ITEMS FROM SYRIA

ICARDA / CIMMYT
P.O. Box 5466, Aleppo, Syria.

Improving yellow rust resistance in the rainfed wheat areas of West Asia and North Africa.
G. Ortiz Ferrara, O.F. Mamlouk, M.A. Moussa, M.G. Mosaad, S.K. Yau, and M.C. Saxena.
Yellow rust (Puccinia striiformis) is an important foliar disease in the rainfed areas of West Asia and North Africa (WANA). During the past two seasons, countries such as Iran, Lebanon, Syria, and Yemen have experienced grain yield reductions from this disease. This is believed to be due to the following reasons: a) presence of new pathogen virulence(s), b) conducive weather conditions (cool and rainy) at the end of the season, c) wide occurrence of the susceptible Yr9 gene present in commercial varieties with the 1B-1R translocation, and d) lack of sufficient seed of resistant varieties to replace the susceptible ones in those countries.
Since the detection of the new race virulence, the CIMMYT/ICARDA Spring Bread Wheat Improvement Project located at ICARDA, Aleppo, Syria, has increased efforts to select and evaluate germplasm with resistance to this pathogen. Evaluation of disease reaction is based on the use of multilocation testing, the modified bulk method of selection under artificially created epidemics, and close cooperation with pathologists at the Center and in those national programs.
This strategy has increased the level of disease resistance in bread wheat germplasm. As an example, because of the increased selection pressure exercised for yellow rust resistance, the project made progress in enhancing the levels of resistance in bread wheat germplasm. Figure 1 presents the percentages of resistant and susceptible families that have been evaluated under artificial inoculation at Tel Hadya. Many families in the resistant segregating material combine different genes for yellow rust resistance.
The project is now planning to conduct race virulence analysis and gene postulation in elite germplasm. Incorporating sources of yellow rust resistance from distant sources such as Aegilops geniculata, Ae. neglecta, and Ae. triuncialis also is planned.
In close collaboration with national programs in the region, the project has identified several lines that combine grain yield and yield stability with good yellow rust resistance. Table 1 shows six bread wheat lines that had higher grain yield and better yellow rust resistance than the national check variety in three of the countries that reported substantial grain yield damage from this disease during 1993 and 1994. These lines are currently under extensive testing and multiplication. Small quantities of this seed are available upon request.
Table 1. Grain yield (GY) and yellow rust reaction (YR) of some promising bread wheat lines of the Regional Bread Wheat Yield Trial for Semi-arid Areas 1993-94 in Iran, Syria, and Lebanon.

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Iran (Moghan) Syria (Izraa) Lebanon (Kfardan)
Cross GY % > YR GY % > YR GY % > YR
kg/ha NC kg/ha NC kg/ha NC
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Tevee-2 5,134 183 R 2,760 107 R 3,111 114 R
Buc'S'/Mn72253 4,610 164 5MS 2,680 104 R 3,000 110 R
Florkwa-1 4,265 152 5MR 2,613 101 R 2,955 109 5MR
Kacino 4,150 148 R 2,560 99 R 2,738 101 TMR
Caskor 3,740 133 R 2,533 98 10MR 2,833 104 R
Kaby 3,575 127 TMS 2,626 102 R 2,833 104 TMR
Mexipak 65 (LC) 3,257 115 20S 2,346 90 100S 2,266 83 100S
Nat. Check (NC) 2,808 100 30MS 2,586 100 40M 2,722 100 100S
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Site mean 3,954 - - 2,548 - - 2,530 - -
LSD 0.05 1,108 - - 749 - - 632 - -
CV (%) 15.3 - - 17.8 - - 15.2 - -
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LC = local check; NC = national check.


Double haploid research for Hessian fly resistance in rainfed wheat.
G. Ortiz Ferrara, P. Lashermes, M. El Bouhssini, M. Merghoum, M. Jlibene, A. Amri, M. S. Mekni, M. Baum, S. Weigand, and M.C. Saxena.
In cooperation with senior scientists in Morocco and with the biotechnology group at ICARDA, the CIMMYT/ICARDA Bread Wheat Improvement Project evaluated during the 1993-94 season a set of double haploids (DH) developed with Hessian fly (Mayetiola destructor Say) resistant material. The technique of production of the DHs was reported by Lashermes et al. (J Genet Breed 45:33-38, 1991). The details of the tested trial were reported in ICARDA's Cereals Program Annual Report for 1993.
The yield trial, consisting of 24 randomly selected Hessian fly Dhs and two resistant and three susceptible checks, was planted at JmFONT SIZE=2 FACE="WP MultinationalA Roman">t Shaim, Morocco, during the 1993-94 crop season. This dry location is a hot spot, where high infestations of this insect pest occur every year under natural conditions. Table 2 presents five of the highest yielding DHs in the trial. Their grain yield was substantially higher than yields of both the Hessian fly-resistant and the susceptible parents. These DHs combine the Hessian fly resistance with other desirable traits such as resistance to yellow rust and Septoria and drought tolerance. This trial is currently under a second year of testing in Morocco. The DH lines and the resistant parents are under seed multiplication at Tel Hadya. Small quantities of these DHs are available upon request.
Because of these encouraging results, the CIMMYT/ICARDA Bread Wheat Improvement Project has expanded its DH work to other areas of research such as yellow rust and cereal cyst nematode (CCN), important biotic stresses in the rainfed areas of West Asia and North Africa.

