الفهرس 
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Abstract
”The genetic materials used in this investigation were three teosinte genotype and two of maize (zea mays L.) to obtain six using factorial mating design in season 2018 at the farm of Genetics Department, faculty of Agricultural Mansoura University, Egypt. During the 2019 season, possible selfing crossing were made for F1 hybrid to obtain the F2 second generation but the hybridization succeeded in only three F1 hybrids which are (P1 x P4), (P2 x P3) and (P2 x P4) for molecular analysis and gene expression. During seasons 2019, 2020 all 11 genotypes (two female, three male parents and their six F1 hybrids) were evaluated in a field trial at Randomized Complete Blocks Design with three replications. Data were recorded on the following traits: number of tillers per plant, plant height per plant, number of leaves per plant, fifth leaf area, stem diameter, Total chlorophyll, green fodder yield per plant in grams, dry fodder yield per plant in grams, tasseling date, silking date, crude fiber content, crude protein content, crude lipid, carbohydrates and total digestible nutrients. The results obtained from this study for combined data :The results revealed that the mean squares due to genotypes and their partitions to parents, crosses and their interactions with years; G x Y, P x Y and C x Y were highly significant for all the studied traits except stem diameter for G x Y and P x Y and silking date for C x Y. Mean squares due to males , female and interaction between them (F x M) and their interactions with Y were significant and highly significant for all the studied traits except males for plant height and total chlorophyll, F x Y for plant height and total chlorophyll, M x Y for total chlorophyll and silking date, F x Y for number of tillers, total chlorophyll, stem diameter and silking date and F x M x Y for tasseling and silking date. The results indicated that the magnitude of the mean squares of genotypes, parents, crosses were highly significant for all studies traits except crosses for crude lipid. Moreover, the magnitudes of the mean squares of females were highly significant for all traits except for crude lipid and carbohydrates. The mean squares of males were highly significant for all traits except crude protein and total digestible nutrients and the mean squares of F x M interaction were highly significant for crude protein and total digestible nutrients. The mean showed that there were differences between parents and crosses, also between females and males in all studied traits. There were no one of the parental genotypes was significantly superior in all studied traits. For tasseling date and silking date, the P5 had the best desirable means for these traits with mean values of 154.33 and 160.33 day, respectively. According to females, the P2 has the best desirable means for all traits except for total chlorophyll and dry fodder yield. For male parents, the P3 exhibited the highest mean values for plant height (253.17 cm.), total leaf chlorophyll (22.49) and green fodder yield (1973.25 g). While, the P4 exhibited the highest means for number of leaves (145.65 L.), fifth leaf area (447.68 cm2.) and stem diameter (1.68 cm.). Crosses were found to be higher than their parents in most studied traits. The mean performance of the six crosses cleared that, the cross P2 x P5 had the best desirable for number of tillers, plant height, number of leaves, stem diameter and green fodder yield with mean values 5.00 t., 387.50 cm., 135.67 L., 2.28 cm. and 3707.22 g., respectively. The cross P1 x P5 had the best desirable means for Fifth leaf area (762.03 cm2.), tasseling date (91.17 day) and silking date (113.00). While, the hybrid P2 x P3 had the greatest mean values for dry fodder yield (505.25 g.). The results showed that the P2 was the best and had the highest mean values for crude protein (6.62%) and total digestible nutrients (55.23). While, the P5 was the best and had the highest mean values for crude fiber (46.47%). Also, the P1 showed the highest grand mean values for crude lipid (3.04%) and carbohydrates (53.21%). Concerning, the mean values of hybrids, the results indicated that the hybrid P1 x P4 was the best and had the highest grand mean for crude protein (7.75%), crude lipid of (2.13%) and total digestible nutrients (55.66). In addition, the hybrid P1 x P5 exhibited the highest mean value for carbohydrates (44.83%). The hybrid P2 x P3 was the highest mean value for crude fibers (41.99%). The results showed that most of studied crosses exhibited different heterotic values to mid-parent in all traits. In the case of tasseling date and silking date the negative value is desirable as a heterotic effect forward early maturity. Therefore, it could be considered the F1 hybrid P1 x P5 was the best combination for tasseling date and silking date with negative heterotic values -17.1 and -1.2 %. In addition, the results showed that all crosses had positive and highly significant heterosis for number of tillers, plant height and stem diameter. The cross P2 x P5 exhibited positive and highly significant heterosis for number of tillers (81.2 %), plant height (61.6 %), number of leaves (90.7 %), total chlorophyll (9.3 %). According to the estimated amounts of heterosis relative to better parents, The results showed that there was positive and highly significant heterosis for plant height in all crosses and The values ranged from 41.3 P2 x P3 to 55.2 for P1 x P3. For, number of tillers, number of leaves and total chlorophyll the magnitude of heterosis were negative and highly significant for all crosses except P2 x P5 in number of tillers (10.7) and number of leaves (7.0). In the case of tasseling date and silking date, the cross P1 x P5 is considered the best combination. The estimated amounts of heterosis relative to mid-parents (M.P %) and better parents (B.P %) for the forage