JOURNAL OF CROP BREEDING
Year:2018 | Volume:10 | Issue:27 |Papers Count:20

The present study was conducted to investigate the genetic diversity and evaluate the drought tolerance indices on 16 genotypes of faba been based on split plot design with three replications in Agricultural Research Center of Borujerd. Irrigation regimes as the including normal and drought stress levels and genotypes were considered as the main and sub plot, respectively. Analysis of variance for yield in normal conditions (N), yield under drought stress (S), and drought tolerance indices including tolerance index (TOL), mean productivity index (MP), harmonic mean index (HM), stress susceptibility index (SSI), geometric mean productivity index (GMP), mean productivity (MP) and modified stress tolerance index (K1STI) showed that the genotype effects for these parameters were significant (P≤ 0. 01). Hence, genotype selection according to MP, GMP, TOL and HM indices led to selection of outstanding genotypes in two conditions (normal and stress). Cluster analysis of genotypes were divided into three groups. According to PCA analysis 73. 2 % of data variations were justified by first component, and it had a high and positive correlation with grain yield in normal and stress conditions, MP, GMP, STT, K1STI, and HM, while there was a low and positive correlation with TOL and SSI. There is found that a positive and significant correlation for yield in normal condition with yield under drought stress and drought tolerance indices (p≤ 0. 01). It had a maximum correlation with K1STI (r=0. 995). GMP had a highest positive correlation with grain-yield in normal and stress conditions, therefore, it is considered as the more appropriate index. Results indicated that selection based on GMP, resulted in choosing the brilliant genotypes in normal and stress conditions.

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.

In order to evaluate the response of rice genotypes to salinity stress at germination stage an experiment was conducted as a factorial experiment in a completely randomized design with three replications in Biotechnology La of Sari Agricultural Sciences and Natural Resources University (SANRU). Sixteen rice genotypes were evaluated at four salinity levels (0, 40, 80 and 120 mM). The results of variance analysis showed a significant effect of salinity on the traits in different rice genotypes. According to the results of the mean comparison of the studied traits, with increasing salinity from the control level to 40, 80 and 120 mM, all traits showed a significant decrease. A simple correlation coefficient between the studied traits showed that the highest positive and significant correlation was observed between germination rate with germination percentage (r = 0. 89). The results of the principal component analysis based on the eight traits in the germination stage showed that the two components were able to justify 77. 66% of total changes. The first component emphasized on root length, root fresh weight, root dry weight, percentage and germination rate in positive direction. The cluster analysis of rice genotypes under stress of different levels of salinity on the basis of studied traits showed that L113, L21, L59, L33 and Shasttak Mohammadi genotypes in the third group had more salt tolerance than control (NONA BOKRA). Regarding the analysis, Shultak Mohammadi and L21 genotypes in terms of tolerance to stress in different levels of salinity were superior to other genotypes in this experiment and could be used in breeding programs.

In order to study the effects of steroidal testosterone hormone on seedling growth, antioxidant enzyme activity and also on callus induction from leaf explants of German Chamomile (Matricaria chamomilla L. ) under in vitroculture, an experiment was conducted based on completely randomized design with three replications using MS medium containing different concentrations of testosterone (0, 0. 01, 0. 1, 1, and 10 mg l-1) alone or in combination with a steady concentration of 1-naphthalene acetic acid (NAA) and Benzylaminopurine (BAP). The results showed that this hormone at concentration of 10 mg l-1 increased seedling length, seedling fresh weight, and root fresh weight. Peroxidase and polyphenol oxidase activities were increased at concentrations of 1 and 10 mg l-1 of this hormone. Also, catalase activity was increased at concentrations of 0. 1 and 1 mg l-1. Although the callus induction from leaf explants were observed after one to two weeks in all media, its growth depending on the presence of phytohormones and concentration of testosterone hormone were different. The most callus fresh weight of leaf explants alone and in combination with NAA and BAP was achieved at low concentration (0. 01 mg l-1) of testosterone hormone that was significantly different from the control. Results of this study showed that this hormone can play an important role in optimizing the growth of plants and improvement of callus growth.

