Tel Hadya Research Articles

Factors influencing the development of bread wheat plant types to be grown in the ‘transitional zone’ in northern Syria

This study sought to identify factors that influence wheat development in the transitional wheat growing zone of northern Syria. Three development factors were studied, intrinsic earliness, and responses to vernalization and to photoperiod. Two sets of wheat were studied, each composed of lines with differing combinations of development factors. Set 1 comprised 20 parental and breeding lines utilized by the CIMMYT/ICARDA facultative and winter wheat breeding program based at Tel Hadya. Set 2 comprised 19 parental and breeding lines utilized by an Australian winter wheat breeding program based at Temora. Field development was recorded in greatest detail at one site. Tel Hadya, using the state of differentiation of the apex of the main tiller of sampled plants. To extend findings, development was also recorded as the time from sowing to ear emergence for later sowings of wheat at Tel Hadya, and in sowings at four other regional sites.

Control of early development in winter and facultative wheats in contrasting field environments

The major factors influencing the development of wheat are responses to vernalisation and to photoperiod, and intrinsic earliness. This study sought to determine how these factors influence the development of field-grown winter and facultative wheats of Australian origin, which tend not to be highly responsive to photoperiod. Of particular interest was the relationship between response to vernalisation and the switch from vegetative to reproductive growth. The effect of these developmental factors in influencing field development was established by correlating measurements from controlled and field environments. Three field environments were studied at 2 sites, a February and an April sowing at Temora (NSW, Australia), and a November sowing at Tel Hadya (Syria). Both sites were around 35� latitude. These environments differed in the duration from sowing to the onset of vernalising temperatures in winter. The onset of vernalisation was most delayed in seedlings for the February sowing at Temora. Vernalisation commenced earliest in seedlings for the November sowing at Tel Hadya, and was then presumed to proceed most rapidly. The 3 development factors were measured in 17 wheat genotypes. These data had been published previously; however, measurements of integrated response to vernalisation were re-expressed in new units, and the experiment was repeated, to attain greater precision. Measurement of each developmental factor was correlated with the timing of double ridge, terminal spikelet, and the beginning and end of spikelet site accumulation in each field environment. Where vernalisation was most delayed after sowing, the strongest correlation was between integrated response to vernalisation and the duration from sowing to double ridge. Where vernalisation was most rapid after sowing, the strongest correlation was between intrinsic earliness and the duration from sowing to the beginning of spikelet site accumulation. This study suggests lack of vernalisation most strongly delays the timing of double ridge in winter wheats, and masks the effect of intrinsic earliness which otherwise influences early development. These findings reconcile the significance of the timing of double ridge with previous quantitative studies of early development in winter and facultative wheats.

Additional Sources of Tolerance to Cold in Cultivated and Wild Cicer Species

Cold tolerance is an important prerequisite for winter sowing of chickpea (Cicer arietinum L.) in Mediterranean environments. Cold‐tolerant lines identified earlier at ICARDA are sometimes not tolerant enough to tolerate exceptionally cold winters which occur occasionally. The objectives of this study were to identify sources of increased cold tolerance and to ascertain associations of cold tolerance with other plant traits. Cold tolerance of 4284 kabuli and 2137 desi germplasm lines, 857 breeding lines, and 59 lines of seven annual wild Cicer species was evaluated during the five winters from 1987 to 1992 at ICARDA sites at Tel Hadya and Breda in Syria. The susceptible check was killed in all 5 yr, indicating the severity of cold winters. Eleven kabuli but no desi germplasm lines, and 14 breeding lines, were tolerant. Among the cultigens, a germplasm line (ILC 8262), a mutant (ILC 8617), and a breeding line (FLIP 87‐82C) were the best sources of cold tolerance, with a consistent rating of three (1‐9 scale, where 1 = free from damage and 9 = all plants killed) over years and locations. Among wild species, 26 lines of C. reticulation, 10 of C. bijugum, four of C. echinospermum, two of C. pinnatifidum, and one of C. judaicum were cold tolerant. Five lines of C. bijugum and four of C. reticulatum had a rating of two, reflecting their better cold tolerance than the cultigen. Correlation studies on 2970 lines indicated that prostrate growth habit during winter months was positively associated with cold tolerance. Some late‐flowering lines were susceptible, others were tolerant to cold; whereas, all early‐flowering lines were susceptible to cold. Cold tolerance had no association with anthocyanin pigmentation on the stem. Older plants were more susceptible to cold than younger plants.

