Seed and Plant
Year:2003 | Volume:19 | Issue:3|Papers Count:10

Brown rust (Leaf rust) which caused by Puccinia recondita f. sp. tritici, is a worldwide major disease of wheat. In order to study the inheritance of resistance of the disease in wheat, a half diallel cross was made among wheat lines including N-75-1, N-75-8, N-75-11, N-75-13, N-75-15, N-75-20 and susceptible cultivar Bolani. Parents and F1 progenies were inoculated at seedling stage in the greenhouse by a pathotype of leaf rust. Latent period, (number of days from inoculation to appearance of the first uredia) and infection type were recorded 9-12 days after inoculation. Two procedures including Griffing, and links and Hayman methods were used to analyse the data. General combining ability (GCA) and specific combining ability (SCA) were statistically significant for both traits. Narrow-sense heritability and broad-sence heritability were estimated 55% and 92% for latent period and 58% and 94% for infection type, respectively. Results showed that line N-75-8 has more recessive genes for longer latent period and lower infection type.

Limitation or lack of chromosome pairing and recombination between related chromosomes is one of the main constrains in wide hybridization programs in wheat. Consequently, useful genes can not be transferred from wild relatives to the cultivated species. The present study was conducted to investigate the effectiveness of the PhI gene transferred from Aegilops speltoides into bread wheat cultivar Chinese Spring (CS), in inducing homoeologous chromosome pairing in interspecific crosses using the Chinese Spring line, CS(PhI), carrying the gene. Chinese Spring as well as CS(PhI) were crossed as female parents with three accessions of Ae. kotschyi (UUSS), one accession of Secale cereale(RR), two amphiploids of Triticum durum-Ae. Caudate (AABBCC), and one amphiploid of Triticum durum-Ae. umbellulata (AABBUU). Meiotic metaphase I chromosome pairing was studied in all the interspecific crosses with CS as well as CS(PhI). The level of pairing was compared in the two sets of crosses using t-student statistical test. Level of chromosome pairing in the two crosses of CS and CS(PhI),was compared with chi-square test, where the level of pairing in the former being as the expected and in the later as the observed values. There was a significant increase in chiasma frequency in all the crosses with CS(PhI) over those with CS. Significant reduction in the frequency of univalents and increase in bivalents, multivalent and chiasma frequency in crosses of amphipods with CS(PhI) as compared to those of CS indicated induced homoeologous pairing. The results of this study unequivocally demonstrated the effectiveness of the PhI gene transferred from Ae. speltoides to hexaploid wheat in inducing homoeologous chromosome pairing. It also suggested that the line CS(PhI) can effectively be used for precise transfer of useful alien genetic variations with minimum linkage drag.

Thirteen strains of Streptomyces were evaluated as a potential biological agent for control of cantaloup mot rot that caused by P. drechsleri. Eight strains of Streptomyces were obtained from soil surrounding the roots of cucurbit plants in Varamin area and five strains were obtained from soil surronding roots of capsicum in glasshouse. Dual culture and cellophane overlay technique were used for in vitro assay. In dual culture and cellophane overlay techniques, all strains of Streptomyces inhibited the growth of P. drechsleri. The inhibition rate varied among strains of Streptomyces and ranged from 33.01% to 93.07% in dual culture and frol1'l36.18% to 100% in the cellophane overlay method. Adding a mixture of 13Streptomyces strains (5 g) prepared in 1 kg wheat bran to soil infested with mixture of six P. drechsleri isolates increased seedling survival by 43.07% (P < 0.05). Also seed treatment with 7.3 x 106 cfu per seed increased plant stand by 50.21% (P < 0.01). Average population of Streptomyces in potting mix decreased at a uniform rate.

