فصلنامه تحقیقات غلات
سال یازدهم شماره 1 (بهار 1400)

The recent water shortage caused a need to find the best way of water and nitrogen management. In this study, the effects of nitrogen (N) fertilizer and irrigation interval at different growth stages were investigated on the yield and yield components of rice (Hashemi variety). The experiment was conducted in factorial based on randomized complete block design with three replications in Rice Research Institute of Iran (RRII), Rasht, Iran, during two years, 2017 and 2018. The studied factors included irrigation (flood irrigation, irrigation intervals of one and two weeks), growth stage (vegetative and reproductive stages) and nitrogen fertilizer levels (40, 60, and 80 kg.ha−1). The studied traits were plant height, panicle length, number of panicles per plant, number of spikelets per panicle, number of filled grains per panicle, number of unfilled grains per panicle, panicle fertility percentage, 1000-grain weight and grain yield. The results of analysis of variance showed that the main and interaction effects of the studied factors on grain yield was significant. Also, the interaction effect of growth period, nitrogen fertilizer and irrigation interval on grain yield during two years was significant at the 1% probability level. The results showed that the grain yield and yield components (except for the number of unfilled grain) significantly increased with the application of nitrogen fertilizer under flood irrigation conditions. Among the studied treatments, the highest and lowest grain yield were belonged to flood irrigation in the vegetative stage with 80 kg.ha−1 nitrogen fertilizer in 2018, and irrigation interval of two weeks in the reproductive stage with 40 kg.ha−1 of nitrogen fertilizer in 2017, respectively. Based on the results of this experiment, flood irrigation during the vegetative growth stage and the application of 80 kg.ha-1 nitrogen fertilizer is recommended as the best irrigation and nitrogen fertilizer management.

Leaf rust is one of the most important wheat diseases in the world and Iran and the use of resistant cultivars is the most effective tool against this disease, however, the resistance of the cultivars becomes ineffective following a selective pressure on the pathogen, which makes the search for new resistance genetic resources unavoidable. The present study was performed to identify these sources of resistance in wheat germplasm. Therefore, 97 accessions from the bread wheat collection of National Plant Gene Bank of Iran were investigated under natural infection condition at Eraghi-Mahale Research Station, Gorgan, Iran, in 2017-2018. The results showed that 46.4% of the studied accessions had a zero infection coefficient that were selected for evaluation at the seedling stage. Seedling evaluation was performed in greenhouse using four pathotypes with determined virulence-avirulence factors. The results of qualitative and quantitative analyzes grouped the studied accessions into different groups with specific resistance to one or more pathotypes. Comparison of resistance response of the accessions with avirulence/virulence formula in the pathotypes indicated the possibility of presence of Lr14a in the accession 5127. Furthermore, these comparisons revealed the possibility of presence of unknown resistance genes in many of the accessions under study. The results of this study showed the valuable capacity of the bread wheat germplasm to possibly identify new genes and sources of resistance to leaf rust. Therefore, it is suggested that additional research be done to evaluate and screen the bread wheat germplasm.

To investigate the effects of foliar application of salicylic acid and selenium on agronomic characteristics and grain protein content of dry land wheat, Sardari variety, a experiment factorial was conducted in randomized complete block design with three replications. Experimental factors were foliar application of 1 mM salicylic acid at of booting, flowering and dough developmental stages along with control (spraying with water), and foliar application of 18 g/ha selenium at stem elongation, heading (spike emergence) and milk developmental stages along with control (spraying with water). The results showed that both salicylic acid and selenium improved the studied traits, so that foliar application of salicylic acid at flowering stage had the highest biological yield (9202 kg/ha) and grain protein (11.3%), and foliar application of selenium at heading and stem elongation stages had the highest biological yield, spike length, grain protein content and number of tillers. Also, combined application of salicylic acid and selenium compared to their separate application had better results on plant height, yield and yield components of wheat, so that the highest grain yield, number of spikes and number of grains per spike were observed in foliar application of salicylic acid-selenium at flowering-stem elongation and booting-stem elongation stages. Therefore, the results of this study showed that foliar application of salicylic acid at booting and flowering stages along with foliar application of selenium at stem elongation and heading stages were the best treatments in this experiment and it is recommended to improve the yield and yield components of dry land wheat.

