فصلنامه علوم زراعی ایران
سال بیست و پنجم شماره 1 (پیاپی 97، بهار 1402)

One of the main priorities of using heterosis for development of hybrid rice is to identify the suitable fertility restorer lines. Therefore, to identify suitable fertility restorer lines and evaluate rice hybrids, 36 F1 hybrids developed from crossing of two cytoplasmic male sterile lines, JelodarA and NedaA, together with 13 lines from local cultivars and four foreign fertility restorer lines as paternal lines as well as JelodarA and NedaA, as second crop, using randomized complete block design in three replications in the research farm of Tabaristan Genetics and Agricultural Biotechnology Research Institute, Sari, Iran, in 2019 and 2020. Mean comparison of morphological traits of F1 hybrids showed that the highest fertility and grain yield belonged to H28, H27, H33, H30 and H29 hybrids, which was mainly due to high fertile tiller number, 1000-grain weight and high panicle fertility. Using SSR molecular markers including RM 171, RM 490 and RM 3148 associated with the fertility restorer genes Rf3 and Rf4 for selection of superior hybrids revealed that RM 3148 marker could identify superior hybrids resulted from crossing of paternal lines IR68078-15-2-1-2-2-R, IR65622-151-1-2-2-2R and IR86403-5-5-2-1-1-1-1-1R with male sterile JelodarA which had similar band as fertility control restorer line and H27, H29 and H33 hybrids. These hybrids had both bands i.e. heterozygous, and based on this marker they carry Rf4rf4 alleles. RM 171 marker also showed the likely presence of Rf4 gene in IR 68078-15-2-1-2-2-R and IR 65622-151-1-2-2-2-R lines and hybrids developed from them. The F1 hybrids had both alleles in heterozygous from Rf4rf4. The results of this experiment showed that IR65622-151-1-2-2-2R was the suitable fertility restorer line for NedaA cytoplasmic male sterile, and IR68078-15-2-1-2-2-R and IR86403-5-5-2-1-1-1-1-1R were suitable fertility restorer lines for JelodarA cytoplasmic male sterile. These fertility restorer lines and cytoplasmic male sterile genotypes can be used in hybrid rice development programs.

To determine the optimal sowing date for new bread wheat cultivars as well as to investigate the relationship between grain yield and agro-climatic indices, a field experiment was carried out as split plots layout in randomized complete block design with four replications in two cropping seasons (2020-2021 and 2021-2022) in Gorgan agricultural research station, Gorgan, Iran. Seven sowing dates (from 01 November to 31 December, with 10-day intervals) were assigned to main plots and four spring bread wheat genotypes (cv. Araz, cv. Arman, cv. Taktaz and N-93-9 promising line) were randomized in subplots. Combined analysis of variance showed that the effect of sowing date was significant on grain yield, biological yield and spike no. m-2. While there was no significant difference between cultivars for the aforementioned traits. The highest grain yield obtained from 11 November (6235 kg.ha-1) and 21 November (6105 kg.ha-1) sowing dates, respectively. In delayed sowing dates (11 December, 21 December and 31 December), grain yield of cv. Taktaz was greater than other genotypes. The three sowing dates, 01 November, 11 November and 21 November, were not significantly different for grian filling duration (42.5, 42 and 40.3 days, respectively). However, grian-filling duration significantly decreased in delayed sowing dates (33, 34.1 and 35.6 days, respectively). The highest cumulative growth degree-days (GDD) for grain filling period was calculated for sowing dates 11 November  and 21 November  (782 and 773 GDD, respectively). In conclusion, the results of this experimebt showed that the highest grian yield and maximum energy use efficiency may obtain from the sowing date window of 11 November to 21 November for Gorgan region in Iran.

Solar radiation affects crop growth and development. Dry matter production by crops has often a positive relationship with radiation absorption by canopy and radiation use efficiency. Therefore, to evaluate radiation use efficiency of rice cultivars, a field experiment was carried out as split-split-plot arrangements in randomized complete block design with three replications in pilot plots in Qaleh-Tal district of Khuzestan province, Iran, in 2019-2020 and 2020-2021 growing seasons. Three rice cultivars; Champa, Anbouri and Danial were assigned to main plots, three planting arrangement; 15 cm × 15 cm, 15 cm × 20 cm and 15 cm× 30 cm, were randomized in sub-plots and seedling age at three levels; 30, 40 and 50-day old seedlings, in sub-sub-plots . Results showed that highest grain yield (9466 kg.ha-1) was recorded for cv. Danial in the 15 cm× 15 cm planting arrangement of 30-day seedling age treatment. The highest leaf area index (5.8) was achieved for cv. Champa in 30-day seedling age treatment. The highest crop growth rate (33.3 g.m-2 .day-1) observed for cv. Danial in 15 cm × 15 cm planting arrangement and 30-day seedling age treatment. The highest (1.95) and lowest (1.22 g,MJ-1) radiation use efficiency (RUE) were obtaibed in 30 and 50-day old seedlings, respectively. The increase of seedling age from 30 to 50 days led to incraese of light extinction coefficient from 0.06 to 0.10. The results of this experiment showed that 30-day old seedling at 15 cm × 15 cm planting arrangement treatment is more suitable for improving grain yield of rice cultivars in the target areas considering the low light extinction coefficient and high radiation use efficiency.

