantitative and qualitative traits led to the selection of four superior hybrids including SBSI043, SBSI042, SBSI041 and SBSI044. Results of combined analysis of these hybrids with a domestic resistant control to rhizomania (Arya) and two foreign resistant controls (Castile and Rosier) and a susceptible cultivar for two years in a field infected to rhizomania in four regions (Mashhad, Shiraz, Hamadan and Qazvin) showed the complete superiority of all four hybrids compared with domestic resistant control. This hybrid was recognized as the best domestic hybrid in the test to determine the agricultural capacity of new domestic cultivars in seven infected and non-infected regions of the country, with an average sugar yield of 8.79 tons per hectare after two foreign controls. The new hybrid SBSI043 is the first cultivar with double-resistant (rhizomania and root knot nematode) named "Asia" and was introduced to growers for spring cultivation in different regions of my country, especially the regions infected to both diseases and exports to Azerbaijan, Syria and Egypt countries.

Green house studying especially for salinity stress needs suitable medium. It is necessary to determine suitable medium in greenhouse studies for screening germplasm, which is easily available, stable in terms of electrical conductivity and cost-effective. Soil, and Perlite are common mediums which are used in green house researches generally, but there weren’t enough reports for study hydroponic system for screening sugar beet germplasm. Drought and salinity stress happens at the same time in most regions of Iran and because of similar tolerance mechanisms for these stresses, drought tolerant germplasm could be used in screening for salinity.so the goal of this project was to evaluate different medium especially hydroponic to screening sugar beet drought tolerance genotype in salinity stress.

The project was conducted in two experiments: (a) A factorial experiment based on completely randomized design with four replications was conducted in SBSI research greenhouse. The first factor was three planting media in combination with nutrition solution as follows: 1) loamy soil with about 5% organic matter, 2) perlite with Hoagland solution, 3) hydroponic environment with Hoagland solution. The second factor consisted of two levels of salinity including normal and salinity (16 dS m-1) treatments and the third factor consisted of two sensitive and tolerant genotypes. (b) 17 selected genotypes were investigated in greenhouse with perlite medium under control and salinity 16 dS m-1 in factorial experiment based on completely randomized design with four replications. Different quantitative and qualitative traits such as root. Shoot and total dry weights, K/Na, Soluble carbohydrates, glycine betaine were measured in both experiments and statistical analysis were done by MSTATC and SPSS and mean were compared in Duncan multiple range test at (α=0.05).

Cross effects of medium and salinity were significant on total and shoot dry weights, P, K/Na. Cross effects of medium, salinity and genotypes were significant on most of the traits. Crop yields under salinity stress were less in soil in comparison to other mediums, also salinity had significant effect on soil EC and Na (P≤0.01), soil and perlite were salinized respectively 6 and 2 times in comparison to normal condition. Which shows that soil is not stable medium for salinity study in green house. The highest yield (3.31 g p-1) was obtained from hydroponic. Yields achieved from hydroponic and perlite mediums were similar under salinity, but water consumption was more in hydroponic than perlite. In establishment stage, the total dry weight, soluble carbohydrates, glycine betaine and K/Na ratio were suitable for selection of sugar beet genotypes under salinity stress. According to all measurements, the clustering in establishment stages and Stress Tolerance Index (STI), HSF-91018, HSF-91040, HSF-92870, HSF-92881, HSF-92884, genotypes were selected as tolerant genotypes as controls.

Sensitive and tolerant genotypes were not distinguished well in hydroponic medium, which related to its potential and was mentioned in other reports. Hydroponic and perlite were in the same group for different traits especially they became less salty than soil but hydroponic system is not useful for root beet but it would be suitable for forage beet because biomass production is more in this condition. Also, soil is not suitable medium for study salinity researches because it became seven times more salty than normal condition. As a result perlite is the best medium for salinity studies in sugar beet because it becomes less salty, it has low weight and cost and has less side effects on environment. According to all measurements, the clustering in germination and establishment stages and Stress Tolerance Index (STI), HSF-91018, HSF-91040, HSF-92870, HSF-92881, HSF-92884, genotypes were selected as tolerant genotypes as controls.

