Breeding effort on increasing grain yield of wheat will incessantly continue because it is indispensable product. Obtaining the genetic information such as genotypic variation, heritability, genetic advance is the fundamental components of these studies. It is important that the maternal effects are put forward throughout successive generations because of genotypic and/or environmental effects as far as variation. This research was conducted to investigate changes of reciprocal crosses throughout successive generations and determine selection criteria for high yield in early generations. For this purpose, the populations were analyzed with regard to genotypic and phenotypic variation coefficient, heritability, genetic advance and Unweighted Pair Group Method (UPGMA) cluster analysis for real crosses, reciprocals and all genotypes separately. According to the results, heritability and genetic advance values of traits investigated were highly varied throughout successive generations among real crosses, reciprocals and all genotypes. This finding indicated that non-additive gen effects or epitasis played a role in inheritance of all traits. Dissimilarity of crosses than their reciprocals indicated variation of successive generation. Dissimilarity value of each parent differed as generation progresses according to combination created. This condition suggested that there were maternal effects in this population throughout successive generations. Grain weight per spike, spike harvest index and spike density had high direct and indirect effects on the grain yield at all of three generations, it proved that these traits can be a selection criterion for early generations.

The present research was conducted to evaluate the M1, M2, M3 and M4 bread wheat (Triticum aestivum L.) mutant populations for yield and yield related traits during 2010-11, 2011-12, 2012-13 and 2013-14 at Tekirdağ ecological conditions. Three wheat genotypes were treated with different levels of gamma rays (100 Gy, 200 Gy, 300 Gy, 400 Gy, 500 Gy and Control). The mutated plants were evaluated along with parental lines (control) for grain yield (GY) and its contributing traits such as plant height (PH), spike length (SL), the number of spikelets per spike (NSPS), the number of grains per spike (NGPS), grain weight per spike (GWPS), harvest index (HI) and thousand grain weight (TGW) under field conditions. The results obtained from the present study showed that the genotypes significantly and variably differed in their response for various traits at different gamma rays doses. The traits such as PH, TGW and grain yield (GY) showed generally reduction with higher gamma irradiation doses as compared to low doses, while mutagenic treatments shifted the mean values mostly towards the negative direction in the other yield components. But, the negative or positive shifts were not unidirectional or equally effective for all the traits. These findings suggested that the variability could be induced through the use of gamma irradiations in bread wheat. Some of the traits showed improvement due to the induced mutations could be used in future wheat breeding programs. The differences in mean values and the nature of variability observed in M2 indicated a possible preference of selection in M3 generation. Öz Bu araştırma, M1, M2, M3 ve M4 ekmeklik buğday mutant populasyonlarını verim ve verime etkili özellikler bakımından değerlendirmek için 2010-11, 2011-12, 2012-13 ve 2013-14 yıllarında Tekirdağ ekolojik koşullarında yürütülmüştür. Üç buğday genotipine farklı dozlarda gamma ışını (Kontrol, 100 Gy, 200 Gy, 300 Gy, 400 Gy ve 500 Gy) uygulanmıştır. Mutant bitkiler anaçları (kontrol) ile birlikte tane verimi (TV) ve bitki boyu (BB), başak uzunluğu (BAU), başakta başakçık sayısı (BABS), başakta tane sayısı (BATS), başakta tane ağırlığı (BATA), hasat indeksi (HI) ve bin tane ağırlığı (BTA) gibi verime etkili özellikler bakımından tarla koşullarında değerlendirilmiştir. Çalışmadan elde edilen sonuçlar, genotiplerin çeşitli özellikler için farklı gamma ışını dozlarına yanıtlarının önemli ve değişken bir şekilde farklı olduğunu göstermiştir. Bitki boyu, bin tane ağırlığı ve tane verimi gibi özellikler düşük dozlarla karşılaştırıldığında yüksek gamma ışını dozlarında genellikle azalma gösterirken, mutagen uygulamaları diğer verim unsurlarında ortalama değerleri çoğunlukla negatif yöne doğru kaydırmıştır. Ancak, negatif ya da pozitif yöndeki kaymalar tüm özellikler için tek yönde ya da eşit derecede etkili olmamıştır. Bu bulgular, buğdayda gamma ışınları kullanılarak varyabilitenin oluşturulabileceğini göstermiştir. Oluşturulan mutasyonlara bağlı olarak gelişme gösteren bazı özellikler gelecekte buğday ıslahı çalışmalarında kullanılab...

This study was carried out to investigate the effects of sowing time, cultivar and seed fungicide applications on root and crown rot disease and grain yield of bread wheat with different earliness traits (Esperia, mid-early; Genesi, late and Anapo, early) in the experiment station of the Department of Field Crops, Faculty of Agriculture, Tekirdağ Namık Kemal University. Four different fungicides pre-treatments (prothioconazole + tebuconazole, carboxin + thiram, prochloraz + tiriticonazole and control) were applied to the seeds of the varieties before sowing in three different times, on 1 November, 15 November and 30 November 2016. The experiment was designed as a split-splitplot with 3 replications. The results of the variance analysis showed that the effect of applying different seed fungicide pre-treatment root and crown rot of bread wheat varieties was statistically significant. While the lowest root and crown rot with 2.67 % was obtained from the second sowing time, the highest root and crown rot was determined with a value of 3.64% for the earliest sowing on 01 November. Among the four different fungicide pre-treatments, the highest root and crown rot (5.59%) was obtained in the control application, while the lowest root and crown rot was obtained in prothioconazole + tebuconazole, carboxin + thiram and prochloraz + triticonazole, with 1.96%, 2.10% and 2.19% root and crown rot, respectively. These data indicate that early sowing may increase root and crown rot severity.