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Durum wheat, Triticum turgidum L. (2n= 4x=28, genome formula AABB) is inferior to bread wheat, T. aestivum L. (2n=6x=42, genome formula AABBDD), in the ability to exclude Na(+) under salt strees, in the ratio of the accumulated K(+) to Na(+) in the leaves under salt stress, and in tolerance of salt stress. Previous work showed that chromosome 4D has a major effect on Na(+) and K(+) accumulation in the leaves of bread wheat. The 4D chromosome was recombined with chromosome 4B in the genetic background of durum wheat. The recombinants showed that Na(+) exclusion and enhanced K(+)/Na(+) ratio in the shoots were controlled by a single locus, Kna1, in the long arm of chromosome 4D. The recombinant families were grown in the field under non-saline conditions and two levels of salinity to determine whether Kna1 confers salt tolerance. Under salt stress, the Kna1 families had higher K(+)/Na(+) ratios in the flag leaves and higher yields of grain and biomass than the Kna1 (-) families and the parental cultivars. Kna1 is, therefore, one of the factors responsible for the higher salt tolerance of bread wheat relative to durum wheat. The present work provides conceptual evidence that tolerance of salt stress can be transferred between species in the tribe Triticeae.

Phytic acid (myo‐inositol hexakisphosphate), the major storage form of P in seeds, is believed to have a negative impact on nutritional quality. Since breeding for low phytic acid has been proposed for several cereals and legumes, it is important to predict the effects of selection against phytic acid on other major grain components. Experiments were conducted to determine the quantitative relationship between grain phytic acid P, total P, and protein in two winter wheat (Triticum aestivum L.) populations, each consisting of F6 progeny of a double cross. Substantial variation in phytic acid P was observed, with the range in values equal to 30 and 48% of the respective population mean. Observed variation in phytic acid P was highly and positively correlated with variation in grain total P (r 0.93 and 0.96 in Populations 1 and 2, respectively), and with variation in grain protein (r = 0.65 and 0.87, respectively). The dose correlation of phytic acid P with both total P and protein indicates that selection against grain phytic acid would lead to undesirable reductions in both grain total P and protein.

A pot experiment was carried out at Nahshala Farm, about 50 km from Al-Ain, UAE, during the 1998\99 growing seasons, using six halophytes : Spartina sp., Distichlis palmeri, Paspalum vaginatum, Juncus roemerianus, Salicornia bigelovii and Batis maritima, under two levels of leaching fraction, 0n25 and 0n50 and three levels of irrigation salinity, 10, 20 and 40 g\l. The objectives of the experiment were twofold : (1) to find out the optimum and threshold of saline water irrigation to keep salinity level down as much as possible in the soil using the leaching fraction technique ; and (2) to study the response (growth and biomass production) of some halophytes to different levels of salinity. The experiment was conducted in triplicate with a split-plot design arranged in a randomized complete block. Results indicate that these halophyte species can be grown productively at a leaching fraction between 0n25 and 0n50 when salinity of the irrigation water is less than 20 g\l. At higher salinities, Salicornia bigelovii can grow and yield satisfactorily under these conditions, while the other species may require more frequent irrigation at higher leaching fractions. Some of these tested halophytes may be able to revegetate the salt-affected lands and be a potential source of forage in these harsh habitats. This study supports the idea of seawater agriculture by demonstrating the possibility of using some high salt-tolerant halophytes at relatively higher leaching fraction in order to maintain satisfactory yield production of such halophytes.

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