Iranian Journal of Crop Sciences
Year:2018 | Volume:20 | Issue:1|Papers Count:6

To investigate the effect of water stress on genetic parameters and combining ability of seed yield and some of the important traits of sunflower, eight restorer lines with different drought tolerance were crossed with three cytoplasmic male sterile lines as tester in 2014. Hybrids with their parents were evaluated in split plot arrangements using randomized complete block design with three replications at Shahrood Agricultural and Research station, Iran in 2014. Irrigation factors were assigned in the main plots at two levels, full irrigation and water deficit stress, and sunflower genotypes (24 hybrids, 11 parental lines, and one check variety) were randomized in sub-plots. Days to maturity, plant height, head diameter, seed number per plant, 1000 seed weight and seed yield were measured and recorded. Results of line × tester analysis showed that the effect of lines and testers in both conditions was significant for all studied traits, except for the head diameter in stress condition. The line × tester interaction effect in normal conditions was significant for seed number per plant and seed yield. Lines C122 and C123 and tester A19 in both conditions had the highest positive general combining ability in grain yield and could be used as suitable parental lines for developing hybrids in sunflower breeding programs. Hybrid A19 × C122 with 5224 kg. ha-1 seed yield and 91 days growth duration produced the highest seed yield under normal irrigation condition. While hybrid A19 × R217 with 1868 kg. ha-1 had the highest seed yield under water stress condition.

Biofertilizers are promising in sustainable agriculture as an alternative to chemical fertilizers and increase soil fertility and plant growth. In this study, effects of chemical and biological fertilizers (PGPR) on quality and quantitative traits of saffron were evaluated. A field experiment was conducted as split plots arrangements using randomized complete block design with three replications at Research Farm of Ardebil Agricultural Research Center, Iran during two growing seasons of 2015-2016 and 2016-2017. Experimental factors were chemical fertilizers NPK (50 and 100% of required chemical fertilizers) assigned to the main plots, and plant growth promoting rhizobacteria including Azotobacter Chrococum Sp, Pseudomonas aeruginosus, Bacillus subtilis and their combination and control treatment randomized subplots. The results indicated that bio-and chemical fertilizers significantly increased flower and stigma length, dry yield of style and stigma and quality traits such as crocin, picocrocin and safranal conetnts as compared with controlApplication of 50% of required chemical fertilizer with application of combined biofertilizer (A. Sp., P. aeruginosus and B. subtilis) increased dry yield of stigma and style by 57% when compared with control. Also, the same treatment increased picocrocin, safranal and crocin contents with 44, 62 and 47 percent, respectively, in comparison to control. The length of flower and stigma were increased by application of combined bio-fertilizers up to 3. 32 and 1. 63 cm, respectively, in comparison with control. In conclusion, application of bio-fertilizers can reduce the use of chemical fertilizers and it can be a sutable ecological strategy for achieving sustainable agriculture and reducing environmental effects.

Seed priming is an effective method for mitigating water stress effect and improving crop yields. To study the effect of seed priming on photosynthetic pigments, seed yield and yield components of safflower cultivars under water stress conditions a field experiment was conducted as split plot factorial arrangement using randomized complete block design with three replications at Shahrood Agricultural and Natural Resources Research and Education Center, Iran for two years (2015 and 2016). The main plot consisted of irrigation at three levels based on the evaporation from class A evaporation pan including; non water stress (60 mm evaporation), mild water stress (120 mm evaporation) and severe water deficit stress (180 mm evaporation) and subplots consisted of factorial of two factors including; safflower cultivars (Goldasht, Sina and Soffeh) and seed priming (Treated seeds with salicylic acid and non treated seeds). Results showed significant increase in seed yield and its components in priming treatment compared to control both years. Therefore, by applying priming, seed yield and oil yield increased by 8 and 14 percent, respectively. Goldasht cultivar had the highest chlorophyll content under non stress (6. 29 mg. g-1FW) and mild stress conditions which resulted in high seed yield and yield components in this cultivar. The highest seed yield (3800 kg. ha-1) was obtained from Goldasht cultivar primed with salicylic acid under non-stressed conditions. However, the highest oil yield (886 kg. ha-1) was obtained from Soffeh cultivar. Results showed that severe stress significantly reduced all measured traits in all cultivars. Under severe stress seed yield (2257 kg. ha-1), oil yield (604 kg. ha-1) and total chlorophyll content (4. 72 mg. g-1FW) decreased by 29, 36 and 32 percent, respectively. It can be conluded that application of seed priming with salicylic acid increased seed yield and improved tolerance of safflower cultivars under water stress conditions.

