Tbe distribution of important plant-parasitic and free-living nematodes in tbe cereal production areas of tbe Central Anatolian Plateau (CAP) of Turkey was investigated witb systematic surveys. Two important plant-parasitic nematode groups were found widely distributed; cereal-cyst nematodes (78.3%) and root-lesion nematodes (42.6%). Cereal cyst nematodes (CCN) were identified as Heterodera filipjevi in 18 provinces. Heterodera latipons was found in only one province. Pratylenchus thornei and P. neglectus were tbe most widely distributed species of root-lesion nematodes. Otber frequently recorded plant-parasitic nematodes belonged to tbe genera Geocenamus (52.4%), Pratylenchoides (35.6%), Helicotyienchus (29.7%) and Paratylenchus (19.2%). Konya on tbe soutbern CAP bad a significantly bigb incidence of P. neglectus as well as free-living nematodes. Tbe incidence of CCN was greatest in areas of sandy soils on tbe CAP, witb densities of up to 95 cysts (100 g soil)"'. Population densities of Geocenamus, Pratylenchus and Pratylenchoides were bigb in some locations. Soil pbysicocbemical properties were investigated for tbeir relationship to nematode distribution. Tbere was a sligbt positive correlation of P. thornei and clay content; conversely, there was a significant negative correlation of P. negiectus witb clay and a positive correlation witb sand. Electrical conductivity (EC) was positively correlated witb P. neglectus. Nematodes in tbe genera Heiicotylenchus, Paratylenchus, Trophurus and Tylenchorhynchus were only recorded at low population densities in tbe sampled area. By contrast, nematodes in tbe genera Aphelenchus, Apheienchoides, Dityienchus, Dorylaimus, Tylenchus and bacterivorous genera bad relatively bigb populations. Total free-living nematodes were positively correlated witb EC and zinc (Zn) concentration. Tbe Zn content of soil was generally at a level deficient for plant growtb.

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Expressed sequenced tags containing simple sequence repeats (EST-SSRs) were used to identify molecular markers associated with yellow rust resistance in wheat (Triticum aestivum L.). A cross between yellow rust resistant (PI178383) and susceptible (Harmankaya99) wheat genotypes was performed and respective DNA pools from the resistant and susceptible F 2 seedlings were constructed. 78 EST-SSR primers were used for bulked segregant analysis and one EST-SSR marker (Pk54), identified as 200 bp fragment, was present in the resistant parent and resistant F 2 hybrids but not in the susceptible ones. 108 wheat genotypes differing in yellow rust resistance were screened with Pk54 and 68 % of the wheat genotypes, known to be yellow rust resistant, had the Pk54 marker, further suggesting that the presence of this marker correlates with yellow rust resistance.

Bulk segregant analysis (BSA) was used to identify molecular markers associated with yellow rust disease resistance in wheat (Triticum aestivum L.). DNAs isolated from the selected yellow rust tolerant and susceptible F 2 individuals derived from a cross between yellow rust resistant and susceptible wheat genotypes were used to established a "tolerant" and a "susceptible" DNA pool. The BSA was then performed on these DNA pools using 230 markers that were previously mapped onto the individual wheat chromosomes. One of the SSR markers (Xgwm382) located on chromosome group 2 (A, B, D genomes) was present in the resistant parent and the resistant bulk but not in the susceptible parent and the susceptible bulk, suggesting that this marker is linked to a yellow rust resistance gene. The presence of Xgwm382 was also tested in 108 additional wheat genotypes differing in yellow rust resistance. This analysis showed that 81% of the wheat genotypes known to be yellow rust resistant had the Xgwm382 marker, further suggesting that the presence of this marker correlates with yellow rust resistance in diverse wheat germplasm. Therefore, Xgwm382 could be useful for marker assisted selection of yellow rust resistances genotypes in wheat breeding programs.