scholarly journals Effect of different pre-treatments on seed germination of Prosopis juliflora and Dalbergia sissoo: a step towards mutation breeding

2020 ◽  
Vol 66 (No. 2) ◽  
pp. 80-87
Author(s):  
Asif Javed Muhammad

For improving the seed germination of Prosopis juliflora and Dalbergia sissoo different treatments were tested, including side cutting, abrasion, overnight soaking in boiling water, scalding in actively boiling water for <br />1 minute and immersion in 30%, 60% and 95% H<sub>2</sub>SO<sub>4</sub> solution. Results showed that abrasion with sandpaper and side cutting were the most effective methods to break seed dormancy in both species, while scalding in actively boiling water for 1 minute, overnight soaking and different concentrations of H<sub>2</sub>SO<sub>4</sub> gave low to zero seed germination. Based on the positive effects of scarification it was concluded that seed dormancy in both species was due to water impermeability of the seed coat. Mutation breeding involves the treatment of large quantities of seeds, therefore abrasion with sandpaper was the most efficient and less labour-intensive method; this method was subsequently used for determination of LD<sub>50</sub> as it is a prerequisite in a mutation breeding program. Abrasion before irradiation had a positive effect on P. juliflora whereas it had a negative effect on D. sissoo seeds. Seeds of both species were exposed to different doses of gamma rays such as 0, 100, 200, 300, 400 and 500 Gy using a <sup>60</sup>Co source. The LD<sub>50</sub> for P. juliflora was 651 Gy based on the rate of seed germination indicating that P. juliflora had tolerance to irradiation and low radiosensitivity to gamma ray. A high LD<sub>50</sub> of 1097 Gy was observed for D. sissoo, suggesting high tolerance to irradiation and very low radio sensitivity. These findings will help to initiate a mutation breeding program in both species to obtain desirable mutants with desirable characteristics such as thornless genotypes, better tree form, disease resistance and increased genetic diversity.

2021 ◽  
pp. 320-325
Author(s):  
Reina Céspedes ◽  
Noel Arrieta ◽  
Miguel Barquero ◽  
Ana Abdelnour ◽  
Nielen Stephan ◽  
...  

Abstract Coffee is one of the most commercially available raw materials, being the tropical product with the highest market value in the world. In Costa Rica it is the third most important product for agricultural exports and provides the main income for many families in the country. However, coffee is under threat due to coffee leaf rust disease (CLR). Mutation breeding in coffee is a promising approach to develop new varieties resistant to CLR. As a new technology for coffee, basic tests related to mutation induction need to be done. The plant material used was Coffea arabica var. 'Venecia' seeds, with a moisture content of 27.3%. The applied irradiation doses were 0, 80, 100, 120, 140, 160 and 180 Gy. For each treatment, three replicates of 200 g were used, with a seed number range of 765-808 units per replicate. The irradiated seeds were planted on the same day. Eighty days after treatment the number of seedlings was quantified, the hypocotyl height and radicle length were measured and the opening of cotyledons was determined for each dose. The effects of the radiation doses on seed germination frequency were recorded. At the dose of 80 Gy, germination was reduced over the control by 9.65%, at 100 Gy by 34.06%, at 120 Gy by 52.76%, at 140 Gy by 60.24%, at 160 Gy by 65.56% and at 180 Gy by 75.40%. Seedling growth was affected and a delay in opening of the cotyledons was observed at higher doses. This radiosensitivity test, based on seed germination as compared with unirradiated control, revealed that the LD50 for the variety tested is in the range 100-120 Gy experimentally, and according to the regression is 125 ± 30 Gy. This dose will be used for further bulk experiments and is of great importance, because the LD50 is considered as the range where the appearance of useful mutations in breeding programmes is favoured. The establishment of these parameters is a necessary advance to continue with measurements of genetic and phenotypical parameters to implement mutation breeding in coffee looking for new sources of resistance against CLR.


2020 ◽  
Vol 100 (6) ◽  
pp. 666-673
Author(s):  
Yunpeng Gao ◽  
Mingwei Zhu ◽  
Qiuyue Ma ◽  
Shuxian Li

