Journal of Plant Production Research
Year:2010 | Volume:17 | Issue:2|Papers Count:12

The interaction of genotype × environment effect, because of disordering effect on genotypes selection has special importance in plant breeding programs. Therefore to better selection, yield and yield stability might be considered simultaneously. In order to study of grain yield stability and the evaluation of different selection methods efficiency, 18 advanced barely lines were studied in four locations, Moghan, Gorgan, Gachsaran and Kohdasht, for three years during 2005 to 2007 growing seasons. The experimental design in all of the locations and years was a completely randomized block design with four replications. Results of three years yields in four locations showed that lines No.1 & 14 with 4256 and 4205 kg/ha and line No.6 with 3289 kg/ha produced the highest and lowest grain yield, respectively. Whereas control cultivar (LB) produced 3609 kg/ha grain yield. Using yield-stability (YSi) index, lines No.14, 1, 11, 2, 12, 5, 18, 15 and 9 were selected as stable lines with high yields, respectively. The line No.14 with YSi=19 and lines No.1 & 11 with YSi=18 were selected as the best lines. Whereas the control cultivar (LB) had YSi=-2. Also line No.10 was selected as the weakest line in yield and stability surveys. Mean comparing analysis among yield means of selected lines using four different selection procedures, showed no significant difference between them, but the order of selected lines was different in four methods. This could be important in the introduction of stable cultivars. Therefore due to higher emphasis of stability parameter in YSi calculating, YSi index is suitable and confidence for selection of high yielding and stable genotypes.

In order to understand diversity among five populations of walnut tree, this research was conducted. Ninety six tree samples were studied for 49 different Qualitative morphological traits (according to IPGRI and UPOV descriptors). Analysis of Variance traits showed significant differences (P<0.01) among all traits, expect of wide of nut form, form of bottom nut, thickness of, hard surface structure, depth of narrow on side of, surface structure, surface tissue, kernel filling and branch cork. Those showed high diversity among native walnut traits in Golestan province. For showing difference of traits among locations, used means comparison and Duncan test. Further results indicated a negative correlation between high altitudes with sensitively to Blight. There was a positive correlation between altitude with cold Tolerance and kernel brightness. Other phenological traits such as seed biophysics and seed morphology (according to IPGRI and UPOV descriptors) were evaluated within this study. This Study showed there are high diversity in native walnuts in Golestan province.

In order to study stress tolerance indices and identifying tolerance genotypes to drought stress condition 16 genotypes of durum wheat were assessed in a randomized complete block design with four replications under two irrigated and rainfed conditions in the Research Station located in west of Iran Ilam in 2006- 2007. Results showed that variation in among durum wheat genotypes under irrigated and rainfed conditions. The highest stress yield, Harmonic mean, Geometric mean productivity and Stress tolerant index were related to the genotype Omrabi3. Correlation analysis between indices, potential and yield produced under stress indicated that the most suitable criteria for identifying tolerance durum wheat genotypes under irrigated and rainfed conditions were Mean productivity and Geometric mean productivity. Multivariate biplot indicated that the genotypes omrabi3, Mrb3/Mna1 and Zardak were located next the vectors of drought tolerance indices, Mean productivity, Geometric mean productivity, Stress tolerant index and Harmonic mean. Distribution of the genotypes in the biplot space indicated that the presence of genetic diversity among the genotypes for drought stress. Cluster analysis showed the farthest genetic distance between droughts tolerance genotypes were omrabi3, Mrb3/mna1, Zardak and also drought susceptible genotype were 15/A/MARGHEG and 9/A/KORDESTAN.

In order to identify the best maturity time for excision of fertilized ovules in interspecific hybridization, intercrosses were made between two diploid (Gossypium herbaceum and G. arboreum, 2n=26) and two tetraploid species (G. barbadense and G. hirsutum, 2n=52). Flower morphology, growth rate of ovules and ovaries, as well as fiber growth pattern in various time scales post anthesis were recorded in parents and hybrid plants and the data were analyzed based on factorial design. The results showed that the effect of genotype (G), day after pollination (DAP) and their interaction term (G×DAP) on ovule and ovary specifications were significant (P£0.01). Various pre or post-fertilization factors affects on ovule growth and viability duration of in-ovulo embryos. Our data showed pollination is crucial for flower retention on plants, induction of ovary growth leading to embryo development. The studied cotton species showed differences in duration of non-fertilized flowers retention. Furthermore, we found that after emasculation the flowers retention period in G. arboreum was the shortest while in G. barbadense it was the longest. Our data reveal that the best time for excision of fertilized ovules to be transplanted in vitro in diploid × diploid and diploid × tetraploid hybridization was two or three days after pollination, respectively. Based on its cross ability, flower maintenance, ovule size and embryo growth in vitro cultures, G. barbadense was found to be superior to other parental lines, thus, might be suggested as a suitable donor parent in interspecific cotton hybridizations.

