جستجوی مقالات مرتبط با کلیدواژه « لاین های نوترکیب » در نشریات گروه « زراعت »

Rice is one of the important and staple food crops in Iran, and its grain yield improvement has always been the most important objective in rice breeding programs. One of the important breeding methods in rice is crossing between selected varieties to develop recombinant inbred lines (RILs), and then identifying promising lines. This experiment was carried out with the aim of identifying high-yielding superior lines. One hundred forty one recombinant inbrd lines together with their parental cultivars were evaluated using randomized complete block design with three replications in research field of faculty of agricultural sciences, University of Guilan, Rasht, Iran, in 2018. Important agronomic traits were measured and recorded for all RILs. Analysis of variance showed that there was significant differences among RILs for all studied traits, indicating significant genetic variation among them. Estimated coefficients of phenotypic and genetic variations as well as variance components also showed that there was considerable variation among RILs population, particularly for number of filled and unfilled grains panicle-1, number of panicles plant-1 and grain yield. The narrow-sense heritability varied from about 20% for panicle length to 43% for grain width, days to maturity, and 1000-grain weight. Factor analysis showed that three main and independent factors explained about 96% of the total observed variance among RILs, and were the main reasons for significant relationships between traits. These three factors were deignated as yield and its components, grain appearance quality and phenological factors. Cluster analysis by UPGMA method classified the 141 studied RILs into three clusters. Cv. Sepidrood and cv. Gharib (parental cultivars) were grouped in the first and second clusters, respectively. Evaluation of the cluster values for different traits showed that the first cluster had the highest values for grain yield and its components and the third cluster for grain dimensions and appearance quality. In conclusion, the results of this experiment showed that there was significant genetic variation among the studied RIls. Therefore, successful improvement of important agronomic traits, particularly grain yield and its components, is feasible. The superior high-yielding lines with desirable appearance quality were also identified.

Heavy metal contamination in soil caused by human activities, such as mining and industrial activities. Is a serious problem all over the world. Lead (Pb) is one of the major heavy metals that tend to accumulate in the surface ground layer and its concentration decreases with soil depth. Soils contaminated with Pb cause sharp decreases in crop productivity thereby posing a serious problem for agriculture.Toxic effects of lead on plants can be attributed chlorosis, reduced growth, blackening of root system, upsets mineral nutrition and water balance, changes in hormone status and effects on the structure and permeability of the membrane. This study was conducted to evaluate several morphological and physiological traits of barely genotypes under lead contamination stress.

In this research, morphological effects of three different densities of lead nitrate (1000,1500,2000ppm) and a control sample on two barley genotypes (Rec and Dom) were investigated in a completely randomized design with five replications. Traits of stem length, root length, leaf number and number of yellow leaves shoot fresh weight, root fresh weight, stem dry weight, root dry weight and ultimately the dry and fresh biological performances for the control and different treatments were measured. After observing the difference between the two parents in response to lead poisoning, on October 16, 2017, 94 inbred lines from Dom and Rec were planted in a completely randomized design with three replications in towenty-cm diameter pots. Then at 2- to 3-leaf stage, seedlings were treated by 0-2000 ppm density lead nitrate.

The results showed that there was a significant difference between Rec and Dom genotype in 2000ppm density respecting the lead resistance, and Dom showed a higher resistance compared to another parent. Stem length, leaf number, number of yellow leaves, stem dry weight; dry and fresh biological performances were affected by lead more than the other traits. The results of the experiment showed that in all morphological and physiological traits, there was a significant difference between the lines in the probability level of 1%. Based on genotypic correlation, there was a positive and significant correlation between photosynthesis and transpiration traits, stomatal conduction, CO2 Concentration, and plant greenness. In addition, there was a positive and significant correlation between fresh and dry biological performance and stem height, root length, shoot fresh weight, root fresh weight, root dry weight, and the number of green leaves. Based on the studied traits and by using cluster analysis, barley inbred lines were divided into 3 and 4 clusters under normal and stress conditions, respectively. The lines 24, 40, 41, 44, 78, 80 with the highest mean of morphological and physiological traits, were placed in cluster 3 under stress condition. These genotype sareamong the lead resistant genotypes. The lines 1, 7, 8, 15, 21, 25, 50, with the lowest mean of morphological and physiological traits, were put in cluster 2 under stress condition and were considered as the genotypes sensitive to lead.

Since tension with heavy metals causes’ significant disruption to plants, so it is essential to understand the traits that are affected by this tensions and relationships existing between them. In this study, photosynthesis, transpiration, stomatal conductance, stem length, number of yellow leaves, fresh and dry stem weight, fresh and dry Biological yield, affected by stress than other traits.

