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Cell membrane stability (CMS) technique was used to screen for drought tolerance, salt tolerant accessions of three Aegilops species, Ae. tauschii, Ae. cylindrica, Ae. geniculata and two hexaploid wheat (Tricitum aestivum L.) cultivars comprising salt tolerant LU-26 and drought tolerant Chakwal-86. The objectives were to see how valid it is for a salt tolerant plant to be drought tolerant as well and to identify the character(s) that may contribute to drought tolerance. Three moisture levels equal to 100, 50 and 25% saturation capacity of the soil were used for plant cultivation. Injury percentage (IP) based on in-vitro desiccation induced by polyethylene glycol (PEG) in leaf tissue was measured through the conductivity of the electrolyte leakage. Injury percentage decreased in all the test material with decrease in soil moisture contents. Ae. cylindrica exhibited minimum injury at 100% soil moisture level followed by Ae. tauschii and Ae. geniculata while drought tolerant wheat cultivars exhibited the maximum. The wheat cultivar Chakwal-86 has been developed for dry areas, with low soil moisture levels, and high water potential enhances the injury percentage. Aegilops cylindrica is a salt tolerant species and can thus tolerate water deficit conditions created due to low osmotic potential. Potassium appeared to play an important role in drought tolerance which was evident from high K+ contents and low K+ leakage from Aegilops cylindrica and drought tolerant wheat cultivar Chakwal-86. It was inferred from the study that salt tolerant species might prove drought tolerant in the areas where water deficit prevails due to the ability to create low intracellular osmotic potentials.

S. 1987. Production and cytogenetic analysis of hybrids between Triticum aestivum and some caespitose Agropyron species. Genome, 29: 537-553. Intergeneric hybrids between Triticum aestivum L. cultivars and 12 traditional Agropyron species were produced in variable frequencies, lowest being 0.35% for A. stipaefolium to a high of 41.98% for A. varnense. The crossing success of T. aestivum cultivars ranged from 'Chinese Spring' > 'Pavon-76' = 'Nacozari-75' > 'Fielder' = 'Fremont' > 'Glennson-81'. All FI hybrids were somatically stable. The new combinations were with A. curvifolium (Thinopyrum curvifolium), A. rechingeri (T. sartorii = rechingeri) , A. scythicum (T. scythicum), and A. stipaefolium (Pseudoroegeneria stipaefolia). All hybrids were perennial and possessed a modified phenotype that was intermediate between the parents involved in the hybrid combinations with major variation in spike morphology (elongated spikes with lax internodes). High-pairing hybrids, presumably owing to suppression of the Ph locus were of T. aestivum -A. scythicum (15.3 1 I + 2.25 I1 rings + 6.92 I1 rods + 0.32 111) and T. aestivum -A. stipaefolium (10.6 I + 7.08 I1 rings + 4.41 I1 rods + 0.54 111). In the other combinations, the pairing was either low or high, and if high, pairing was attributed to autosyndetic association of the alien genome chromosomes. Based on the meiotic pairing data, alien species that were segmental allotetraploids or partial autopolyploids, or segmental allohexaploids or autoallohexaploids, may be advantageous in developing backcross derivatives with synthetic genomes. Production of fertile amphiploids was restricted to T. aestivum -A. rechingeri. ., et FAROOQ, S. 1987. Production and cytogenetic analysis of hybrids between Triticum aestivum and some caespitose Agropyron species. Genome, 29 : 537-553. Des hybrides intergknkriques entre des cultivars de Triticum aestivum L. et 12 especes communes d'Agropyron ont kt6 produits en frkquences variables, depuis les plus basses avec 0,35% pour A. stipaefolium vers les plus hautes avec 41,98% pour A. varnense. Le succes des croisements des cultivars de T. aestivum a Cvoluk comme suit: 'Chinese Spring' > 'Pavon 76' = 'Nacozari 75' > 'Fielder' = 'Fremont' > 'Glenson 81 '. Tous les hybrides F, ont kt6 stables sur le plan somatique. De nouvelles combinaisons ont kt6 faites avec A. curvifolium (Thinopyrum curvifolium), A. rechingeri (T. sartorii = rechingeri), A. scythicum (T. scyticum) et A. stipaefolium (Pseudoroegeneria stipaefolia). Tous les hybrides se sont avkrks vivaces et posskdaient un phknotype intermkdiaire entre les parents impliquks dans les combinaisons hybrides, mais avec une variation majeure dans la morphologie de l'kpi, soit des kpis allongks avec des entrenoeuds inkgaux. Les hybrides dont les appariements furent klevks, prksumkment en raison de la suppression du locus Ph, ont kt6 ceux de T. aestivum -A. scythicum (1 5,3 1 I + 2,25 I1 (en anneaux) + 6,92 11 (en bitonnets + 0,32) et de T. aestivum -A. stipaefolium (10,6 I + 7,08 I1 (en anneaux) + 4,41 I...

The salt tolerance potential of various Aegilops species of different genome combinations viz., Aegilops squarrosa, Ae. cylindrica, Ae. ovata, Ae. triuncialis, Ae. variabilis, Ae. bicornis, Ae. longissima, Ae. umbellulata, and Ae. sharonensis was tested to identify the high salt-tolerant genotype(s). Screening was done in cement tanks filled with gravel and Hoagland nutrient solution. Salinity was created by mixing Na2SO4, CaC12, MgC12 and NaCI in the ratio of 10:5:1:4 and induced by a stepwise increase in electrical conductivity (EC). In response to salinity, significant inter-and intraspecific differences were observed in plant height, number of tillers and number of leaves. Inter-and intragenomic variations for cation uptake were also significant. Species with DD and CD genome were found to be highly tolerant. Possible factors responsible for these observations have been discussed.

Intergeneric hybrids between Triticum aestivum L. and conventional rhizomatous Agropyron species were produced in variable frequencies. They were recovered in high percentage frequencies for T. aestivum cultivars with A. acutum (14.6%), A. intermedium (48.0%), A. pulcherrimum (53.3%), and A. trichophorum (46.6%). The crossability percentages with the highly crossable cultivar 'Chinese Spring' for these Agropyron species accessions were 33.12%, 65.0%, 53.3%, and 65.4%, respectively. Autosyndetic associations of two of their three genomes gave mean meiotic chromosome association data of 17.0 I (univalents) +1.53 II (ring bivalents) + 7.04 II (rod bivalents) +1.43 III (trivalents) +0.05 IV (quadrivalents) +0.01 IV (pentavalents) for A. acutum and of 21.8 I + 1.56 II (rings) +7.22 II (rods) +0.84 III + 0.04 IV for A. intermedium. Chromosome pairing at metaphase I was comparatively lower for A. pulcherrimum (34.4 I + 0.2 II (rings) +3.4 II (rods) +0.14 III) and A. trichophorum (36.7 I + 0.35 II (rings) +2.26 II (rods) + 0.04 III) hybrids with T. aestivum. Hybrids of wheat with A. campestre and A. repens were obtained in low frequency. Direct crossing did not permit T. aestivum/ A. desertorum hybridization. However, by utilizing the 2n=10x=70 A. repens/A. desertorum amphiploid as the pollen source, hybridization with T. aestivum did indeed occur. Aneuploidy was prevalent in this hybrid combination while all other hybrid combinations were apparently normal.