Iranian Rice Cultivars Research Articles

Yield Gap and Morphophysiological Traits of Rice Cultivars: the Affect of Seedling Age

Understanding yield-limiting traits can help researchers reduce rice yield gap, a key step in increasing yield and sustainability. This research therefore involved two steps: (i) monitoring 100 paddy fields of farmers to identify the most important variables to enter into a CPA model (comparative performance analysis) for the yield gap in the Sari region of northern Iran in 2015 to 2016, and (ii) investigating the effect of seedling age on local and improved cultivars in this region (Mazandaran province) in 2016 and 2017. The field experiment was conducted in a factorial experiment based on a randomized complete block design (RCBD) with three replications. The three seedling ages were 20, 27 and 34 days old for six Iranian rice cultivars (three local cultivars: Tarom Hashemi, Tarom Mahalli and Sang Tarom; and three improved rice cultivars: Fajr, Neda and Shiroodi). Of the 150 variables studied in the first experiment, eight independent variables were chosen for the final model. In the yield model, the average and maximum yields were 4437 and 6690 kg ha-1 , respectively, with an estimated yield gap of 2253 kg ha-1 . This yield gap was related to seedling age, transplanting date and seedling number per hill. Those factors were responsible for 104, 224 and 534 kg ha-1 , i.e. 5, 10 and 24 percent, respectively. The results of the second experiment demonstrated that all investigated traits were significantly affected by seedling age. Twenty-day-old seedlings yielded the greatest panicle length, flag leaf length, number of panicles per m2 , filled spikelet percentage, grain yield, harvest index, protein content, protein yield, nitrogen harvest index. Accordingly, the model’s precision is good and can be applied both to estimate the quantity of yield gap and to determine the portion of each constraint in the yield variables. Importantly, as the calculated yield potential is reached based on actual data in each paddy field, the yield potential is attainable. A seedling age of 20 days created better conditions for growth and yield for both local and improved cultivars.

Study of Biochemical and Molecular Changes of Iranian Rice Cultivars in Interaction with Bacterial Pathogen Xanthomonas oryzae pv. oryzae Causes Leaf Blight Disease

Study of Biochemical and Molecular Changes of Iranian Rice Cultivars in Interaction with Bacterial Pathogen Xanthomonas oryzae pv. oryzae Causes Leaf Blight Disease

Association analysis using SSR markers and identification of resistant aerobic and Iranian rice cultivars to blast disease

Blast disease is one of the most important diseases of rice with the fungus Magnaporthe oryzae as the causal agent. This research was carried out to evaluate the blast resistance in aerobic rice genotypes in comparison with Iranian lowland rice cultivars as a randomized complete block design by measuring area under the disease progress curve (AUDPC) on 53 rice genotypes with three replications in 2017 and 2018 years. Furthermore, molecular evaluation was done using 30 genes-based markers and linked SSR markers along with 60 random SSR markers. According to the results, aerobic rice genotypes, IR82310-B-B-67-2, IR82589-B-B-114-3, IR82616-B-B-64-3, IR82589-B-B-84-3, and IR82635-B-B-143–1 (ranged from 4.11 to 5.96) and Iranian rice cultivars Nemat, Sange-Tarom and Sepidroud (ranged from 4.46 to 4.72) had the lowest AUDPC, indicating they had the least infection severity during different stages of the experiment. Iranian native rice cultivars showed the most susceptibility, and association analysis via stepwise regression showed a significant relationship between some of the markers and AUDPC. Two gene-based markers of Pi5 and Pib and RM259 were detected in accordance with previous studies, and eight SSR markers (RM12091, RM217, and RM3498 with positive effect along with RM234, RM276 RM1300, RM8007 and RM480 with negative effect) were identified as informative markers in relationship with AUDPC for the first time. RM12091 and Pi5 had the highest adjusted R2, accounting for 30.2% and 25.2% of AUDPC variation, respectively. The most effective identified markers could be considered in marker-assisted selection after final validation using different environments and genetic backgrounds. In addition, the results of this study can help demonstrate the significant potential of aerobic rice genotypes for resistance to blast disease.

