Development of Four New Ug99 Resistant Wheat Varieties for Afghanistan

Qasem Mohammad Obaidi1, Mahmood Osmanzai2, Ravi Singh3, Javier Pena3, Hans Joachim Braun3 and Rajiv Sharma2


1 Agricultural Research Institute of Afghanistan, Kabul, Afghanistan

2 International Maize and Wheat Improvement Center (CIMMYT)-Afghanistan

3 International Maize and Wheat Improvement Center (CIMMYT)-Mexico

Corresponding Author: Rajiv Sharma

E-mail: rk.sharma@cgiar.org

 

Wheat (Triticum aestivum L.) is the most important food grain in Afghan agriculture and its economy as it is grown in about 2.5 m ha (Anonymous 2010), which is about 80% of the area cultivated under all cereals. The total wheat production in 2010 was recorded at 4.5 m tons, which accounts for 79% of all cereals produced in Afghanistan (Anonymous 2010). Wheat alone accounts for 60% of the total caloric intake at a per capita consumption rate of 162 kg/year (Government of Afghanistan 2003). The wheat grain is imported to meet the production gap. Increasing wheat yield through improved high yielding new varieties is more cost effective and sustainable option. Of all wheat area in Afghanistan, 45% is irrigated and 55% rain fed. The wheat growing environments are further complicated by the occurrence of diverse wheat diseases, pests and abiotic stresses (Sharma et al. 2011).

The Constraints to Wheat Production
Afghanistan’s wheat crop is threatened by a new, devastating form of stem rust known as Ug99 (Singh et al. 2008). This is a new strain of stem rust that is virulent on more than 85% of all wheat varieties, globally, and is a threat to global food security. Unchecked, Ug99 can destroy wheat crops through explosive epidemics. According to conservative estimates, Ug99 can cause up to 20% reduction in the country’s annual wheat production. However, individual farmers and villages could face up to 80% potential loss in wheat production due to localized famine, causing greater upward shifts in wheat prices. Many farmers throughout Afghanistan continue to grow old wheat varieties. Not only are these varieties highly susceptible to Ug99 wheat stem rust, but their inherent yield potential is low by today’s standards. Replacement of these varieties with modern, high yielding varieties will both protect farmers against the inevitable attack of stem rust and other diseases, and also increase wheat yields by at least 15%. The inevitability of Ug99’s migration from Iran (where it was reported in 2007) to Afghanistan, coupled with the presence of dangerous new races of yellow rust, are of such importance that rust surveillance and rust resistant varieties are now inseparable components of efforts to enhance wheat productivity. Rust resistance must be coupled with all of the agronomic and grain quality traits that make a variety superior, and fortunately, these traits can be combined into improved varieties. Explicit focus on the threat of Ug99 and other rusts helps minimize the chance of great economic losses from epidemics as encountered earlier in many parts of world. The most immediate and sustainable approach to achieving national food security in wheat is to replace current, outdated varieties with new, higher yielding and disease resistant varieties.

Solutions to the Constraints:
Since Afghanistan does not have a home grown wheat breeding program, it depends on the introduction of new wheat varieties from outside. Mexico based International Maize and Wheat Improvement Centre (CIMMYT) is providing, through its Kabul office, large number of newly developed high yielding and disease resistant genotypes to Afghanistan. Agricultural Research Institute of Afghanistan (ARIA) in collaboration with CIMMYT-Afghanistan has already taken urgent steps by releasing four Ug99 resistant wheat varieties viz., Baghlan 09, Koshan 09, Muqawim 09 and Chonte #1 in the country (Table 1). These genotypes, bred by CIMMYT, Mexico were introduced into Afghanistan through Elite Bred Wheat Yield Trials during 2007 and 2008. These genotypes were selected based on their consistent performance and resistance to major diseases including stem rust race Ug99. Based on their superior multilocation performance, the genotypes were then evaluated in multilocation national trials (Table 2). These promising genotypes not only yielded higher but were also resistant to the prevalent races of rusts in the country, had suitable end use quality and possessed other desirable traits (Table 3). The seed of these varieties is now entering the national seed chain and farmers will start benefitting from them from next year onward. The seed production targets during 2010-11 crop season aim at having around nine percent of total certified seed from these four varieties in the country for the next crop season.

End use suitability:
The elite genotypes developed at CIMMYT, Mexico are selected not only for high yield and disease resistance but are also screened for their end use suitability in terms of sedimentation volume, dough mixing and dough strength-extensibility parameters, gluten strength etc (Pena et al. 2002). The four genotypes released in Afghanistan were found to possess essential quality parameters required for making typical Afghan bread:

Koshan 09: This variety has white, hard grain. Its sedimentation volume, dough mixing (mixographic) and dough strength-extensibility (alveographic) parameters indicate that this variety has medium strong gluten with tendency of showing good extensibility. This variety has good high- plus low- molecular weight glutenin composition and does not carry the 1B/1R translocation, which is good from the processing point of view. This variety, if managed well (split N fertilization) should be more than acceptable for bread.


Muqawim 09: This variety has white and hard grain, very high sedimentation volume and strong-extensible type gluten (alveograph parameters). Its gluten quality is so high (strong) that it can be used to correct the baking quality of other varieties of inferior gluten strength.


Baghlan 09: Another white, hard grained variety with intermediate sedimentation volume and intermediate dough mixing properties. The alveograph shows that this variety has gluten that tends to be weak but has good extensibility. It can be used, without any problem, in the production of all kinds of flat breads at the household level and in small bakeries using medium speed mixing equipment.


Chonte #1: White, hard grained variety with low values for sedimentation and short dough mixing time. In the Alveograph this variety shows weak but extensible gluten type. It is suitable mainly for household production of wheat-based products (flat breads and other traditional foods).


The synergistic collaboration between CIMMYT and national agricultural research system of Afghanistan, represented by ARIA endeavoured the needed and has been able to offer Afghan farmers the best international wheat breeding research currently has to offer to this region. The success achieved warrants further action on part of national seed production system to make these varieties available to the farming community. Even though the varieties developed are armed with long lasting adult plant resistance, the ARIA-CIMMYT collaboration, however, has to keep pace in order to be always ready with options since the pathogens of this all important food crop keep evolving.

 

References
Anonymous (2010) Agricultural Prospect Report. Ministry of Agriculture, Irrigation and Livestock. Government of Islamic Republic of Afghanistan. Kabul, Afghanistan.

Government of Afghanistan (2003) National Rural Vulnerability Assessment Survey (NRVA). Ministry of Rehabilitation and Rural Development.

Pena RJ, Trethowan R, Pfeiffer WH and Van Ginkel M (2002) Quality (end use) improvement in wheat: Compositional, genetic and environmental factors. J. Crop Prod., 5: 1-37.

Sharma R, Osmanzai M and Ward RW (2011) Wheat Research: a crucial prerequisite to food security in Afghanistan. Afghanistan Research Newsletter. No. 28, January/ February 2011. pp 2-5.


Singh RP, Hodson DP, Espino JH, Jin Y, Njau P, Wanyera R, Foessel SA and Ward RW (2008) Will stem rust destroy the world’s wheat crops? Advances in Agron., 98: 271-309.