Table 2. Performance of double haploid Hessian fly-resistant bread wheat lines under natural infestation and dry conditions (less than 300 mm) at JmFONT SIZE=2 FACE="WP MultinationalA Roman">t Shaim, Morocco, 1993-94.
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Line GY % of % of (kg/ha) HFRP HFSP
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Shi#4414/Crow//Gomam 2,975 121 153
Shi#4414/Crow//Gomam 2,933 119 151
Shi#4414/Crow//Gomam 2,883 117 148
Tsi/Vee//Shi#4414/Crow 2,775 113 129
Vee's'/Saada 2,650 108 124
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Shi#4144/Crow (HFRP) 2,458 100 127 *
Saada (HFRP) 2,458 100 127 *
Tsi/Vee's' (HFSP) 2,158 88 111 *
Vee's' (HFSP) 2,141 87 110 *
Gomam (HFSP) 1,942 79 100
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Site mean 2,214
LSD 0.05 632
CV (%) 14.0
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HFRP = Hessian fly resistant parent;
HFSP = Hessian fly susceptible parent.
* = compared over lowest yielding HFSP.

Differential responses of durum and bread wheat to excess soil boron.
S.K. Yau, M. Nachit, G. Ortiz-Ferrara, J. Ryan, and M.C. Saxena.
Boron (B) toxicity in crops, caused by high soil B levels, occurs commonly in dry areas. It has been observed, usually in barley crops, in many countries of West Asia and North Africa. A project on this problem was initiated in 1992. Because much work has been done on bread wheat by the Waite Institute and CSIRO in South Australia, the emphasis of the project was shifted to durum wheat, which is one of the most important crops in West Asia and North Africa. Results of three experiments conducted in 1994 are given below.
(1) Screening at the seedling stage for B-toxicity tolerance. In 1993 and 1994, screening of the regional durum wheat observation nurseries did not identify entries with lower or comparable B-toxicity symptoms and shoot B concentrations than the tolerant Australian bread wheat check cultivar, Halberd. To find sources with a higher level of B-toxicity tolerance, some land races from the region were screened. Significant differences in foliar symptom scores were observed. Those with the least B-toxicity symptoms were selected for further experimentation (see 3 below). Currently, 150 randomly selected durum accessions, collected from six countries in the region, are under screening.
(2) Confirmation of B-toxicity tolerance in lines selected from seedling test. Of the 246 advanced durum lines and 140 bread wheat entries from the regional nurseries screened in 1993, 15 durum and 13 bread wheat lines with low B-toxicity symptoms and low shoot B concentrations were retested in pots. Two treatments were used: a control (0.4 ppm hot water extractable B) and +B (50 mg B/kg soil, giving a hot water extract of 18 ppm B).
Four durum lines showed a lower reduction in grain yield than Halberd bread wheat under the +B treatment (Table 1). However, all selected lines had higher B-toxicity symptom scores than Halberd at the seedling stage. The best line, Awalbor, suffered a 10 % yield decrease with a high B level, but still maintained higher grain yield than Halberd under +B treatment. Crosses with these lines are being made to incorporate their B-toxicity tolerance into existing cultivars and promising breeding lines.
Table 1. Performance of the most B toxicity-tolerant durum and bread wheat lines (in terms of least % reduction in grain yield when grown in soil to which 50 mg B/kg soil [+B] was added as compared to the control [-B]).
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B toxicity Difference Grain % difference over
symptom in days to yield -B plants
Name/ score at heading (g/pot) ____ _______________
cross +B¹ (+B - -B) ______________ Straw Grain
-B +B yield yield
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Durum wheat.
Awalbor² 2.0 10.5 4.53 4.05 +23.7 -10.6
Awalbit B-1³ 2.0 8 3.89 2.89 +16.5 -25.6
Awalbit B-2⁴ 2.0 10 3.61 2.54 +14.8 -29.6
ICA84-1555-B⁵ 2.0 4.5 3.56 2.39 -13.3 -33.0

