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نوع مقاله : مقاله پژوهشی

نویسنده

چکیده

Effect of Water Stress and Spraying of Potassium Iodide on Agronomic Traits and Grain Yield of Bread Wheat (Tiriticum aistivum L.) Genotypes

M. Ezzat Ahmadi * -Gh. Noormohammadi2- M. Ghodsi3- M. Kafi4

Abstract
In order to study the effect of water stress and chemical desiccation (potassium iodide) on grain yield and agronomic traits of 8 wheat genotypes, a field experiment was conducted using a split split plot design based on a randomized complete block design with three replications in Torogh Agricultural and Natural Resources Research Station (Mashhad, Iran) in 2006-2007 and 2007-2008. Main plots were assigned to two levels of water stress treatments; D1: optimum irrigation, and D2: cessation of watering from anthesis to maturity stages. Sub plots were assigned to eight bread wheat genotypes: 9103, 9116, 9203, 9205, 9207, 9212, C-81-10 and Cross Shahi (drought sensitive); and photosynthetic conditions with two levels: P1: using of current photosynthesis and P2: inhibition of current photosynthesis were in sub-sub plots. The results showed that the effects of water stress and photosynthetic conditions on number of total florets per spike (NTF/S), seed set percentage (SSP), spike harvest index (SHI), duration of grain filling (DGF) and grain yield (GY) were significant. There was a significant difference between genotypes for spike dry weight at anthesis (SDWA), number of spikletes per spike (NSP/S), NTF/S, SSP, SHI, spike partitioning coefficient (SPC), plant height (PLH), spike length (SL), DGF and GY. 9103 genotype produced the most GY (7870 kg/ha) under D1P1 treatment. The least GY ( 1114 kg/ha) related to Cross Shahi cultivar under D2P2 treatment. Considering that C-81-10, 9103 and 9116 genotypes showed the highest grain yield, potential for reserves and remobilizations of assimilates under different irrigation conditions thus, these genotypes could be introduced as promising in breeding programs for arid and semi-arid regions.

Keywords: Triticum aestivum L., Cessation of watering, Chemical Desiccation, Spike, Grain yield


Genetic Variation of the Traits in Isolated Lines From Local
Populations of Flax (Linum usitatissimum L.)

N. Pooladsaz 1- G. Saeid2*

Abstract
Genetic variation for the traits in flax breeding programs can be used for selection of desirable genotypes for agronomic traits. This study was conducted at the Research Farm of Isfahan University of Technology in 2006 to investigate genetic variability for different agronomic traits of breeding lines isolated from 6 local populations of flax. In this study, 73 isolated lines by single plant selection along with the local populations and "Flanders" cultivar from Canada (as the control genotypes) were evaluated in a randomized complete block design with two replications. The results showed that there were significant differences among the genotypes for all of the studied traits such as capsules per plant, seeds per capsule, 100-seed weight, seed yield per plant and seed yield per plot. The range of variation for days to maturity, plant height, seed yield per plant and seed yield was 113 to 164 days, 32.8 to 68.4 cm, 0.16 to 1.39g and 375 to 2450 kg/ha, respectively. High phenotypic and genetic coefficients of variation were observed for number of seedlings per m2, rate of infected plants by powder mildew, branches per plant, capsules per plant, seeds per capsule, seed yield per plant and seed yield. Also, high broad-sense heritability (74.9 to 96.2%) was observed for all the traits, with the exception of days to 50% emergence that had moderate heritability (40.8%). Seed oil content which was determined for 10 higher yielding lines had high variation (36.9% to 40.4%) and high broad-sense heritability (99%). Cluster analysis classified the genotypes in to 4 groups in which the genotypes of two groups had the highest seeds per capsule, seed yield per plant and seed yield.

Keywords: Flax, Local populations, Genetic variation, Heritability, Agronomic traits


The Effect of Seed Size on Seed Vigor Indices of Different Wheat Cultivars
(Triticum aestivum L.)

H.R. Tavakoli Kakhki * - A. Beheshti 2 - M. Kazemi 31

Abstract
Germination and beneficial seedling establishment is affected by different seed vigor indices. In order to study the effect of seed size on seed vigor indices of wheat, a factorial experiment with two factors was conducted in a completely randomized design with four replications at the Agricultural Natural Resources Research Center Lab of Khorasan Razavi. The first factor was thirteen genotypes of wheat in three types of growth, containing winter, facultative and spring and the second factor was seed size in four levels including 3, 2.5, 2 and 1.5 millimeter. Germination percentage, germination rate, shoots and root length, seedling growth rate and shoot:root length ratio characteristics were investigated. Analysis of variance showed that the effect of wheat cultivars and seed size on traits was significant (p≤ 0.01) but interaction effect of seed size and wheat cultivar was significant (p≤ 0.01) only for shoot and root length, seedling growth rate and shoot:root length ratio. The highest and lowest seedling growth rate was (15.85 and 8.23 mg dry weight/germinal seedling) that they were related to 3 and 1.5mm seed size, respectively. According to these observations the most and least percentage and germination rate was related to these seed size treatments. Correlation coefficient of seed size and seedling growth rate was highly significant (r=0.85 p≤ 0.01). Stepwise regression method indicated that the seed size (x1) and shoot length (x2) as independent variables could be described (r2=0.84) seedling growth rate as a dependent variable in y= -5.000955+(5.128078x1)+(0.78494x2) equation.

Keywords: Seedling growth rate, Germination rate, Correlation, Regression

The Effect of Fertilizer and Manure on Forage and Grain Yield of Millet (Panicum miliaceum) and Bean (Phaseolus vulgaris) In Intercropping

A.Tavassolli * -A. Ghanbari 2-M. M. Ahmadi 3- M. Heydari4

Abstract
This experiment was conducted in 2007 in Shirvan Agriculture Research center. The experiment was split plot in randomized complete block design with three replications. Main factors consisted of unfertilized (A1), 100% fertilizer (A2), 100% manure (A3), 50% fertilizer + 50 % manure (A4) treatments and sub factors consisted of sole crop of millet (B1), 75% millet + 25% bean (B2), 50% millet + 50% bean (B3), 25% millet + 75% bean (B4), and sole crop of bean (B5). Dry matter yield, grain yield, 1000 kernel weight, harvest index (HI), land equivalence ratio (LER), photosynthetically active radiation (PAR) and soil moisture content and soil temperature in each crop were calculated. Results indicated that the fertilizer and manure treatments had significant effect on millet and bean grain and dry matter yield (p