Tiller Development and Contribution to Yield under Different Moisture Regimes in two Triticum Species

AbstractThe number of productive tillers is an important yield component in wheat and is affected by water stress and genetic factors. A greenhouse experiment was conducted during spring 1992 at ICARDA, Tel Hadya, Syria, with eight genotypes representing two Triticum species (Triticum turgidum L. ssp. durum and Triticum aestivum L. ssp. aestivum) under four soil‐moisture regimes (95 %, 75 %, 55 %, and 35 % field capacity) to study the effect of water deficit on tiller development and tiller contribution to grain yield. In the highest watering regime appearance of Tiller 1 was delayed in both species. Also Tiller 2 was suppressed in this treatment in durum, while its appearance was delayed in aestivum. In the driest treatment, a majority of the tillers were suppressed and the ones which emerged were delayed. In durum, the heat units required to produce successive leaves on the tillers were higher than that for the main stem and increased with increasing water stress, causing high rate of tiller abortion. In aestivum, each tiller, once produced, developed leaves at the same rate as on the main stem. Phyllochron of tillers as well as main stem was not affected by water stress in aestivum. In aestivum, contribution by tillers to yield was higher than that of durum in all treatments. Results indicate that early appearance of tillers and faster rate of leaf appearance under water stress result in higher tiller survival and greater tiller contribution to final yield. Hence, tiller dynamics under water stress can be used as a selection criterion for breeding for drought tolerance.

Leaf development and phenology of Triticum aestivum and T. durum under different moisture regimes

Wheat grain yield production in the rain-fed areas is limited by water deficits during crop growth. A greenhouse experiment was conducted during spring 1992 at ICARDA, Tel Hadya, Syria, with eight genotypes representing two Triticum species (Triticum turgidum var. durum and Triticum aestivum L.) under four soil-moisture regimes (95%, 75%, 55%, and 35% field capacity) to study the effect of water deficit on leaf development. The phyllochron was similar in the two species across the watering regimes. The range in variation in phyllochron among the genotypes was similar in the two species. Phyllochron response to water stress among genotypes was distinct in the driest regime in both species. Cham 6 (T. aestivum) and Gallareta (T. turgidum var. durum) had similar phyllochron across all moisture regimes whereas in other genotypes phyllochron was higher in the dries regime. Leaf area decreased with increasing moisture stress. Triticum turgidum var. durum genotypes were later in flowering as they had, on average, one leaf more than Triticum aestivum genotypes with similar leaf appearance rates.

Phyllochron Response to Vernalization and Photeperiod in Spring Wheat

An understanding of how environment controls the initiation and development of the leaf is required to construct dynamic crop simulation models. The aim of this study was to determine the effect of vernalization and photoperiod on total number of leaves at anthesis, leaf emergence rate, and phyllochron in 20 spring wheat genotypes (Triticum aestivum L.). An experiment was conducted under greenhouse conditions during spring 1992 at ICARDA, Tel Hadya, Syria, with all combinations of three photoperiods (8‐, 12‐, and 16‐h daylength) and two vernalization treatments (vernalized and nonvernalized). Total number of leaves on the main stem at anthesis decreased with increasing photoperiod. Vernalization reduced the total number of leaves on main stem at anthesis in the eight vernalization‐sensitive genotypes. Leaf number on the main stem was linearly (r = 0.99) related to accumulated growing degree days (°C d). Genotypes differed in leaf emergence rates. Leaf‐emergence rate increased with increasing photoperiod. Phyllochron decreased with increased daylength from 124 °C d leaf−1 at 8 h to 97 °C d leaf−1 at 16‐h photoperiod. These results suggests that, to model leaf appearance and canopy development in wheat, genotypic coefficients of phyllochron need to be determined in relation to photoperiod. Additionally, the effect of vernalization at inductive photoperiods on the phyllochron in genotypes adapted to heat‐prone tropical environments needs further study.