The seeds of Cercis chinensis Bunge are important for reproduction and propagation, but strong dormancy controls their germination. To elucidate the causes of seed dormancy in C. chinensis, we investigated the permeability of the hard seed coat and the contribution of the endosperm to physical dormancy, and we examined the effect of extracts from the seed coat and endosperm. In addition, the effectiveness of scarification methods to break seed dormancy was compared. Cercis chinensis seeds exhibited physical and physiological dormancy. The hard seed coat played an important role in limiting water uptake, and the endosperm acted as a physical barrier that restricted embryo development in imbibed seeds. Germination percentage of Chinese cabbage [Brassica rapa subsp. chinensis (L.) Hanelt] seeds was reduced from 98% (control) to 28.3% and 56.7% with a seed-coat extract and an endosperm extract, respectively. This demonstrated that both the seed coat and endosperm contained endogenous inhibitors, but the seed-coat extract resulted in stronger inhibition. Mechanical scarification, thermal scarification, and chemical scarification had positive effects on C. chinensis seed germination. Soaking non-scarified seeds in gibberellic acid (GA3) solution did not promote germination; however, treatment with exogenous GA3 following scarification significantly improved germination. The optimal method for promoting C. chinensis seed germination was soaking scarified seeds in 500 mg·L−1 GA3 for 24 h followed by cold stratification at 5 °C for 2 mo.


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1765
Author(s):  
Wei Zhang ◽  
Lian-Wei Qu ◽  
Jun Zhao ◽  
Li Xue ◽  
Han-Ping Dai ◽  
...  

The innate physiological dormancy of Tulipa thianschanica seeds ensures its survival and regeneration in the natural environment. However, the low percentage of germination restricts the establishment of its population and commercial breeding. To develop effective ways to break dormancy and improve germination, some important factors of seed germination of T. thianschanica were tested, including temperature, gibberellin (GA3) and/or kinetin (KT), cold stratification and sowing depth. The percentage of germination was as high as 80.7% at a constant temperature of 4 °C, followed by 55.6% at a fluctuating temperature of 4/16 °C, and almost no seeds germinated at 16 °C, 20 °C and 16/20 °C. Treatment with exogenous GA3 significantly improved the germination of seeds, but KT had a slight effect on the germination of T. thianschanica seeds. The combined treatment of GA3 and KT was more effective at enhancing seed germination than any individual treatment, and the optimal hormone concentration for the germination of T. thianschanica seeds was 100 mg/L GA3 + 10 mg/L KT. In addition, it took at least 20 days of cold stratification to break the seed dormancy of T. thianschanica. The emergence of T. thianschanica seedlings was the highest with 82.4% at a sowing depth of 1.5 cm, and it decreased significantly at a depth of >3.0 cm. This study provides information on methods to break dormancy and promote the germination of T. thianschanica seeds.


2021 ◽  
Vol 22 (3) ◽  
pp. 1357
Author(s):  
Ewelina A. Klupczyńska ◽  
Tomasz A. Pawłowski

Environmental conditions are the basis of plant reproduction and are the critical factors controlling seed dormancy and germination. Global climate change is currently affecting environmental conditions and changing the reproduction of plants from seeds. Disturbances in germination will cause disturbances in the diversity of plant communities. Models developed for climate change scenarios show that some species will face a significant decrease in suitable habitat area. Dormancy is an adaptive mechanism that affects the probability of survival of a species. The ability of seeds of many plant species to survive until dormancy recedes and meet the requirements for germination is an adaptive strategy that can act as a buffer against the negative effects of environmental heterogeneity. The influence of temperature and humidity on seed dormancy status underlines the need to understand how changing environmental conditions will affect seed germination patterns. Knowledge of these processes is important for understanding plant evolution and adaptation to changes in the habitat. The network of genes controlling seed dormancy under the influence of environmental conditions is not fully characterized. Integrating research techniques from different disciplines of biology could aid understanding of the mechanisms of the processes controlling seed germination. Transcriptomics, proteomics, epigenetics, and other fields provide researchers with new opportunities to understand the many processes of plant life. This paper focuses on presenting the adaptation mechanism of seed dormancy and germination to the various environments, with emphasis on their prospective roles in adaptation to the changing climate.


2015 ◽  
Vol 43 (1) ◽  
pp. 153-158 ◽  
Author(s):  
Faruk TOKLU

An experiment was conducted under laboratory and field conditions in order to evaluate the effects of different priming treatments, specifically KNO3 (1%), KCl (2%), KH2PO4 (1%), ZnSO4 (0.05%), PEG-6000 (20%), IBA (100 ppm), Mannitol (4%), GA3 (100 ppm) and distilled water, on seed germination properties and several agro-morphological plant characteristics of red lentil. Seeds not primed were used as a control. GA3 treatment increased shoot length. The control (non-primed seeds) treatment resulted in increased seedling root number and length. Distilled water, ZnSO4 and control treatments increased germination rate and percentage. In the pot experiments, GA3 treatment increased plant height and seedling emergence rate, whereas KCl treatment improved the number of nodules, as well as root and shoot dry weight when compared to the control. ZnSO4 treatment increased yield components and grain yield in field conditions. The results of this study showed that ZnSO4, GA3 and PEG-6000 seed priming treatments may be useful tools due to their positive effects on germination rate, germination percentage, yield component and grain yield of lentil.


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