Emre Ilker

Evaluation of genotype x environment interactions in maize hybrids using GGE biplot analysis

Seventeen hybrid maize genotypes were evaluated at four different locations in 2005 and 2006 cropping seasons under irrigated conditions in Turkey. The analysis of variance showed that mean squares of environments (E), genotypes (G) and GE interactions (GEI) were highly significant and accounted for 74, 7 and 19 % of treatment combination sum squares, respectively. To determine the effects of GEI on grain yield, the data were subjected to the GGE biplot analysis. Maize hybrid G16 can be proposed as reliably growing in test locations for high grain yield. Also, only the Yenisehir location could be best representative of overall, locations for deciding about which experimental hybrids can be recommended for grain yield in this study. Consequently, using of grain yield per plant instead of grain yield per plot in hybrid maize breeding programs could be preferred by private companies due to some advantages.

Identification of resistance to Eurygaster integriceps Put. on some bread wheat genotypes

Sunn pest ( Eurygaster integriceps Put.) is one of the most important pests of wheat in Eastern Europe including Turkey, West and Cen-tral Asia. Its damage on leaves, stems, spikes and grains reduce the baking quality of flour made from damaged grains. In this study, some wheat genotypes from Turkey and ICARDA were evaluated for the pest resistance. The genotypes were planted in a randomized block design using hill plots in nylon mesh screening cages in wheat growing season of 2011-2012 and 2012-2013. Sunn pest population was collected from Canakkale province, where the pest was intensely found in recent years. The plants of each hill plots were infested with one male and one female Sunn pest adults. The results with 12.5% sucking damage showed that the genotypes from ICARDA had higher resistance than the landraces from Turkey to Sunn pest. Especially, the genotypes IC3 and IC4 from ICARDA and TR7 from Turkey with respect to their SED and DSED values were found the most promising genotypes resistant to Sunn pest for future breeding programs.

Ege Bölgesinde İkinci Ürün Mısırda Zararlı Zyginidia pullula (Boherman, 1845) Hemiptera: Cicadellidae)’nın Neden Olduğu Ürün Kaybı ve Ekonomik Zarar Eşiği Üzerinde Araştırmalar

Bu c alisma, ikinci urun misirin onemli zararlilarindan Zyginidia pullula (Boherman, 1845) (Hemiptera: Cicadellidae)’nin misir bitkisinde Ekonomik Zarar Esiginin (EZE) belirlenmesi amaciyla yurutulmustur. Calismalar 2011-2013 yillarinda Bornova Zirai Mucadele Arastirma Enstitusu laboratuvarlari ile Ege Universitesi Ziraat Fakultesi’ne ait Bornova’daki deneme alanlarina kurulan kafeslerde gerceklestirilmistir. Arazi calismalari ise 2011-2014 yillari arasinda Aydin (Merkez, Cine, Kocarli, Soke), Izmir (Bergama, Menemen) ve Manisa (Merkez, Akhisar, Salihli, Saruhanli) illerinde 2-4 yaprak asamasindaki ikinci urun misir alanlarinda yurutulmustur. Kafeslere tesaduf bloklari deneme desenine gore ekilmis misir bitkilerine bitki basina 10, 30 ve 100 adet olacak sekilde kitle uretimi yapilan Z. pullula erginleri salinarak denemeler kurulmustur. Haftalik olarak zararli sayimi, zarar belirtileri degerlendirilmis ve elde edilen tane verim degerlerinin ortalamalarina regresyon analizi uygulanmistir. Kafes calismalari sonucunda zararlinin EZE degeri bitki basina 13 birey olarak saptanmistir. Sayim sonuclarina gore Aydin iline bagli Cine ve Kocarli ilcelerinde, Izmir iline bagli Bergama ve Menemen ilceleri ile Manisa iline bagli Saruhanli ilcelerinde misir tarlalarinda zararlinin populasyonunun EZE degerini astigi saptanmistir. Bu sonuclara bagli olarak zararlinin misir uretim alanlarinda epidemi yapma potansiyeli oldugu saptanmistir. Ayrica calisma ile kanyas gibi yabani Graminae turlerinin ara konukculuk yaparak zararlinin yogunlugunun artmasina neden oldugu gozlenmistir.

COMPARISON OF MEAN YIELD COMPONENTS AND FIBER QUALITY PARAMETERS OF ADVANCED BULK GENERATIONS IN F2, F3 AND F4 INTERSPECIFIC AND INTRASPECIFIC COTTON POPULATIONS

The performance of interspecific and intraspecific cotton hybrid populations were compared to investigate the correlation among F2, F3 and F4 bulk generations in terms of yield, lint percentage, and fiber quality during 2009 to 2011. In addition to that, this research investigated the effect of combining abilities on hybrid performance at further generations. For this purpose, nine interspecific and six intraspecific hybrids with eight parents were evaluated under west part of Turkey (Aegean region) environmental conditions. With the generation progresses, the highest drop in fiber length and fiber strength was detected in interspecific duo to the inbreeding depression and genetic breakdown in advanced populations. Based on 15 tested hybrids, the observed mean yield and fiber quality in the F2 does not adequately predict the performance of hybrids in the F4 generation. Thus, selection of individual plants should be delayed until the F4 generation especially for interspecific hybrids, but individual plants would be selected at early generation in intraspecific hybrid populations. In the study it was found that a higher general combining ability (GCA) does not necessarily confer a higher specific combining ability (SCA) and that the GCA and SCA were independent of one another, and that in F4 high yielded hybrid population was obtained from cross which at least one parent of hybrid has maximum positive GCA effects. These results show that instead of use only one criteria, F2 performance for intraspecific hybrids and F3 performance for interspecific hybrids, low heterosis and inbreeding depression, combining ability of parents could be used together to determine the most promising hybrid populations to be used as a source for further selection.