JWSS - Journal of Water and Soil Science

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Aqueous extraction of gum from flaxseed was optimized using Response Surface Methodology (RSM). In this study the effect of temperature (45-100 °C), pH (3-7) and water/seed ratio (4-24), on the dependent variables including: yield, protein and apparent viscosity of extracted gum were investigated. The results showed that temperature and pH are two major effective factors on yield and quality of extracted gum (purity and apparent viscosity), whereas water/seed ratio had minor effects. The optimized conditions of extraction were as follows: temperature 85- 90 ^oC pH 6.5- 7.0 and water/seed ratio 14. Apparent viscosities of extracted gums were determined and the effect of extraction conditions on rheological properties of flaxseed gum was investigated.

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To determine yield stability and to evaluate genotype interaction with environment interaction, 18 genotype of barley (Hordeum vulgare L.) and a control group were evaluated in a randomized complete block design with 4 replications in 3 successive years (1997-2000) at 10 research stations. Simple and combined analysis of variance revealed significant genetic differences between yield genotypes for grain yield. The results of combined analysis of variance indicated that genotypic and genotype were significant through interaction with environment. Therefore, different stability parameters including, environmental variance (S²_i), environmental coefficient of variation (C.V_i), mean of variance of interaction (θ_i), interaction variance (θ_i), equivalence ( W²_i), stability variance (σ²_i), linear regression coefficient (b_i, β_i), mean of squares of deviation from regression (S² _di) and years within location MS for a genotype, averaging over all locations (MS_y/l) were determined. Based on all the stability parameters, genotype 18 was known as the most stable one and genotypes 17 and 11 ranked lower. Genotype 5 with the highest yield was known to be the most adaptable one at fertile environments and is recommended for these locations. In addition, genotype 9 with good yield and low yield variance (1.58) and regression coefficient of less than 1 is suggested for unfertile locations.

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To facilitate the interpretation of data from a genotype by environment experiment (GE), a cluster method is proposed to group genotypics according to their response to the environments especially when the GE interaction is large. The interaction structure of two-way classification data often can be identified if the data stratified into homogeneous subsets. In this paper four GE interaction cluster methods are proposed for this purpose. The stability of the 10 maize hybrids including 9 hybrids that were the best hybrids in yield trials and KSC 301 (check hybrid) were evaluated for 2 years in 4 locations of Iran. The randomized complete block design with 4 replications was conducted for each environment with different layouts. Simple analysis of variance revealed significant genetic differences between hybrids for grain yield. The results of combined analysis of variance indicated that genotype × year, genotype × location, and genotype × year × location interaction effects were significant (P < 0.01). Results also showed that models 1 and 3 and models 2 and 4 had the same responses. Hybrids 8 (K1263/1 × KE8212/12) with high yield stability in both models 1 and 3 were in one group and other hybrids were in another group. In models 2 and 4 results led to 3 groups: Group1 included hybrids 3, 7 and 9 that were very stable and had high yield group 2 included hybrid 1 alone that had medium stability and yield and group 3 included other hybrids that had low stability and yield.

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Germplasm collection is the base of plant breeding. Iran is one of the most important centers of genetic diversity due to different climates and the old civilization.In this study we decided to collect melon accessions. The north and center of Iran were selected for this purpose. Fifteen qualitative and six quantitative traits were measured on thirty eight accessions. The cluster analysis by the use of UPGMA method and Jaccard coefficient helped separate the horticultural groups of Cucumis melo L. (Cantaloupensis, Inodorus, Flexousous, Reticulatus). The relationship between 30 of these accessions was assessed using 10 RAPD primers. The polymorphism was determined to be19%. The cluster analysis could not separate the horticultural groups of Cucumis melo L., showing that these groups are closely related. However, VB84 primer separated the tow Snakemelon.

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Biological indicators are considered soil quality elements, due to their dependence on soil organisms. In order to investigate The effect of compost and vermicompost enriched by chemical fertilizers and manure on soil organic carbon, microbial respiration, and enzymes activity in basil plant's rhizosphere, a field experiment was conducted as a split-plot design with randomized complete blocks and three replications in 2006. The main plot involved six levels of fertilizer including: 20 and 40 tons of compost enriched, 20 and 40 tons of vermicompost enriched per hectare, chemical fertilizer and control without fertilizer and sub-plot, and period of application (two, three and four years). The results showed that application of compost and vermicompost at all levels increased soil organic carbon (OC) and soil microbial respiration, microbial biomass and urease activity compared to the controls (p<0.05), but increasing trend among the treatments was not similar. The maximum amounts of OC, soil microbial respiration and enzyme activity were observed in 40 tons of vermicompost enriched with chemical fertilizer ha-1 with four years of application. In high levels of compost application, the urease activity was decreased.