A Combined Method of Image Processing and Artificial Neural Network for the Identification of 13 Iranian Rice Cultivars

Due to the importance of identifying crop cultivars, the advancement of accurate assessment of cultivars is considered essential. The existing methods for identifying rice cultivars are mainly time-consuming, costly, and destructive. Therefore, the development of novel methods is highly beneficial. The aim of the present research is to classify common rice cultivars in Iran based on color, morphologic, and texture properties using artificial intelligence (AI) methods. In doing so, digital images of 13 rice cultivars in Iran in three forms of paddy, brown, and white are analyzed through pre-processing and segmentation of using MATLAB. Ninety-two specificities, including 60 color, 14 morphologic, and 18 texture properties, were identified for each rice cultivar. In the next step, the normal distribution of data was evaluated, and the possibility of observing a significant difference between all specificities of cultivars was studied using variance analysis. In addition, the least significant difference (LSD) test was performed to obtain a more accurate comparison between cultivars. To reduce data dimensions and focus on the most effective components, principal component analysis (PCA) was employed. Accordingly, the accuracy of rice cultivar separations was calculated for paddy, brown rice, and white rice using discriminant analysis (DA), which was 89.2%, 87.7%, and 83.1%, respectively. To identify and classify the desired cultivars, a multilayered perceptron neural network was implemented based on the most effective components. The results showed 100% accuracy of the network in identifying and classifying all mentioned rice cultivars. Hence, it is concluded that the integrated method of image processing and pattern recognition methods, such as statistical classification and artificial neural networks, can be used for identifying and classification of rice cultivars.

Differentialexpression of Asiii uptake, Antioxidant System, and Asiii -Conjugating Compounds of Two Iranian Rice Cultivars Adapted With Two Different Climates

Differentialexpression of Asiii uptake, Antioxidant System, and Asiii -Conjugating Compounds of Two Iranian Rice Cultivars Adapted With Two Different Climates

Genetic Mapping and Validation of Quantitative Trait Loci (QTL) for the Grain Appearance and Quality Traits in Rice (Oryza sativa L.) by Using Recombinant Inbred Line (RIL) Population.

Rice grain shape and nutritional quality traits have high economic value for commercial production of rice and largely determine the market price, besides influencing the global food demand for high-quality rice. In order to understand the genetic components of grain appearance traits in paddy, brown, and head rice, 15 traits were evaluated by using 157 recombinant inbred lines (RILs) derived from a cross between two Iranian rice cultivars Ali-Kazemi (A) and Kadous (K). A significant variation was observed and showed transgressive segregation among the RILs. Correlations between the visual appearances of grain traits were studied. A linkage map with 65 polymorphic SSR markers was constructed, which covered 1517.32 cM of the rice genome. A total of seven QTLs were identified on four chromosomes, 1, 6, 9, and 12, associated with four traits, which are explained by the total phenotypic variation of 44.27% and LOD score of 32.77 in 2014 and 2015, respectively. Among these, four QTLs for two traits were consistently flanked by RM23904 and RM24432 on chromosome 9. Single QTL for head grain length (HGL) expressed in both the years on chromosomes 1 and 9. A major QTL for seed weight was detected on chromosome 9, which explained 10.18% of the phenotypic variation. The additive effect of all the QTLs was positively contributed by Ali-Kazemi allele, except one QTL on chromosome 6 (qBGL_6) that showed a negative additive effect being contributed by the Kadous allele. The study also validated the identified QTLs with the polymorphic SSR markers that were previously reported. Novel QTLs were identified on chromosomes 6 and 9, and many of the polymorphic markers were found to be associated with milling processing of grain quality, cooking, and nutraceutical properties of rice by extensive literature and database analysis. Therefore, these validated QTLs and marker information could be utilized in the marker-assisted selection to improve grain appearance and nutritional grain quality traits in rice.

Differential responses of two Iranian rice cultivars to arsenite toxicity

Arsenic (As) is a toxic metalloid which is usually found in rice fields as a contamination and has negative effects on the plant growth and reduces the crop yield. Similar to heavy metals, the deleterious effects of As may be due to, at least in part, the amount of absorbed As and disturbance of the plant water status. In this connection, different varieties of the same species may show differential performances. Comparative responses to 75 µM AsIII were evaluated in two Iranian rice cultivars adapted to moderate-humid vs. very warm and dry climates (Hashemi and Amber, respectively). Although both cultivars absorbed AsIII, but its translocation factor was lower in Amber accompanied by accumulation of soluble sugars and glycine betaine and lower level of internal ABA. Moreover, adverse effect of AsIII onrelative water content and stomata closure was less prominent in Amber, compared to Hashemi. Results suggest that cultivars adapted to dry conditions are more capable to withstand against As and to control its entrance to human food chain.