This research was carried out for the purpose of urea fertilizer, organic matter and PGPR bacteria effects on yield and some growth indices on winter wheat (Triticum aestivum C.V Alvand). This research was carried out with factorial experiment on completely randomized design with 4 replication in greenhouse. Treatments included bacteria 4 levels, without bacteri, A. brasilense, A. chroococum, integrated both of the bacteria, nitrogen fertilizer 3 levels, without urea.150 Kg/hectar urea, 300 Kg/hectar urea and organic matter two levels without organic matter and 30 Ton/hectar. Bacteria treatments had significant effects on Dry Weight, Tillering and N uptake (P<0.01). Integrated treatments of both bacteria was better than alone. Urea treatment had a significant effects on measured adjectives (P<0.01). Organic matter treatments had significant effect on dry weight (P<.05).

To remove unfavorable traits of new cereal Tritipyrum (2n=6x=42, AABBEbEb), various crosses between primary Tritipyrum lines (female) with Iranian bread wheat varieties (2n=6x=42, AABBDD) was performed and a F2 selfing population consisted of 1810 possible secondary Tritipyrum seeds (2n=6x=42, AABBD(0-14) Eb(0-14)) were produced. The chromosome constitution and homology index of 11 plants of this F2 progeny was assessed by genomic in situ hybridization (GISH). The results indicated that 1) without using Chinese spring DNA as a blocker differentiation between A, B, D and Eb chromosomes was impossible, 2) Secondly differentiation between A, B, D and Eb informs of single or pairs (rod or ring) chromosomes was improved by adding the preblocking hybridization step, using Chinese spring genomic DNA as probe, to normal GISH protocol. Third the Eb chromosome counts in F2 plants showed the feasibility of selection of the so called secondary Tritipyrum genotypes (F2) with different number of D and Eb chromosomes for favorable agronomic traits by genomic in situ hybridization as a powerful cytogenetic assisted marker selection (CAMS).

In order to study the effect of planting date on duration of phenological periods in wheat cultivars, a randomized compelet block design experiment with four replications was conducted in Gorgan University of Agricultural Science and Natural Resources research station. The factors were eight sowing dates (14 December, 20 January, 18 February, 20 March, 16 April, 21 May, 30 July and 6 August) and seven cultivars (Aria, Atrak, Koohdasht, Shirudi, Tajan, Taro and Zagros). Final grain yield was measured and phenological stages were monitored by 20 and 10 individuals, respectively. The results revealed that the days from planting to emergence and emergence to stem elongation were different significantly. Correlation coefficients of emergence rate against temperature indicated a strong correlation in all cultivars (R2 ³0.9). In this research, both temperature and photoperiod affected stem elongation rate. Minimum of days to emergence and stem elongation were observed in 30 July (3.17 and 23.33 days) and 6 August (3.07 and 19.93 days). Increasing of the days from emergence to stem elongation in the first sowing date in comparison with last sowing dates caused the coincidence of optimum leaf area production with the highest incoming radiation to canopy. This was one of the most important factors which affected yield variability between different sowing dates (changed from 4773 Kg ha-1 to 370 Kg ha-1 when sowing date was delayed from 14 December to 21 May). Also, results revealed that days from emergence to stem elongation is so critical to determine grain yield, as had significant correlations with yield (R2³0.84) and LAI (R2³0.79).

In order to genetic analysis of rice seed vigour, a cross was carried out between Tarom Mahalli (tolerant to osmotic stress) and Khazar (sensitive to osmotic stress) crosses. Linkage map based on SSR markers was derived using 74 polymorphic markers and 192 F2 individuals. Germination rate, radicale and plumule length were recorded from 20 plants per 192 F3 families. The loci related to germination traits, were detected using of composite interval mapping. This map covered 1231.5 cM of the genome. qGR-1b on chromosome 1 and qRL-12a on chromosome 12 explained 23% and 25% of phenotypic variability related to germination rate and radical length, respectively. The allele from Tarom Mahalli parent in qRL-12a increased root length, 6.70 mm. Major QTLs related to shoot length were detected on chromosomes of 5 and 12. qGR-1b, qRL-12a, qRL-5 and qSL-12 could be used as a potential condidate to be genetically manipulated by marker-assisted selection in rice germination traits breeding methods.

Harvest index is one of the important parameters in estimation of modules of seed yield prediction. Since, this parameter undergoes changes under various conditions. Therefore, this research was aimed to prepare relations to estimate it. for this purpuse, a compound analysis experiment with randomized complete block design with four replications was conducted at the Gorgan University of Agricultural Sciences and Natural Resources Univercity Research Farm in 2005. The treatments were four wheat varieties (Koohdasht, Shirudi, Tajan, Zagros) and six different sowing dates (14 December, 20 Jan, 20 Feb, 20 March, 16 Apr, 17 May). The results indicated that a significant difference was obvious in different sawing dates in respect to the slope of Harvest Index line (dHI/dt). These changes were attributed to mean temperature, pre-Grain filling accumulated biomass, and fraction of post-anthesis (fG) producted dry matter. Therefore, based on obtained results and evaluated models, fG was the best optian for simulation of dHI/dt and Harvest Index, in this respect, RMSE of dHI/dt for all varities by fG was 0.25 percentage per day which was the lowest one. Therefore, these relations can be used to evaluate the slope of Harvest Index line, or to model grain yield in crop simulation models.