Estimation of Some Genetic Parameters for phenological, Morphological and productivity Traits in Two Bread Wheat Crosses

The experiment was grown in a Randomized Complete Blocks Design with three replications during two seasons. Generations means analysis method was used to study the genetic parameters for number of days to heading, number of days to maturity, plant height, number of spikes per plant, number of grains per spike and grain yield per plant of two bread wheat crosses Triticum aestivum L. (Gairwel7 x Douma4), (Azaz1 x Soued), Results have shown that both additive and dominance genetic effects were high significant in most evaluated traits, with predominance of the dominance genetic effects’ values. Also, epistatic genetic effects have contributed to inheritance of most studied traits. The signs of dominance and dominance x dominance were opposite in most examined traits indicating duplicate epistasis for all studied traits of the first cross and for number of days to maturity, plant height and number of grains per spike of the second cross, that indicates that the selection for these traits should be delayed after several generations. High phenotypic variations were composed of high genotypic variations and less of environmental variations, indicating the presence of high genetic variability for different traits and less influence of environment. Highly significant heterosis relative to mid and better parents in F1 was recorded for most characters, accompanied with inbreeding depression for all traits in F2. Narrow sense heritability and genetic advance were low in most cases due to the dominant of non-additive genetic action in controlling the genetic variation of the most studied traits.

Genetic Parameters of Some Quantitative Characters in Three Maize (Zea mays L.) Hybrids

Six population seeds of three yellow maize hybrids were formed at Agricultural Research Center, Homs, during 2008 and 2009 growing seasons. Their plants were evaluated in 2010. The present work aims to determine the genetic parameters in six populations (P1, P2, F1, F2, BC1, and BC2). Mean square results showed significant differences among mean values for all traits in all crosses. Significant heterosis values were positive and relative comparing to mid and better parent for most traits. The potence ratios exceeded (+1) in all traits and crosses except ear height, indicating thus over-dominance. In breeding, depression values were significant in most traits for Cross-1, while their values were non- significant in all traits for Cross-2 except plant height, and also in Cross-3 except plant height and grain yield per plant. In most traits epestasis or dominance gene action occupied the first rank in the genetic effects in order of importance to cross, with the exception of number of rows per ear, number of kernels per row and grain yield per plant where additive gene action occupied the first rank for Cross-2 and Cross-1 respectively. Therefore, it could be suggested that selection for most studied traits in the subsequent generations will be relatively more effective than in the early generations.

Genetic variance, heritability, correlation and path coefficient analysis in some Bread Wheat Crosses (Triticum aestivum L.)

The present investigation was conducted during 2010/2011 and 2011/2012 growing seasons at Karahta station for field crops research, General Commission for Scientific Agricultural Researches (G.C.S.A.R.), Syria. Forty five hybrids F1 produced using a half diallel cross among ten bread wheat (Triticum aestivum L.) genotypes, in 2010/2011 season, were evaluated during 2011/2012 season in order to study som of the genetic parameters for grain yield per plant, its components, some morphophysiological and quality traits to determine the basic criteria for selection.

Genetic behavior for some quantitative traits in a hybrid of durum wheat

This study was carried out at Karahta station, Department of Field Ccrops researches, General Commission for Scientific Agriculture Researches (GCSAR), Damascus Country Side, Syria during the 2009-2010and 2010-2011 growing seasons to estimate gene action for grain yield and its components. Seeds of the durum wheat hybrid (Sham5 X Azgar1) were grown in three replicates. Results indicated that the used genotypes had good variation to be used as parents in wheat hybridization program to achieve significant genetic advance. Mean square results showed significant differences among mean values of the five populations for all studied traits in the hybrid and in most traits, epistasis or dominance gene action occupied the first rank to the genetic effects. It was suggested that selection for most studied traits in the subsequent generations is relatively more effective than in early generations.

Evaluation of some genetic parameters for some quantitative traits in two maize hybrids (Zea mays L.)

The research was conducted at the Maize Researches Department, General Commission for Scientific Agriculture Researches (G.C.S.A.R.) Damascus, Syria during the summer growing seasons of 2010, 2011 and 2012. Treatments were arranged in a Randomized Complete Blocks Design with three replications. The research aimed to evaluate genetic parameters for some traits like days to 50% silking, plant and ear height, ear length, ear diameter, number of rows per ear, number of kernels per row, 100 kernel weight and grain yield per plant using generations means analysis of two maize hybrids (IL.292-06 × IL.565-06, IL.459-06 × IL.362-06) to detect epistasis and estimates of mean effect [m], additive [d], dominance [h], additive × additive [i], additive × dominance [j] and dominance × dominance [l] parameters. Results showed that the additive - dominance model was adequate to demonstrate the genetic variation and its importance in the inheritance of most studied traits. Nonallelic gene interaction was operating in the control of genetic variation in most studied traits. The signs of [h] and [l] were opposite in most studied traits for the two crosses. Also, the inheritance of all studied traits was controlled by additive and non-additive genetic effects, but dominance gene effects play the major role in controlling the genetic variation of the most studied traits, suggesting that the improvement of those characters need intensive selection through later generations. The phenotypic variations were greater than genotypic variations for all studied traits in the two crosses, indicating greater influence of environment in the expression of these traits. Highly significant heterosis relative to mid and better parents, respectively was found for all characters, and this accompanied with inbreeding depression for all traits. Narrow sense heritability and genetic advance were low in most of the traits due to the dominance of non-additive gene action in controlling the genetic variation of the most studied traits and this predict low to medium values of genetic advance through selection process.