Response of Mediterranean grassland to phosphate and stocking rates: livestock production

SUMMARYThree rates of phosphate (0, 25 and 60 kg/ha P2O5) were applied for 7 years to phosphate-deficient grassland at Tel Hadya, north Syria. Liveweight, milk yield, wool production and supplementary feeding of Awassi sheep were monitored for six seasons (1985/86 to 1990/91). The experiment was grazed at low (0·8 sheep/ha per year) and high (1·7 sheep/ha per year) stocking rates from the second to the fourth season, while in the fifth to seventh seasons stocking rates were increased to 1·1 and 2·3 sheep/ha per year, respectively. The experimental site was typical of communally owned, degraded grasslands within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and steep slopes.The results showed that annual applications of phosphate, even at 25 kg/ha, improved pasture and sheep productivity. Liveweights were higher on fertilized plots in five out of six years, significantly so in the last three. Milk production was also higher on phosphate-treated plots, and the need for supplementary feeding was reduced, especially in the last three years, when rainfall was below average. The results suggest that stocking rates can be significantly increased by annual applications of small amounts of superphospate, and that doing so is profitable.Use of the results depends on the presence of native legumes, the level of soil phosphate, and the ability of farmers to control grazing of these communally owned grasslands. A strategy to fulfil these criteria is suggested.

Registration of Eight Ascochyta Blight‐Resistant, Early Maturing, Large‐Seeded Chickpea Germplasms

Released in 1992, these Cicer arietinum germplasms were developed from crosses between ascochyta blight (Ascochyta rabiei)-resistant, late-maturing, intermediate type (pea-shaped, small, orange seeds) germplasm accessions and early maturing, high-yielding, kabuli type (ram-head-shaped, large, beige seeds) lines in the ICRISAT-ICARDA Kabuli Chickpea Project in Syria. Recurrent selection for resistance to A. rabiei and other agronomically desirable traits was conducted at Tel Hadya, Syria. All 8 lines were resistant to A. rabiei both in the field and greenhouse and have typical kabuli type seed. Three of them, FLIP90-98C (PI578065), FLIP91-22C (PI578068) and FLIP91-46C (PI578070), have early maturity (≤131 days to 50% flowering). The lines FLIP91-2C (PI578066), FLIP91-24C (PI578069), FLIP91-50C (PI578071) and FLIP91-54C (PI578072) have large seeds (40-50.6 g per 100 seeds) and medium maturity. FLIP91-18C (PI578067) has both early maturity and large seeds

A comparison of the performance of Turkish and Syrian strains of Awassi ewes at two levels of nutrition

Although milk is an important product of sheep systems using the Awassi breed in the Near East, typically giving 25% of the gross income, there is little information on the yields of Awassi ewes at defined levels of nutrition. The Awassi is the dominant breed of sheep in the Near East. It is the only breed in Jordan, Lebanon and Syria, which have a total sheep population of 16.9 million. In Iraq about 50% of the 7.8 million sheep are Awassis. There are also approximately 1 million Awassi sheep in Turkey, mainly in the south along the border with Syria. Turkish Awassi ewes have been selected for milk yield for many years at the Ceylanpinar State Farm.In 1991, ICARDA purchased 40 ewes, aged 2 years, from the Ceylanpinar flock. In 1992, these ewes and 40 ewes selected at random from 2 year old ewes in the flock at ICARDA's Tel Hadya station at Aleppo, in northern Syria, were compared, using two levels of nutrition in lactation. The ewes in the ICARDA flock are typical of well managed flocks in northern Syria.