Rhizomania is the most destructive disease in spring sugar beet along with root-knot nematode and are spreading in some parts of Iran. The best control method against these two diseases is using resistant cultivars. Therefore, the aim of this study was to develop and select a high yield hybrid resistant to rhizomania and root knot nematode. Twenty-seven full-sib families (S1) from SB-34 origin which screened with molecular markers for rhizomania and root knot nematode resistance gene, were used to develop double resistant hybrids. In the spring of 2015, vernalized families were crossed to one single cross (7112*SB-36) in separate isolates. In summer, S1/S2 seeds from the paternal plants and three-way cross hybrid seeds from maternal plants were harvested and cleaned. Out of 27 isolates, only 19 isolates had adequate seeds from both parental lines. In autumn of the same year, selected hybrids were planted in greenhouse in Karaj. Seedlings were analyzed by SCAR and SNP markers linked to rhizomania and root knot nematode resistance genes to determine gene frequencies in hybrids. Based on the results of molecular evaluation, 14 hybrids were selected. In the spring of 2016, selected hybrids along with some controls, overall 20 varieties, were planted in two rhizomania-infected areas in Khorasan Razavi and Fars based on randomized complete block design with six replications. Roots were harvested in autumn and qualitative and quantitative characteristics such as root yield, sugar content, and white sugar yield were measured. Data were analyzed using SAS 9.1.3 software. According to the results of field trials and the frequency of rhizomania resistance gene and root node nematode in the laboratory, hybrid SB36*(7112*930620) with 10.92 t/ha white sugar yield to be used.

Food security is affected by many factors, including increased demand, high input prices, soil degradation, the need to limit greenhouse gas emissions, and increased competition for land and non-potable water. In addition, climate change is expected to have an increasing impact on performance, with statistical analysis of product performance indicating that such an event is taking place. The purpose of plant breeding programs is to develop new varieties with improved characteristics such as yield and nutritional quality. Sugar beet is a root crop specific to temperate regions mainly produced as a sucrose source for human diets. Sugar beet can be planted on any continent except Antarctica, but it performs best in temperate climates. Worldwide production of sugar beet is relatively stable. Studies on the effect of environment and year on sugar beet yield has a long history in Iran. However, it is difficult to achieve a general conclusion due to the dispersion and disparity in the results of various studies. In this study, a meta-analysis method was used to integrate and re-analyze results of independent experiments to achieve a single result.

Twenty-one experiments carried out at Motahhari Research Station in Karaj, Iran during 2002-17 were evaluated. The effect size was calculated and studies were weighted by replication. Then, the mean effect sizes were estimated followed by confidence intervals, effect size back-transforming and graphs were designed.

Among studied years, the highest mean root yield of 89.5, 89.1 and 87.8 t ha-1 were obtained in 2018, 2006 and 2012, respectively. Results integration showed that in 2006, 2011, 2014, and 2017, root yield of sugar beet increased by 19.2%, 2.2%, 2.8% and 18.6%, respectively. Different parameters can be used to describe improved agricultural productivity; one of which is the yield increase over time attributed to advances in plant breeding as well as changes in crop operations and environmental conditions (especially climate). Another parameter is the yield potential of a crop described as the performance of a cultivar grown in compatible environments without nutrient and water restrictions and under the effective control of pests, diseases, weeds, and other stresses. Meta-analysis results showed that increase in sugar yield of sugar beet genotypes was similar to the root yield, with the difference that in the years 2006, 2011, 2014 and 2017, variations in percentage was less than root yield. One of the most important results in this study was the illustration of the reduction in slope of negative relationship between root yield and sugar yield in commercial cultivars.

In this study, trials were performed under normal conditions and in a disease-free environment. According to the obtained results, use of meta-analysis method in breeding programs to estimate the effect of year on performance along with other statistical methods is recommended.