Among the crops, cereals have been special important and triticale is the most successful man made cereal. In present research, water deficit stress effects on 19 triticale genotypes (X Triticosecale wittmack) and two wheat cultivars (Triticum aestivum), Shiraz (sensitive to water deficit stress) and Kavir (tolerant to water deficit stress) were tested. Therefore, two separate field experiments were performed based on Randomized Complete Block Design with 3 replications. In the first experiment, normal irrigation was used and in the second experiment irrigation has been eliminated at flowering step. Vegetative and yield component triats such as plant height, spike length, number of spikelets per spike, grains per spike, tiller number in plant, thousand grain weight, biological yield and grain yield were measured. Relative water content (RWC) and rate of leaf water loss (RWL) and total chlorophyll content as physiological traits were evaluated. Results showed that although water deficit stress decreased grain yield in different genotypes in comparison of normal irrigation, some genotypes tolerated water deficit stress and produced relatively high yield. Genotype ELTCC1 showed superior in thousand grain weight and number of spikelets per spike in normal irrigation condition and biological yield, grain yield, grains per spike and plant height in stress condition. Overall, we can introduce ELTCC1 and ELTCC15 genotypes as desired genotypes, because they showed more tolerance in comparison with other genotypes based on tolerance and susceptible indices and also yield in stress and normal irrigation conditions.

The aim of present study was to determine the relationship between grain yield and important agricultural characteristics for six lines of rice and Shiroodi cultivar as control in rice research station (Tonekabon) in west of Mazandaran Province in 2015. The experiment was conducted in a randomized complete block design with three replicates. Analysis of variance showed that there was a significant difference between genotypes for all studied traits except flag leaf width, which indicates the appropriate variation among the studied genotypes. Results of mean comparison test showed that the highest and the lowest grain yield were belong to line No. 5 (7831. 7 kg. ha-1) and No. 204 (6884. 3 kg. ha-1) respectively. Results showed that there were positive and significant correlation between grain yield and number of tiller, 1000-grain weight, filled grain number and number of total grains per panicle. Using stepwise regression method showed that 1000-grain weight, filled grain number and number a tillers had the maximum effect on grain yield. Results of path analysis showed that 1000-grain weight an important and effective trait can be used for selection of high yielding rice lines in breeding programs.

In present study, 72 barley double haploid lines with two parents were studied. The experiment was arranged in a completely randomized block design with two replicates under normal and boron stress in hydroponic condition in 2013. The traits Fresh and dry weight of root and shoot, length of root and shoot, length of the largest leaf and the height of whole plant were measured. Statistical analysis was done for phenotypic surveys such as analysis of variance, mean comparison and correlation between traits. These results showed meaningful difference among the lines in most traits. Maximum correlation was seen between length of root and the height of whole plant (0/934, 0/925). QTL analysis was carried out using genetic linkage map derived 327 AFLP molecular marker and using QTL cartographer software with composite interval mapping method. In general, 29 QTL were found for the studied traits (17 QTL for normal condition and 12 QTL for born stress condition, respectively), in which, explained that the phonotypical variance has been vitiated for 10 to 27. 56 percent. The highest and the lowest phonotypic variances were belonging to root and shoot length ratio in born stress condition, The LOD ranged between 2/50-4/32. The highest and lowest LOD were attained for the QTLs of root and shoot length ratio and leaf length, respectively. In percent study, only one QTL was placed at similar place and was stable (leaf length, 3H). Therefore, it can be used for marker assisted selection.