Rainfall and temperature effects on lentil (Lens culinaris) seed yield in Mediterranean environments

SUMMARYLentil (Lens culinaris Medikus) is a rain-fed crop in North Africa and West Asia whose yields are limited by the amount and distribution of rainfall and winter cold. This study aimed to quantify the effects of climatic variables on lentil seed yields through the fitting of simple empirical models to trial data of two cultivars sown at six sites, 1983–89, representing 31 environments in Syria. The ranges over environments were 152–527 mm for total season rainfall and 1–52 for the number of frost nights. Overall, the total seasonal rainfall accounted for 40·8% of the variance in mean seed yield (1·27 t//ha, S.D. 0·82) with a response of 5·68 kg/ha/mm. A multiple regression model with monthly rainfall from November to May explained 67·6;0% of the variance in mean seed yield. From November to February the response of seed yield to rain was < 10 kg/ha/mm; rain in March, the period of late vegetative growth, made the most important contribution to seed yield. The response to April rain was negative. At Tel Hadya (the most frequently used site), the total seasonal rainfall accounted for 79·8% of the variance in mean seed yield, and the addition of the number of frost nights to the model improved the fit to 92·7%. Winter cold had a smaller effect on yield than rainfall, with no consistent overall effect, but differences over regions. The cultivars contrasted in their responses to drought (78S26002 was superior to ILL4400 at seasonal rainfall levels down to 134 mm) and the number of frost nights at Breda and Tel Hadya (78S26002 was more susceptible to cold than ILL4400). Thus, despite the predominant influence of rainfall on yield, the genetic variability in response to moisture and cold shows the scope for selection under rainfed Mediterranean environments.

Adaptation of spring-sown chickpea to the Mediterranean basin. I. Response to moisture supply

Chickpea is grown in spring as a rainfed crop in West Asia and North Africa (WANA) regions in areas with mean annual rainfall of not less than 400 mm but where the rainfall amount and distribution are highly variable. We hypothesized that for WANA, the best-adapted cultivars should produce high yields in years with low rainfall and be responsive to moisture supply in years with high rainfall. Studies were therefore conducted to determine whether there is genetic variability in response to moisture supply and if so, to develop breeding strategies that support our hypothesis. Chickpea cultivars of diverse origin were grown under a soil moisture gradient using a line-source sprinkler irrigation system at Tel Hadya, northern Syria during the 1986/87, 1987/88 and 1988/89 seasons. In 1986/87 rainfall (359 mm) was similar to the long-term average but temperatures in the March-May period were lower. In 1987/88 rainfall was high (504 mm); and in 1988/89, it was low (234 mm) and temperatures during the March-May period were higher than the long-term average. Rainfed mean grain yields were 0.984 t/ha in 1986/87; 1.099 t/ha in 1987/88 and 0.187 t/ha in 1988/89. Cultivars varied significantly in response of grain yield to moisture supply (3.93–9.29 kg/ha/mm in 1986/87; 2.15–8.19 kg/ha/mm in 1987/88; and 3.10–9.57 kg/ha/mm in 1988/89). Responsiveness to moisture supply (regression slope) was highly correlated with yield potential. However, the correlation between the responsiveness to moisture supply and drought (rainfed) yield was non-significant. Widely adapted (stable) cultivars (i.e. cultivars which are considered well adapted to variation in moisture supply) in 1986/87 and 1987/88 were those with high mean yield, high rainfed yields and high yield potential; and in 1988/89 when the rise in temperature in spring was fast, additional requirements for wide adaptation were early phenology and high harvest index. Chickpea cultivars with wide adaptation had deep root systems and high pre-dawn leaf water potential.

Sources of resistance to ascochyta blight in wild Cicer species

Ascochyta blight [Ascochyta rabiei (Pass.) Lab.] is the major foliar disease of chickpea (Cicer arietinum L.). In search of better sources of resistance to ascochyta blight, 201 accessions of 8 annual wildCicer species were evaluated in field and greenhouse for 3 years (1988 to 1991) at Tel Hadya, Syria. One accession each ofC. judaicum Boiss (ILWC 165) andC. pinnatifidum Jaub. & Spach. (ILWC 159) were consistently rated resistant in both field and greenhouse evaluations. Another three accessions ofC. judaicum (ILWC 61, ILWC 154, ILWC 199) and six accessions ofC. pinnatifidum (ILWC 78, ILWC 88, ILWC 155, ILWC 160, ILWC 162, ILWC 203) were resistant or moderately resistant. The blight-resistant accessions ofC. judaicum originated from Jordan, Lebanon, Syria, and Turkey; and those ofC. pinnatifidum from Syria and Turkey. None of the accessions ofC. bijugum, C. chorassanicum, C. cuneatum, C. echinospermum, C. reticulatum andC. yamashitae were resistant to blight.