In order to understand the role of maternal parent in producing sugar beet cultivars resistant to rhizomania, root rot, and beet cyst nematode diseases, 12 single crosses resistant to rhizomania, three normal single crosses, and two male sterile lines were crossed with two pollinators. One of the pollinators (SB36-S1-3) was resistant to beet cyst nematode and the other one (33345-93) was resistant to rhizomania and root rot. The presence of rhizomania and cystic nematode resistance gene in parents and hybrids was determined. Hybrids were evaluated in two trials of 20 (hybrids resistant to rhizomania and beet cyst nematode) and 16 cultivars (hybrids resistant to root rot and rhizomania) in five locations including Shiraz, Ghazvin, Mashhad, Torbat-e-Jam and Hamadan. In 20 cultivars trial, hybrid (201-25*301-28) *SB26-S1-3 with the presence of 35% MN gene and 100% Rz1 gene as well as 6.53 t/ha white sugar yield (equivalent to 149% of Arya) was selected as the superior hybrid. In this trial, foreign control cultivars namely Toucan and Succara produced 5.85 and 8.08 t/ha white sugar yield, respectively. In 16 cultivars trial, hybrid (201-25*301-28) *33345-93 with 132% of the control cultivar Ekbatan in terms of white sugar yield (4.72 t/ha) was the superior hybrid. This hybrid lost 10% of its individual plants during the growing season because of root rot. Under this condition, Ekbatan, Boomerang, Perimeir, Novodoro, and Sharif cultivars lost 12, 7, 12, 4 and 28 % of their plants during the growing season, respectively. Hybrid (201-25*301-28) *33345-93 produced 6.23 t/ha white sugar yield which was more than Novodoro (5.55 t/ha), Boomerang (5.52 t/ha) and Perimeir (3.97 t/ha). Single cross 201-25*301-28 with 90% presence of Rz1 gene, virus concentration of BNYVV in a level of Brigita, resistant foreign control, and producing highest sugar yield in crosses with both of pollinators was introduced as a superior maternal parent for new hybrid production.

Rhizoctonia root rot disease is considered as one of the important diseases in sugar beet. Using resistant cultivars decreses production costs, especially application of fungicides and increases the efficiency in controlling of root rot disease. Therefore, growing of resistant cultivars is considered the best approach for disease control. To achieve this goal and to determine yield potential of new sugar beet hybrids resistant to Rhizoctonia root rot disease, 92 hybrids as well as susceptible and resistant cultivars were evaluated in two experiments in research field of Ekbatan station of Hamedan, Iran in 2016. Considering the experimental results and with respect to the average effect of pollinators and single crosses, 20 hybrids were selected and evaluated in Karaj, Hamedan, Ghazvin, Torbate Jam and Shiraz regions in 2017. Evaluation of hybrids in term of resistance to rhizoctonia was simultaneously performed under micro-plot conditions in Hamedan. In both years (2015 and 2016), the experiment was conducted in randomized complete block design with six replications. The results of resistance evaluation under micro-plot conditions reavealed that five hybrids consisting; 9, 13, 16, 4 and 18 were more resistant than cv. Ekbatan for resistance to rhizoctonia root rot disease. Yield potential evaluation in different locations showed that new hybrids had desirable level of yield potential and most of them had no significant difference with cv. Ekbatan.Considering the results of resistance to rhizochtonia disease and yield potential evaluation, three hybrids no. 4 (SC(P.395*P.90)*P.165), no. 9 (SC(P.395*P.90)*P.121) and no. 16 (SC(P.395*P.23)*P.165) that were more resistance with higher yield potential in comparison with cv. Ekbatan were identified as promising hybrids for being evaluated in Value for Cultivation and Use (VCU) test.