Different physiobiochemical and transcriptomic reactions of rice (Oryza sativa L.) cultivars differing in terms of salt sensitivity under salinity stress.

Salinity stress is the most important and common environmental stresses throughout the world, including Iran. The aim of this study was to investigate the expression of several important genes involved in the salinity tolerance of the rice cultivars differing in salt sensitivity. In this research, the expression of four mitochondrial genes, H2O2, malondialdehyde (MDA), proline, sodium, potassium and superoxide dismutase (SOD), was measured in Iranian rice cultivars and two well-known international varieties as checks in response to 100mM salt stress. The results show that the activity of SOD in the tolerant cultivars is much higher than in the susceptible ones under saline conditions (100mM NaCl). The study of the gene expression in the tolerant and sensitive cultivars also showed that the expression of the genes increased in the early hours of the stress, with the exception of the OsGR1. Moreover, the amount of the expression in the tolerant cultivars was far more than the susceptible ones. The result of this study showed that the function of a set of antioxidant enzymes can lead to detoxification of the reactive oxygen species, so in order to better understand ROS scavengers, a comprehensive study on the antioxidant system should be conducted.

Two Iranian Rice Cultivars’ Response to Nitrogen and Nano-Fertilizer

This experiment was carried out as split factorial in randomized complete blocks design with three replications in Sari, Iran during 2013 and 2014. Rice cultivars were chosen as the main factor including Tarom Mahalli and Tarom Hashemi. Nitrogen rates (34 and 69 kg N ha−1 and nitroxin) with nano-particle (nano-potassium, nano-silicon and control) selected as the subfactor. The results indicated that the amount of total tiller per hill and fertile tiller per hill for Tarom Hashemi was more than Tarom Mahalli in both years. The highest paddy yield in both years was observed for Tarom Hashemi, the main reason behind it is increasing panicle length and fertile tiller number for this cultivar. For Tarom Hashemi, the highest paddy yield (5000 kg⋅ha−1) was produced with 34 kg N ha−1 and nano potassium application. For Tarom Mahalli, the highest paddy yield 4657 kg⋅ha−1 was obtained with nitroxin and nano potassium consumption. The highest harvest index was achieved with nitroxin and nano-silicon consumption. Therefore, nano particle consumption in both cultivars resulted in improved yield.

Molecular and physiological performance in response to drought stress in Iranian rice cultivars

The drought is one of the major challenges in rice production in Iran where it is the second most important crop after wheat. Hence, there is an increasing need to develop rice genotypes with drought-tolerant background. Determining drought tolerance mechanisms would be the first priority in order to have a successful rice breeding program. In the present study, three popular rice (Oryza sativa L.) cultivars including Neda, Amol3, and Sang-tarom having contrasting features against drought stress were tested in two water-deficit treatments at both vegetative and reproductive stages. Some important morphological and physiological characteristics related to the drought tolerance mechanism such as ABA content in leaves, size of stomatal apertures, and root length in vegetative phase as well as root volume and weight of panicles in reproductive phase were evaluated. Further, the expression profiles of four important transcription factors involved in drought tolerance regulatory networks, MYB3R-2, ZFP252, AP37, and AP59, were examined by means of quantitative RT-PCR. The data showed that the responses of Neda to drought stress conditions are closer to Amol3 than to Sang-tarom. In Neda, no reduction was observed in stomatal aperture size while the maximum dry and fresh weights of panicles found in Neda under mild drought stress conditions was a remarkable property among the cultivars in long-term drought stress. The genes expression profiles of AP37, AP59, MYB3R-2, and ZFP252 also showed lower levels of increase in Neda compared to Sang-tarom and Amol3.

Molecular and Physiological Performance in Response to Drought Stress in Iranian Rice Cultivars

Molecular and Physiological Performance in Response to Drought Stress in Iranian Rice Cultivars

Evaluation of Allelopathic Effects of Iranian Rice Cultivars (Oryza sativa L.) on Growth Factors of Barnyard Grass (Echinochloa cruss-galli L.)

