الفهرس 
Combining ability.Only 14 pages are availabe for public view
 |  | from | 110 |  |  |
| | | from | 110 | | |
Abstract
The aim of this study was to assess the variations among set a half diallel cross using eight varieties for drought characters, estimating combining ability and genetic components.For this objective, the investigation was carried out at the Experimental Farm of Etay Elbaroud,Agricultural Researches Station, during the two seasons of 2015/16and 2016/17,Eight diverse wheat varieties(Triticum aestivum, L.)and 28 F1’s were planted in two experiments. The first experiment was normally irrigated 4 irrigations (Non stress) and the second one was irrigated one time after planting irrigation (Stress).Parental cultivar Giza 17(P7) ranked the first one for straw yield per plant under stress condition, Giza 168 (P8) for No. of spikes per plant under normal irrigation as well as combined analysis and Gemmeiza
12 (P4) for spike length and for no. of grains per spike under both and across irrigation treatments and the combined analysis. The parental combination(P4 Gemmeiza12 x P8 Giza 168)gave the highest mean values for garin yield/plant in normal irrigation treatment, the cross(P3 Gemmeiza 11 x P4 Gemmeiza 12 )in drought environment and the cross(P6 Misr 1 x P7 Giza 171)under the combined data. General (GCA) and specific (SCA) combining ability mean squares were highly significant for all the studied traits in both environments as well as the combined analysis. Such results indicated that both types of combining ability are important in the inheritance of these traits. It could be concluded that the parent P7 (Giza 171) seemed to be the best general combiner for grain yield plant-1 and most of yield components as no. of grain spike-1 in both environments and the combined data, 1000 -grain weight and harvest index in the drought treatment and the combined data and grain yield in the normal irrigation. The crosses;(P6 Misr 1 x P7 Giza 171),(P1 Gemmeiza 7 x P8 Giza 168),(P4 Gemmeiza 12 x P7 Giza 171)an(P3 Gemmeiza 11 x P5 Sids 12)exhibited the highest significant and negative heterotic effects relative to mid and better parents under normal condition for days to heading, days to maturity, flag leaf angle and plant height. For 1000-grain weight, and grain yield per plant the highest significant and positive mid parent heterosis was recorded for the crosses (P4 Gemmeiza 12 x P8 Giza 168) in the combined analysis and( P6 Misr 1 x P7 Giza 171) under normal condition for harvest index.The best ŝij effects were detected for the crosses P6 (Misr1 )x P7 (Giza171), P7 x P8(Giza168) and P1 (Gemmeiza7)x P6(Misr 1)at both conditions and their combined data for
grain yield and some traits stadied.