Progression of Fusarium head blight on six wheat cultivar Falat, Tajan, Zagross, Millan, Frontana, Sumai#3 and one resistant line ( SHA3/ SERI/NANJING 833//Lira) was evaluated by various epidemiological models including Monomolecular, Logistic, Gompertz, Log-Logistic and Weibull, under controlled conditions in the greenhouse. In Falat and Tajan cultivars, there was no difference between various models' coefficient of determination (R2), and efficiency for all of them were the same. For Zagross, Monomolecular model with highest R2 and lowest MSe (R2=0.9834, MSe=0.00011), and in Millan, Monomolecular (R2=0.9741, MSe=0.00035) and Weibull models (c=2) (R2=0.9744, MSe=0.00045) were considered to be the best fitted models. In Frontana, Weibull model (c=2) with highest R2 and lowest MSe (R2=0.9918, MSe= 0.000076) was preferred to the others. For resistant line also the Weibull model (c=2) (R2=0.9901, MSe= 0.000089) was accepted as the best fitted model. Sumai#3 cultivar showed little infection and naturally, none of these models were fitted to its data. The nature of monocyclic or polycyclic of the disease was also studied in the present investigation in Falat cultivar. The results showed that spores produced on inoculated spikes could not infect intact spikes.

For genetic diversity study, 130 accessions of sorghum were evaluated in Karaj for two years (1998-99) under field conditions. Considerable diversity was observed in most of the traits. All of accessions were pigmented. Days to 50% anthesis ranged from 5,5 to 114 days and 58 to 150 days in the first and second years, respectively. Plant height at 50% flowering differed from 44 to 240 with a mean of 132.92 cm. Panicle exsersion showed all levels of diversity. Panicle shape and compactness showed ten levels of diversity. Panicle length ranged from 7 to 55 cm. The weight of 100 seed ranged from 1.01 to 5.07g with a mean of2.7g. Multiple regression showed that 59% of variation of 100 seed weight included in grain covering, panicle exsersion, panicle compactness, and waxy bloom. Results of factor analysis showed that eight factors expressed 71.3% of total variations in the collection. The first factor consisted of days to 50% flowering, glume color, grain covering, grain luster, panicle length, stalk juices and juicy flavour accounted for 28.1% of variations. Provinces were divided into four groups by cluster analysis. Mazandaran, Golestan and Hamaccessions appeared at the first cluster, Tehran, Khorasan and Kerman accessions at the second cluster, Yazd, Isfahan and Fars accessions at the third cluster and Sistan and Balochestan at the fourth cluster. Sistan and Baluchestan accessions in comparison with others, showed the least genetic similarity. Finally, due to the presence of high diversity in the collection, the I sorghum collection can be used for different purposes in sorghum breeding.

In order to investigate the effects of supplemental irrigation and nitrogen rates on yield and yield components of wheat, a field experiment was conducted as split plot arranged in a randomized complete block design (RCBD) with three replications, during 1999-2002 at Maragheh Agricultural Research Station of Dryland Agricultural Research Institute (DARI). The treatments included four levels of irrigation (rainfed, 1/3, 2/3 and 3/3 of full supplemental irrigation) as main plots and fiveN rates (0, 30, 60, 90 and 120 kgNha-1) as subplots. Grain, Straw and biological yield, harvestindex, height, kernel number per spike (SIP) and 1000KWwere determined from the middle of each plots. Yields of rainfed conditions varied with seasonal rainfall and its distribution, with all main factors had significant effects. With irrigation, crop response were generally significant up to 60 kgNha-1. Optimum level of supplemental irrigation was 1/3 of full supplemental irrigation with 60 kgNha-1 had maximum water use efficiency (30kgmm-1) and good yield. (minimum water use especial one time irrigation at planting time).

Acid PAGE separation was performed on gliadin proteins of 43 bread wheat promissing lines and cultivars grown in Iran. Gliadin formulae were determined based on the electrophoretic mobility and intensity of gliadin components. A total of 58 gliadin components with different electrophoretic mobilities and 53 gliadin electrophoregrams were detected in the bread wheats analysed. The estimation of genetic similarity between 43 bread wheat, using simple matching coefficients (SM), showed a range of similanty coefficients between 0.45-0.98. All the bread wheats were detectable by their gliadin formula. Out of 43 bread wheats analysed, seven were heterogeneous and showed two to three gliadin biotypes. The biotypes differed from each other for at least three components in one region to several components in different electrophoretic regions. Present results confirm that gliadin markers can be considered as a fingerprint to identify unknown samples and intra cultivar heterogeneity of wheats. Besides, catalouges of gliadin formulas of Iranian bread wheats were prepared for the first time. The data obtained in this study can be used to determine the relationship between gliadin components and morphological and agronomical traits in Iranian breadwheat breeding programs.