Using resistant cultivars is the best way to reduce damages caused by sugar beet root rot and rhizomania. In order to develop resistant cultivar to these diseases, sugar beet genotypes were evaluated under artificial inoculation to rhizoctonia and one of the pollinators was selected as the most resistant population to rhizoctonia (SB19) in 2003. Self-fertile lines and hybrids were derived from non-inoculated roots of this population in 2004 and 2005, respectively. Selected hybrids were compared in terms of yield in different regions for two years and also pollinator lines were evaluated in terms of resistance under micro plot conditions in Hamedan. Results showed that sugar yield of a hybrid that its pollinator was selected as Ekbatan cultivar’s pollinator was 10.2 t.ha-1 and decease index of its pollinator was 2.16. Average sugar yield of Ekbatan in infested and non- infested regions with rhizoctonia was 9.1 and 7.0 t.ha-1, respectively. According to the results of yield and resistance to rhizoctonia evaluation, 10 superior lines were selected. In order to obtain resistant hybrid to rhizoctonia as well as tolerant torhizomania, 18 hybrids were developed by crossing those 10 superior lines with some male sterile lines that were resistant to rhizomania. Yield comparison of the hybrids was performed in three different regions that were naturally infested with rhizoctonia and rhizomania during 2010 and 2011. Two-years averages of sugar yield for (7112*SB36)*S1-24 hybrid that was released as Ekbatan in those regions were 8.7, 8.9 and 9.3 ton.ha-1, respectively. In general, results indicated that yield and resistance of Ekbatan cultivar was similar to the foreign resistant cultivar. The time needed to reach 90% seed germination by Ekbatan was 80 hours that is faster than that for Flores and Jolgeh cultivars. This indicates the higher germination rate of this cultivar.

Over 50% of the sugar beet fields in Iran are infested by rhizomania and beet cyst nematode diseases. Using resistant varieties is a simple and efficient method of managing these diseases. In 2015, Shokofa was released as the second domestic monogerm variety, resistant to both rhizomania and beet cyst nematode. White sugar yield of this variety under infested field condition was 7.44 tha-1 which was in the same group as foreign control Ludwina (8.28 tha-1) and domestic control Tous (7.32 tha-1). In an experiment conducted in greenhouse, the resistance of Shokofa variety to cyst nematode was evaluated and results showed that the average number of cyst on Shokofa root was 30, while two foreign controls including Pauletta and Sanetta infested with 23 and 26 cysts respectively, and the susceptible control Jolge was infested with 114 cysts. Based on two on-farm experiments conducted in Khoy and Fariman Sugar Factories in 2014, the sugar yield of Shokofa was 9.23 tha-1 that was almost equal to sugar yield of Toukan cultivar (9.47 tha-1), a foreign sugar beet control. However, under rhizomania infected fields in Neishabor and Qazvin Sugar Factories, the sugar yield of Shokofa was 7.17 tha-1 which was higher than all domestic and foreign controls.

Autumn sugar beet planting demands less water than spring, however, one of the main requirements of autumn planting is bolting-resistant cultivars. Depending on the climatic conditions of the sugar beet growing region, different levels of bolting-resistance is required. The aim of the present study was to develop and evaluate sugar beet pollinators resistant to bolting based on half-sib genotypes selection. In October 2010, 250 half-sib families developed from two tetraploid populations 12460 and 12650 were grown and screened for bolting resistance in Oltan Agricultural Research Station in Moghan, Ardabil, Iran. Based on the results of bolting evaluation, four and one resistant populations were selected from 12460 and 12650 populations, respectively. In 2013, 120 families were developed from four populations of 12460 and 90 half-sib families were developed from single population of 12650. Selected families together with parental populations, four resistant and one susceptible controls were grown in autumn in 2013-14 and 2014-15 in randomized complete block design with three replications, in Moghan. Considerable variation was found among half-sib families for bolting resistance. Ninety-eight families in population 12460, and 47 families in populations 12650 showed significantly higher resistance than parental population illustrating the positive effect of selection for bolting resistance. Narrow-sense heritability for bolting resistance was estimated 85% and 66% for half-sib families developed from 12460 and 12650 populations, respectively.

