Non-additive Type Of Gene Action Research Articles

Genetic Effects Assessment through Line × Tester Combining Ability for Development of Promising Hybrids Based on Quantitative Traits in Gossypium hirsutum L.

Line × Tester combining ability analysis involving five lines (cultivars i.e., CIM-446, CIM-473, CIM-506, CIM-554 and SLH-284) and three testers (cultivars viz., CIM-496, CIM-499 and CIM-707) was carried out during 2015 and 2016 to determine the inheritance for earliness, yield and lint traits in upland cotton. Genotypes revealed significant (P≤0.01) variations for all the traits. On average, F1 hybrids showed the significant increase over parental means for yield traits. Mean squares due to general (GCA) and specific combining ability (SCA) were highly significant, which suggested that additive and non-additive gene actions were involved in controlling all the characters. However, the preponderance of non-additive type of gene action observed for majority of the traits. Lines (SLH-284, CIM-473) and pollinators (CIM-707, CIM-496) were leading general combiners for majority of the traits. F1 hybrids (CIM-473 × CIM-496, SLH-284 × CIM-707 and CIM446 × CIM-496) which involve best general combiners, showed the leading performance for yield and lint traits. Heritability was moderate to high with appreciable genetic gain for majority of the traits. Except for lint %, the correlation of seed cotton yield was positive with other traits. The significance of additive and non-additive components suggested integrated breeding strategies with delayed selection for development of cotton hybrids with improvement in earliness and seed cotton yield.

Gene action conditioning resistance traits to spotted stem borer, Chilo partellus, in grain sorghum

Understanding the mode of gene action conditioning traits of interest in sorghum is important for effective and efficient plant breeding programs. The objective of this study was to establish the nature of gene action for components that contribute to resistance to spotted stem borer, Chilo partellus, in grain sorghum. The experimental material consisted of seventeen sorghum lines with varying levels of resistance to C. partellus. Genetic analyses were performed using a line x tester method using Genstat statistical software. There was significant variation among the F1 for C. partellus resistance and grain yield. The general combining ability (GCA) for deadheart damage was significant (P ≤ 0.01) implying that this trait was governed by an additive type of gene action. Specific combining ability (SCA) for exit holes and stem tunneling were significant (P ≤ 0.01) suggesting that these characters were conditioned by both additive and non-additive types of gene action. Lines ICSA 472, ICSA 464, ICSB 474 contributed high levels of resistance to hybrids while IESV 93042 SH, IS 21879 and IESV 91131 DL were good sources of genes for high grain yield. This observation implied that grain yield and stem borer resistance traits should be considered in development of C. partellus resistant sorghum since a resistant line doesn’t necessarily yield high and vice versa. Generally, results of this study indicated that it would be possible to breed for high C. partellus resistance from this set of germplasm for cultivation by farmers in areas where the insect pest causes epidemics.

Gene action and combining analysis for kernel yield and its attributing traits in maize [zea mays (l.)

Eight maize (Zea mays L.) genotypes were crossed in a half diallel mating design.The analysis of variance for combining ability revealed that mean sum of squares due to general combining ability were found significant for all the traits except cob girth, whereas, the specific combining ability effects were found highly significant for all the characters except anthesis-silking interval. The low ratio (<1.0) of GCA to SCA variance for sixteen traits indicated that non-additive type of gene action was predominant in the expression of yield and component traits. Based on estimates of general combining ability effects revealed that four parents BLD-11 (5.19), CML-338 (4.28), VL-1032 (1.68) and VL-109178 (1.25) were found good general combiners because they registered significant and positive gca effects. The estimates of sca effects revealed that 23 hybrids were exhibited significant positive sca effects. The spectrum of differences in sca effects for this trait ranged from -2.70 (CBE-98 × CML-338) to 27.57 (CBE-98 × MRCN-3) and the top most three hybrids for kernel yield per plant on the basis of specific combining ability effects were CBE-98 × MRCN-3 (27.57), CBE-98 × BLD-11 (23.16) and CBE-26 × BLD-11 (21.20).

Combining ability and Heterosis analysis for grain yield and yield associated traits in Pea (Pisum sativum L.)

