Seed and Plant
Year:2008 | Volume:23 | Issue:4|Papers Count:15

Wheat crop development is defined as a sequence of phenological events controlled by environmental factors as well as genetics determining differentiation in plant morphology and functions of some organs. It commences with germination and terminates with physiological maturity in each crop life-cycle and can be divided into different distinguishable stages/phases. To study the phenology of bread wheat genotypes, 20 different cultivarsor promising lines adapted in four different agro-climatic (cold and temperate cold; temperate; southern warm and dry; northern warm and humid) zones were studied, using a randomized complete block design with three replications, under field conditions in Karaj, during three successive cropping seasons (2000-2003). The results revealed that genotypes were significantly different in the duration of different phenological stages. Genotypes associated with cold and temperate cold zone were of longer crop life-cycle which was mainly due to differences in the duration of their vegetative phase (Sowing to Double Ridge). The results also indicated that in all four agro-climatic zones, developmental phases including Sowing to Double Ridge (S-DR), Double Ridge to Terminal Spikelets (DR-TS), Terminal Spikelets to Anthesis (TS-Anth) and Anthesis to Physiological Maturity explained 0.39%, 68%, 0.63% and 0.52% of variations in grain yield, respectively. Correlation studies between different developmental stages and yield components also indicated that, in all four agro-climatic zones, the number of spikes m-2 was positively correlated with the duration from Sowing to Terminal Spikelets, however, it was negatively correlated with the duration from Terminal Spikelets to Anthesis. The relationship between Thousand Kernel Weight (TKW) and the duration of S-DR and S-Anth was negative. It is concluded that phenlogical studies can be utilized to study the adaptation of different genotypes to different agro-ecological zones and to explain the variation in grain yield and its components.

In order to study the effects of sowing date and plant density on quantity and quality of yield of sweet corn KSC403, an experiment was conducted in Gorgan Research Station for three years (2001-03). Four sowing dates (9th April, 29th April, 19th May and 8th June), and four plant densities (45000, 55000, 65000 and 75000 plants per hectare) were evaluated in form of factorial experiment (4´4) within randomized complete block design. The results showed that quality and quantity of forage (stem, leaf, cob ear, and spout ear) were affected by sowing date and plant density. Maximum dry forage yield, crude protein and crude fiber, 7724, 694 and 2139 kgha-1 respectively, were obtained in the second planting date. Dry forage yield, crude protein and crude fiber were also influenced by plant densities and maximum dry forage yield, crude protein and crude fiber, 7330, 644.4 and 2048 kgha-1 respectively, were obtained in 75000 plant ha-1 density. With increasing plant density, forage yield increased and maximum forage yield was obtained in 75000 plants per hectare density. As ear length decreases by increase in plant density, 55000-65000 plants per hectare is the best density for sweet corn to obtain the highest forage yield and ear quality in Golestan province.

Autumn sown chickpea compared to spring sown crop, produces more seed yield. One of the constraints in autumn sowing at the cold regions is cold injury. To investigate cold resistance and find cold tolerant genotypes for autumn sowing in cold areas of Iran, ten advanced genotypes of chickpea were evaluated in a Randomized Complete Block Design with three replications in Maragheh Agricultural Research Station, during 2003-05 cropping seasons. Cold hardiness among the chickpea genotypes were measured by examining the alive and dead seedlings after being exposed to natural winter and spring cold weather and expressed in percentage. The absolute minimum temperature during 2003-04 and 2004-05 years were –15 and –22.5oC with snow cover and –10 and –7.5oC without snow cover, respectively. Combined analysis of variance showed that there were significant differences among genotypes for 100 seeds weight, plant height, and days to 50% flowering, days to 50% maturity, number of pods per plant and primary shoots. Resistant chickpea genotypes (91-95% winter hardiness) comprised only 10% frequency percentage and tolerant genotypes (71-90% winter hardiness) 70 percent. Ggenotype FLIP 00-78C (with 91% cold hardiness as resistant genotype) was produced the highest seed yield (1507 Kgha-1). Seed yield had a significant and positive correlation (r = 0.655**) with cold hardiness percentage, and highly resistant or resistant genotypes produced seed yield more than total mean. On the whole, three genotypes FLIP 00-78C, FLIP 00-75C and FLIP 96-90C with cold tolerance rate 3 and less than 3, cold hardiness percentage more than 83% and seed yield more than 1190 Kgha-1, were identified as superior genotypes.