In this research, the reaction of 138 sugar beet half-sib families and their 11 parental populations to powdery mildew (Erysiphe betae Weltzien Vanha) was studied in a randomized complete block design with three replications at Motahari Research Station, Karaj, Iran in 2013. A linear scale of 0-9 was used for disease rating. On the basis of disease scoring conducted in 10th September, 22 genotypes with a score lower than 2.5 were found to be disease resistant. The families HSF-850, HSF-853, and HSF-848 with the disease score of 1, 1.2, and 1.3, respectively, were the most resistant families. Regression analysis showed that white sugar yield and sugar content were decreased by increasing the disease. Cluster analysis classified the initial populations as well as their half-sib families into 7 groups. Among these, most of the tolerant/resistant genotypes were clustered in the group 5 which could be used for resistance transfer. The cluster 2 included the genotypes HSF-584, HSF-582, HSF-557, HSF-551, HSF-866, HSF-844, HSF-670, HSF-556, HSF-628, HSF–610, HSF-564, HSF-685, HSF–619, HSF–664, and HSF-558 which were considered as families with optimum root yield, white sugar yield, white sugar content and sugar content. Therefore, these families could be used as pollinator parents to develop hybrid varieties or they can be exploited in the next cycle of family selection to develop new half-sib or full-sib families.

O-type lines have an important role in sugar beet breeding as their cross with CMS lines results in male-sterile single cross production which can be used as female in cultivar development. In this study, thirty-six O-type lines resistant to rhizomania disease were produced from two breeding populations. Lines were evaluated for rhizomania resistance in Zarghan station, Fars province using a randomized complete block design with four replications. At harvest, roots were scored for infection to rhizomania. At the same time, genotypes were evaluated for the presence of resistance gene using molecular marker. Among O-type lines, lines 32302 and 32304 had lower scores than imported resistant check cultivar and in total, 18 lines together with two parental lines and resistant check cultivar were placed in one group. Gene presence percentage for resistant and susceptible check cultivars was 92 and 0%, respectively. There was 65% association between gene presence and average disease infection score of genotypes.

Bolting results in fibrous root formation, impurity increase and quality reduction in sugar beet. In order to develop bolting tolerant hybrid, 464 tetraploid pollinators were evaluated in three regions including Kashmar, Darab, and Moqan, Iran in 2009-10. Eleven selected pollinators were crossed with a diploid female parent. Bolting tolerance and quantitative and qualitative traits of triploid hybrids together with five tolerant controls were evaluated in a randomized complete block design with four replications at Safiabad Agriculture Research Centre in 2011-12.Significant difference was observed among cultivars for bolting percentage. The minimum (1.02%) and maximum (8%) bolting was observed in (474*7112)*(19669–9–HSF–4) and (474*7112)*(19669–11–HSF–8) hybrids, respectively. Significant difference was observed among the hybrids for root yield and white sugar yield. The maximum (9.80t.ha-1) and maximum (5.83 t.ha-1) white sugar yield was obtained in (474*7112)*(19669–2–HSF–4) and (474*7112)*(12460–2–HSF–2) hybrids, respectively. Based on the results, hybrids derived from the pollinators 19669–9–HSF–4 and 19669–11–HSF–8 showed the minimum and maximum bolting percentage, respectively. In conclusion, the hybrid (474*7112)*(19669–7–HSF–2) is recommended as superior hybrid for sowing in Khuzestan province and similar regions.

Developing new drought tolerant sugar beet varieties, is one of the most effective ways to decrease the production damage caused by drought stress. In this research 23 superior families selected from 150 half-sib families, crossed with a female parent under drought stress condition. Based on the results four new hybrids were obtained by crossing between, two drought tolerant half-sib families as male parents, with two monogerm female parents. Paya cultivar as one of the hybrids showed the highest average root yield (50.50 t/ha) compared to check variety Gadouk with 36.50 t/ha in preliminary and advanced experiments, during 2010-2014 under drought stress and non-stress conditions. Also, the average seasonal water use of Paya was 15000 and 9500 m3/ha under non-stress and stress conditions respectively, which showed 30-40% saving in water use. The new cultivar indicated superiority root yield 17, 22 and 10 t/ha more than check cultivar Gadouk, under drought stress conditions, in onfarm trials in Karaj, Mashad and Shirvan regions.

