Salinity Effects on Seedling Growth and Yield Components of Rice
Flood irrigation practices that are commonly used in California during the early stages of rice (Oryza sativa L.) establishment may contribute to salinity damage and eventually decrease yield. Knowledge of salinity effects on rice seedling growth and yield components would improve management practices in fields and increase our understanding of salt tolerance mechanisms in rice. Salinity sensitivity of rice was studied to determine salinity effects on seedlings and yield components. Plants of rice cultivar M-202 were grown in a greenhouse in sand and irrigated with nutrient solutions of control and treatments amended with NaCl and CaCl2 (2:1 molar concentration) at 1.9, 3.4, 4.5, 6.1, 7.9, and 11.5 dS m−1 electrical conductivity. Shoot dry weights of seedlings were measured at five harvests in the first month after seeding. Seedling growth was significantly reduced by salinity at the lowest salinity treatment, 1.9 dS m−1. At 1.9 and 3.4 dS m−1, significant reduction of seedling growth occurred at longer cumulative thermal time than at higher salt levels. Seedling survival was significantly reduced when salinity was 3.40 dS m−1 and higher. Highly significant linear responses of grain weight per plant, grain weight per panicle, spikelet number per panicle, and tiller number per plant to salinity were observed. There was a common lowest salt level for fertility and pollen germination beyond which they were significantly reduced by salinity. Harvest index was significantly decreased when salinity was at 3.40 dS m−1 and higher. Tiller number per plant and spikelet number per panicle contributed the most variation in grain weight per plant under salinity. Reductions in seedling survival, tiller number per plant, and spikelet number per panicle were the major causes of yield loss in M-202 under salinity. The compensation between spikelets and other yield components was confounded with salinity effects, but was believed to be minor relative to the reduction of spikelets due to salinity and, therefore, not sufficient to offset yield loss even at moderate salt levels. [1]
Compatible Growth and Yield Models for Loblolly Pine
Past studies in loblolly pine mensuration have resulted in the development of numerous analytic models for growth and yield. Most have treated growth and yield as essentially independent phenomena with no attempt to develop models that possess the logical compatibility which must exist between growth and yield observations. The present study develops models intended to express realistically the relationships between growth and yield. As an initial step, previously-used basal area and cubic-foot yield models were examined and screened for use in the analysis. The yield models selected for use were differentiated with respect to age to produce models for cubic-foot and basal area growth. The resulting growth models, together with the selected model for cubic-foot yield, were then fitted to data obtained in the five-and-ten-year remeasurements of 102 permanent sample plots located in three states. Equations were developed for cubic-foot yield, basal area growth, cubic-foot growth, basal area projection, and cubic-foot volume projection. Three of these equations can be used to predict total per acre production for various rotation ages and thinning regimes.. [2]
Screening plant growth-promoting rhizobacteria for improving growth and yield of wheat
Aims: Plant growth promoting rhizobacteria (PGPR) are commonly used as inoculants for improving the growth and yield of agricultural crops, however screening for the selection of effective PGPR strains is very critical. This study focuses on the screening of effective PGPR strains on the basis of their potential for vitro in auxin production and plant growth promoting activity under gnotobiotic conditions.
Methods and Results: A large number of bacteria were isolated from the rhizosphere soil of wheat plants grown at different sites. Thirty isolates showing prolific growth on agar medium were selected and evaluated for their potential to produce auxins in vitrol mg . Colorimetric analysis showed variable amount of auxins (ranging from 1·1 to 12·1−1) produced by the rhizobacteria in vitro and amendment of the culture media with l-tryptophan (ll mg -TRP), further stimulated auxin biosynthesis (ranging from 1·8 to 24·8−1). HPLC analysis confirmed the presence of indole acetic acid (IAA) and indole acetamide (IAM) as the major auxins in the culture filtrates of these rhizobacteria. A series of laboratory experiments conducted on two cv. of wheat under gnotobiotic (axenic) conditions demonstrated increases in root elongation (up to 17·3%), root dry weight (up to 13·5%), shoot elongation (up to 37·7%) and shoot dry weight (up to 36·3%) of inoculated wheat seedlings. Linear positive correlation (r0·99) between = in vitro auxin production and increase in growth parameters of inoculated seeds was found. Based upon auxin biosynthesis and growth-promoting activity, four isolates were selected and designated as plant growth-promoting rhizobacteria (PGPR). Auxin biosynthesis in sterilized vs nonsterilized soil inoculated with selected PGPR was also monitored that revealed superiority of the selected PGPR over indigenous microflora. Peat-based seed inoculation with selected PGPR isolates exhibited stimulatory effects on grain yields of tested wheat cv. in pot (up to 14·7% increase over control) and field experiments (up to 27·5% increase over control); however, the response varied with cv. and PGPR strains.