To estimate heritability and association between traits traits, 148 recombinant inbred lines and their parents (Yecora Rojo and No. 49) were evaluated in Alfa lattice design with two replications under normal and water deficit conditions during two cropping season (2013-15). Results showed that there were significant differences between genotypes for all studied traits. The estimated heritabilities for spikes per square meter, stem weight, biomass, spike length, peduncle length, peduncle weight, shoot length, number of grains per spike and spike weight were in the range of 15.04 to 22.41 and for grain yield, 1000- kernel weight and harvest index were in the range of 25.93 to 26.92, respectively. Under water deficit conditions, estimated heritabilities for spike length, spike weight, shoot length, spike per square meter, biomass, peduncle weight, peduncle length and stem weight were between 13.64 to 19.35 percent and for number of grains per spike, harvest index, thousand kernel weight and grain yield were in the range of 22 to 25.61 percent. The highest genetic gain in both conditions belongs to peduncle weight and harvest index, respectively. Finally based on regression and path analysis traits of number of grains per spike and 1000- kernel weights were identified as the most effective traits on grain yield in both conditions. Therefore, use of harvest index, grain yield, number of grains per spike and grain weight as indicators of selection, probably can provides access to high-yielding lines.

Given the importance of rice for food and its strategic position in the global food security, it is necessary the comprehensive study of the diversity of its germplasm to achieve high performance, quality and other important economic and agronomic traits. For this purpose, 137 rice recombinant lines from F6 population derivated from Tarom Deilamani and Saleh cultivars as maternal and paternal parents, respectively, along with four check cultivars (Tarom Deilamani, Hashemi, Saleh and Ali Kazemi) were evaluated in an augment design un four blocks for 11 important quantitative and qualitative traits. The results of analysis of variance showed a non-significant difference between studied lines for all traits except amylose content and gelatinization temperature traits. The factor analysis presented three factors that explained 87% of total variation and according to the factors loading were named related to grain number, plant type and structure and cooking quality, respectively. Cluster analysis results based on Ward's minimum variance and Square Euclidean distance criteria grouped the cultivars in three main groups that the number of groups was confirmed based on discriminant function analysis. Identification of available phenotypic variation, provide useful information in collection management and allow breeders to approach valuable genetic resources.

Tillering and secondary stems in graminea plants are permanent characters, whereas there were being food matters and proper temperature for regeneration. Ratooning or regeneration phase is explained to remain of plant for growing in next season. Recombinant inbred lines (RILs) consisting of 80 lines, derived from a cross between Hashemi and Nemat were used to analyze the genetic basis ratooning ability of rice. Recombinant inbred lines were tested with 177 polymorphic microsatellite markers. Linkage map were constructed with 170 microsatellite markers and its total lengths was 1590 cM which the mean space between markers was 9.3 cM. Using of Inclusive composite interval mapping (ICIM) method, 14 QTLs were detected on chromosomes 1, 3, 5, 6, 7, 8 and 11 for the panicle number, hundred grain weight, fertility percentage and grain yield of ratoon. Among these mapped QTLs, qpfr1for panicle number, qgwr1ýþ þfor hundred grain weight ýand qfpr1ý for fertility percentage of ratoon ýý, controlled 25.12 %, 23.46 % and 22.64 % of the phenotypic varianceýþ,þý respectively.ý The qyr6ýþ þwas the major QTL for grain yield of ratoon on chromosome 6, controlled 19.95 % of the phenotypic varianceý. One new QTLs were identified for grain yield of ratoon which was located on chromosome 8.

To identify drought tolerant lines among 168 recombinant inbred lines derived from a cross between Hindi variety of L3685 (high yielding, erect type and early growth) as female parent and Iranian variety of Qazvin (with prostrate growth and late growth) as male parent, two experiments were conducted in randomized complete block design with three replications under non-stress and drought stress conditions at the experimental Field of Shahrekord University in 2013. Results of combined analysis of variance showed that there were significant differences among lines under study in both experimental conditions in terms of grain yield (P≤0.01). Significant interaction of line×conditions revealed that lines responded differently to drought stress based on grain yield. Results also indicates that lines 160, 125 and 129 were promising lines under both conditions in terms of grain yield. Positive and significant correlation between tolerance indices and grain yield under stress and non-stress conditions indicated that the STI, MP, HARM and GMP indices may identify promising from non promising lines. Based on the above criteria, lines 160, 125, 48, 103 and 129 were recognized as drought tolerant lines. According to the results of principal components analysis, the first and second components determined 97.8% of the total variations among genotypes under study for drought resistance indices. The distribution of lines in the biplot showed genetic variations to the drought stress and thus lines 160, 125, 48, 129 and 103 were identified as high yielders under drought stress condition.

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.