Mapping of QTLs for frost tolerance and heading time using SSR markers in bread wheat

Selection for complex genetic traits, such as frost tolerance, can be simplified in plant breeding programs when linked markers were detected. The use of microsatellite markers for tagging and mapping important genes or QTLs is a goal in wheat genetic projects. In this study, 200 microsatellite markers were studied and after parental assay, 41 polymorphic SSR markers were used for genotyping of 280 F2 individual plants derived from F1 generation of wheat cross (Norstar× Zagros). The progeny of individual F2 plants were used as F2:3 families for the assessment of LT50 and heading time. Single marker analysis revealed that seven markers with total of 27% of phenotypic variance determination linked to LT50 and five markers linked to the heading time. Two markers that were located on 2B and 5A chromosomes affected both LT50 and heading time significantly. It was assumed, therefore, that someclosely linked QTLs or QTLs with pleiotropic effects govern both traits simultaneously, as the LT50 of F2:3 families were significantly correlated with the heading time of F2:3 families, Thus, it is concluded that later heading time is associated with the higher level of frost tolerance in wheat

Evaluating Tolerance Indices of some New Maize Hybrids Imposed to Drought Stress

In order to investigate drought tolerance indices of 14 maize hybrids to different levels of water deficit, a split-plot experiment was conducted in complete randomized block design with four replications at the Agricultural Research Station, University of Tabriz. The main plots consisted of three levels of irrigation regimes (control, mild and severe water deficit) and sub-plots of 14 corn hybrids. Drought tolerance indices were calculated for the grain yields produced. Under mild drought condition, hybrids like SC702, SC500 and K3647×K18 were tolerant based on tolerance index (TOL) and stress susceptibility index (SSI) indices while hybrid SC 500 was the most tolerance one. Based on stress tolerance index (STI), mean productivity (MP) and geometric mean productivity (GMP) indices under both mild and severe stress conditions hybrids K166×K18, SC500، K3647×K18 and SC400 were found to be the most tolerant to water deficit than others. The STI and GMP indices that had highest positive correlation with grain yield under both of these stress conditions. Thus these two indices were determined as the best indices for selection of tolerant hybrids. Cluster analysis based on these two indices classified hybrids into two groups under mild stress and in three groups under severe stress conditions. Biplot graphs for two main components based on principle components analysis (PCM) displayed that SC500 to be a tolerant maize hybrid in both mild and severe drought stress conditions with high yield performance. Also, hybrids SC700 and SC704 were low yielders under both control and stress conditions and thus were identified to be as sensitive hybrids

Evaluation of Drought Tolerance of Bread Wheat Recombinant Inbred Lines

To evaluateresponse of bread wheat recombinant inbred lines to water deficit, a split plot experiment arranged in randomized complete block design (CRBD) was conducted using eight recombinant inbred lines and their parental cultivars (Roshan and Super Head) with three replications under three irrigation levels (80, 120 and 160 mm evaporation from class A pan) at the Agriculture Research Station of Islamic Azad University, Tabriz Branch during 2009. The results of analysis of variance data collected revealed significant difference among lines and irrigation levels for grain yield. While line × irrigation level interaction was non significant for grain yield. Based on SSI and TOL, drought tolerance indices lines number 1, 7, 41 and Roshan cultivar under 120 mm evaporation, and lines number 7 and 19 under 160 mm evaporation were the tolerant lines. Under both stress conditions according to STI, MP and GMP indices, lines number 37, 38 and Roshan cultivar were recognized as the tolerant lines to water deficiet. Cluster analyses based on grain yield and drought tolerance indices recognized the lines number 1, 30, 32, 37, 38, 41 and Roshan cultivar under 120 mm and lines number 30, 37 and 38 and Roshan under 160 mm evaporation as the most drought tolerants and higher producers

Response of Bread Wheat Recombinant Inbred Lines to Drought Stress and Their Grouping

In order to study the response of bread wheat recombinant inbred lines to drought stress and their grouping an experiment was conducted in split plot based on randomized complete block design with three replications at Islamic Azad University, Tabriz Branch the Agriculture Research Station. Main factor consist of different levels of irrigation (80, 120 and 160 mm evaporation water from class A evaporation pan) and sub factor included the lines. Result of analysis of variance revealed significant differences among different levels of irrigation for the most of the traits. Mean comparisons showed that drought stress reduced the value of these traits. Significant differences were observed among lines for all the traits except non fertile tiller number. Line × stress interaction was non significant for all of the traits studied. Cluster analysis using WARD algorithm based on the traits under study assigned the lines into two separate groups. Discriminate analysis confirms this grouping. Factor analysis based on principle component analysis and varimax rotation, showed that the first four factors accounted for about 88.69 percent of the total variation. The result revealed that yield and its components and plant height were important traits for selection of promising lines

Study of Yield and Effective Traits in Bread Wheat Recombinant Inbred Lines (Triticum aestivum L.) under Water Deficit Condition

The effects some traits on seed yield of recombinant inbred lines of wheat under water deficit stress was studied. This research was done at the Agricultural Research Stations, Islamic Azad University, Tabriz Branch in 2010- 2011. 28 recombinant inbred lines of wheat bread with two parents (Norstar and Zagros) in split plot experiment based on a randomized complete block design with three replications at two irrigation levels (70 and 140 mm evaporation from pan class A) were studied. Analysis of variance indicated a significant genetic differences in all traits under study among the lines. Lines No. 32, 163 and 182 produced highest yield under both irrigation levels. Number of spikes, grains per spike and harvest index had the highest positive correlation with grain yield. Path analysis based on stepwise regression showed that under the normal irrigation conditions, number spike (0.556), number of grains per spike (0.278), weight of 1000 grain (0.259) and the drought stress number spike (0.430), straw yield (0.276) and peduncle length (0.323) had the most direct and positive effect on yield respectively

