Yield Reductions of Wheat Cultivar Obora (UTIQUE96/FLAG-1) due to Russian Wheat Aphid (Diuraphis noxia) Infestation under Field Conditions at Selected Districts of West Showa Zone, Ethiopia

Background: Wheat (Triticum aestivum L.) is an important cereal crop as being consumed as staple food in the world as well as in Ethiopia. The production of wheat in Ethiopia decreased due to the incidence of insect pests. Out of insects’ pests the Russian wheat aphid (Diuraphis noxia) is the recent one that causes yield loss either directly or indirectly. Methods: The experiment was carried out at selected districts of West Showa zone, Ethiopia during off cropping season 2019 to evaluate the yield reduction in wheat crop due to the invasion of Russian wheat aphids. Malamar, Dimethoate, neem seeds, leaves, Beaveria bassiana and Metarhizium anisopliae were used in form of spray. Result: However, Malamar and Dimethoate highly significantly lowered the population of Diuraphis noxia. The combination of Beaveria bassiana and Metarhizium anisopleae significantly lowered the population of Russian wheat aphid. The combination of Neem leaf and Neem seeds, as well as Beaveria bassiana, proved to be effective against Russian wheat aphid yet they were protected and sound against the environments. Malamar showed the maximum decrease in Diuraphis noxia populations followed by Dimethoate, the combination of Beaveria bassiana and Metarhizium anisopleae.

Effect of projected climate scenarios on the yields of potato crop and agronomic adaptation options as evaluated by crop growth model

Potato is the most important non-cereal crop in the world and the most prominent winter season crop in India. Growth and yield of potato crop is very much sensitive to higher temperatures and the moisture stress. Hence, the anticipated increase of temperature due to global warming and climatic variability will have anadverse impact on potato production. Keeping this in view, a research work was carried out with the objectives to assess the impact of climate change on potato production and evaluating agronomic adaptation options through a crop growth simulation model (CGSM). Field experiments were carried out to prepare the minimum dataset for calibration and validation of one CGSM, namely InfoCrop. After validation, the model was used to predict the future tuber yield of ten selected stations situated under different agroclimatic regions of the State. In the future scenario 2050, the simulated yield for mid November planted crop likely to be about 11% less than the present level of mean yield. If the crop is planted in December, the percentage of yield reduction may be around 25%.The projected yield reduction, for the stations of higher latitude, is found to be negligible. Three possible agronomic adaptation options, viz., adjustment of date of planting, increase of seed rate and varying sprout length of seed tubers, have been tried as adaptation strategies to combat the adverse effects of climate change. It is concluded that the mid-November planting and longer sprout length will be the best adaptation option. However, the enhanced seed rate is not a viable adaptation option.

Economics of wheat as influenced by natural farming, organic farming and recommended package of practices

A field experiment was laid out on split-plot design with two uneven controls viz. four foliar concentrations of cow urine and jeevamrutha under natural farming which were compared with Organic farming (OF) and Recommended package of practices (RPP) given by UAS, Dharwad. The treatments were replicated thrice. The study revealed that RPP recorded significantly higher grain yield, straw yield, gross return, net return and B:C ratio than OF and natural farming practices. The grain yield reduction in the best treatment (cow urine @ 50 % + jeevamrutha @ 100 %) was 16 % lesser than RPP and 2 % higher than OF. However, the cost of cultivation in natural farming with cow urine @ 50 % + jeevamrutha @ 100 % was lesser to the extent of 6.91 and 30.42 % than RPP and OF. Our study indicates that the irrigated wheat can be grown under natural farming conditions profitably.

Effect of soil moisture stress on growth light azimuth and yield of dryland sorghum

Based on weekly data for 4 years (1986-1989) at Bellary, soil moisture balance for rabi sorghum has been worked out for both irrigated and non-irrigated conditions. These soil moisture values have been used to identify periods of water stress which the crop experienced. during the growth cycle. The extent of yield reduction due to the stress was then evaluated from the actual soil water content and total available water extent and discussed. The ratio of evapotranspiration to potential evapotranspiration and water requirement of the crop has also been worked out to assess the stress situation of the crop during its growing period. This ratio has been found to be related to moisture availability at the root zone.

Response of Plant Growth and Development, and Accumulation of Hydroxyl-cinnamoyl Acid Derivatives to Selected Shade Nets and Seasonality of Field-grown Bush Tea (Athrixia phylicoides DC.)

Horticultural practices and quality of bush tea (Athrixia phylicoides DC.) are critical for herbal tea industrialization. The objective of the current study was to determine the effect of selected shade nets and seasonal variation on plant growth and development, and hydroxycinnamic acid content of field-grown bush tea. The trial was laid out in a randomized complete block design consisting of three shade nets (black, green, and white) and control or full sunlight with three different light intensities (40%, 50%, and 80%) replicated three times. Proportion of intercepted radiation by the canopy, chlorophyll content, plant height, and fresh and dry mass were measured, and hydroxycinnamic acid accumulation was determined. In addition, hydroxycinnamic acid composition was determined using liquid chromatography linked to mass spectrometry (LC-MS). The application of shade nets resulted in plant growth and yield reduction as compared with the plants exposed to full sunlight during summer followed by white shade net. The accumulation of hydroxycinnamic acid was higher in 80% white shade net plots compared with unshaded plants (control) and the other shade nets. Therefore, lack of shading provides a conducive environment to enhance plant growth and development of bush tea. The white shade net (80%) was an effective microclimate tool to enhance accumulation of caffeoylquinic acid (m/z 353), p-coumaric acids (m/z 337), dicaffeoylquinic acid (m/z 515), and tricaffeoylquinic acids of bush tea. This study is the first to demonstrate light as a determining factor for production of chlorogenates in bush tea plants. Future studies will be conducted to determine the effect of light on extracts of the bush tea using different solvents.