فصلنامه علوم زراعی ایران
سال بیست و سوم شماره 1 (پیاپی 89، بهار 1400)

To evaluate sugar beet germplasm for identifying drought tolerant genotypes, precise methods are required for application of drought stress. A field experiment carried out as split arrangments in randomized complete block design with four replications in Karaj, Iran in 2007 and 2008. Main plots consisted of eight irrigation treatments with furrow and tape drip irrigation methods after 30 mm (except furrow irrigation) 80, 130 and 180 mm evaporation from the class A evaportation pan. Four sugar beet genotype; 7112, BP Karaj, BP Mashhad and BP Karaj (I13*A37.1) were randomized in sub-plots. The 30 mm level of tape drip irrigation was applied at two levels of %75 and %100 sugar beet crop water requirement. Combined analysis of variance showed that there was significant differences between irrigation treatments, for root yield, sugar yield and white sugar yield. The lowest root yield obtained in tape irrigation after 130 mm (41.2 t.ha-1) and 80 and 180 mm (41.7 t.ha-1) evaporation from calss A evaporation pan, respectively.  The highest root yield obtained in furrow irrigation after 80 and 130 mm (> 50.8 tha-1) evaporation from class A evaporation pan, respectively. Tape irrigation after 80 mm evaporation and furrow irrigation after 130 mm evaporation from class A evaporation pan had the lowest (6.35 t.ha-1) and highest (9.31 t.ha-1) sugar yield, respectively. Average water use in furrow irrigation after 80 mm evaporation from class A evaporation pan (common irrigation practice with 8-10 days interval) was 16000 m3.ha-1. However, average water use in drip tape irrigation after 30 mm evaporation from class A evaporation pan to meet 75% sugar beet crop water requirement was 7350 m3.ha-1. The highest and lowest irrigation water productivity belonged to drip tape irrigation after 30 mm (1.56 kgsugar.m-3) and furrow irrigation after 180 mm (0.42 kgsugar.m-3) evaporation from class A evaporation pan, respectively. Considering the results of this research, tape drip irrigation after 30 mm evaporation from class A evaporation pan with supplying 75% of sugar beet crop water requirement was identified as suiable irrigation system for application of drought stress for screening sugar beet germplasm.

The effect of drought stress on the relative expression of Aquaporin, Dehydrin, Putative leafy cotyledon 1-like protein (Ha-L1L) genes in two sunflower lines [ENSAT254 (tolerant) and LC1064C (susceptible)] was investigated using real time PCR technique. The lines with different response to drought stress were planted using completely randomized design with three replications in greenhouse of faculty of agriculture and natural resources of Urmia University, Iran, in 2018. Plants were kept at 100% of field capacity until 8 leaf stage. After this stage, some pots were kept at the same field capacity but some other were irrigated to reach 80%, 60% and 40% of field capacity. Samples were taken atone, two and three weeks after application of drought stress. The highest relative expression of Dehydrin gene was observed 21 days after drought stress at the stress level of 40% of field capacity in ENSAT254 (tolerant genotype), which is approximately 2.9 times more than that in LC1064C (susceptible genotype) under the same treatment. The highest relative expression of Aquaporin gene was observed in ENSAT254 genotype 14 days after application of drought stress at the stress level of 40% of field capacity. A study of the relative expression of the Putative leafy cotyledon 1-like protein gene showed that in the first week, while any changes in the expression of gene was not observed in LC1064C (susceptible genotype) at any drought stress intensities, in the ENSAT254 (tolerant genotype) the expression of gene had increasing trend across different drought stress intensities, from 80% to 40% of field capacity. Fourteen and 21 days after application of drought stress, major changes in the relative expression of the gene was observed in the LC1064C (susceptible genotype). This implies that this gene may play an essential role in drought tolerance. However, it is not a function of plant water status; therefore, this regulator may not participate in the positive regulation of the Dehydrin gene, but may regulate it negatively. Totally, the different pattern of gene expression in the two genotypes suggests that they responded differently to drought stress. Should the drought tolerance of ENSAT254 be confirmed at the molecular level, this line can be potentially used in the production of drought tolerant hybrid cultivars.