Response of Bread Wheat Recombinant Inbred Lines to Water Deficit

Response of 8 bread wheat recombinant inbred lines along with their parental cultivars (Roshan and Super Head) to water deficit was evaluatedin a split plot experimentarranged in randomized complete block design (CRBD) with three replications under three irrigation levels (80, 120 and 160 mm evaporation from the pan) at the Agricultural Research Station of Islamic Azad University, Tabriz Branch in 2009. Univariate analysis of variance revealed significant difference among lines with respect to all the traits studied. Significant differences were observed among irrigation levels for grain yield and thousand-grain weight. Line × stress interaction was significant for harvest index and number of fertile and non-fertile tillers. Roshan cultivar produced highest grain yield. In the factor analysis, the first three factors explained 86.95% of total variation. The two first factors were named as growth and grain yield factors, respectively. Cluster analysis, using WARD algorithm, based on all the traits grouped the lines into two cultivars. Grouping was confirmed by discriminate analysis

Heritability of Some Characters Related to Bread Quality of Wheat

To determine the inheritance of bread making quality of bread wheat by diallel crossing, the F1 seeds of a 5 × 5 half diallel along with their parents were grown in water-stress and non-stress conditions, in a randomized complete blocks design, at Islamic Azad University, Ardabil, Iran, in 2009, and 8 characters related to their bread quality along with 1000-seed weight and hectolitre mass were evaluated. The result of combined analysis of variance showed that the effect of stress on protein content, SDS sedimentation volume, wet gluten content, 1000-seed weight and hectolitre mass was significant . The interaction effect of genotype and stress was significant (P<0.01) for the loaf volume and hectolitre mass, and this showed different reactions of the genotypes in the stress and non-stress conditions. Also, the effects of genotype were significant for all the traits except for Zeleny sedimentation volume, grain moisture content and wet gluten content. This shows that the conditions are suitable for diallel analysis and separation of sum of squares of traits. Significance of general combining ability for loaf volume, grain hardness, moisture absorption percentage, SDS sedimentation volume, 1000-seed weight and hectolitre mass shows presence of additive effect and specific combining ability for 1000-seed weight and hectolitre mass shows non-additive gene effects in the control of these traits

Evaluation of Spring Bread Wheat Lines (Triticum aestivum L.) and Their Classification by Using Some Agronomic Traits

To obtain superior genotypes from 30 advanced spring bread wheat cultivars a field experiment in RCBD was carried out in 1388. Traits like yield, yield components, harvest index, peduncle length, awn length, number of leaf, plant height, flag leaf area, penultimate leaf area, days to booting, days to spike emergence, days to flowering and physiological maturity were recorded. Analysis of variance showed significant difference among genotypes for the traits measured at %1 probability level. This indicates considerable genetic variations among the lines evaluated. Cluster analysis of traits measured, grouped lines into three categories. Eight lines were located in third cluster with respect to some traits including grain yield and other important traits like biological yield, number of seed per spike, spike length, peduncle length, plant height, flag leaf area, and number of spike per m² were found to be superior. By using factor analysis, five factors determined 78.99% of total variation. In this analysis, the first factor could account for 35% of total variation and nominated as effective factor on grain yield. Line with accession number of N-75-5 was found to be highest yielding (289.5 g/m2 (as compared with the other lines

Relationship Between Yield and Yield Components of Maize Hybrids under Different Irrigation

To evaluation the response of some maize hybrids to water deficit stress, a field experiment in 2010 was conducted using a split-plot plan on the basis of complete randomized block design with four replications at the Agricultural Research Station, University of Tabriz (Khalatpoushan). Main plots consisted of three different irrigation regimes (non-stress, mid-stress and sever-stress) and sub plots of 14 maize hybrids. Results showed significant differences among hybrids and irrigation regimes for all traits studied. Analysis of variance revealed significant differences among hybrids and also irrigation levels for all traits except ear diameter. The best model for stepwise regression based on all traits at the average of conditions, indicated that four responsible traits like number of rows per ear, 300-grain weight, number of grains per row and number of leaves per plant remained in model, which justified 83 percent of the total variations in yield performance. The path analysis showed that the number of rows per ear had the highest direct effect on yield. Based on principal component analysis the first component had a major factor on the weight of 300 seeds, plant height, ear length, flag leaf area, ear diameter and corn cob diameter and the second component had a big factor on plant dry weight, number of kernels per row, number of leaves per plant, number of rows per ear and grain yield. Principal component analysis (PCA), based on all of traits studied determined two principal components that could justify the 78 percent of vaiations. In this research the first component named as the growth-morphological factor and second component named as the yield factor

Response of Some Grain Sorghum Genotypes to Water Deficit

To study the effect of drought stress on some grain sorghum lines, a split plot experiment based on complete randomized block design with three replications was conducted during 2007-8 at the Agriculture Research Field of Islamic Azad University, Tabriz Branch, Iran. Irrigations after 60, 120 and 180 mm evaporation from the pan were assigned to main plots and seven lines of grain sorghum to sub plots. Multivariate analysis of variance was fulfilled for fixation of type Ι error. Analysis of variance showed significant differences among lines and irrigations for most of the traits. Based on mean comparison, KGS5 and KGS15 showed the highest means for most of the yield related traits. Path analysis was conducted by using the stepwise regression on mean of irrigation levels. Results showed that panicle length and 1000 kernel weight were the most effective components on grain yield