In order to evaluate of distinctness, uniformity and stability (DUS) of morphological traits, three new genotypes of cotton (GT40, TBL60 and SKT134) were tested using a complete randomized blocks design with 4 replications. In general, 39 quantitative and qualitative morphological characteristics were measured. Results showed quantitative morphological characteristics including number of stem nodes to the lowest fruiting branch (at flowering stage), fruiting branch length, fruiting branch nodes number, ginning outturn, fiber length, elongation and fineness, plant height and boll petiole length of genotypes significantly were distinct. Also genotypes qualitative morphological characteristics: pollen color, position of stigma relative to anthers, bract size (at green maturity), type of flowering, intensity of leaf green color (at flowering stage), Leaf size and pubescence of lower side, stem pubescence in upper part, boll opening time (when 50% of the plants have at least one boll opened) and degree of opening (at full maturity) significantly were distinct. Generally, achieved results showed, GT40 genotype based on yellow pollen color, upper position of stigma relative to anthers, small leaf size, medium stem pubescence in upper part, short plant height (at green maturity) and early boll time of opening (when 50% of the plants have at least one boll opened) was distinct from TBL60 and SKT134 genotypes. Also TBL60 genotype due to non-clustered type of flowering, medium leaf intensity of green color (at flowering stage), medium bract size (at green maturity) and medium boll petiole length were distinct from SKT134 genotype. Therefore, this research results characterized distinct morphological characters having uniformity and stability of three cotton new genotypes in the course of introduction as cultivars which could be used for mentioned cultivars registration for having plants breeders' right. Also, with due attention to uniformity and stability of distinctness of eight qualitative morphological characteristics, can used these characteristics as descriptors of cultivars which would introduced for those genotypes seed production fields control and certification of genetical purity and genuineness.

St. John’ s wort is a traditional medicinal plant that has been used from ancient time for the treatment of neurological and psychiatric diseases. A successful in vitro propagation system for the St. John’ s wort was optimized. Different explant type (single node and stem cutting with two nodes) were used in Murashige and Skoog (MS) medium in different concentrations (MS full, 3/4 MS and 2/3 MS) supplemented with BA (0. 05, 1. 0, 2. 0 mgl-1) and sucrose (30 and 45 gl-1). The optimum proliferation rate of St. John’ s wort was obtained in 2/3 MS medium containing 30 gl-1 of sucrose and 0. 1mgl-1 BA with single node explant. Also, evaluation of results revealed that the number of proliferated shoots will increased in MS media supplemented with BA along with reduced concentrations of sucrose. The in vitro generated shoots were cultured on half-strength MS medium containing 0, 0. 2, 0. 4, 0. 6, 0. 8 and 1 mgl-1 butyric acid (IBA). The results showed that all proliferated shoot were rooted in plant growth regulators free medium. But, using and increasing the concentration IBA in rooting media can increases the number of roots and average of root length per each explant.

Wheat stem rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the most important diseases of wheat, worldwide. New sources of resistance to stem rust could be found in synthetic hexaploid wheat (SHW) genotypes due to their high genetic diversity. In order to recognize the genetic structure of the population of the stem rust, following race analysis of 12 Pgt isolates, resistance of 348 SHW genotypes were evaluated using the infection type on a scale of 0 to 4 ratio to the four selected isolates from Gorgan and Broujerd (in 2014 and 2015) at seedling stage using randomized complete block design with two replications. Based on the reactions of differential wheat genotypes, the Pgt races TKTTF and TTTTF were identified among all isolates displaying virulence on the stem rust resistance genes Sr5, Sr6, Sr7a, Sr7b, Sr8a, Sr8b, Sr9a, Sr9b, Sr9d, Sr9e, Sr9g, Sr10, Sr12, Sr14, Sr15, Sr16, Sr17, Sr18, Sr19, Sr20, Sr21, Sr22, Sr23, Sr28, Sr30, Sr34, Sr36, Sr37, Sr38, SrTmp and SrMcN. Combined analysis of variance showed statistical significance between SHW genotypes in seedling stage in terms of their reaction to Pgt isolates. Furthermore, the significant isolate × genotype interaction suggests isolate-specific resistance in some genotypes which displays resistance to at least one Pgt isolate. Isolate-specific resistance was observed in 16% of genotypes, whereas 61 and 23% of the SHWs (such as lines 22842, 22857, 22862, 22863, 22864) were susceptible (infection type of 3-4) and resistant (infection type of 0-2) to all four Pgt isolates, respectively. Results of this research as the first report of SHWs resistant to prevalent Iranian stem rust races could be exploited in breeding programs using identified resistant genotypes which carry seedling resistance genes.