Due to the importance of genetic diversity especially the necessity to assess the diversity among wild relatives of bread wheat (Triticum aestivum L.), the present study was conducted to evaluate the genetic diversity of 52 wheat genotypes (49 wild relatives genotypes of bread wheat along with three Iranian wheat genotypes) using 10 ISSR and two SSR markers. The results showed that a total of 12 studied markers produced 145 polymorphic bands with an average number of 11.4 and 15.5 polymorphic bands and 1.60 and 1.43 effective alleles for ISSR and SSR markers, respectively. The ISSR marker 17899A with the highest effective number of alleles (1.8), Nei’s gene diversity index (0.44) and Shannon’d diversity index (0.63) was the most valuable marker in this study. Cluster analysis method based on simple matching coefficient matrix and farthest neighbor algorithm grouped the studied genotypes into five clusters including 10, 6, 24, 9 and 3 genotypes, respectively, and the discriminant function analysis also determined the accuracy of this grouping to be 100%. The results of principal coordinate analysis (PCoA) also showed that the four most important principal components accounted for a total of 31.59% of the total variance. Grouping the genotypes using the first and second components with explaining 10.94 and 8.22% of the total variance, respectively, divided the genotypes into five groups, so that three Iranian wheat genotypes were placed into one cluster. In total, the results showed that the markers used in this study with acceptable polymorphism could be introduced as useful and desirable markers for evaluating genetic diversity and differentiation of wheat genotypes and possibly other cereals.

The first step in maize breeding programs is to use the genetic diversity existing between populations, cultivars and genotypes. Molecular markers provide the possibility to estimate the breeding value of agrobiological traits of genotytpes using best liner unbiased prediction (BLUP). In this study, the breeding value for ten traits including weight of 100 grains, days to maturity, diameter of ear together with grain, ear length, leaf weight, leaf number, plant height, stem diameter, leaf length and yield were predicted in 73 lines with high phenotypic diversity under normal and stress conditions using the best liner unbiased prediction (BLUP) procedure. Considering the sum of ranks of the breeding values ​​of all the studied traits, P13L3, Line1, Line4 and Line17 were the best genotypes. Under normal conditions, P3L2 genotype for days to maturity and plant height, Line6 genotype for diameter of ear together with grain and yield and Line19 genotype for ear length, plant height, yield and stem diameter showed high and positive breeding values. Under salt stress conditions, Line2 genotype for weight of 100 grains, diameter of ear together with grain, ear length and Line16 genotype for days to maturity, leaf weight and plant height showed high and positive breeding values. As genotypes with high and positive breeding values can better transfer their characteristics to their progenies, so they can be introduced as a suitable parent for breeding of these traits in breeding programs.

Studying the interaction of genotype ×environment and identifying high-yielding and stable cultivars is very important for breeders. In this research, the yield stability and compatibility of ten grain sorghum genotypes were evaluated in seven regions of Iran, Karaj, Gorgan, Birjand, Isfahan, Shiraz, Hamadan and Zabol, during two years (2019-2020). The experiment was performed as randomized complete block design with three replications in all years and regions. The results of combined analysis of variance showed that the effect of location, year and genotype and all their interactions on grain yield significant at 1% probability level. The results of AMMI analysis also showed that the main effect of genotype, environment and interaction of genotype × environment as well as the first five main components of interaction on grain yield were significant (p≤0.01). In total, the cumulative share of the five main components was 93.61%. Genotypes 5 and 4 had the most positive and negative interactions, respectively. Although these genotypes had high grain yield, they were known as unstable genotypes. Genotypes 2 and 7 were selected as stable genotypes and are recommended to all regions based on the AMMI1 model. In this experiment, genotype number 7 with the lowest AMMI  stability value (ASV) was recognized as the most stable genotype and genotype number 1 with the highest ASV was recognized as the most unstable genotype. In terms of stability, genotype number 6 with the highest grain yield (7379 kg.ha-1) was ranked after genotypes 7 and 3. Genotype number 7 with the lowest value of interaction compared to the two axes (IPCA1 and IPCA2) was known as stable genotype and genotypes 2 and 9 had the highest values ​​of interaction. In terms of other stability indices such as MASV, SIPC, DZ, EV and ZA, genotypes 7 and 3 were determined as the most stable genotypes.