Conclusions: It was concluded that the strain, which produced the highest amount of auxins in nonsterilized soil, also caused maximum increase in growth and yield of both the wheat cv.
Significance and Impact of Study: This study suggested that potential for auxin biosynthesis by rhizobacteria could be used as a tool for the screening of effective PGPR strains. [3]
Journal of Experimental Agriculture International
All authors are welcome to submit their manuscripts (Book chapter, Complete Books, monographs, etc). We are also happy to announce a high discount on the processing charge of the books as an introductory offer. We are also looking for interested reviewers and editors to review/edit the upcoming books. We hope that like our journal section this Book Division will also be well accepted by scholarly communities. [4]
Influence of Integrated Nutrient Management on Growth and Yield of Sweet Corn (Zea mays L. saccharata) under Temperate Conditions of Kashmir Valley
The growth and yield response of sweet maize (Zea mays (L.) saccharata) to varying levels of organic and inorganic fertilizers during the growing seasons of kharif 2010 and 2011 was studied under temperate conditions of Kashmir Valley. Twelve treatments comprising of sole and combination of organic and inorganic fertilizers were laid in a randomized block design with three replications. The results revealed that application of T10 [75% (NPK) + FYM (4.5 t/ha) + Biofertilizer (Azotobacter + Phosphate solubilizing bacteria (PSB))] significantly increased the number of days taken to tasseling, silking and milky stages and various other growth characters viz., plant height, leaf area index and dry matter accumulation at 15 days interval from sowing upto harvest and crop growth rate and relative growth rate at 7 days interval from 15 DAS upto harvest whereas, the lowest values of these parameters were recorded in unfertilized control. The treatment T10[75 % (NPK) + FYM (4.5 t/ha) + Biofertilizer (Azotobacter + Phosphate solubilizing bacteria (PSB))] proved to be significantly superior to rest of the treatments including unfertilized control in increasing cob yield with and without husk, fodder yield and green biomass yield during both years of experimentation, however, ratio of cob to fodder yield during 2011 and 2012 were recorded highest in treatment T3 [FYM (18 t ha-1)] and T2 [Recommended NPK kg ha-1 (90:60:40)], respectively, whereas unfertilized control recorded the lowest ratio of cob to fodder yield.. [5]
Reference
[1] AcamZeng, L. and Shannon, M.C., 2000. Salinity effects on seedling growth and yield components of rice. Crop science, 40(4), pp.996-1003.ovic, T., 2001. Commercial application of enzyme technology for poultry production. World’s Poultry Science Journal, 57(3), pp.225-242.
[2] Clutter, J.L., 1963. Compatible growth and yield models for loblolly pine. Forest science, 9(3), pp.354-371.
[3] Khalid, A., Arshad, M. and Zahir, Z.A., 2004. Screening plant growth‐promoting rhizobacteria for improving growth and yield of wheat. Journal of Applied Microbiology, 96(3), pp.473-480.
[4] Beiragi, M.A., Khorasani, S.K., Shojaei, S.H., Dadresan, M., Mostafavi, K. and Golbashy, M., 2011. A study on effects of planting dates on growth and yield of 18 corn hybrids (Zea mays L.). Journal of Experimental Agriculture International, pp.110-120.
[5] Rasool, S., Kanth, R.H., Hamid, S., Raja, W., Alie, B.A. and Dar, Z.A., 2015. Influence of Integrated nutrient management on growth and yield of sweet corn (Zea mays L. Saccharata) under temperate conditions of Kashmir valley. Journal of Experimental Agriculture International, pp.315-325.