Freidan region with more than 11000 ha cultivation area of potato is an important seed potato production region in Iran. Tubers produced in this region were used in other areas and each year need more than 25000 ton virus free potato tubers for planting. To determine the duration of potato tubers being left free from viruses and the rate of infection of commercial potato cultivars to potato virus Y (PVY), potato virus X (PVX), potato virus M (PVM), potato virus S (PVS) and potato leaf roll virus (PLRV), an experiment was conducted in a complete randomized block design with four treatments included cultivars (class SE: Agria, Marfona, Konkord and Cosima) in four replications in Rozveh experimental station in 2003-2004. The cultivars were pre-emerged in laboratory and tested by ELISA, and healthy tubers were planted. At harvest time the tubers from two central rows in each treatment were collected and kept at 10oC. In the second year the tubers were planted as the previous year and at harvest time, 250 tuber samples of each cultivar were collected from two central rows and kept at 10oC and dark condition. After breaking dormancy, the tubers were planted in pots. When the plants reach to 10 cm high, leaf samples were collected and tested by ELISA against the viruses. The results showed that PVY is dominant virus in the region with the highest infection rates in Marfona, and lowest infection rate in Konkord. The highest and lowest infection rate, to PVS, PVM and PLRV were observed in Marfona and Konkord, respectively. Regarding to the results, PVY could be used as an index indicating the duration time of potato tubers being used in successive planting for producing seed tubers.

Eight rice genotypes with two checks (Dasht and Nemat) were evaluated in three locations of Mazandaran province for two years (1999-2000), in a RCBD with four replications. This study was carried out to determine the qualitative and morphological traits and yield stability to select the best genotypes. The results of combined ANOVA showed significant differences among genotypes. The effects of location, year, genotype´location and genotype´year were not significant. The interactions of year´location, and year´location ´ genotypes were significant that proved the existence of interaction between genotype and environment. Grain yield stability using ten different methods, showed that Nemat cultivar (genotype 7310) with less variance (S2i) and coefficient of variability (CVi) of environment, less coefficient of regression of mean yield on environmental index (bi) and variance of deviation from regression linear (S2di), was the most stable genotype. Genotype 7304 having bi equal to unity, less S2di and high yield, was the most stable genotype. There were no significant differences between the mean yield of genotype 7304 and genotypes 7302, 7303, 7305 and 7306. Regression line slope of these high yielding genotypes was equal to unity too. Therefore they had high general adaptability. Nemat cultivar and genotype 7305 with less mean and standard deviation of ranking (R, S.D.R) and genotypes 7304 and 7303 based on Wricke, s equivalence (Wi2) and Shukla, s stability variance (s2i), had the highest stability, respectively. The cooking quality of genotypes 7302, 7304, 7306, 7307 and 7308 was excellent with intermediate amylose content and gelatinization temperature. Consequently the genotypes 7304 and 7302 having higher mean yield compare to Dasht, and desired cooking quality and morphological traits were selected as elite genotypes.

Estimation of genotype ´ environment (GE) interaction is very important for plant breeders. The additive main effects and multiplicative interaction (AMMI) model is the combination of the analysis of variance (ANOVA) and principal components analysis (PCA) which calculates both additive and multiplicative effects. To estimate GE interaction by AMMI model, ten corn hybrids including nine hybrids that were the best hybrids in yield trials, and KSC301 were evaluated for two years in seven locations of Iran in a randomized complete block design with four replications. Results showed that the first four IPCAs and the fifth IPCA were significant at 1% and 5% probability levels, respectively. The first IPCA displayed 25.2% of GE interaction sum of squares and the other IPCAs 65.1% of GE interaction sum of squares. Four parameters including SIPC4, AMGE4, ASV and EV4 were calculated for stability determination of corn hybrids. ASV parameter showed positive and highly significant correlation with Wricke ecovalence (r=0.76) and Huehn's S2 nonparametric statistics (r=0.67). EV4, SIPC4 and ASV parameters had no correlation with each others. The highest grain yield belonged to hybrids No. 8 and No. 2 with 9705 and 9272 kgha-1 respectively. According to ASV parameter, hybrid No. 8 was determined as a stable hybrid with minimum interaction (260.274) and maximum grain yield (9705 kgha-1) and hybrid No. 3 with minimum interation (1899.58) was determined as unstable hybrid. According to obtained results for stability determination, hybrid No. 8 was selected as the most stable hybrid and ASV parameter was selected as the best stability parameter regarding its accurate results in comparison to the other AMMI parameters.

Common smut is one of the most prevalent fungal diseases of maize which causes high qualitative and quantitative losses on yield. One of the best controlling methods of the disease is use of resistant hybrids. In order to evaluate the resistance of 18 early maize genotypes, an experiment was carried out in RCBD with two replications at Karaj, Isfahan, and Mashhad. Inoculation of the ears was done by syrange (3ml spore/ear) at silking stage. Disease severity on ears was assessed 3-4 weeks after appearance of the first disease symptoms. The results of combined analysis of variance and mean comparison showed differences in disease severity among examined materials. Based on disease severity (0-7), the responses of genotypes were ranked in five groups (highly resistance to highly susceptible). Line KE 72012/12 was highly resistant and OH43/1-42 susceptible. K 1264/5-1 ´ K 615/1 and KE 72011/1 ´ K 1264/5-1 were susceptible and resistant hybrids, respectively.