Determination of resistance sources is essential for development of varieties resistant to biotic and abiotic stresses. Germplasm evaluation can offer valuable breeding materaials which result in different tolerant combinations. In this study، 47 sugar beet monogerm o-type lines (male strile maintainer) along with two susceptible and two resistant checks were evaluated for resistance to Cercospora leaf spot in in vitro conditions using leaf disk method. The test was conducted based on a completely randomized design with three replications. In each replication، 10 leaf disks from 10 plants were checked for every genotype. The leaf disks were sprayed with fungal spores in in vitro conditions and after 8 days the number of spots was counted in leaf area index. Based on the results، most of the genotypes showed susceptibility، but 5 monogerm lines had no significant difference with resistant check. The selected genotypes along with three susceptible genotypes، a susceptible check and a resistant check were evaluated in natural infected conditions. The trial was carried out using to a completely randomized block design with four replicates. Plots were scored three times according to a 1-9 scale and the mean of four replications was used as the score of each genotype every time. According to the results، the susceptible genotypes recevived high score and were susceptible in the field condition. From 5 selected genotypes، only one line acted in a similar way to resistant check and had no significant difference with it.

To determine tetraploid pollinators resistant to Cercospora leaf spot disease and bolting with optimum yield and quality, five tetraploid pollinators were crossed with a male sterile line, SB17. The hybrid seed was harvested from the male-sterile line. The hybrids together with four controls including resistant and susceptible cultivars (a total of 9 cultivars), were evaluated in a randomized complete block design with four replications in autumn sowing over two years in Dezful, Khuzestan, Iran. The yield stability of the hybrids was evaluated in spring sowing over two years in Karaj. Combined analysis results showed that hybrids SB17 * Jot-18 and SB17 * B65T had the lowest infection index (3.12 and 3.93, respectively) and bolting rate (0.87 and 0.75%, respectively). Based on sugar yield results obtained from Dezful experiment, hybrids were classified in three clusters in which hybrids SB17 * Jot-18, SB17 * B65T, Monotona, and Leila were placed in one group. The hybrid SB17 * B65T had the highest sugar yield (7.13 t/ha) in Karaj. It is suggested that the tetraploid pollinator B65T can be used in breeding programs to produce leaf spot disease and bolting resistant hybrids.

Beet necrotic yellow vein virus (BNYVV) or rhizomania is one of the most important and destructive diseases of sugar beet (Beta vulgaris L.) in the world. This disease is considered as a limiting factor of sugar beet production in Iran such as Khorasan, Fars, West Azerbaijan, Isfahan and Kermanshah. In order to develop of resistant variety, as simple and easy methods for disease control, a germplasm carrying the Rhizomania resistant gene was incorporated into the selection program in 2002. At harvest, desirable single plants were selected and S1 seeds were produced from each individual plant under cage in 2003. In 2004, each S1 family was test-crossed with a monogerm male sterile female. In 2006, yield trials conducted in a disease nursery in Fars province showed that a hybrid SB37×SHR02-P.4 was superior. This hybrid, coded as SBSI006, was further evaluated in naturally infected fields for disease resistance and root yield during 2008-2012. Results of combined analysis showed that the above-mentioned hybrid with a root yield of 76.12 t/ha was significantly different from the susceptible (Jolgeh, 41.08 t/ha) and recently developed tolerant (Zarghan, 49.12 t/ha) check varieties. The relative superiority of this hybrid as compared to the domestic varieties Zarghan and Pars in yield trials conducted in the field of sugar factories as well as research-extension fields of Khorasan province and also the frequency of disease resistance genes in 70% of the plants of this hybrid makes the hybrid suitable for the northeastern part of the country, considering that the disease agent has a high genetic variation in Great Khorasan province. The hybrid is a diploid monogerm variety tolerant to Rhizomania disease and is suitable for spring sowing. The growing period of this variety is 180 days with the most suitable sowing date being late March. The optimum plant density of the variety is recommended to be 120000 plants per hectare.

