Selection Some Promise Genotypes of Wheat ( Triticum aestivum L . ) Under Local Conditions of Qatar

Ten wheat (Triticum aestivum) genotypes namely G1, G2, G5, G8, G11, G12, G16, G17, G19, G20 were entered from CIMMYT and were screened for desirable characteristics during the growing seasons of 2007/2008 and 2008/2009 respectively. Both trials were conducted in the Department of Agricultural Research (Rawdat AL Faras Station ) under prevailing local Qatar environmental conditions. The analysis of variance (ANOVA) showed significant differences (P < 0.01) between genotypes for all studied characteristics except the seed yield (P > 0.05). The mean of seed yield was 4375kg / ha for the genotypes while it was 2500 kg / ha for the local Check Doha 88. Dunnett test showed significant differences (P < 0.05) between the genotypes G2, G5, G8, G20 and Doha 88 for seed yield. The correlation was positive between t days to heading and days to maturity (r = 0.759*). This study recommends the selection of genotypes with the highest seed yield namely G2 and G5


Introduction
Wheat (Triticum aestivum L.) is one of the most important and widely cultivated crops in the world, used mainly for human consumption and support nearly 35% of the world population.Nearly 95% of wheat grown today is hexaploid, used for the preparation of bread and other baked products (Debasis and Khurana, 2001).Many consumers in Qatar prefer wheat produced organically (without agrochemicals) for direct consumption, and in baking bread and other processed products such as harees with meat, mash.Doha -88 (licensed at 1988) is the lonely local genotype of wheat in Qatar, and there aren't any improved varities.The mandate of the bread wheat breeding program at International Maize and Wheat Improvement Center (CIMMYT) is to develop broad-based and high yielding bread wheat germplasm for the developing countries to enhance wheat production worldwide (Kohli et al., 1991).Analysis of environmental and genotypic factors is always important in plant breeding (Jackson et al., 1996;Yan and Hunt, 1998).Terminal heat stress is a common abiotic factor for reducing the yield in certain areas of West Asia and North Africa (Ferrera et al., 1993).Heat stress is an important constraint to wheat productivity affecting different growth stages specially anthesis and grain filling.It has already been established that heat stress can be a significant factor in reducing the yield and quality of wheat (Stone and Nicolas 1995;Aziz et al., 2009).Grain yield was negatively related to the thermal time accumulated above the base temperature of 31Cْ (Ferris et al., 1998;Mian et al., 2007).High temperature above 32Cْ has been reported reducing grain yield and grain weight (Bluementhal et al., 1995, Gibson and Paulsen, 1999, Wardlaw et al., 2002).Therefore, in Qatar environment there is a dire need to develop genotypes that are either tolerant to terminal heat stress or that mature early without yield losses and thus escape the stress.CIMMYT Genebank contains a large number of wheat entries which collected from different country, these genotypes distributed and tested under hot environments like Qatar.So, this research achieved through a scientific cooperation program between the Department of Agriculture Affaire in Qatar and CIMMYT (Table 1) to improve and develop some new varieties of wheat under local conditions (high temperature with full irrigation) in Qatar.
The major goal of this work to study some Agronomic and yieldcharacteristics, then selection some promise genotypes which had a high seed yield under high temperature.

Materials and Methods
Ten genotypes of wheat G1,G2,G5,G8,G11,G12,G16,G17,G19,G20 and local check Doha -88 were separately sown in a randomized complete block design (RCBD) ).Hand weeding and pesticide application were done after seedlings emergence.Irrigation water was applied according to the recommended plant requirements.All other agronomical practices were adopted.When maturity was achieved, the genotypes were harvested per each plot and data were recorded to plant height (cm), days to heading, seed yield (kg/ha), length of spike (cm) and days to maturity (days from agriculture to maturity).Analysis of variance (ANOVA), Coefficient of variability (CV%), Correlation coefficient (r ), Standard Error (SE ±) and Dunnett test were performed using SPSS 15 software.

Result and Discussion
Mean of plant height was (77.93) cm, day to heading (88.69), day to maturity (146.3),length of spike (11.04) cm, seed yield (4375) kg / ha for genotypes (table 2).Analysis of variance (ANOVA) showed that differences between genotypes were significant for all studied characteristics (P < 0.01) except seed yield (P > 0.05).(table 3).The genotype 5 had the highest seed yield (4711) kg / ha, followed genotype 2 (4649) kg / ha, then genotype 20 (4640) kg / ha while the seed yield for local check was (2500) kg / ha (table 2).In other hand, Dunnett test for seed yield showed a high significant (P < 0.01) between the genotypes and local check (table 4).The correlation analysis revealed that special attention should be given to the importance of days to heading, The selection to maturity thinkable by selection to heading because the correlation was a significant strong positive correlation (r = 0.75*) between days to heading and days to maturity (table 5).Our results are in accordance with (May and Van Sanford, 1992;Joshi et al., 2007) who reported positive correlation between days to heading and days to maturity.

Conclusion
The result suggests to selection the G2, G5, G8 and G 20 that showed maximum seed yield under local conditions in Qatar.This study revealed that these genotypes can be utilized in breeding programs for development of wheat varieties having heat tolerance at terminal growth stage.
Department of Agricultural Research (Rawdat AL Faras Station) in Qatar environment (high temperature: Table*).Seeds were sown in 15 rows of 5 m length with spacing 25 cm between rows on November of 2007/ 2008 2009 / 2008 -.Plots were fertilized with super phosphate (P2O5: 46% P) and Urea (46%N

Table 4 .
Dunnett test for seed yield kg / ha genotypes of wheat compared to local Check (Doha-88) * significant at 0.01 level, *significant at 0.05 level, ns: not significant. *