In order to investigate the ability of aqueous hull extract of Iranian rice cultivars in controlling barnyard grass germination and seedlings growth, a factorial experiment was carried out at both Laboratory and greenhouse based on RCB (Randomized Complete Blocks) with 3 replication. In this study which was performed in 2010 at Tarbiat Modares University, the effects of 20 rice cultivars hull extract were considered on germination and seedling growth of barnyard grass weed at four concentrations (0, 5, 10 and 15 percent). Lab studies showed that some of the rice cultivars have stimulating effects on barnyard grass growth, while some others have inhibiting effects. Khazar cultivar showed the highest inhibiting effect on germination percentage, germination rate, radicle length, plumule length, radicle and plumule dry weight. Breeded cultivars had higher inhibition effects than natives, while the native cultivars were more stimulating on barnyard grass seed germination. The greenhouse part of study showed that Khazar cultivar causes significant reduction in germination percentage, germination rate, radicle length, radicle and plumule dry weight and whole plant dry weight of barnyard grass. Neda cultivar showed the highest effect in controlling plumule length. The study showed that various rice cultivars have different effects on inhibiting or stimulating the growth factors of barnyard grass.

Analysis of flavor volatiles of some Iranian rice cultivars by optimized static headspace gas chromatography–mass spectrometry

Static headspace coupled to gas chromatography–mass spectrometry (SHS-GC–MS) was applied to the extraction and analysis of volatiles in some Iranian rice varieties. Optimization of static headspace sampling was investigated by full factorial design and a face-centered central composite design procedure. According to the results of full factorial design, the effective parameters of static headspace sampling were extraction temperature (T) and extraction time (t). Then a central composite design was applied to find the optimum level of these factors. The results of three replications of experiments under optimal conditions (T = 100 °C, t = 900 s) indicated that, there is a good agreement between the predicted (5.28) and experimental (5.20) responses (98.48 %). Then developed method was used for analysis of volatile chemicals in three Iranian rice cultivars. According to the results of GC–MS analysis 26, 21, and 19 chemicals were assigned to Domsiah, Deylamani, and Tarom rice samples, respectively. The major compounds identified in these samples were the alkyl aldehydes. The results obtained are promising for future isolation and identification of the flavor volatiles of other rice cultivars by SHS-GC–MS analysis. The method of static headspace GC–MS has been developed and has proven to provide an effective means for simple and rapid quantitative analysis of the aroma compound of rice. A central composite design was applied to found the optimal conditions. The results of three replications of experiments under optimal conditions (T = 100 °C, t = 900 s) indicated that, there is a good agreement between the predicted (5.28) and experimental (5.20) responses (98.48 %). Then, developed method was used to analyze the volatile chemicals in the rice samples. A total of 26, 21, and 19 chemicals were assigned to Domsiah, Deylamani, and Tarom rice samples, respectively.

Genetic Analysis of Resistance to Races of Magnaporthe grisea the Causal Agent of Blast Disease in some Iranian Rice Cultivars

To study genetic architecture of resistance of rice to blast disease, five diverse rice cultivars viz. Neda, Dasht, Domsiah, SHZ-2 and Ahlami tarom were selected and all cross combinations were made among them (a half-diallel). All genotypes including ten F1 together with their five parents, were evaluated in RCBD with three replications for components of resistance to blast in Rice Research Institute of Iran in Rasht and Amol during 2005-2007. Analysis of variance showed that there were significant differences among all rice cultivars and their cross combinations for all traits. Combining ability analysis based on Method II and Model Mixed B (Griffing) revealed that mean of squares for GCA and SCA were significantly different, hence both additive and non-additive components of genetic variance were important in controlling of traits. For most of traits additive components were predominant. Cultivars Neda, Dasht and SHZ-2 were good combiner for increasing resistance to blast disease. Most of combinations showed high significant SCA for components of resistance. Genetic analysis through Hayman`s method also proved the results obtained via Griffing’s method.

