Two new wheat varieties for irrigated conditions of Afghanistan

New high yielding and disease resistant wheat genotypes were introduced in 2008-09 crop season through 4 th Elite Bread Wheat yield Trial (EBYT) as well as 2 nd Stem Rust Resistance Screening Nursery (STEMRRSN). One genotype from EBYT performed 15% higher than commercial variety, Mazar 99 during five years of testing at over eight locations in Afghanistan and was therefore recommended for release for commercial cultivation. Another genotype, Wafer-15 from STEMRRSN showed superior performance (11 to 33% higher yield) than commercial varieties during three years of testing at six locations in Afghanistan and was therefore released in 2015 for commercial cultivation. Both varieties were found resistant to prevalent rust diseases as well as to Ug99 race of stem rust.


INTRODUCTION
Afghanistan is a land locked country with an agrarian economy with 23 million (over 70%) population living in rural areas (FAO, 2016).Wheat is the staple food of Afghans and occupies about 2.5 million hectares with an average production of about five million tonnes annually (Persaud, 2012;Akbar Waziri et al., 2013).Wheat yield in Afghanistan is relatively lower than other countries in the region.Lack of adequate number of resistant varieties for different production environments is one of the major reasons for this.International Maize and Wheat Improvement Centre (CIMMYT) in collaboration with Agricultural Research Institute of Afghanistan (ARIA) have been working to identify suitable high yielding wheat varieties for Afghanistan.CIMMYT, ARIA and other stake holders have successfully released about 34 new wheat varieties in the country before 2000.Introducing new germplasm and identifying new adapted varieties is a continuous activity since new races/pathotypes of diseases continually evolve rendering popular varieties susceptible (Zamarai et al., 2013).Yellow rust has been and is the major wheat disease of Afghanistan rendering varieties susceptible quite frequently.Therefore, breeding/selecting for new high yielding resistant varieties is crucial for Afghanistan's food security.The present paper reports identification and release of two new high yielding, disease resistant wheat varieties for *Corresponding author.E-mail: rk.sharma@cgiar.org.
Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License  1).Wafer-15 was tested only for three years at six locations viz., Kabul, Nangarhar, Baghlan, Kunduz, Balkh and Herat.The trials were laid out in randomized complete block design (RCBD) with three replications.Plot size consisted of six rows of six meters each.Standard recommended agronomic practices were adopted to raise a successful crop in the irrigated conditions.Observations were recorded on days to 50% flowering, days to maturity, plant height, 1000 kernel weight and grain yield.
Disease severity was also recorded as per modified Cobb's scale of Peterson et al. (1948).The genotypes were also sent to Ug99 stem rust screening facility at Njoro, Kenya for scoring for Ug99 resistance.

RESULTS AND DISCUSSION
The two genotypes tested across Afghanistan on an average had higher yield than the check varieties intended to be replaced.Wahadat 15 (Table 2) yielded an annual average from a low of 4853 to a highest of 6453 kg/ha during different years.The five years' average of 5557 kg/ha was found to be only numerically higher (4%) than Chonte#1 and Ariana 07, however it yielded whopping 15% higher than the popular variety Mazar 99.Similarly, Wafer 15 yielded an annual average ranging from 4809 to 7040 kg/ha with an overall average of 5960 kg/ha.Wafer-15 showed superior performance over the check varieties ranging from 11 (Ariana 07) to 33% (Solh 02).Wahadat 15 took about 141 days to mature and attained a height of 91 cm.This variety had a potential yield of 6453 kg/ha and an average 1000 kernel weight of 36 g.Wafer 15 on the other hand matured in 153 days with an average height of 92 cm.The highest yield recorded for Wafer 15 was 7040 kg/ha and its 1000 kernel weighed 39 g (Table 3).
Frequent detection of new virulent races of rust reduces availability of resistant varieties (Zamarai et al., 2013).Afghan wheat acreage of about 2.5 million hectares requires close to 300,000 tonne of seed.However, at a given time, not more than 10-15 resistant varieties are available in seed chain.A robust seed chain to produce even 10% of national requirement should ideally have 20 to 30 varieties, so that about 20 varieties can produce certified seed, and other 10 are either being inducted or are on their way out.This will ensure a much needed mosaic of resistance genes in farmer fields and will avoid monoculture which generally leads to break down of resistance when a single variety occupies large

Table 1 .
Genotypes introduced into Afghanistan for testing adaptation.

Table 2 .
Average yield of test genotypes over years at several locations in Afghanistan.

Table 3 .
Salient features of two new varieties for Afghanistan.Both these varieties were found resistant to yellow rust in Afghanistan under field conditions.The two varieties showed acceptable disease reaction under artificial infestation at Kenya for both yellow as well as stem rust including Ug99 race of stem rust.Both varieties were released by Afghanistan Government in 2015 for commercial cultivation by farmers.