In order to study and compare the correlation between the quantitative and qualitative traits of sugar beet genotypes, using multivariate methods under Rhizoctonia disease a trial was carried out at Miandoab Agricultural and Natural Resources Station in 2014. The experimental design was randomized complete block design with four replications. The experimental materials were sixteen sugar beet genotypes. Analysis of variance showed significant differences among the genotypes for all traits, except root sodium content. Based on stepwise regression analysis, gross sugar yield, molasses sugar content and gross sugar content by justifying %89. 99 of changes in white sugar yield were considered as the most effective traits in justification of white sugar yield. Factor analysis identified five factors by justifying 81. 62% of total data variances. Finally, the three groups were set up in the cluster analysis at similarity distance of 10. The cluster 2 was subjected to groups a (the highest rate) for yellowing score, uniformity score, growth score, healthy plant number, root yield, gross sugar yield, white sugar content, white sugar yield and extract percentage, and was placed in group b (the lowest rate) for root potassium content and alkalinity. Eventually, based on path analysis and regression analysis, the gross sugar yield was determined as the most effective trait on the white sugar yield and the genotypes in cluster 2 were identified suitable for cultivation under the conditions of Rhizoctonia infestation.

Heterotic groups distinguished among breeding populations provide basic information to help plant breeders to control heterosis consciously. Development of alfalfa free hybrids can provide heterosis through parents' selection with crossing between partially inbred lines from two or three generations of selfing. In order to study of combining ability for forage dry matter, height and regrowth rate, selected partially inbred lines from the second generation of eight ecotypes of alfalfa were evaluated in a half-diallel cross design. Field experiments were performed in a randomized complete block design with three replications, including eight parents and 28 hybrids (F1) at Karaj and Arak during 2014-2015. Graphical GGE biplot method was applied to analyze the data. Based on the results of analysis of variance, mean square of GCA and SCA, and their interaction with environment were significant(p<0. 01). GGE biplot graphical method showed the highest positive GCA for Nikshahri and the highest amount of negative GCA for Kowzareh and Rahnani as parents of crosses for all traits. SCA was maximum for two specific parents, Nikshahri × Ghahavand and Nikshahri × Silvana crosses. Results also indicated that crossing between the Iranian partially inbreds (S2) of alfalfa to produce free hybrids can provide opportunities to exploit heterosis potential and improve forage yields.

In order to study of variation and correlation between yields and yield components in oilseed rape, an experiment was designed using line×tester method. Fifteen hybrid derived from crosses of three spring type and high yielding testers (SPN34, RGS003, SPN1) with five spring lines with moderate yield (SPN3, SPN9, SPN36, SPN30, DH4) were tested using a randomized complete blocks design with two replications in Seed and Plant Improvement Institute during 2014-15. Totally 21 traits were studied. Mean squares for all 21 traits except flowering time were significant at 5% to 1% levels. Grain yield positively correlated with, oil yield (0. 999), biological yield (0. 868), first pod height from ground level (0. 627), the number of seeds per pod (0. 546) and the pod length (0. 523). According to the results of path analysis, oil yield (1. 016) and oil percent (0. 379) had the most direct and indirect effects on grain yield, respectively. Cluster analysis based on the square Euclidean distance and Ward's method, classified crosses in three clusters and the accuracy of the results of clustering was confirmed by discriminant analysis. Six independently principal components were identified in the analysis of principal components, and this component could explain 89. 20 % of the total variation. In general, the most important affecting traits was grain yield, which can be used to for direct selection of grain yield in segregating generations.

