الفهرس 
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Abstract
The study was carried out to evaluate some maize-teosinte hybrids under water stress conditions, seven parent genotypes i.e., maize (S.C. 130, S.C. 168, T.W.C. 321 and T.W.C. 352) as female and teosinte (Gemmeiza 3, Gemmeiza 4 and Sakha 1) were used as male. Genotypes were crossed using by line × tester mating design to produce 12 F1 crosses. Tested genotypes, i.e., seven parents (four maize and three teosinte) as well as their 12 F1 crosses were evaluated under three irrigation regimes i.e., irrigation every 12 (normal), every 18 (moderate) and every 24 days (stress regime). Mean performance and combining ability (general and specific). For tested genotypes (growth characters and forage production, physiological parameters, chemical composition in forage plants, grains yield and its components of maize as well as water use efficiency/ fad and drought tolerance indices. Results cleared that, analysis of variance was highly significant among the tested genotypes (parents and crosses) for most characters studied under the three irrigation regimes. The three teosinte parents were superior to the four maize parents in most growth characters and forage productivity under the three irrigation regimes. Moreover, teosinte parents Gemmeiza 3 (T1) and maize parent S.C. 130 (L1) produced the highest values of most characters as well as forage productivity. In addition, all 12 tested crosses had the highest values of most measured traits that were higher than that obtained by their parents (maize or teosinte). S.C. 130 x Gemmeiza 3 (L1 x T1) cross which gave the highest values under the three irrigation regimes. Exposing the tested seven parents (four maize and three teosinte) and their crosses to drought stress by increasing irrigation intervals from 12 to 18 and 24 days caused a gradual decrease in their most characters as well as fresh and dry forage yields/ fad. Maize genotype S.C. 130 (L1) and teosinte genotype Gemmeiza 3 (T1) exhibited highly significant (useful) GCA effect for most characters studied as well as fresh and dry forage yields/ fad generally in all tested irrigation regimes. Crosses (L1 x T1, L4 x T3) exhibited the highest significant positive desirable SCA effect for all studied as well as fresh and dry forage yields fad-1 (under the three irrigation regimes). GCA/SCA variance for all traits studied were less than unity under all irrigation treatments. The data showed generally that water use efficiency (WUE) of the three tested teosinte parents was superior to the four tested maize parents under the three irrigation regimes. The highest values of WUE for teosinte parents were obtained by Gemmeiza 4 (T2) genotype, while for the maize parents were obtained by SC130 (L1) genotype at the three irrigation regimes. All 12 F1 crosses (maize x teosinte) significantly surpassed their parents in WUE under three irrigation regimes. The highest values of WUE were obtained by crosses (L1x T1), (L2 x T1), (L4 x T3), (L3 x T3) and (L3 x T2) in descending order when they were irrigated every 24 days (stress regime). All tested teosinte parent genotypes are generally considered more tolerant to drought stress than all tested maize parent genotypes under moderate irrigation regime. Moreover, teosinte Gemmeiza 3 (T1) genotype was superior in the drought tolerant under stress irrigation regime. Crosses (L1 x T1), (L1 x T2), (L2 x T1), (L3 x T3) and (L4 x T3) exhibited the lowest values of drought tolerance indices (TOL, RYR % and DSI) when they were grown under the stress irrigation conditions, indicating that those crosses were found to be the best crosses (maize x teosinte) to drought tolerance in this study.