Authors:M. Modarresi, V. Mohammadi, A. Zali, and M. Mardi
High temperature is a major determinant of wheat development and growth and causes yield loss in many regions of the world. This study was conducted to assess heat stress effects on yield and yield related traits of wheat. The 144 recombinant inbred lines derived from the cross of Kauz (heat tolerant) and MTRWA116 (susceptible) together with some commercial cultivars were evaluated during 2006–2007, 2007–2008 under normal and heat stress (late sowing) conditions. Grain yield, head length, kernels per spike, spiklets per spike, plant height, grain filling duration, peduncle length and 1000 kernels weight were measured. The results showed a significant difference among RILs for all traits in stress and control conditions. High temperature significantly decreased all traits specially grain yield (46.63%), 1000-kernel weight (20.61%) and grain filling duration (20.42%). Grain yield was most affected and spikelets per spike was least affected (11.77%). Grain yield under heat stress was directly correlated (r = 0.49) with yield in normal condition. Head length and grain yield had the highest (93.18%) and the lowest (62.97%) heritability, respectively. Peduncle length and grain filling duration showed the highest correlation with yield under both normal and heat stress conditions suggesting that these two traits could be used as reliable screening tools for development of heat-tolerant genotypes.
Authors:E. Farshadfar, R. Mohammadi, M. Aghaee, and J. Sutka
Water deficiency is a major constraint in wheat production and the most important contributor to yield reduction in the semiarid regions of the world. species related to wheat are valuable genetic sources for different traits including resistance/tolerance to biotic and abiotic stresses. To locate the genes controlling the physiological and agronomic criteria of drought tolerance, disomic addition lines of secale cereale cv. Imperial (donor) into the genetic background of Triticum aestivum cv. Chinese Spring (recipient) were tested under field, greenhouse and laboratory conditions. Disomic addition lines exhibited significant differences for relative water content (RWC), relative water loss (RWL), water use efficiency (WUE) and stomatal resistance (SR), indicating the presence of genetic variation and the possibility of selection for improving drought tolerance. Three physiological variables, RWL, WUE and SR, with high correlation with the stress tolerance index (STI) and germination stress index (GSI), contributed 69.7% to the variability of yield under stress (Ys) in the regression equation. Based on the physiological multiple selection index (MSI) most of the QTLs controlling physiological indices of drought tolerance were located on chromosomes 3R, 5R and 7R. The contribution of addition line 7R to the MSI was 47%. The evaluation of disomic addition lines for STI and GSI revealed that most of the QTLs involved in these quantitative criteria of drought tolerance are located on 3R and 7R. Cluster analysis and three dimensional plots of Ys, yield potential (Yp) and MSI indicated that 3R and 7R are the most important chromosomes carrying useful genes for improving drought tolerance.
Authors:M. Rajabi Hashjin, M.H. Fotokian, M. Agahee Sarbrzeh, M. Mohammadi, and D. Talei
Knowledge of morpho-protein patterns of genetic diversity improves the efficiency of germplasm conservation and development. The objective of present study was to evaluate 116 genotypes of Triticum turgidum from seven countries in terms of morphological traits and seed protein banding patterns. The results showed highly significant differences among the genotypes for the traits. The correlation between grain yield and weight per spike was significant and positive, while the correlation between days to heading, length of peduncle and plant height was significant and negative. The factor analysis classified the traits in to four main groups which accounted for 74.4% of the total variability. Sixteen allelic compositions were identified in the genotypes for high molecular weight glutenin subunits. The three alleles were present at the Glu-A1 locus and 8 alleles at Glu-B1. The null allele was observed more frequently than the 1 and 2 alleles. Two alleles, namely 17 + 18 and 20, represented more frequent alleles at Glu-B1 locus. The genetic variability in Glu-A1and Glu-B1 loci were 0.42 and 0.81, respectively. The cluster analysis based on morphological traits and HMW-GS clustered the genotypes in to six and seven groups, respectively. The results indicated the presence of high genetic variability among the genotypes. Our findings suggest that the plants belong to different clusters can be used for hybridization to generate useful recombinants in the segregating generations, the genetics and breeding programs for improvement of durum wheat.