Drip irrigation that is applicable in row crops leads to decrease in water use, changes the environmental and humidity conditions of root and increases water productivity. In order to compare drip and furrow irrigation methods, a research was conducted in Agricultural and Natural Resources Research Center of Khorasan for two years (2002-2003). Statistical design was split plot adopting complete randomized block with three replications. Main plots were amount  of irrigation water, 50, 75 and 100 percent of crop water requirement, and sub plots were irrigation methods drip (tape) irrigation and furrow irrigation. The results showed that crop yield was not significantly different in any of the treatments in the first year, but it was significantly different in irrigation methods in the second year. Yield in drio irrigation (2821.2 kgha-1) was 16% less than that in furrow irrigation (3755.8 kgha-1), but water use efficiency in drip irrigation was 61% more in furrow irrigation method. Yield components such as number of plants per square meter, number of bolls per plant, weight of boll and number of branches were not significantly different in two irrigation methods. Total water used (mean of 3 irrigation water) in drip and furrow irrigation methods were 7002.38, 11464.9 cubic meter per hectare, respectively. It was concluded that irrigation water in drip irrigation was 50.4 percent less than that in furrow irrigation. The most and the least water use efficiency were 0.34 kgm-3 in drip and 0.21 kgm-3 in furrow irrigation.

Sweet cherry (Prunus avium L.) is one of the most important temperate fruits in the world. Most sweet cherry cultivars are self-incompatible and have usually problem with fertilization and fruit set, so they need suitable pollinizer for good fruit setting and commercial yield. The present study was carried out on sweet cherry cultivar Ghermez Rezaeieh as seed parent tree and Zarde daneshkadeh, Protiva, Sorati Lavasan, Haj-Yosefi and Meshkinshahr cultivars as pollen parent trees. Treatments (Pollens) were applied in randomized complete blocks design (RCBD) with three replicates. All laboratory and microscopic examinations of the collected samples were carried out in the Department of Horticultural Science, Tarbiat Modares University (TMU), Tehran, Iran and Controlled hybridization and pollination performed in the Seed and Plant Improvement Institute (SPII), collection orchard at Kamalabad, Karaj during 2004 and 2005 growing seasons. In order to determine the compatibility or incompatibility of various pollens on Ghermez Rezaeieh two methods were used: controlled pollination and examination of pollen tube growth with fluorescence microscopy. The results based on controlled pollination showed that MeshkinShahr and Protiva cultivars are compatible and Zarde daneshkadeh, Sorati Lavasan and Haj-Yosefi are incompatible cultivars with Ghermez Rezaeieh. The mean of fruit set in Ghermez Rezaehe cultivar with use of pollen grains of Zarde daneshkadeh, Protiva, Sorati Lavasan, Haj-Yosefi and Meshkinshahr were 0.54, 40.49, 0.24, ,0.80 and 61.36 percent respectively .The results also showed that sweet cherry cv. Ghermez Rezaeieh is a self-incompatible cultivar (fruit set=0) and it needs compatible and suitable pollinizer for fruit set. The results based on microscopic examinations showed that pollen tube of Meshkinshahr cultivar reached into the Ghermez Rezaeieh ovary flowers in 96 hours after pollination. These microscopic examinations and observations confirmed the obtained results from controlled hybridization in garden. In conclusion, Protiva and Meshkinshahr were selected as the best pollinizers for Ghermez Rezaeieh cultivar.

In order to study genetic of quantitative traits in wheat under normal and moisture stress conditions, several genetic parameters such as average degree of dominance, proportion and distribution of dominant and recessive alleles in all parents and dominance direction were evaluated in ten cultivars of bread wheat, using a half diallel. Parents and their hybrids were separately planted in a randomized complete block design under normal and moisture stress conditions in the second year. Results of analysis of variance in normal moisture condition showed genetic variation among genotypes for most of the traits except for tiller and fertile tiller number, awn length and 50% heading date, whereas in stress condition results of analysis of variance were not significant for awn length, 50% heading date, dry weight of root and flag leaf area. There were over dominance effect for number of spikelet per spike, number of kernel per spike, 1000- kernel weight, biomass, weight grain yield and harvest index, complete dominance for stomata number per unit of leaf area, and partial dominance for peduncle length, spike length and dry weight of root in normal moisture condition. The results in normal moisture condition also showed that all traits were controlled by dominant alleles, except number of stomata per unit of leaf area that was controlled by recessive alleles. In stress conditions there were over dominance effect for number of spikelet per spike, spike length and number of kernel per spike, complete dominance for number of stomata per unit of leaf area, and partial dominance for peduncle length, 1000- kernel weight, biomass, weight, grain yield and harvest index. In stress condition, all traits were controlled by dominant alleles except 1000-kernel weight that was controlled by recessive alleles.

