Latest News on Growth of Rice : May 21

[1] Effect of silicon on the growth of rice plant at different growth stages

Rice plants (Oryza sativa L. cv. Akebono) were cultured in Kimura B solution. The effect of silicon on plant growth and the characteristics of the uptake and distribution of silicon at different growth stages were studied from both aspects: the addition and removal of silicon during the vegetative, reproductive and ripening stages.When silicon was removed during the reproductive stage, the dry weights of straw (stem+leaf blade) and grain decreased by 20 and 50% respectively, compared with those of the plants cultured in the solution with silicon throughout the growth period. Conversely, when silicon was added during the reproductive stage, the dry weights of straw and grain increased by 243 and 30%, respectively, over those of the plants cultured in a solution devoid of silicon throughout the growth period. The effect of silicon on the dry weights of straw and grain was small when silicon was either added or removed during the vegetative and ripening stages.

[2] Efficiency of plant growth-promoting rhizobacteria (PGPR) for the enhancement of rice growth

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replace chemical fertilizers, pesticides, and supplements. Here, we have isolated and characterized the PGPR from the rhizosphere soil of rice field for the enhancement of growth of rice. Rhizosphere soils were collected from different areas of Mymensingh in
Bangladesh. Ten isolates of bacteria, designated as PGB1, PGB2, PGB3, PGB4, PGB5, PGT1, PGT2, PGT3, PGG1 and PGG2, were successfully isolated and characterized. Subsequently, to investigate the effects of PGPR isolates on the growth of rice, a pot culture experiment was conducted. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21
days of inoculation. Isolates PGB4, PGT1, PGT2, PGT3, PGG1 and PGG2 induced the production of indole acetic acid (IAA), whereas only PGT3 isolate was able to solubilize phosphorus. Most of isolates
resulted in a significant increase in plant height, root length, and dry matter production of shoot and root of rice seedlings. Furthermore, PGPR isolates remarkably increased seed germination of rice.

[3] Effect of brassinosteroids on salinity stress induced inhibition of seed germination and seedling growth of rice (Oryza sativa L.)

The effect of 24-epibrassinolide and 28-homobrassinolide on the inhibitionof germination and seedling growth of rice (Oryza sativa) induced bysalinity stress was studied. Brassinosteroids were found to reverse theinhibitory effect on germination and seedling growth. The activation ofseedling growth by brassinosteroids under salinity stress was associatedwith enhanced levels of nucleic acids and soluble proteins.

[4] Assessing the Effects of Water Management Regimes and Rice Residue on Growth and Yield of Rice in Uganda

Aim: This study was conducted to assess the influence of different water and rice straw management practices and rice genotypes on growth and yield of rice in Uganda.
Study Design: Field experimental design was a Randomized Complete Block Design while the screen house study design was a Completely Randomized Design.
Place and Duration of Study: The study was conducted in the field at National Crops Resources Research Institute (NaCRRI) Namulonge and in the screen house at Kyambogo University during the period of February-July 2013.
Materials and Methods: Ten rice genotypes obtained from the cereals program at NaCRRI Namulonge were grown under different water management regimes, with and without rice straw incorporation both in the field and screen house. Water management regimes used were alternate wetting and drying (AWD), continuous flooding (CF) and continuous drying (CD).
Results: A significant variation in grain yield was observed among rice genotypes and under different water management regimes (P<0.001). Use of rice straw influenced rice yield in the screen house (P<0.001) but not in the field (P=0.23); interactions of water management x genotype and water management x rice straw x genotype influenced rice yield in the field (P=0.003) but not in the screen house (P=0.5). Higher yield gain was observed under the water-saving technology alternate wetting and drying compared to continuous flooding or drying.
Conclusion: This study has indicated significant variations in field performance of rice under different water management regimes and rice straw usage. These findings are therefore important because they suggest that efficient management of water resources and rice residues from rice fields coupled with the use of drought tolerant rice varieties could be an effective integrated approach to improve rice yield and an adaptation strategy to the observed climate variability.

[5] On Improving Seed Germination and Seedling Growth in Rice under Minimal Soil Salinity

Aims: It was assumed that two- way approach i.e. nutrient-priming with potassium salt of the seeds and later on ammonium sulphate application may be binary beneficial for growth of rice besides evidencing genetic variability under salt stress

Study Design: The experiment was laid out in Complete Randomized Design with three replications.

Place and Duration of Study: The study was conducted in laboratory and glass house of Soil Salinity Research Programme of Land Resources Research Institute at National Agricultural research Centre, Islamabad, Pakistan during the period from May to August, 2016.

Methodology: Seeds of Oryza sativa (cv. KS-282 and BAS 385) were primed with potassium nitrate. In the second phase of the study, the primed seeds were raised in a minimal saline soil with ammonium sulphate nutrition gradually up to 150 mg Kg -1.

Results: Bas-385 was more responsive for mean germination time than KS-282. In Bas-385 and KS-282 germination was 100 and 90 percent. Germination rate index of Bas-385 was 16 percent higher than that of KS-282. Biomass of Bas-385 seedlings was higher than that of KS-282 with the treatments. In both the cultivars of rice, Na+/K+ ratio was in antagonistic relation R = (- 0.99) with the gradual increase in ammonium sulphate application. Potassium ion was accordant with sulphate ion and N concentration.  Bas-385 was more tolerant to KS-282 based on Na+/K+ ratio and bio mass.

Conclusion: BAS 385 (salt sensitive) superseded to KS-282 (salt tolerant) under minimal salt stress due to nutrient priming and then enhanced nutrition.

 


Reference

[1] Ma, J., Nishimura, K. and Takahashi, E., 1989. Effect of silicon on the growth of rice plant at different growth stages. Soil Science and Plant Nutrition35(3), pp.347-356.

[2] Ashrafuzzaman, M., Hossen, F.A., Ismail, M.R., Hoque, A., Islam, M.Z., Shahidullah, S.M. and Meon, S., 2009. Efficiency of plant growth-promoting rhizobacteria (PGPR) for the enhancement of rice growth. African Journal of Biotechnology8(7).

[3] Anuradha, S. and Rao, S.S.R., 2001. Effect of brassinosteroids on salinity stress induced inhibition of seed germination and seedling growth of rice (Oryza sativa L.). Plant Growth Regulation33(2), pp.151-153.

[4] Awio, T., Bua, B. and Karungi, J., 2015. Assessing the effects of water management regimes and rice residue on growth and yield of rice in Uganda. Journal of Experimental Agriculture International, pp.141-149.

[5] Ali, A., Mahmood, I.A., Suhaib, M., Ullah, M.A. and Ishaq, M., 2017. On Improving Seed Germination and Seedling Growth in Rice under Minimal Soil Salinity. Asian Research Journal of Agriculture, pp.1-7.

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