فصلنامه زراعت و اصلاح نباتات
سال پانزدهم شماره 2 (تابستان 1398)

This study was performed to evaluate and compare quantitative and qualitative forage yield of Iranian and foreign alfalfa cultivars and ecotypes as well as correlation between traits and genetic variation among them. Therefore, 12 cultivars and ecotypes of alfalfa were evaluated in a randomized complete block design with three replications at research field of Islamic Azad University, Karaj, Iran for two years 2016-2017. The results showed significant differences for forage yield, agronomic traits and forage quality. Significant interactions of year × ecotype was observed for fresh forage yield and total dry forage yields and also plant height. Among the studied ecotypes, the ecotypes Mohajeran, Malekkandi and Ghahavand indicted the highest fresh and dry forage yield. The results of simple correlation showed that the highest positive and significant correlation between fresh and dry forage yield (0.98). Principal component analysis showed that 74% of the total variance was justified by the first two components. Results of cluster analysis divided the studied genotypes into three groups. In the first group, the ecotypes of Ghahavand, Mohajeran and Malekandi were considered to be the best in terms of forage yield, while in the second group they were Chaleshtar, Legend and Sequel were best for forage quality. In the third group, the other cultivars were classified as having average forage yield and quality

In order to evaluate of agronomical traits and fruit yield in 23 breeding hybrid cultivars of greenhouse cucumber, and determine the relationship between these traits, a randomized complete block design with three replications was performed in the research greenhouse of Islamic Azad University, Isfahan (Khorasgan) Branch in 2014-15. Data was collected for these traits: total fruit yield, total fruit number, number and fruit yield on three periods, plant height, length and width of leaf, length and diameter of fruit, days to flowering and fruiting and the first flower node. Coefficient of correlations showed that total number of fruit and fruit diameter had significant and positive correlation with fruit yield. Path analysis revealed that fruit number had the highest direct and positive effect on fruit yield. Therefore this trait could be used as selection criterion for selecting genotypes with high fruit yield. Step wise regression showed that total fruit yield and fruit yield on mid fruit production period explained 96.30 percentage of fruit yield variation. On the other hand, total fruit yield and fruit number on final fruit production period explained the highest amount of total fruit number variation.

In order to investigate phenotypic and genotypic correlations between physiological characteristics related to drought tolerance and genetic variation and estimating the genetic parameters of these indices in rain-fed condition, 19 genotypes of bread wheat were cultivated in a randomized complete block design with three replications in the research field of Agricultural Research Campus Natural Resources of Razi University of Kermanshah, Iran during 2014-15. analysis of variance (ANOVA) showed significant differences for the grain yield (YS), the cell membrane stability )CMS), the relative water loss )RWL(, the leaf water loss (LWL), the relative water protective (RWP), the water use efficiency )WUE( and the leaf greenish value )LGV( under rain-fed condition. The polygon view of GT biplot showed that genotype no. 12 (wc-4931) was the best genotype compared to other genotypes due to YS, WUE, ELWR and LGV. A high positive genetic and phenotypic relation was observed between WUE and Ys, FV/FM and LWL and, ELWR and LGV. In other hand, High heritability and genetic gain were observed for YS, CMS and WUE that reflect the additive gene action. Accordingly, due to the high propotion of additive effects in CMS, YS and WUE, it was suggested that the evaluation of genotypes must be done at erarly generarion of inbreeding.

Bolting is always one of the limitations of sugar beet autumn cultivation. In this regard, a factorial experiment based on randomized complete block design with three replications was conducted on semi-resistant cultivar of Sharif at Moghan Research Station during two seasons of 2014-16. Experimental factor A (planting date) with three levels including a1 (10th October), a2 (25th October) and a3 (16 November) and second experiment factor (B) paclobutrazol foliar application with two levels b1 (300 mg / l) and b2 (no spraying). The results of combined analysis of variance showed that the effect of planting date was significant at 5% probability level for the white sugar content, root sodium, extraction coefficient sugar and molasses sugar, and also the interaction between planting date and paclobutrazol was significant for bolting at 5% probability level. Comparison of the mean data showed that the first sowing date showed the highest bolting and root yield with 20.88% and 51.52 ton / ha, respectively, and the second sowing date had 50.8 ton / ha root yield. Which was in the same statistical group as the first planting date. But the bolting on it was 5.29%. The interaction effect of second planting date and consumption of paclobutrazol with 57.44 ton / ha and 4.23% had the highest root yield and the lowest bolting, respectively.Keywords:" Paclobutrazol"," Sugar beet"," Autumn sown"," Bolting"," Root yield"

The aim of this study was to evaluate the tomato plant induced resistance to Rhizoctonia solani using bio-control bacteria of Bacillus subtilis. Three bacterial isolates including B1 (un-irradiated B. subtilis), B600 and B419 (gamma-irradiated B. subtilis mutants) were used in this study. Results showed the highest activity of polyphenol oxidase enzyme in plant infected with pathogen. This increase in polyphenol oxidase activity was due to the response of the plant to the pathogen, which led to an increase in the activity of the enzyme, indicating an increase in oxidation in the plant. All treatments except B1 + Pathogen showed lower levels of peroxidase enzyme activity than the pathogen infected plant. All the plants treated with bio-control bacterial showed a significant increase in chlorophyll a compared to control. In plants treated with bio-control agents, the highest level of chlorophyll b in B600 + Pathogen and B1 + Pathogen were measured. The highest Disease Incidence percentage (DI%) was observed in plant pathogen (negative control) and the lowest DI was observed in plants treated with B419 + Pathogen. In plants treated with bio-control agent, the highest amount of chlorophyll b was calculated in B1 + Pathogen and B600 + Pathogen treatments. The highest percentage of Disease Incidence percentage (DI%) was observed in the pathogen-infected plant and the lowest in the B419 + Pathogen treatment. The treatment with bio-control agent increased tomato yield and even the highest yield was recorded in the B419 + Pathogen treatment.

AbstractTo study the effect of salinity and seed size on germination response, seedling growth and seed conversion efficiency in barley under salt stress conditions, a factorial experiment based on a completely randomized block was conducted in 2018. The first factor was salinity in four levels (zero (control), 4, 8 and 12 dS/m) and the second factor was seed size (in three sizes, small sizes (1000 grain weight less than 25 g), average (1000 grain weight between 25-48 g), large (1000 grain weight above 48g). In this study, the highest seed germination percentage (89%), daily germination average (4.02% seed), root length (5.04 cm), stem length (5.32 cm), stem dry weight (0.026 g), was allocated to the zero level of salinity (control). Also, the lowest amount of antioxidant enzyme activity was assigned to zero salinity level. Among the different seed sizes, the highest germination percentage (86.56%), mean daily germination (4.9 seeds), were belonged to seed with small size and the highest root length (5.31 cm), stem length (5.94 cm), stem dry weight (0.026) and amount of antioxidant enzyme activity were observed in seed white large size. Among interactive treatments, the highest average daily germination time was observed in large-sized seed at 12 d.S and the highest root dry weight (0.065 g), seedling dry weight (0.091 g), the weight of stored grain consumption (0.062), and percentage of transfer of seed reserves was significant (78.96) was belonged to seed with large size in zero salinity (control).