Yield and Water Use Efficiency of Faba Bean Sown at Two Row Spacings and Seed Densities

SummaryThe performance of promising genotypes of faba bean developed for areas with limited rainfall was compared with the local landrace, ILB 1814, at Tel Hadya in Syria during 1989–1988 using different row spacings and sowing densities. In the last two years of the trials the performance of the improved genotypes and ILB 1814 was compared with and without supplemental irrigation. Yields of ILB 1814 were better than the highest yielding genotypes in some years and similar to them in others. In seasons with limited rainfall the best yields were obtained by using a narrow row spacing and dense sowing, and yields were significantly improved by irrigation. Grain yield was correlated with biomass and the number of pods per unit area. The percentage of radiation intercepted was highest in ILB 1814, particularly when sown with a narrow row spacing and at a high plant density. Soil water extraction, evapotranspiration and water use efficiency were improved by sowing at a narrowrow spacing and high plant density.Los nemátodos de las plantas y la agricultura continua

Lodging in Lentil as Affected by Plant Population, Soil Moisture and Genotype

SummaryThe effects of levels of soil moisture and plant population on lodging and associated losses from mechanical harvesting of two lentil genotypes, one susceptible and one resistant to lodging, were investigated during 1986–87 and 1987–88 at Tel Hadya in northern Syria. High plant population increased lodging because the crowded plants had thin stems, while high levels of soil moisture caused lodging because biological yield was increased. When biological yields were high a two tonne increase in biological yield led to a one point increase in lodging score. Mechanical harvesting increased losses in biological yield due to lodging by 12% compared with yields obtained by hand harvesting under rainfed conditions and by 24% at the highest level ofsoil moisture. It is suggested that supplementary irrigation should be used in dry seasons in trials to select genotypes resistant to lodging.Decaimiento de la lenteja

Relationship Between Cold Severity and Yield Loss in Chickpea (Cicer arietinum L.)*

AbstractSeed yield in chickpea (Cicer arietinum L.) is substantially increased by advancing sowing date from the traditional spring to early winter at low to medium elevation areas around the Mediterranean Sea. This shift, however, increases the probability of the exposure to subzero temperatures as low as ‐10 °C for up to 60 days in a year. These low temperatures often reduce seed yield of cold‐susceptible cultivars. Yield losses from cold were estimated in two experiments conducted at Tel Hadya, Syria. In experiment 1, of 96 genotypes sown on nine dates ranging from autumn to spring during the 1981–82 season, those lacking tolerance to cold were killed and produced no yield in autumn sowing, whereas lines with cold tolerance produced nearly 4 t/ha which corresponds to a four‐fold increase over spring sowing. Moderately cold‐tolerant genotypes sown during early winter produced substantially more seed yield than the normal spring‐sown crop. Seedlings were more cold tolerant than the plants in early or late vegetative stages. In experiment 2, in which yield loss due to cold in the field was estimated in 12 yield trials comprising 288 newly bred lines in the 1989–90 season, the regression of cold susceptibility on seed yield in each of the trials was highly significant and negative. On average, winter‐sown trials produced 67 % more seed yield than spring‐sown trials, but 125 out of 288 genotypes produced yield more than double in winter sowing. Early maturing lines suffered severe cold damage and many lines produced no seed.

Field evaluation and simulation of frost tolerance in Syrian durum wheat landraces

Forty-nine Syrian durum wheat landraces were sown in late Nov. 1989 at Tel Hadya, Syria (a low-yielding site) and 38 were sown in mid-Dec. at Homs (a high-yielding site) with or without N + P fertilizer. Jan. frosts caused less than 5% apparent foliar damage in any of the landraces. However, foliar damage by Mar. frosts averaged 23% (range 3-65%). Late frost tolerance of foliage appeared to be related to minimum winter temperatures in the regions of origin, with landraces from coastal regions showing the highest sensitivity. Fertilizer did not significantly affect foliar damage. In simulation studies based on observed foliar damage rates at Tel Hadya due to Mar. frosts, foliar damage alone did not decrease grain yield but decreased straw yield. Additional floret damage decreased grain yield and increased straw yield.