Phenotypic evaluation of scutellum-derived calluses in ‘Indica’ rice cultivars

By using amenable MS based medium containing 4 mg l-1 2,4-Dichlorophenoxyacetic acid (2,4-D), 0.4 mg l-1 benzyl-aminopurine (BAP), 30 g l-1 sucrose, 8 g l-1 Agar-agar, qualitative and quantitative traits of calluses initiated from four genetically and commercially valuable Northern Iranian rice cultivars including Hashemi, Hasani, Gerdeh, and Gharib were studied. Five seeds were placed in each Petri dish and three replicates of eight Petri dishes per replicate were incubated in a growth chamber at 25 ±2 °C in the dark and the averages for every replicate were employed in the analyses. Several important parameters related to callogenesis of the cultivars including rate of non-viable seeds, necrotic, scutellar, slow growing, and non-scutellar calluses, simultaneous callus induction from scutellar and non-scutellar tissues, seeds with appropriate callus, and root emergence were compared. Accordingly, calli of Gharib and Hashemi were highly responsive in callogenesis, while Gerdeh and Hasani produced dissatisfying calluses. Necrotic calluses, scutellar calli, and non-viable seeds were positively correlated with each other; although they were negatively correlated with non-scutellar calli, simultaneous scutellar and non-scutellar calli induction, and root emergence. The results of the present study are expected to be the first promising step to generate genetically manipulated Iranian indigenous rice cultivars.

Assessment of flavor volatiles of modified Iranian rice cultivars during the gelatinization process

A combined GC-MS with the headspace solid-phase microextraction (SPME) method has been employed for the analysis of the flavor volatiles of two modified Iranian rice cultivars during gelatinization. In order to optimize the different experimental parameters, the effect of fiber composition, water content of the rice samples, and equilibrium time were investigated. As a result, while gelatinization progresses, the amount of volatile compounds would increase as well. Therefore, a broad range of the flavor volatiles of rice could be extracted, concentrated, and identified. Altogether, 54 and 66 components were identified for HD5 and HD6 rice samples, respectively, of which 33 unique compounds were not detected previously. The identified volatile components in the modified cultivars belong to the chemical classes of aldehydes, ketones, alcohols, and heterocyclic compounds, phenolic compounds, and hydrocarbons.

Characterization and Assessment of Flavor Compounds and Some Allergens in Three Iranian Rice Cultivars during Gelatinization Process by HS-SPME/GC-MS

A combined gas chromatography mass spectrometry with headspace solid-phase microextraction method has been utilized for the analysis of the flavor volatiles of three different rice cultivars including two modified Iranian rice cultivars and Hashemi rice cultivar during gelatinization. As a result, while gelatinization would progress, the amount of the volatile compounds would be also increased. Altogether, 74, 55 and 66 components were identified for Hashemi, HD5 and HD6 rice samples, respectively, which 56 unique compounds were not identified, previously. Subsequently, seven fragrance chemicals have been detected, which were most frequently reported as contact allergens in the European Union.

The Physicochemical Properties of Starch Component of six Iranian Rice Cultivars

Using a wide range of techniques, including differential scanning calorimetry, X-ray diffraction, Rapid Visco Analyser and Fourier Transform Infera Red Spectroscopy, some physicochemical properties of the starch fraction of six Iranian rice cultivars (Tarom, Tarome Hashemi, Neda, Ramezani, Fajr and Kamfirouzi) [1]were studied and compared. DSC data showed that starch granules of different rice cultivars had different gelatinization properties in terms of enthalpy, onset, peak and conclusion temperatures of gelatinization. All samples had similar X ray patterns (A type), different degrees of starch crystallinity. The rheological behaviour of rice powders during heating and the effects of heat processing were studied and compared in excess water from 25 to 95 °C. The samples were different in their pasting properties. This study indicates that starch properties should be mentioned as a crucial parameter determining the quality of rice cultivars.

Zinc Efficiency is Not Related to Bicarbonate Tolerance in Iranian Rice Cultivars

Zinc Efficiency is Not Related to Bicarbonate Tolerance in Iranian Rice Cultivars

Yield, yield components and physico-chemical characters of the ratoon crop of Iranian rice cultivars

The ratooning ability of five Iranian rice cultivars and the grain quality of the ratoon crop were evaluated in a randomized complete block design with four replications in consecutive years from 1999 to 2001 to select promising lines for economical ratoon culture. The main crop was harvested by cutting 30 cm above the soil surface for regrowth of the second (ratoon) crop. The ratoon grain yields (kg/ha) varied greatly among the cultivars, ranging from 144.9 (Haseni) to 1472.1 (Sang-e-Tarom). In general, the ratoon crops had fewer fertile spikelets, fewer spikelets per panicle, shorter panicle length and fewer primary and secondary branches per panicle than the main crop. The gelatinization temperature and gel consistency of rice grains from ratoon crops were lower than those of the main crops. The amylose content (%) of the grains from ratoon crops varied from 23.1 (Sang-e-Tarom) to 21.4 (Dailamani).