Bread wheat. GRU 90201736 1.0 7.5 2.45 2.23 +10.0 - 9.2
Shi#4414/Crow'S' 1.2 0.5 3.75 3.17 -16.9 -15.5
NS.12.5.3/Atfn 2.5 2 4.08 3.37 -10.2 -17.4
Shi#4414/Crow'S' 1.5 1.5 4.29 3.05 -16.4 -29.0
Shi#4414/Crow'S' 2.2 8 4.27 3.00 -21.6 -29.7
Shi#4414/Crow'S' 1.0 6 2.56 1.66 -10.9 -35.4
C183.24/C168.3 2.5 5.5 4.63 3.00 +12.7 -35.5
/3/Cno*2/7C//Cc/Tob
Kavz'S' 1.7 9 5.14 3.29 +15.6 -36.0

Bread wheat checks.
Halberd (tolerant) 1.0 6.5 5.30 3.37 -14.4 -36.4
Greek G61450 0.7 4.5 3.50 3.41 +17.0 + 2.4
(highly tolerant)
Zidane (susceptible) 3.0 7.5 2.86 1.72 -36.3 -39.9
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¹ 0-9 scale: 0 = no symptom, 9 = severe symptom. Scores taken at heading.
² = Awl 1//Memo/Goo.
³ = Awl 2/Bit.
⁴ = Awl 2/Bit.
⁵ = T.A73-74/D.Coll-01.1y/3/Pg/Chap//21563/4/Crosby.
All bread wheat lines also showed a reduction in grain yield under the +B treatment, except the highly tolerant check, Greek G61450 (Table 1). Eight of the lines had a lower percent yield reduction than Halberd. GRU 90-201736, an accession collected from Morocco, had only a 9 % yield decrease, but its yield under +B was lower than that of Halberd. One of the lines derived from the cross `Shi#4414/Crow'S'= and the line from `NS.12.5.3/Atfn' had lower yield reductions than Halberd, and the latter yielded as well as Halberd under the +B treatment.
(3) Effects of excess soil B on agronomic characters in durum and phenotypic differences. An experiment on effects of B-toxicity on grain yield and other agronomic characters in durum wheat was conducted, because they had not been studied previously. Nine durum entries, including four land races and two bread wheat checks (Table 2), were grown in pots to maturity under low N fertility and with three replicates in a plastic house. These entries were selected to represent the range of severity in B-toxicity symptoms observed in a previous screening. Three soil B levels were created by adding 0 (B0), 25 (B25), and 50 (B50) mg B/kg soil, giving hot water extracts of 0.3, 7.1, and 17.4 ppm B, respectively.
Table 2. Mean B-toxicity symptom scores and shoot B concentrations at B25 and B50, delay in heading, and reduction/increase in grain and straw yield from B0 to B50 treatments for durum wheat test entries and bread wheat checks.
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% difference over -B plants
B-toxicity Shoot B Delay in ___________________
symptom concentration days to Straw Grain
Name/cross score¹ (ppm) heading yield yield
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Gezira 17² 0.7 282 3.7 +34.6 - 2.8
Omrabi 5 0.8 240 6.0 -15.6 -10.4
Haurani² 1.3 334 7.0 -11.6 -31.7
Oued Zenati³ 1.1 245 2.0 - 6.7 - 1.4
Cham 3 2.3 329 7.7 -11.8 -14.7
Jordan 21³ 1.1 356 8.0 -16.6 -25.
6 Deraa 1.3 380 8.0 -13.1 -11.9
Cham 1 1.3 391 11.3 + 5.0 -29.0
Cakmak 2.8 347 4.3 -19.3 -30.0

Tolerant bread wheat check

Halberd 0.3 203 2.3 + 1.4 - 6.1


Susceptible bread wheat check

Schomburgk 0.8 225 4.7 - 9.8 -16.0

Mean 1.4 323 6.4 - 6.1 -17.5
LSD (P = 0.05) 0.3 77 4.2 20.8
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¹ 0-5 scale: 0 = no symptoms, 5 = severe symptoms. Scores taken at seedling stage. ² Cultivar developed from local land race.
³ Land race.
High soil B levels caused foliar B-toxicity symptoms, increased B uptake and shoot B concentration, and reduced seedling dry weight and grain yield, but had no significant effect on straw yield. Emergence, heading, and ear emergence were delayed, but germination and number of ears were not significantly affected by high soil B levels. Plant height was significantly increased by high B levels, but B had no effects on flag-leaf length, width, or area. The number of grains in main tillers was not affected, but thousand-kernel weight was decreased significantly.
Significant differences were observed between entries for all the traits measured. Gezira 17 (a cultivar developed from a Syrian land race) and Oued Zenati (an Algerian land race) were the most tolerant durum entries (Table 1). Both cultivars had low B-toxicity symptom scores and low shoot B concentrations at B25 and B50, only slight delay in heading, and little or no reduction in grain and straw yields at B50, compared with B0. When compared with the tolerant Australian bread wheat cultivar, Halberd, the delay in heading and reduction in yield were similar, but the two durum entries had higher symptom scores and shoot B concentrations.