<div style="text-align: justify;">Climate change is a recent challenge on crop production and productivity in the world. The objective of this paper is to review the major effects of climate change on the production and productivity of wheat in the high lands of Ethiopia. Effects of climate change on wheat would be mainly through changes in [CO2], temperature, rainfall, length of growing period, actual growth rate and increased evapo-transpiration, which may lead to reduce yield or complete crop failure. Moreover, flower fertilization and grain set are highly sensitive to heat stress during mid-anthesis. In C3 crops like wheat, the elevated CO2 level is expected to increase productivity as a result of higher CO2 diffusion through stomata leading to a higher photosynthesis rate. But, elevated [CO2] may have negative effects on the grain-quality of wheat in terms of protein, lipids, number of mitochondria and nitrogen contents. Unlike CO2, elevated temperature affects crop production negatively by increasing rate of respiration; hastening plant growth and development; increasing photorespiration of wheat, reducing photosynthetic efficiency due to O2 interrupts the photosynthetic path way instead of CO2, increasing rate of water loss by increasing evapo-transpiration and decreasing nutrient use-efficiency through increased rate of decomposition and mineralization. As a result, wheat area is forecast to be displaced by other crop types. In order to tackle this issue, major mitigation and adaptation measures for example promoting area closures and conservation agriculture-based (CA), agroforestry practices, efficient use of energy sources, etc. should be practiced and given special attention by the communities as well as the government to solve the effects of climate change on wheat production and productivity in the country.</div>

<div style="text-align: justify;">Effect of Climate Change on the Production and Productivity of Wheat Crop in the Highlands of Ethiopia: A Review</div>

<div style="text-align: justify;">Field experiments were conducted in 2013 and 2014 with eight treatments consisting of combination of four shading periods (shading during vegetative phase (V), reproductive phase (R), whole growing season and a control treatment) and two irrigation regimes (irrigation after depleting 40 and 80 % of available water). Under limited irrigation conditions, the highest PSII quantum yield, the capacity of electrons move beyond QA and electron move from intersystem to PSI acceptor side reduced, with greater decline degree in sunlight treatment. The minimum seed yield was recorded by plants treated with limited irrigation and whole growing season shade. Changes in the state of the photosynthetic electron transport chain and photorespiration rates in response to different shading treatments were primarily related to leaf water loss. In general, the results revealed that shading caused some shade avoidance responses in soybean, which finally reduced seed production.</div>

Interactions of shading conditions and irrigation regimes on photosynthetic traits and seed yield of soybean (<em>Glycine max </em>L.)

<p>C4 photosynthesis is the primary mode of carbon capture and drives productivity in several major food crops and bio-energy grasses. Gains in productivity associated with C4 photosynthesis include improved water and nitrogen use efficiencies. Within grasses rice and brachypodium are used as model species. Since these two crops are using C3 photosynthesis for their growth and development, it cannot be used as model for to study C4 photosynthesis. In order to characterize the evolutionary innovations and to provide genomic insight into crop improvement for the many important crop species, a new genomic and genetic model species is required. Minor millets have small diploid genomes, shorter life cycles, self pollination and prolific seed production. Due to these characteristics it gains importance over major C4 species which lack all of these traits. Within Minor millets, Setaria italica and Setaria viridis are used as model systems since these crops fulfils all the traits responsible to be a model species. Importantly, Setaria species uses NADP-Malic enzyme subtype C4 photosynthetic system to fix carbon and therefore is a potential powerful model system for dissecting C4 photosynthesis. C4 grasses have a shorter distance between longitudinal veins in the leaves than C3 grasses. The C4 grasses have denser transverse and small longitudinal veins than the C3 grasses. It indicates that C4 grasses have a structurally superior photosynthate translocation and water distribution system by developing denser networks of small longitudinal and transverse veins. Setaria has high vein density and kranz anatomy that helps to concentrate CO2 in the bundle sheath cells. This minimizes photorespiration thereby prevents the loss of energy.</p>


Effect of Climate Change on the Production and Productivity of Wheat Crop in the Highlands of Ethiopia: A Review

Interactions of shading conditions and irrigation regimes on photosynthetic traits and seed yield of soybean (Glycine max L.)

Minor millets as model system to study C4 photosynthesis - A review