Estimation of statistical genetic parameters and heritability for oil, protein and yield traits in soybean hybrids (Glycine max (L.) Merr.)

The present study was conducted at the First of May Station belongs to the General Commission For Scientific Agricultural Research (GCSAR) at Damascus during 2011 and 2012 growing seasons to estimate gene action, heritability, genotypic and phenotypic coefficient variations (GCV, PCV) and genetic advance for two crosses of soybean. The five population (P1, P2, F1, F2, F3) of each cross were grown in a randomized complete block design (RCBD) with three replications in order to evaluate oil and protein contents and seed yield traits. Results of mean square analysis showed significant differences (p<0.05) among mean values of the five populations for all studied traits between the populations of each cross. The second cross achieved high broad and narrow sense heritability (66%, 44%) for protein content, high value of phenotypic and genotypic variations in seed yield in the second cross achieved (18.03,17.30) and high value of expected genetic advance was obtained 11.09%. In most traits, epistasis of the dominance × dominance type of gene action occupied the first rank in order of importance in controlling inheritance of the evaluate traits in both crosses indicating the importance of selection in late segregating generations to improve these traits. These findings are supported by high values of heritability, which was related with low to moderate expected genetic advance in two crosses.

Inheritance of some quantitative characters in durum wheat

This study was carried out at Karahta station of field crops research department General Commission for Scientific Agriculture Researches (G.C.S.A.R.) Damascus Syria during the 2009 -2010 and 2010 -2011 growing seasons to estimate gene action, potency ratios, heterosis and Inbreeding depressions. Five population seeds of two single hybrids (Cham-5 × Azeghar-1), (Bohoth-5 × Gidara-2) were formed by crossing of four inbred lines. The crosses were subjected to randomized complete block design (RCBD) with three replications in order to evaluate plant height (PH), number of grains per spike (GRSP), flag leaf area (FLA), thousand kernel weight (TKY) and grain (p<0.05) yield per plant (GYP). Mean square results showed significant differences among mean values of the five populations for all studied traits in all crosses. Significant heterosis values compared to mid and better parent were observed for all traits with exception of (PH) (5.82, 1.62)%, (GRSP) (27.49 9.66)% and(TKY) (3.05 7.53)% for Cross-1. (GYP) (82.46, 96.63)% for Cross- 2. (GRSP) (9.09 5.14)%. The potency ratios exceeded (+1) in all traits and crosses except (PH) (-2.23) for Cross-2. Indicating that over-dominance towards low placement. The results indicated that Inbreeding depression values were significant for all traits in Cross-1 except for (GRSP) (10.33), and (TKY) (15.23). While its values were non- significant for all traits inCross-2except (GRSP) (25.46*). In most traits epestasis or dominant gene action occupied the first rank in controlling these traits in both crosses. It could be suggested that selection for most studied traits in the subsequent generations will be relatively more effective than in early generations.

Genetic analysis of some traits in segregating generations of two maize (Zea mays L.) hybrids

This research was conducted at the Maize Research Department (Kharaboo) of General Commission of Science Agriculture Research (GCSAR), Damascus, Syria, during the growing seasons of 2009, 2010 ad, 2011 to study the genetic behavior of days to 50% silking, plant height, ear length, 100 grains weight and yield per plant by using generation mean analysis (GMA) of two individual hybrids of maize, to estimate the heritability, Phenotypic (PCV), and genotypic (GCV) coefficient variations and the genetic advance.

Genetic Analysis of Some Quantitative and Qualitative Traits in Cotton (Gossypium hirsutum L.)

Succes of a breeding program depends, to a great extent, on understanding the gentic behavior of the traits. This investigation was conducted to study and examine the inheritance of some economically important characters such as: total bolls number, actual bolls number, ginning percentage , boll weight, harvest index, flowering earliness, maturity earliness, plant height,and fiber fineness.

General and Specific Combining Ability and Genetic Parameters (Zea mays L.) of Single Crosses in Corn

Six inbred lines of maize namely; A (1), B (2), C (3), D (4), E (5) and F (6) were used in half diallel cross. The seeds of inbred lines and its single cross hybrids were cultivated in an experiment using randomized completely block design (RCBD) with three replicates, at Twaitha Research Station, Plant Breeding Improvement Center, Iraq, during autumn season (2016). The parents and F1 were significantly differed at 5% for number of days to tasseling and silking, plant height (cm), ear diameter (cm) and yield per plant. Some hybrids showed a significant desirable heterosis for studied traits such as days to tasseling and silking. While plant height and yield per plant for all hybrids showed a significant desirable heterosis (deviation of F1 from mid parents). The mean squares of general and specific combining ability were highly significant for all traits. The additive and dominance variances were differed from zero for all studied traits. The broad sense heritability values were high for all studied traits. Narrow sense heritability was moderate for number of days to tasseling, plant height and ear diameter, but it was low for number of days to silking and yield per plant. The average degree of dominance was higher than one for all traits.