In order to determine the most proper sowing date and barley cultivar, this study was conducted in a sandy loam soil at the farm of Agricultural Bank, Bardsir, Kerman during growing seasons of 1998-99 and 2000-01. Four sowing dates (Oct. 15, Oct. 30, Nov. 15 and Nov. 30) as the main factor, and four barley cultivars and lines (Makouee, CB-74-2, MB-73-6 and Valfajre) as the sub factor were studied in a split plot experiment, within randomized complete block design with three replications. Analysis of variance, mean comparison with Duncan's Multiple Range Test, correlation between yield and related traits and stepwise regression were used as statistical procedures. According to the results, the effect of sowing date on grain yield, Grains/ear, ears/m2 and plant height was significant at 0.01 level. Reduction in these traits was observed due to early and/or delay in sowing. The highest yield was obtained from CB-74-2 line in the second and third sowing dates, (6.861 and 6.503 tha-1, respectively). There was a positive significant correlation at 0.001 level between yield and Grains/ear, ears/m2, and also between yield and plant height at 0.01 level. Among these traits, only two traits (grains/ear and ears/m2) could fit in the regression model (R2= 0.698).

Heterosis is defined as the superiority of a hybrid over its parents. Inbreeding depression called as the decreasing of hybrid vigour due to inbreeding. The present investigation was carried out to study heterosis and inbreeding depression in rapeseed. The seven diverse parents were crossed in all possible combinations. Forty-two F1S along with seven parents were planted in randomized complete block design with two replications over three environments. Inbreeding depression was calculated for fourteen and heterosis for twenty-one characters. Glucosinolate, oil content and fatty acids measured by spectrophotometer, NMR and gas chromatograph sets, respectively. TERI(OE)RI5 x TERI(OE)R983 showed high negative heterobeltiosis for days to 50% f10wering and days to maturity, it is suitable hybrid for development of early cultivars. TERI(OE)R983xHNS9801 exhibited high negative heterobeltiosis for plant height. Results showed that heterosis breeding was not suitable for development of dwarf cultivars. The highest positive heterobeltiosis for seed yield/plant over three environments was observed in GSC3A00xHNS9801with mean performance of 14.3 grams. Mean of inbreeding depression was 45.63% in this hybrid. Results showed that heterosis breeding was suitable method to increase seed yield. In most of hybrids oil content showed negative heterobeltiosis over three environments. Mean of inbreeding depression in this characters was 2.39%. Results showed that selection for high oil content was more effective than hybrid production. The highest negative heterobeltiosis for glucosinolate concentration over three environments was observed in GSC3A00xNPN02. The lowest glucosinolate concentration was observed in GSC3A00xTERI(OE)R983 with mean performance of 80.6 μmol/g,.For oleic acid content, there was no cross with positive and significant heterobeltiosis over three environments. The highest negative heterobeltiosis for linolenic acid content was observed in HNS9802xNPN01 with mean performance of 10.7% The highest negative heterobeltiosis for erucic acid content was observed in TERI(OE)R983xGSC3A00 with mean performance of 2.3%. It showed that heterosis breeding was not suitable for development single zero cultivar. Characters with low and high inbreeding depression could be basically controlled by additive and non-additive gene action, respectively.

For successful wheat production in cold regions, close attention must be paid to all factors that influence the ability of wheat plants to abtain maximum cold tolerance. The effect of different sowing dates of bread wheat (Triticum aestivum L.) cultivars with different growth habit on grain yield and winter survival was studied in cold regions of Ardabil. An experiment was conducted in a randomized complete block design in stripplot arrangements with five sowing dates (7 act., 17 act., 27 act., 6 Nov., and 16Nov.) and three wheat (amid cross as spring and Azadi cross and Barakat as winter). The results showed that the highest grain yield and less winterkill were obtained from early seeding of winter types. A significant (P<0.05) decrease in grain yield and high winterkill was occurred with delay in seeding of winter habit cultivars. Spring habit cultivar showed the highest winterkill and significantly (P<0.05) loss of grain yield in the early sowing date. While, a significant reduction in winterkill and increase of grain yield was observed in the late seeding of spring habit cultivar compared to early sowing date. From these results it can be concluded that sowing date x cultivar interaction determines the optimal sowing date in cold regions. Also, planting of a winter habit wheat cultivar at optimal sowing date can increase wheat production in cold region of Ardabil.