quality traits, The results were showed that there was positive and highly significant heterosis relative for crude protein, crude fibers except few cases. The cross P1 x P4 exhibited positive and highly significant for crude proteins and crude fibers relative to mid-parents (46.2 and 15.4 %) and better parents (20.5 and 48.6 %). Also, it had positive and highly significant relative to mid-parent (M.P %) for total digestible nutrients (4.1%). On the other hand, there were negative and highly significant heterosis relative to mid-parent estimates and better parent for crude lipid and carbohydrates in most crosses. The results revealed that the P2 had positive and highly significant GCA effects for number of tillers, number of leaves and green fodder yield. While, P1 have negative and highly significant GCA effects for tasseling date toward earliness. For males, the P3 was the best general combiner which exhibited positive largest magnitude values for number of leaves (6.32), green fodder yield (159.85) and dry fodder yield per plant (32.81). While, the P5 was the best general combiner which exhibited positive largest magnitudes for number of tillers (0.48), fifth leaf area (8.56 cm2) and total chlorophyll (0.89). General combining ability effects for all forage quality traits data showed that the P1 had positively and significant GCA effects for crude proteins and total digestible nutrients. For males, the results indicated that the male parent P4 had the highest positive GCA effects for crude lipids (0.29%) and crude fiber (0.96). The male parent P5 had the highest positive GCA effects for the carbohydrates (1.37%). Specific combining ability effects (SCA) of each cross for agronomic traits, the results showed that the cross P1 x P3 had positively (desirable) and significant or highly significant for plant height and total chlorophyll. Highly significant and desirable positive values SCA were found in the cross P2 x P4 for fifth the leaf area. The best desirable estimates of SCA effects for number of tillers, number of leaves and green fodder yield were obtained by the cross P2 x P5. The most height crosses that showed high SCA effects had one or two good combiner parent. The results showed that only three out of six crosses in all forage quality traits exhibited positive specific combining ability effects, these crosses, P2 × P5 for crude protein (0.55), cross P1 × P4 for crude fiber (0.60) and the hybrid P2 × P4 for carbohydrates (0.62). The hybrid P2 × P5 had the highest positive SCA effects for total digestible nutrients (0.57). The results indicated that females was higher than those males and interaction between females × males for the number of tillers, number of leaves, fifth leaf area, stem diameter, crude protein, crude fiber and total digestible nutrients. While, males were higher than those females and interaction between females × males for dry fodder yield, tasseling date, silking date, carbohydrates and crude lipid. Moreover, the females × males interaction were higher than those females and males in their relative contributions for plant height total chlorophyll and green fodder yield. Genetic parameters which included additive and dominance variance in addition to heritability in broad (h2b%) and in narrow (h2n%) senses for all studied agronomic traits showed that the magnitudes of non-additive genetic variance were larger than their corresponding estimates of additive genetic variance for all the studied traits except fifth leaf area, dry fodder yield per plant, crude fibre and carbohydrates . The results illustrated that high heritability value in broad sense (H2b %) were detected for all agronomic traits and These values ranged from for stem diameter 11.01 to 97.23 % for fifth leaf area, respectively. for the forage quality traits, These values ranged from(5.13) for crude lipid to(45.16%) for crude protein.
Molecular assessment : During the 2020 season, some vegetative traits were evaluated for the second generation (F2) population resulting from only 3 hybrids of the first generation (F1) (P1xP4, P2xP3 and P2xP4), parents and F1, and through the evaluation, the highest and lowest plants in these traits were selected from all populations With a focus on described tillering ability. from these selected plants, samples were taken from green leaves before flowering to isolate DNA and RNA for use in SCoTs and SSRs techniques using a number of primers for each technique. The most important results obtained were as follows : Seven primers used in the SSR technique succeeded in producing many different DNA sequences, where the SSR technique showed a molecular diversity (polymorphism%) ranging from 83 to 100% and the average value of the resolving power Rp ranged from 1.58 to 3.16. In addition, the genotypes revealed 12 unique markers and eight positive molecular markers associated with tillering ability in maize. The results revealed the efficiency of SSR as markers assisted selection for tillering ability in maize. Eight primers used in the SCoT technique succeeded in producing many different DNA sequences, where the SCoT technique showed molecular diversity (polymorphism%) ranging from 67 to 100% and the average value of the resolving power Rp ranged from 0.421 to 4.421. In addition, the genotypes showed 18 unique markers and eight positive molecular markers associated with tillering ability in maize.The comparison between the SCoT technique and the SSR technique showed that the molecular diversity (polymorphism%) for both was close and there were no clear differences in the mean of the resolving power (Rp) as well as the diversity index for each. The experiment indicates the reliability of SSR markers which would be a solid and beneficial resource for future genetic and genomic studies, such as genetic mapping, comparative genomic analysis, genetic diversity and molecular marker-assisted farming for selection of promising genotypes.