Developing Improved Varieties of Bread Wheat and Registration of “Shaki” Variety

Introduction

Bread wheat (Triticum aestivum. L) is the most common cultivated wheat species-taking up to 95% of the wheat and staple food for consumers worldwide [1]. Wheat constitutes a staple food worldwide, providing ~20% of the total calories and proteins in human diets globally [2]. Wheat is one of the major cereals grown for use as food and industrial raw materials in Ethiopia. Bread wheat in Ethiopia is used in different forms such as bread, porridge, soup, and roasted grain. In addition to the grain, the straw of bread wheat is used for animal feed, thatching roofs, and bed decking [3]. Wheat is also a strategic commodity that generates farm income and improves food security status [4]. Wheat is grown across a diverse range of agroecology and Ethiopia has huge potential and suitable agro ecology for growing wheat. Wheat is widely produced in the highlands and mid- altitudes of Ethiopia. In spite of the presence of wide agro- ecologies suitable for wheat production; elasticity of wheat to be grown from extreme lowlands to highlands; increased demand for wheat due to population growth, urbanization, and expansion of agro-industries; wheat production is left behind by 25 to 30% to its demand in Ethiopia [5].

According to Akcura et al., 2006 reports plant breeders are highly concerned with the development and release of high yielding, stable, and stresses resistant crop varieties. A stable genotype is one possessing constant performance irrespective of changes in environmental conditions [6, 7]. A fruitfully developed new variety should be stable and broadly adaptable over a wide range of environments on top of high yielding potential [8]. Dia [9] reported that to identify superior genotypes across multiple environments plant breeders conduct trials across locations and years during the final stages of cultivar development. Several studies of genotype by environment interactions (GxE) and yield stability have been reported on wheat grown under different locations and conditions in Ethiopia [10, 11, 12, 13]. Each variety has a genotype-specific ability to maintain performance over a wide range of environmental conditions [14].

Several varieties of bread wheat have been released for large-scale production in Ethiopia [5, 15]. However, their high-yielding potential and rusts resistance ability will not last long mainly due to the stem and yellow rusts epidemic [16, 17, 18]. Yellow and stem rust diseases continued as the major biotic threat to wheat production in Ethiopia. Nowadays, Ethiopia has reached on stage where bread wheat cannot be produced without the application of fungicides, especially in wheat belt Zones like Arsi, West Arsi, and Bale Zones [19]. Hence, the Ethiopian Wheat Research Program introduces thousands of bread wheat germplasms annually from CIMMYT and ICARDA and evaluates germplasms under quarantine blocks and in a series of yield trials over locations and years.

Different varieties with rust resistance and high yielder were released in Ethiopia which will help to boost the farmer income and food security. However, most of these cultivars were out of production due to their susceptibility to rust. Plant breeders evaluate and select breeding material empirically for adaptation to wider environments every year. To enhance farm profitability through using of improved bread wheat technologies in Ethiopia, there is a need to develop climate- smart varieties which are high yielding varieties, rust- resistant, high yielder, and suitable for different cropping systems prevalent in different agro-ecological in the country. Therefore, the objective of the present paper is to develop improved varieties of bread wheat and register the “Shaki” variety.

Materials and Methods

Initially, in 2015, 50 genotypes were introduced from CIMMYT under 23HRWYT and planted in Ethiopia under a quarantine site. Based on agronomic performance, yield data, and disease resistance Shaki was selected and planted in an observation nursery in 2016, in preliminary variety trials in 2017, and in national variety trials for two consecutive years (2018-2019) with twenty-three advanced bread wheat genotypes and two standard checks at Kulumsa, Asasa, Robe Arsi, Bekoji, Areka, Holeta, and Adet. The advanced genotypes were selected or screened from observation nurseries and preliminary variety trials in the preceding years. The genotypes were arranged in alpha lattice design with a plot size of 6 rows of 2.5 m by 1.2 m (3 m2) long and 0.2m inter-row spacing. Every plot was planted at a seed rate of 150 kg ha-1. Except for the genetic and other environmental variations, other agronomic management practices were applied uniformly to each plot. Fertilizer was applied at the recommended rate for the specific location. Finally, data were collected for days to heading, days to maturity, plant height, thousand seed weight, hectolitre weight, and grain yield; and diseases data (stem rust, leaf rust, yellow rust, and septoria). Agronomic traits for multi environments were combined and analyses were carried out. Finally, based on the results for agronomic performance and disease resistance two candidate genotypes viz. ETBW9606 and ETBW9089 were selected and verified on farmer’s fields along with two st. checks Hidase and Lemu in 2020. At the maturity stage, the National Variety Release Committee has evaluated the field with the farmers and proposed to release a candidate variety, ETBW9089 (Shaki) for official registration in the country as a commercial variety for the end-user.

Summary and Conclusion

Increasing the production of foodstuffs in developing countries against the background of rapid population growth, widespread food shortage, malnutrition and the destruction of the natural resource base remains important for the future. Therefore, there is a need to intensify crop production through the application of relevant innovations including better crop varieties adapted to varying agro- ecological conditions and socioeconomic set-ups. A successful variety must produce a high yield in favorable environments and still should produce an acceptable yield under less favorable ones. In general, both yield and stability of performance should be considered simultaneously to take advantage of the useful effect of GE interaction and to make a selection of the variety more precise and refined. Shaki was the best yielding bread wheat variety. It is stable ingrain yield performance over locations and years. It was resistant to major wheat rust diseases that prevailed in the growing areas. Farmers also preferred the variety for its superior performance over the existing local variety, which is manifested by better grain yield, and disease resistance. Likewise, the variety has white grain color and it has good general acceptance for bread with high quality. Hence, Shaki was verified and officially released for midland and Highland wheat-growing areas of Ethiopia in 2021.

Acknowledgments

The authors would like to thank the Ethiopian Institute of Agricultural Research (EIAR) and Kulumsa Agricultural Research Center (KARC) and other collaborating centers to carry out this research.