Leaf area and crop growth in relation to phenology of barley in Mediterranean environments

In a barley/livestock farming system of northern Syria, high biomass production in addition to high grain yield is desirable. The aim of this study was to assess the effect of environment and phenology on growth and yield of barley in northern Syria. Leaf area duration (LAD), specific leaf area (SLA), crop growth rate (CGR) on a thermal time basis, and biological and grain yields were compared for entries representing three contrasting development patterns: early heading spring types (pattern A), medium early heading winter types (pattern B), and late heading spring types (pattern C). The experiment was conducted in 1988/89 at two sites: Tel Hadya (TH, 250 mm precipitation) and Breda (BR, 180 mm). Cold damage occurred in winter and, especially at BR, drought stress developed in spring.

Resistance to Six Races of Ascochyta rabiei in the World Germplasm Collection of Chickpea

Ascochyta blight [caused by Phoma rabiei (Pass.) Khune & J.N. Kapoor; syn. Ascochyta rabiei (Pass.) Lab.] is the most important disease of chickpea (Cicer arietinum L.) in many countries. Progress in breeding blight‐resistant cultivars has been hampered by the absence of dependable sources of resistance. An effort was made to screen the world germplasm collection against races of P. rabiei with the objective of identifying resistant sources. A total of 19 343 germplasm accessions of chickpea (12 749 desi and 6594 kabuli types) were evaluated for resistance to six races of P. rabiei at Tel Hadya, Syria, between 1979 and 1991. Germplasm accessions were sown in the field during the winter season and inoculated by scattering ascochyta blightdiseased chickpea debris and spraying a spore suspension of a mixture of six races of P. rabiei prevalent in Syria and Lebanon. In greenhouse evaluations, germplasm accessions were grown in pots and inoculated by spraying the spore suspension of a composite of the six races; inoculated plants were incubated in plastic moist chambers for 1 wk. Blight severity was scored on a scale of 1 to 9, where 1 to 4 = resistant, 5 = tolerant, and 6 to 9 = susceptible. Only three desi accessions (ICC 4475, ICC 6328, and ICC 12004) and two kabuli accessions (ILC 200 and ILC 6482) were resistant in repeated field and greenhouse evaluations. Another six desi and three kabuli accessions were resistant in repeated Held tests but tolerant in greenhouse evaluations. These accessions will be used as sources of resistance in the ascochyta blight‐resistance breeding programs.

Vesicular-Arbuscular Mycorrhiza and Phosphorus Uptake of Chickpea Grown in Northern Syria

SUMMARYInoculation with vesicular-arbuscular mycorrhizal fungi (VAMF) improved growth of chick-pea (Cicer arielinum L.) and doubled phosphorus (P) uptake at low and intermediate levels of P fertilization in a pot experiment on sterilized low-P calcareous soil. In field experiments at Tel Hadya, northern Syria, growth, shoot P concentration and seed yield of spring-sown chickpea remained unaffected by inoculation with VAMF or by P fertilization. The mycorrhizal infection of chickpea was high (approximately 75% of root length mycorrhizal at the flowering stage) irrespective of inoculation with VAMF or P fertilization and may ensure efficient P uptake under field conditions.

Adaptation of Lentil Seed Yield to Varying Moisture Supply

Lentil (Lens culinaris Medikus) is an important component of ralnfed farming systems in West Asia and North Africa; it is also grown under irrigation in Egypt and Sudan. Our objectives were to determine the adaptation of a range of lentil genotypes to a wide spectrum of moisture regimes. Thirty‐four diverse genotypes were grown for two seasons (1984–1985 and 1985–1986) at three locations varying in water supply, in northern Syria and Lebanon. At one location (Tel Hadya, Syria), the crop was given two supplementary irrigation regimes. Variation in mean seed yield per plant was largely explained (R2 = 0.833**) by the variation in water supply. Two supplementary irrigations (50 mm each) resulted in a 20% increase in seed yield per plant. Genotypic performance was adequately summarized by genotype means and their linear responses to different levels of moisture supply, allowing selection of genotypes for either wet or dry conditions.