In order to assess the heritability of short vegetation period (early maturity) of sugar beet hybrids, an experiment was carried out in randomized complete block (RCB) design with 4 replications in Abdolrasoul Motahari Agricaltural Research Station of Sugar Beet Seed Institute, Karaj, Iran in 2009. In this research, the heredity of the traits in testcrosses derived from crosses of 18 half sib families with a male sterile line accompanied by a short vegetation period check variety was evaluated under late sowing condition (about late June). ANOVA results showed that there were no significant differences among the testcrosses for most of the traits- Means comparison showed that the hybrids 3, 9, and 16 had slight difference with the check variety for most traits. The testcross 3 was considered suitable for short growth period which was comparable with the commercial check variety. For morphological traits (such as leaf number and crown height) and some impurity traits (such as sodium and extraction coefficient of sugar), narrow- sense heritability was high. Therefore, there is still possibility to improve the above- mentioned traits with respect to the short vegetation period in the half- sib families. For root yield, sugar yield, and white sugar yield, the heritability was about zero. Root yield had significant positive correlations with sugar yield, white sugar yield, root diameter, and crown height and significant negative correlation with sugar content.

Rhizomania is the most important disease of sugar beet in Iran and some other parts of the world, and plays an essential role in decreasing sugar yield in fields. The best approach to control this disease is to use resistant varieties. Tagging the resistance genes in breeding programs, by molecular markers is necessary. In this study, some breeding populations and commercial varieties of sugar beet originated from Rz1 resistance source were used for validation and repeatability of 6 repulsion molecular markers. Accordingly, ELISA data related to greenhouse evaluation of rhizomania resistance were used in some breeding populations. For molecular analysis, DNA was extracted from leaf samples and RAPD-PCR was performed by using the primers related to the markers of interest. The RAPD-PCR products were separated by gel electrophoresis, After electrophoresis, was stained with ethidium bromide and was observed using gel documentation device and finally was scored for the presence or absence of marker bands. In next step, conformation of the markers with ELISA data in single plants were measured in breeding populations and the precent presence of the markers in commercial varieties was determined. Comparison between ELISA and molecular analysis results showed that repulsion markers (the markers linked to the susceptibility allele) PN3 and PN7-2 had acceptable agreement with ELISA (92% and 98% respectively), susceptible varieties (87% and 90% respectively), and resistant varieties (75% and 97% respectively). Also, the results of the gene dose effect showed that the average OD value of ELISA of the dominant homozygote plants (Rz1Rz1) was significantly lower than the heterozygote plant (Rz1rz1) in the repulsion markers.

In this research, 30 sugar beet breeding populations developed by crossing of sugar beet monogerm and multigerm male strile lines with nematode resistant wild sources (W-1009 contaning resistance gene from Beta procumbens and W-1010 contaning resistance genes from Beta maritima) were compared with resistant and susceptible checks with respect to nematode resistance and yield. The experiments were conducted as randomized complete block design with four replications in 2005- 2006, under beet cyst nematode (BCN) infested fields in Mashhad and Khoy areas. The reproductive factor (RF) of BCN was also estimated. The number of eggs and larvae of the nematode in the first and second year of the trials in the two areas was 424 and 476 cysts or larvae per 100g soil, respectively. The results of field trials and cluster analysis based upon sugar yield showed that the genotypes 231×(MSC2×W-1009)-P, 231×(MSR×W-1009) ×FC709-2, 231×(MSR×W-1010) and 231×(MS261×W-1010) had high yield potential and were grouped with the foreign resistant check in the same cluster. However, the genotypes 231×(MSR×W-1010), 231×(20447×W-1009), 261×(MS20314×W-1009) and 231×(MC2×W-1009) had the lowest reproduction factor (RF) in the field trials. Therefore, the above-mentioned genotypes could be used for developing nematode resistant varieties. Among those, the genotype 231×(MSR×W-1010) was superior to the resistant checks with respect to both traits and thus it was identified as a resistant genotype with a high yield potential.