Rice is one of the important and staple food crops in Iran, and its grain yield improvement has always been the most important objective in rice breeding programs. One of the important breeding methods in rice is crossing between selected varieties to develop recombinant inbred lines (RILs), and then identifying promising lines. This experiment was carried out with the aim of identifying high-yielding superior lines. One hundred forty one recombinant inbrd lines together with their parental cultivars were evaluated using randomized complete block design with three replications in research field of faculty of agricultural sciences, University of Guilan, Rasht, Iran, in 2018. Important agronomic traits were measured and recorded for all RILs. Analysis of variance showed that there was significant differences among RILs for all studied traits, indicating significant genetic variation among them. Estimated coefficients of phenotypic and genetic variations as well as variance components also showed that there was considerable variation among RILs population, particularly for number of filled and unfilled grains panicle-1, number of panicles plant-1 and grain yield. The narrow-sense heritability varied from about 20% for panicle length to 43% for grain width, days to maturity, and 1000-grain weight. Factor analysis showed that three main and independent factors explained about 96% of the total observed variance among RILs, and were the main reasons for significant relationships between traits. These three factors were deignated as yield and its components, grain appearance quality and phenological factors. Cluster analysis by UPGMA method classified the 141 studied RILs into three clusters. Cv. Sepidrood and cv. Gharib (parental cultivars) were grouped in the first and second clusters, respectively. Evaluation of the cluster values for different traits showed that the first cluster had the highest values for grain yield and its components and the third cluster for grain dimensions and appearance quality. In conclusion, the results of this experiment showed that there was significant genetic variation among the studied RIls. Therefore, successful improvement of important agronomic traits, particularly grain yield and its components, is feasible. The superior high-yielding lines with desirable appearance quality were also identified.

This study was conducted to investigate the physiological and biochemical responses of wild and cultivated chickpea germplasm to cold stress, and to identify cold tolerant genotypes in field and controlled conditions. Twenty chickpea genotype including; 10 of cultivated chickpea (Cicer arietinum L.) genotypes, eight wild chickpea (Cicer reticulatum) genotypes, and two cold-sensitive ILC 533 line and cold-tolerant (cv. Saral) controls were evaluated using randomized complete block design with three replications in the dry conditions of Saral agricultural research station, Kurdistan, Iran, in two cropping seasons (2019-20 and 2020-21). Agronomic and phenological traits were measured and recorded. Meanwhile, the chickpea genotypes were subjected to a gradual decrease in temperature in the growth chamber under controlled environment, and their biochemical and physiological traits were measured and recorded. Analysis variance showed that chickpea genotypes had significant differences for physiological traits such as peroxidase activity, electrolyte leakage and chlorophyll b content. Path analysis revealed that 100 seed weight traits followed by membrane stability and peroxidase activity had the most direct and positive effect on seed yield. The results of this experiment showed that high-yielding genotypes such as FLIP 11-86C (889.62 kg.ha-1) and FLIP 11-03C (795.72 kg ha-1) had cold tolerance rating score  of three and moderate electrolyte leakage index, and were selected as superior cold tolerant genotypes.

Integrated weed management has been considered as an important strategy to increase the effectiveness of herbicides and reduce its adverse environmental impacts. In this study, the effect of weed management methods on growth indices and harvest index of  dragon’s head (Lallemantia iberica F. & C.M.) was investigated. The experiment was carried out as split plots layout in randomized complete block design with three replications in faculty of agriculture of Tabrize University in 2015-2016 cropping season. Two levels of herbicides (application and no-application of Trifluralin pre-emergence herbicide) was assigned to main plots, and seven levels of weed management; weed infected (without hand weeding) and weed-free (with hand weeding) dragon’s head and usage of mulch and cover plants (weed infected dragon’s head, weed-free dragon’s head, dragon’s head + mulch of straw and stubble, dragon’s head + lentil (Lens culinaris), dragon’s head + bitter vetch (Vicia ervilia), dragon’s head + barley (Hordeum vulgare), dragon’s head + hairy vetch (Vicia villosa) were randomized in sub-plots. Sampling of weeds in dragon’s head field showed that weed species such as fat hen (Chenopodium album L.), wild chicory (Cichorium intybus L.), green bristle (Setaria viridis L.), cocklebur (Xanthium strumarium L.), field bindweed (Convolvulus arvensis L.) and saltwort (Salsola kali L.) were dominant weeds. The highest weed density (48 plant.m-2) and dry weight (281.8 g) in dragon’s head field were obtained in no-aplication of Trifluralin, and in the treatment of dragon’s head + straw and stubble mulch, and the lowest in application of trifluralin herbicide. The average plant height of weeds (44.5 cm) was in no –weeding treatment. Means comparison showed that among the weed management methods using straw and stubble mulch and cover crop of hairy vetch significantly reduced plant height of weeds. Weed infection decrease biological yield and harvest index of dragon’s head. The highest seed yield (195.9 g m-2) belonged to hand weeding + herbicide application treatment. The highest biological yield (533.2 g.m-2) related to without weeding + herbicide application treatment. The highest harvest index (43.4%) related to mixed cropping of dragon’s head with hairy vetch + no application of herbicide treatment. The results of this experiment showed that hand weeding and application of Trifluralin herbicide were the most effective treatments in dragon's head performance.