Review on the Effect of Seed Rate and Improved Varieties on Grain Yield of Bread Wheat (Tritium Aestivum L.) in Ethiopia

Wheat is one of the strategic crops in Ethiopia, because of its role for food security, import Substitution and supply of raw material for agro-processing industry. Wheat Produced by 4.6 million smallholder farmers on 1.8 million hectares of land with an estimated annual production of 5.0 million tons at an average productivity of 2.9 t/ha which has been consistently increasing for the last 25 years, but much lower than the world average 3.3 t/ha. The lowest yield is attributed to many factors, such as the wheat variety, seed rate, seed source, unavailability of quality seed, use of poor quality seeds and inappropriate seed size are some of the factors. Seed rate are the most important management factor affected the agronomic characteristics of wheat. Seeding rate can impact on wheat tillering, grain yield and protein quality. Hence, achieving higher agronomic performance and better end-use quality requires optimizing and periodically reviewing management practices such as seeding rates. However, in varieties that produce fewer tillers, higher seeding rates compensated for reduced tiller. In a dense wheat population, grain yield decreased due to competition between plants that induced self-regulation. So optimum seed rate is recommended depending on the growth habit of the varieties and soil fertility level for increasing wheat production and productivity.