The aim of this study was to evaluate the efficiency of yield stability analysis models and to assess genotype × environment interaction effect on grain yield of 20 durum wheat genotypes for identifying high yielding and adapted genotypes by BLU and AMMI models using experimental data of four cropping cycles (2009-2013) in five filed stations in warm rainfed regions of Iran. The results of Likelihood ratio test (LRT) showed that the effect of genotype and genotype × environment interaction on grain yield was significant. Therefore, the best linear unbiased predictors (BLUPs) analysis was considered appropriate for these data. According to AMMI stability value (ASV) index, genotypes 11, 8, 14, 19 and 16 had more yield stability. Simultaneous selection index (ssiASV) based on ASV identified genotypes 8, 11, 4 and 10 in terms of grain yield and yield stability as superior genotypes. Given that by using these simultaneous selection indices, genotypes with different patterns for multivariate trials can be considered similar, the results can be misleading. Based on the first two main components, AMMI2 biplot diagram identified genotypes 19, 3, 14 and 11 as genotypes with yield stability. The results of the mosaic diagram showed that the contribution of genotype and genotype × environment interaction were 14.94% and 85.06% of the total variation, respectively. Based on weighted average of absolute scores (WAASBY) index using BLUP analysis, genotypes 4, 8, 11, 10 and 7 were identified as high yielding with yield stability. In general, usin mixed model as well as all the components in calculating the WAASBY index, it can be concluded that this index is superior to other indices.

To evaluate grain yield of barley cultivars in different planting times and identifying genotypes suitable fro delayed planting under rainfed conditions, this study was carried out  in 2015-2016 and 2016-2017 cropping cycle in Torogh research station in Mashhad, Iran. Two planting times; autumn and dormant seeding and 12 barley genotypes were compared as split plot arrangements in randomized complete block design with three replications. Two planting times were assigned to main plots and 12 barley genotypes were randomized in sub-plots. Barley cultivars included; Sahand, Abidar, Ansar, Nader, Yea168, Sararoud1, Mahoor, Khorram and Eizeh. Phonological development and grain yield and yield components were measured and recorded. The results showed that there were significant differences among cultivars. At the autumn planting, anthesis occurred under optimum range of temperature. However, in delayed planting, anthesis occurred under temperature stress conditions in most cultivars. Mahoor and Khorram cultivars with mean of 2291 and 2119 kg.ha-1, respectively had the highes grain yield, and Abidar, Ansar and Sararoud1 with mean of 1518, 1619 and 1625 kg.ha-1, respectively, had the least grain yield. Based on the results of this experiment, Mahour and Khorram cultivars are suitable for cultivation in Mashhahd region and other similar areas. However, if there is high risk of winter frost damage (based on long-term meteorological information), Nader and Sahand scultivars can be grown. For dormant seeding only spring cultivars such as Mahoor and Khorram due to higher grain yield and yield adaptability are most suitable.

One of the most important challenges for plant breeding has always been genotype × environment interaction. In present study, genotype × environment interaction was invesitigated for 13 winter oilseed rape genotypes in six cold and temperate cold locations in Iran using non- parametric statistical methods during 2014-2017 growing seasons. Four methods; Hildebrand, Bredenkamp, Kubinger, and De Kroon/van der Laan to verify the main effect of genotype and environment as well as gennotype ×environment interaction effect. Also, Nassar and Huhn, and Thennarasu as well as Foxchr('39')s superiority index and summation rank of Kang methods were used for assessment of dadaptability of ghenotypes. Determination of significant main and interaction effect revealed that all effects were significance with the exception of interaction effect in Kubinger method. By using plot from the first method of Nassar and Huhn and Thennarasu, genotype BAL921 with mean seed yield of 4078.6 kg.ha-1 was superior to the other genotypes. Fox and sum of ranks of Kang methods identified cv. Nafis and cv. Nima with mean of 4336 and 3902.4 kg.ha-1 seed yield as adapted cultivars. Identification of superior genotype(s) is more reliable by method that considers high yield and yield stability of genotype(s). In this study, Fox and sum of ranks of Kang methods was more efficient than other non-parametric statistical methods used due to having the features, therefore the genotypes selected using these methods were identified as the most suitable genotypes.

