EVALUATION OF SOME MAIZE-TEOSINTE HYBRIDS AND THEIR PARENTS UNDER WATER STRESS CONDITIONS

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