Performance of any breeding program is mainly due to the correlation among yield and relative importance of each component. This study was conducted to analysis the correlation among grain yield and some important traits in seventhin spring canola (Brassica napus L. ) cultivars at the farm in safiabad, from 2014 to 2015. A randomized complete blocks design with four replications was used. The analysis of variance results indicated highly significant differences in canola genotypes for all studied traits, that it can indicate genetically variation be utilized for the effective selection for improving grain yield. Mean comparision showed that RGS003 and Hayola401 cultivars had higher grain yield than the other cultivars. The correlation coefficients among the grain yield and 1000-seed weight, number of seed per pod, HI and days to maturity were positive and significant. Results of stepwise regression analysis revealed that 1000-grain weight, number of pods per plant and days to maturity had significantly effects on grain yield. Path coefficient analysis revealed that the number of seed per pod and 1000-seed weight had the largest direct effects on grain yield, its seams possible to be use as selection criteria in breeding programs for improving grain yield of spring rapeseed cultivars.

In order to determine the genotype × environment (GE) interactions and yield stability, an experiment was conducted with 10 promising genotypes of rice and two control varieties (Shiroudi and Fajr) in four regions of Mazandaran (Amol, Babol, Sari and Tonkabon) using randomized complete blocks design with four replications during two cropping seasons (2012-2013). Analysis of variance showed significant differences for grain yield among genotypes. Combined ANOVA was also performed following Bartlett uniformity test (for uniformity of error variances). Results showed significant differences among the genotypes. Non-significant effects observed for location. year and genotype × location and genotype × year interactions means that the genotypes had similar response over different locations and years. Stability of genotypes were evaluated using seven different methods including: the variance and coefficient of environmental variability, Wricke’ s equivalence, Shukla’ s stability variance, coefficient of regression, the variance of deviation from regression, within location variance. Results showed that genotype No. 4 and control variety Fajr, were determined as stable genotypes, because of low S2i, CVi, MSy/p, Qi2 and Wi2 and bi equal to unity and non-significant S2di.

Simplifying the selection procedure to improve yield of new genotypes of rice is necessary. in order to evaluate relationship among grain yield and other agronomic traits, an experiment was conducted in agricultural and natural resoures research center in 2015-2016 year. In present study, 10 rice genotypes were studied in randomized complete blocks design with three replications. Grain yield along with other 10 agronomic traits were evaluated. Results derived from analysis of variance showed that there were significant differences among the studied genotypes for all the traits. Results of factor analysis showed that four main and independent factors explained about 80. 31% the total variation of the measured traits. So that, four factors namely shape and size grain (28. 44%), yield and it's component (23. 58%) and morphological (28. 29%) factor. Stepwise regression analysis showed that only two traits (the numbers of filled and unfilled grain per panicle) were significantly positive and negative affected on grain yield respectively. Results derived from path analysis showed that numbers of filled grain per panicle maximum direct effect (0. 82) was ratio other traits on grain yield, and indirect effect of this trait through to number of unfilled grains per panicle on grain yield was 0. 1. The number of unfilled grains per panicle showed direct effect and positive 0. 36. Therefore, the important traits as selection criteria for grain yiled improvement in rice plant are numbers of filled and unfilled grain per panicle respectively.

To improve a complex characters such as grain yield with low heritability, indirect selection through other characters and selection index based on different effective traits were used. For this purpose, 96 F3 families derived from Roshan and Kavir crossing, together with parents, F1 and F2 progenies were cultivated. In lattice design with 2 replications under drought stress conditions in research field of Shahid Bahonar University of Kerman at growing season of 2012-2013. In present study, the Smith-Hazel and Pesek-Baker selection indices were computed based on five traits including main spike weight, awn length, flag leaf width, 1000-grain weight and yield. In addition, direct and correlated responses were calculated for the mentioned traits. In Smith-Hazel index awn length and in Pesek-Baker index main spike weight had the highest selection response. The highest estimated relative selection efficiency for improvement of grain yield was obtained via selection for main spike weight and awn length. Main spike weight, awn length and 1000-grain weight showed positive response in all indices, while, flag leaf width revealed negative responses. Thus, selection based on these indices will resulting selection of families with high awn length, grain weight and low flag leaf width. Results showed that Pesek-Baker index had the highest selection efficiency and can be used to select appropriate genotypes in the present cross and bread wheat breeding programs.