This experiment was conducted to determine the general and specific combining abilities and heterosis for grain yield and yield associated traits in pea as a source of protein through line x tester analysis. Grain yield and its inheritance were carried out for investigation through a 12 x 3 line x tester analysis. Experimental materials comprising 15 parents and their 36 hybrids. The materials were planted in a randomized block design with three replications. The general combining ability and Specific combining ability effects were significant indicating the presence of both additive and non-additive types of gene actions. Heterosis was determined as the superiority over mid parent heterosis as well as better parent (HBP). Grain yield showed highly significant heterosis ranging from -36.29 to 8.77and relative heterosis ranged from -25.85 to 13.19 respectively.

Estimation of combining ability and heterosis for yield and yield attributing traits in Indian mustard (Brassica juncea)

Indian mustard [Brassica juncea (L) Czern. and Coss.] is an important oilseed crop which occupies leading position in oilseed sector of Indian agriculture. Development of high yielding genotypes with high oil content in Indian mustard has been a major breeding objective owing to high edible oil import in India. Present study was conducted with a set of 53 genotypes, that included 40 crosses and 13 parents evaluated for pooled estimation of combining ability and heterosis for yield and yield attributing traits during rabi 2014-15 under timely sown, late sown and extra late sown environmental conditions. The crosses were developed in line × tester design involving 8 lines and 5 testers during rabi 2013-14. The genotype × environment interaction was significant for almost all the traits studied indicating differential response of genotypes to the change in environments. The pooled analysis of variance over environments revealed sufficient differences among environments, parents, hybrids and parent vs. hybrids for most of the traits studied. Importance of both additive and non-additive types of gene actions was observed for seed yield and yield attributing traits. Estimates of GCA effects indicated that NRCHB-101, Pusa Bold and RGN-73 were good general combiners for seed yield/plant and yield attributing traits, i.e. 1000-seed weight, siliqua length, number of primary branches and number of secondary branches. The parent, Pusa Mustard-25 showed good combining ability for dwarfness and early maturity. The hybrids, viz. NRCHB-101 × EC552577, NRCHB-101 × BPR543-2, Pusa Mustard-25 × EC552577, BAUM-2007 × EC552577 and BAUSM 92-1-1 × RGN-73 had significantly high SCA effects, &gt;15% heterobeltiosis and high per se performances for seed yield per plant. The parents showing good combining ability would be identified as promising genotypes and the hybrids having high SCA effects with high heterobeltiosis could give transgressive segregants for seed yield and yield attributing traits under different sowing conditions.

Genetic analysis for various agromorphological and quality traits in bread wheat (Triticum aestivum)

A study was made to estimate gene action and combining ability effects involving 10 diverse parents and their 45 F1s (half diallel approach) developed and evaluated during 2012-13 and 2013-14 crop seasons, respectively. The general combining ability (GCA) estimates for bread wheat (Triticum aestivum L.) genotypes namely, HD 2967 (days to maturity, plant height); DBW 90 (plant height, spikelets/spike, grains/spike, grain yield); HD 2824 (plant height, spikelets/spike); HD 3095 (spikelets/spike, grains/spike, grain yield); and HD 2733 (plant height, days to maturity and grains/spike) showed favourable GCA effects. Estimates of specific combining ability (SCA) effects revealed that cross combinations DBW 90 × HD 2733, HD 3095 × RAJ 4246, PBW 435 × HD 2824, PBW 435 × RAJ 4246 and HD 2967 × RAJ 4246 showed high and significant SCA effects, and thus might be exploited through heterosis breeding to improve these traits. Significant values of additive (D) and dominance (H1) variance for six traits (plantheight, grains/spike, spikelets/spike, 1000-grain weight, gluten content and grain yield) indicated that expression of these traits is controlled by both additive and non-additive type of gene action. Positive and significant values of h2 for plant height, grains/spike, spikelets/spike, 1000-grain weight and grain yield; indicated preponderance of dominance component. Average degree of dominance (H1/D)1/2 was more than unity in most of the F15 for grains/spike, spikelets/spike, 1000-grain weight, gluten content and grain yield, thereby indicating the preponderance of over-dominance gene action. Positive and significant values of F-test indicated the preponderance of dominance and positive genesin the expression of these traits. The proportionate distribution of dominant and recessive alleles indicated presence of dominant alleles in the parents. Regression analysis indicated that days to maturity, plant height, grains/spike, 1000-grain weight, gluten content and grain yield were governed by dominance gene action. Genotype HD 3095 contained maximum dominant genes for days to maturity, spikelets/spike; while HD 2967 for plant height, grains/spike, 1000-grain weight and HD 2824 for gluten content and grain yield that thus these could be utilized as donorsfor bi-parental mating or diallel selective mating system for improvement in these traits.

