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Abstract The aim of this research is to study the heterosis, combining ability and correlations for yield and its components beside heading date,plant height and tiHering ability in wheat. In (,.IS~· udy, sex parental genotypes from different origins were used as the following: 1. Giza 157 2. Pavon 3.City straws 4. Hatry 5. Floranae 6.Mario The above-mentioned genotypes were used in a diallel cross du ri ng 1989/J 990 and 1990/1991 seasons at the agricultural research station ,Moshtohor. Hybrid vigour were estimated as a percentage of Fl deviation in comparison to the better parent. General and specific combining ability were est imated according to ”Griffingll in addition to Phenotypic. Genotypic and environmental correlation coefficients. Results can summarized as the following :- 1. MeaDS: Pavon was the best genotype for heading date. and had the lowest number of tillers, spikelets number , grain number per spike and the total plant weight. On the other hand, Hatry was the latest one for the heading date and the 1ar&eStin plant beilht and had tbe lowest Dumber of 1000 kernel weight. Floranae had a aood titlering ability, and less spike length and less araiD yield per plant. City straws was tbe best one Cor1000 kernel wei&btand for the grain number per spike beside the grain yield per plant. Giza 157 was the best CorDumber of spikeIets per spike and to some extent in train number per spike and craiD)’ieId per plant. .61 ---_._------------- --- Mario was found to be the biggest for spike number per plant, spike length and the total plant weight. 2. Heterosis: Heterosis was appcar-d ;l’” ~orn(’cr(’lC:’:::i”n~.1’. range from ·1.13 % to 5.89 % for heading date and from tt.46 to 7.17 % for plant height and from 7.96 to 12.55 % for number of tillers per plant and from 5.19 to 16.48 % for spike number per plant and it showed negative heterosis in case of spike length. from 1.14 to 2.44 were observed for spikelets number per spike and from 8.08 to 16.42 % for the 1000- kernel weight per plant and from 5.30 to 29.23 % for grain yield per plant. 3. Cornbinine ability:- The best varieties for general combining ability were:- Pavon, Giza 157, City Straws and Mario for Flowering Date. Mario, Pavon, Giza 157 for Shorter for stem. Hatry, Floranae and City Straws for 1000- kernel weight. City Strawes, Giza 157 and Mario for the Yield weight per parent. All the studied characters showed highly significant specific combining ability either in Positive or in negative change. The correlation between hybrid vigour and Specific combining ability showed highly positive significant differences for all the studied characters which revealed the superior effect for gene action for hybrid vigour and specific combining ability. 4.Correlationi The correlation results revealed the following :- Flowering date showed siaoificanUy nea;ative genotypic. and phenotypic correlation with the plant yield, Spike length , Kernel Number. Number of spikelets per spike, lOGO- Kernel weight and the total plant weight. It revealed significantly positive genotypic and phenotypic correlation with spike number , Tillering ability 62 and plant height. Plant height revealed significantly negative genotypic and phenotypic correlation with yield t Spike length, kernel number, Splkelets number per spike, 1000- kernel weight ami the total plant weight. At the sametime, It showed positively significant and ;,.,enotypicand phenotypic correlation with spike length, tillering ability and Flowering date. Tillering ability character revealed that significantly negative genotypic abd phenotypic correlation with yield, Spike length, Kernel number, Spikeletes number and the plant weight and at the sametime , it showed Donsignificant negative genotypic and phenotypic correlation for 1000- kernel weight. It showed also significant positive genotypic and phenotypic correlation toward the flowering date and plant height. Number of spikes per plant revealed significant positive genotypic and phenotypic correlation with number of spikeletes and non- significant with yield It showed significantly positive genotypic and phenotypic correlation with number of tillering per plant, 1000 - kernel weight, total plant weight , flowering date and plant height and non - significant with the spike length. The Spike length character showed significantly negative genotypic and phenotypic correlation with tillering ability, Flowering date and plant height. It showed non - significant correlation with the number of spikes per plant. IT revealed also significantly posit ive genotypic and combining ability. |