To investigate the effect of plant density on agronomic traits of winter rapeseed (Brassica napus L.) cultivars under foliar application of salicylic acid a factorial split-plot arrangement in randomozide complet block design with three replications was carried out in Karaj, Iran, in two cropping seasons (2015-2017). Plant density at three levels of 40, 50 and 60 plants.m-2 and salicylic acid at two levels of 0 (non-application) and application with a concentration of 1‰ in two stages of 6 leaf and stem elongation were assigned in main plots and rapeseed genotypes; HW118, WPN6, HL3721, L14, Tassilo and Natali were randomized in sub-plots. The Plant density × salicylic acid × genotype interaction effect was significant (P≤0.01) on plant hight, number of silique on the main stem and branches, seed number of silique on the main and branches, 1000-seed weight, seed yield, oil yield, biological yield and total chlorophyll content. This interaction effect was also significant (P≤0.05) on seed oil content. All rapeseed genotypes showed positive responses to foliar  application of salicylic acid at different plant densities, and L14 and Natali genotypes in 40 plants.m-2 and application of salicylic acid had the highest seed yield (5629 and 5448 kg.ha-1), oil yield (2444 and 2352 kg.ha-1) and 1000 seed weight (5.3 and 5.1 g), respectively. Therefore, for rapeseed production, especially in low densities (40 plants.m-2), foliar application of salicylic acid is suitable for increasing seed yield.

To study the genetic control of grain yield and its components in rice using Hayman graphical method, 56 progenies obtained from diallel mating with eight parents (64 genotypes in total) were evaluated using randomized complete block design with three replications at research field of the Rice Research Institute of Iran in 2013. Agronomic traits, grain yield and its components were measured and recorded. Estimation of genetic parameters for grain yield by Hayman’s method showed that the additive variance (D) was less than the two components of dominance variance (H1) and (H2), and the average degree of dominance of genes is greater than one (1.741). Results showed that grain yield, filled grain number per panicle, 100-grain weight, panicle number per plant, and plant height were under the control of additive and non-additive effects as well as maternal and non-maternal effects. Line RI184421 (Sepidrood × Hasansaraei) and line 23 (IR75479-199-3-3) had the highest number of dominant and recessive alleles for grain yield, respectively. Plant height and panicle length was affected by the incomplete dominance effect, and grain yield, filled grain number per panicle, 100-grain weight and panicle number per plant were controlled by the overdominance effect. The broad-sense heritability of studied traits was high (˃ 90%). Narrow-sense heritability was high for plant height, indicating the importance of additive effects in the genetic control of this trait. Based on the results of this study, it is recommended that to improve grain yield and its components in rice that are controlled by the non-additive gene effects by using hybrid technology and to improve traits such as plant height and panicle length using selection based breeding methods due to the key role of additive effects in their genetic control.

Genotype by environment interaction is one of the complicated issues in plant breeding programs for development of high-yielding with yield stability genotypes. To evaluate seed yield and yield stability of oilseed rape in four southern and northern warm regions of Iran (Zabol, Gorgan, Haji Abad and Sari), nine open pollinated spring oilseed rape lines together with seven cultivars were evaluated using randomized complete block design with three replications in two cropping cycles (2017-19). The results showed that G9 (SRL-95-16) and G12 (OG-AL) genotypes had the highest and the lowest seed yield with mean seed yiled of 3412 and 2507 kg.ha-1, respectively. In this study, seed yield wassignificantly different in different environments. The genotype × environment interaction was investigated using GGE-bioplot stability analysis. According to the which-won-where model of the GGE-biplot model, most of the studied environments were located in or close to the mega-environment 2 which included genotypes G2 (SRL-95-7) and G9 (SRL-95-16) as the best genotypes in this mega-environment. Also, the study of the average tester coordinates showed that G2 and G9 genotypes as superior to all check genotypes like G11 (Dalgan which ranked third) and as the best genotypes considering both seed yiled and yield stability. Also, these two genotypes had the shortest distance from the hypothetical ideal genotype in comparison with other lines and check cultivars. Therefore, considering seed yield and its stability, two genotypes G9 and G2 were identified as suitable genotypes for the southern and northern warm regions of Iran.