In order to estimate the genetic parameters in ressitance to fusarium ear rot, this study was carried out using complete diallel crosses of five maize inbred lines. Twenty five genotypes including crosses and reciprocals, as well as parents, were evaluated in a randomized complete block design with three replications, in 2005. Twenty plants were artificially inoculated in each plot with conidia of Fusarium verticillioides, and disease severity and Percentage of infected ears were assessed on them at maturity stage. Diallel analysis by Grifing's method one, revealed the importance of additive and non-additive gene effects in genetic control of disease severity and percentage of infected ears. Significant reciprocals effects showed that maternal effects could be important in inheritance of disease severity. Lines K18 and K74/1 showed the highest negative and positive combining ability for disease severity, respectively.

Classical cytological studies were carried out to give karyological information about five hybrid cultivars of sugarcane. Root tips pretreated with saturated a-bromonaphthalene solution for 8 h at 4oC. The roots were fixed in 1:1 chromic acid 1%: formaldehyde 10% for 48 h, followed by hydrolysis in 1N NaOH for 15 min at 60oC. After enzymatic digestion of Hematoxylin-stained roots, each root tip was squashed in a drop of 45% acetic acid. Karyotype analysis showed that chromosome size varied from 0.571 mm to 5.076 mm with predominance of m chromosome types; so that more than 50 paired chromosomes were m type in each cultivar. Multivariate tests of significance and ANOVA showed that, except for TF%, the means of Symmetry Index, Dispersion Index, Difference of Range of Relative Length, Coefficient of Variation, and Haploid Set Length were significantly different among cultivars. The karyotypes were similar with respect to TF%-based symmetry and centromere position of more than 90% of the chromosome pairs. These results showed apparently, that the evolution of karyotype in S. officinarum has mainly involved chromosome number and polyploidy rather than chromosomal changes and karyotype asymmetry.

Sixty six genotypes of sunflower including cytoplasmic male sterile lines along with their maintainers lines, restorer lines and commercial cultivars were evaluated in tow separate experiments under stress and normal conditions in a randomized block design with three replications in Khoy Agricultural and Natural Resources Research Station in 2004. Stressed experiment was irrigated after 150mm evaporation from class A pan to exert water stress. Each experimental plot consisted of three meter single row with 60cm row spacing and 25cm space between plants. During growing season, plant characteristics including number of days to flowering, growth period duration, plant height, head diameter, 1000 seed weight, seed number per head, oil content, harvest index, seed and oil yield was measured. Stress susceptibility index, stress tolerance index and MP and TOL indices calculated for seed yield. According to the were results, lines A312, A152, B225, CMS19 and R21A with SSI ranged from 0.47 to 0.63 were the highest tolerant lines to water stress. Considering STI, Azargol, line A28 and Alstar with STI 1.06, 0.99 and 0.96, respectively had the highest tolerance to water stress. Because of positive and significant correlation between head diameter, stem diameter and plant height with seed yield and STI, these traits could be used as criteria for determining drought tolerance in sunflower. STI had more efficiency than the other indices for determination of tolerant genotypes.

This study was carried out in 2006 to assess the effects of research, research achievements, impact and efficiency indices, estimate of cost and benefit of activities and impact of research results in SPII. Necessary data on number of released improved cultivars, distributed seeds of those cultivar, cultivated areas of each cultivar and yield increase by improved cultivars during 2000 to 2005 was collected from different research departments at SPII. Data on budget and costs were obtained from program and Budget Office of the Institute. According to the results of the assessments, during the period between 2003 and 2005, impact indices of agronomy recommendations, introduced cultivars, new plants introduction, new ideas presentation were 55, 26, 16 and 56 cases, respectively. Increasing of staff scientific level and stablishment of research places and facilities were 10310 and 64500 million Rials, respectively. Efficiency indices of SPII for articles published in ISI and Scientific Journals were 20 and 157 cases. Presented papers in conferences were 495 cases, edited and translated books were 12 cases, and number of final reports of projects and technical reports were 458 and 92, respectively. Number of scientific consultations of projects in national and international level was 65 cases. Number of national and international conferences hold by SPII was 44 cases and sharing or participating in preparation of standards was 19 cases. Present value of gross income increase and cost activities of research results were estimated 24579 and 620 thousand million Rials during 2000-2005. Net value of SPII was estimated 23959 thousand million Rials in that period. The net present value of activities in Cereal, Oilseeds, Potato and Onion and Maize and Forage crops Research Department were estimated 17941, 3530, 2006 and 756 thousand million Rials, respectively. Benifit cost ratio of activities of SPII during 2000 to 2005 was 39.7. These estimated benefits were only a part of economic benefits of SPII.