Authors:B. Vaezi, A. Pour-Aboughadareh, R. Mohammadi, M. Armion, A. Mehraban, T. Hossein-Pour, and M. Dorii
Successful production and development of stable and adaptable cultivars only depend on the positive results achieved from the interaction between genotype and environment that consequently has significant effect on breeding strategies. The objectives of this study were to evaluate genotype by environment interactions for grain yield in barley advanced lines and to determine their stability and general adaptability. For these purposes, 18 advanced lines along with two local cultivars were evaluated at five locations (Gachsaran, Lorestan, Ilam, Moghan and Gonbad) during three consecutive years (2012–2015). The results of the AMMI analysis indicated that main effects due to genotype (G), environment (E) and GE interaction as well as four interaction principal component axes were significant, representing differential responses of the lines to the environments and the need for stability analysis. According to AMMI stability parameters, lines G5 and G7 were the most stable lines across environments. Biplot analysis determined two barley mega-environments in Iran. The first mega-environment contained of Ilam and Gonbad locations, where the recommended G13, G19 and G1 produced the highest yields. The second mega-environment comprised of Lorestan, Gachsarn and Moghan locations, where G2, G9, G5 and G7 were the best adapted lines. Our results revealed that lines G5, G7, G9 and G17 are suggested for further inclusion in the breeding program due to its high grain yield, and among them G5 recommended as the most stable lines for variable semi-warm and warm environments. In addition, our results indicated the efficiency of AMMI and GGE biplot techniques for selecting genotypes that are stable, high yielding, and responsive.
Authors:R. Prasanna, S. A. Mohammadi, B. M. Prasanna, and P. K. Singh
Twenty cyanobacterial strains of the genus Tolypothrix, including 15 strains of T. tenuis, three strains of T. ceylonica, and one each of T. nodosa and T. bouteillei, that were collected from various agro-ecological regions of India were evaluated for important parameters related to nitrogen fixing potential, such as acetylene reduction activity, total protein and chlorophyll content. Distinct differences were observed in nitrogen fixing potential at both inter- and intraspecific levels. The T. tenuis strains, in general, exhibited superior nitrogen fixing ability as compared to strains belonging to other species. A statistical procedure based on simultaneous consideration of performances of various strains with respect to different parameters under study aided in identification of three highly promising T. tenuis accessions, namely ARM586, ARM75 and ARM460, for potential exploitation as biofertilisers.
Authors:A. Etminan, A. Pour-Aboughadareh, R. Mohammadi, L. Shooshtari, M. Yousefiazarkhanian, and H. Moradkhani
In the present study, efficiency of the artificial neural network (ANN) method to identify the best drought tolerance indices was investigated. For this purpose, 25 durum genotypes were evaluated under rainfed and supplemental irrigation environments during two consecutive cropping seasons (2011–2013). The results of combined analysis of variance (ANOVA) revealed that year, environment, genotype and their interaction effects were significant for grain yield. Mean grain yield of the genotypes ranged from 184.93 g plot–1 under rainfed environment to 659.32 g plot–1 under irrigated environment. Based on the ANN results, yield stability index (YSI), harmonic mean (HM) and stress susceptible index (SSI) were identified as the best indices to predict drought-tolerant genotypes. However, mean productivity (MP) followed by geometric mean productivity (GMP) and HM were found to be accurate indices for screening drought tolerant genotypes. In general, our results indicated that genotypes G9, G12, G21, G23 and G24 were identified as more desirable genotypes for cultivation in drought-prone environments. Importantly, these results could provide an evidence that ANN method can play an important role in the selection of drought tolerant genotypes and also could be useful in other biological contexts.