As water is the most restrictive factor in national agricultural production, it is necessary to take decreased water consumption and increased water us efficiency in crop production into consideration. Nowadays, spring sugar beet production areas are concentrated in the region with water limitation and hence, the increase in spring production area contradicts the principle of water and soil conservation. Using new regions for autumn sugar beet sowing allows the increase in warm and semi-warm beet production areas. To develop sugar beet production in Province of Kerman and to find new climates, the study was conducted in Jiroft area in strip split split plots based on Randomized Complete Block Design (RCBD) with three replications during 2007-2008. Three sowing dates (September 6, October 7 and November 6), five cultivars (Rasoul, Monatuna, 9597, SBSI002 and SBSI003) and three harvesting dates (April 4, May 5 and June 5) were evaluated. Results showed significant effects of sowing and harvesting dates on white sugar yield. The effects of sowing date variations were greater than those of harvesting date so that growth period shortened by two months (due to delayed sowing date) decreased white sugar yield by 72.5% whereas and growth period prolonged by the same amount (due to delayed harvesting date) increased the white sugar yield by 55.1%. The highest white sugar yield (13.71 ton.ha-1) was obtained by early sowing (September 6) of SBSI002 and harvesting in May 5(with 240 days growth period). Considering favorable agro-climatic conditions in Jiroft region belonging to warm zone of Province of Kerman, it seems that the region has the potential for fall cultivation of sugar beet.

Stem going in sugar beet at first years is call bolting. Bolting is undesirable physiological phenomena that almost occurred in planting of winter sugar beet. Planting of winter sugar beet required to resistance cultivars to bolting for avoidance of flowering in spring harvest time. Aim of this experiment using of cycocel for avoidance of flowering in winter sugar beet. Experiment carry on in form of factorial in base of randomize complete block design with three replication in winter 2009. We have two cycocel factors comprise of foliar application in two levels 0 and 1000 ppm and foliar application time with seven levels comprise of control seed sprayed, 6th November, 6th December, 6th November & 6th December, seed sprayed &6th November & 6th December,6th February, 6th November & 6th December&6th February.Result showed that application of cycocel reduce bolting percentage and caused delay of flowering process but winter cold severe condition in Karaj have been effects dominant on cycocel treatments as at the end of sampling date was not significant different between cycocel and control treatments on bolting. Percent of bolt in control treatment and cycocel was 48.59%,43.38% respectively.The best time for spraying cycocel was 6th february with the lowest percent of bolt (39.2%).

In the present study selected indicator from previous studies (non-placental markers AM2), on DNA of single plants of modification mass obtained by cross breeding wild species Beta maritima (having resistance gene Rz2) with sugar beet were called to F2BC1 mass were investigate. To do this first about 1160 seeds of target mass were planted and after one month plants preparation, about 100 Seedling applied to evaluate the phenotypic resistance to the rhizomania contaminated soil was moved to the greenhouse and two months were maintained in this soil. During this period, DNA of plant leaf samples was extracted. Then the quality and quantity of extracted DNA spectrophotometrically was determined. Next, AM2 markers related- primer on single plant DNA with PCR-RAPD method was used to amplify fragments of DNA template. After electrophoresis, RAPD-PCR reaction products in one percent agarose gel and staining gel and observation of the band pattern, presence or absence of markers in a single plant was marked. Then the resistance level of plants cultivated in soil contaminated by the virus concentration in plant roots with Elisa serological tests in the laboratory was determined. Thus the resistant and susceptible plants were identified. The relationship and degree of correlation and agreement between markers (based on molecular data) and resistance (based on ELISA data) in desired single plants was found. By comparing the mean and variance analysis for non-balanced completely randomized design, it was found that the average values of absorbed ELISA of dominant heterozygous and homozygous genotypes has no significant difference. Also comparison of the results for the existence percentage of markers traits as a balanced completely randomized design with four genotypes, including mass F2BC1 (having resistance gene Rz2), Regina (Rhizomania susceptible control varieties), Paulleta (Rhizomania resistant control varieties) and breeding mass S1 (with Resistance gene Rz1) showed that there is no significant differences between genotypes and reproducibility of non-placental markers AM2 in different genotypes was confirmed.