The optimum sowing date and genotypes adapted to climatic conditions of target regions play significant role in achieving the maximum crop yield. To investigate the interaction of soybean genotypes to sowing date, a field experiment as split ararngements in radomized complete block design with three replications was carried out in Safiabad Agricultural Natural Resources Research and Education Center of Dezful, Iran for two successive seasons (2014-15). Main plots consisted five levels of sowing date (21st June, 5th July, 20th July, 3rd August and 17th August) and subplots included; 7 genotypes (2001, 2002, Persing × Epps, Saman, Migmat, SG20 and Salend). Results showed that the highest number of pods per plant (66) belonged to cv. Salend in second sowing date (5th July) and the lowest (17. 7) belonged to genotype 2001 in sowing date 17th August. Results showed that sowing date had significant effect on plant height, and delaying in sowing date led to decrease of plant height in all genotypes and increased growth duration. The results of combined analysis of variance showed that effect of sowing date was significant on seed yield. The highest (3479 kg. ha-1) and the lowest (1698 kg. ha-1) seed yield belonged to sowing dates of 21st July and 18th August, respectively. Average of two years revealed that Salend and SG20 had higheer seed yield. Migmat had the highest seed protein content in all sowing dates. The highest oil content (25. 9%) obtained in the second sowing date and genotype 2001. The lowest oil content (21. 6%) belonged to cv. Saman in the last sowing date (17th August). Considering the results of this experiment and crop rotation in the region, soybean genotypes (group VI-VII) and sowing date in late of July can be recommended for North Khuzestan conditions.

To investigate the effect of different tillage systems in early seeding of sugar beet, a field experiment was conducted under two climatic conditions: Karaj, Motthari field station, in three years (2012-2013, 2013-2014 and 2014-2015) and Mian-do-Ab, Iran in two years (2012-2013 and 2013-2014). Nine seedbed preparation methods were examined including: two methods for fully preparing the seedbed in the fall (without and along with barley seeding), three methods for dormant seeding (along with barley seeding, without barley seeding and without barley seeding along with creating furrows after thinning in spring), two methods of preparing of seed bed in two season: fall and spring (without and using combined tillage), a minimum plowing method and a method for fully preparing of seed bed in the spring using randomized complete block design. Soil texture and organic matter content were also determined in each treatment in advance. The results showed that regarding to climate change, the dormant seeding in Karaj and Mian-do-ab would be at high risk. In Karaj conditions, one of the treatments of the seedbed preparation in two stages, including: deep Moldboard plowing in fall+ combined tillage in the spring, due to its desirable quantitative and quality characteristics of root during three years of experiment (in average 66 and 12 t. ha-1 root and sugar yield, respectively), was dtermined as a superior treatment. Where the planting is done on falt seedbed, other deep moldboard plowing, disc, leveler and chisel plow in the autumn + disk in the spring (in average 67 and 11 t. ha-1 root and sugar yield, respectively) can be used. In Mian-do-Ab conditions, seedbed preparation in autumn including; deep moldboard plowing, disk, leveler and disk in autumn (in average 9 and 57 t. ha-1 root and sugar yield, respectively) was identified as superior treatment. Using this method, in addition to the possibility of optimal seedbed preparation, it would be possible to practice early seeding.

Adaptation and grain yield stability of 16 promising lines of bread wheat toghether with cv. Chamran and cv. Aflak, two commercial cultivars as controls, was studied in six experimental field stations; Zabol, Ahwaz, Darab, Dezful, Iranshahr, Khorramabad, Iran for two successive cropping cycle (2012 – 14). The experiments were conducted using randomized complete block design with three replications. The results showed that 81 percent of total variation observed for grain yield was related to environmental effects, 3 percent to genotype effect and 16 percent to G×E interaction. The polygon-view of GGE biplot led to the identification of eight superior lines (lines no. G14, G12, G15, G11 and G16) and two mega-environments. Among the test locations, Zabol and Dezful had a high discriminating ability to show differences between the lines and cultivars at ideal environment. Simultaneous evaluation of grain yield and stability through average environment coordinate (AEC) biplot showed that lines no. G14 (S-91-14), G12 (S-91-12), G15 (S-91-15), G9 (S-91-9) and G13 (S-91-13) with the higher grain yield (6167, 6102, 6315, 6131 and 6252 kg. ha-1, respectively) were the most stable lines. Finally, lines S-91-15 and S-91-13 with higher yield and wide adaptation were selected as the superior lines for being release as new commercial bread wheat cultivars.