Drought is one of the most destructive abiotic stresses worldwide that affects growth, development and final yield of crops. Reactions of thirteen rainfed spring 2-row barley genotypes and cultivars of cold areas of Iran to water stress were evaluated based on phenological, physiological and morphological traits. The experiment was carried out as factorial experiment based on a randomized complete blocks design with three replications under three irrigation treatments (normal irrigation and irrigation based on the 60% and 80% of available soil water depletion). The water stress was exerted two weeks before flowering. Results of mean comparisons showed that all the studied traits were reduced with increasing the level of water stress except branching of roots, root length and root length to plant height ratio. Taking all traits together, it is possible to identify two drought tolerant 71938 and 72566-1 genotypes and two Abidar and Dayton/Ranney cultivars which produced the highest yield under normal irrigation and both water stress conditions. Also, 71704 genotype could tolerate the first water stress level but not the second stress level. However, Denmark cultivar didn’ t produce favorable yield in normal condition but was comparatively tolerant to both water stress levels. So, after doing competition tests under water stress in actual rainfed conditions in cold-dry and semi-dry land, these genotypes can be recommended for cultivation in these areas, and also can be used for improvement of drought tolerant genotypes in breeding programs.

In order to detect the QTL associated with nitrogen-deficiency tolerance at seedling stage, a population of 96 lines derived from Ahlami Tarom and Neda cross were studied at 2014. For genetic linkage map construction, 30 SSR and 15 ISSR makers were used. The resulted linkage map covered 1411. 3 cM of rice genome with an average of 15. 34 cM distance between two markers. A total of 37 QTLs were identified for the traits under study. qRV-10 under conditions of nitrogen deficiency explained 11. 4% of the phenotypic variations of root volume. QTLs controlling root number (qRN-3 and qRN-6b) and root weight (qRW-5b and qRW-5c) under normal conditions were detected in the major stress that this is justified QTL accounted for over 20 percent of phenotypic changes. Markers linked to the QTL as markers linked to traits are likely to be used for marker-assisted selection in breeding programs.

In order to evaluate the effect of drought stress and determine of effective traits on grain yield and estimate of genetic parameters, 18 mutant rice lines were studied in normal and drought stress conditions. The experiments were carried out separately using randomized complete block design with three replications during cropping season 2014-2015 at Iranian Rice Research Centers in North of Iran, Rasht. High values of heritability, genetic advances and genetic variances were observed for plant height, tiller number, filled grain number and unfilled grain number in both conditions, but grain productivity and grain yield were appeared only under drought stress conditions. This indicated the additive effects of genes in controlling of these traits and, therefore, these traits can be improved by selection in breeding programes. There were positive correlations between grain yield and tiller number, panicle exsertion, grain productivity and width and length of flagh leaf in normal irrigation condition. Grain yield had also positive correlation with flagh leaf width, panicle exsertion, filled grain number, grain productivity and width and length of grain under drought stress conditions. Regression and path analyses indicated positive effects of grain width, grain productivity, flagh leaf width, filled grain number, tiller number and internode length in normal irrigation conditions and grain productivity, grain width and tiller number under drought stress conditions. Therefore, it is possible to improve grain yield using these variables. The genotypes including G1, G2, G3 and G4 had the highest values of grain yield (2788, 2163, 2178 and 2194 kg ha-1) under drought stress conditions, and influencing traits on grain yield. Due to the stress index (SI), these genotypes were also as drought tolerant and, thus, can be used for introducing the drought tolerance cultivar.