GENETIC MECHANISM CONTROLLING SELECTED WITH IN BOLL YIELD COMPONENTS AND PHYSIOLOGICAL TRAITS OF GOSSYPIUM HIRSUTUM L. UNDER SALINITY STRESS

An experiment was conducted to elucidate the genetic governance of within boll yield components and physiological trait of cotton under control and salinity stress. Ionic concentration varied in all of the genotypes at both salinity levels, ie., higher Na+ concentration was observed in stress condition. Male, female interaction was significant in lint mass per unit seed surface area, chlorophyll content, K+ /Na+ ratio, concluding that within boll yield components and ionic concentration in cell are controlled by non-additive type of gene action. High broad sense heritability and mild narrow sense heritability estimates revealed that within boll yield components and physiological traits are probably controlled by additive and non-additive gene action with pronounced effect of non-additive gene action under control and salt stress condition. Genotypic and phenotypic coefficient of variability was vigorous in stress condition due to the interaction of salinity tolerant genes of tolerant genotypes. Genetic governance is influenced due to specific environmental factors therefore care should be taken in the entitlement of genetic governance of particular traits.

Genetic effects of combining ability studies for quantitative traits in intraand interspecific crosses of diploid cotton (G. arboreum and G. herbaceum)

Forty-five intra- and interspecific diploid or desi cotton hybrids ( G. arboreum x G. herbaceum ) derived from half diallel mating design, by involving ten diverse parents of G. herbaceum and G. arboreum were evaluated to study combining ability for seed cotton yield and its component traits. Mean squares due to GCA and SCA variance were highly significant for all the 11 agro-morphological characters studied. The variance due to GCA and SCA for mean squares was highly significant, which suggested that additive and non-additive gene action is involved for controlling all the characters. Combining ability analysis suggested the preponderance of non-additive type of gene action for all the traits except days to 50 % flowering and no. of monopodia per plant. Based on per se performance, parent GAM- 165 and cross GBhv- 282 x G-27 was superior for seed cotton yield and lint yield per plant. The parent G-27 and GBhv- 287 was found to be the best general combiner for majority of the traits. Based on sca effects, GBhv- 282 x G 27 exhibited significant sca effects for seed cotton yield per plant, lint yield per plant, number of bolls per plant, boll weight and no. of sympodia per plant. Heterosis breeding will be useful for diploid cotton improvement due to presence of non-additive type of gene action.

Combining ability analysis for yield and its component characters in maize (Zea mays L.)

Line × tester analysis was carried out involving fourty two lines and three testers in maize for assessing the combining ability for yield and its component characters. Hybrids recorded significant variance for all characters studied. Variance due to parents were significant for characters viz., days to 50% tasseling, days to 50% silking, plant height (cm), ear height (cm), cob length (cm), cob girth (cm), number of grain rows per cob, number of grains per row, number of grains per cob, 100 grain weight (gm) and grain yield per plant (gm). The variance due to sca was higher than gca indicating the predominance of non-additive type of gene action for the above mentioned traits. Among the lines, the line RML 12, was identified as the best general combiner with higher per se performance for most of the yield contributing traits followed by RML1, RML 26, RML 27 and RML 34. Considering the testers, RML 48 was found as the best general combiner with better mean performance for most of the yield contributing traits followed by RML 47. Among the crosses, RML12 x RML48 was found to be the superior with positive significant sca effects and better mean performance for grain yield, cob girth, number of grain rows per cob and no of grains per cob. Similar superior positive significant sca effects with better mean performance were also observed in RML26 x RML48 (no of grains per cob, grain yield per plant and grain yield per plot), RML27 x RML48 (grain yield per plant, grain rows per cob, grains per cob) and RML37 x RML48 (cob girth, hundred grain weight, grain yield per plant and grain yield per plot.

Investigating morpho-physiological traits and agro-meteorological indices in green gram [Vigna radiata L. Wilczek] for terminal heat tolerance

Forty genotypes of greengram were studied to ascertain the genetic variability and trait association among some important morpho-physiological traits and agro-meterological indices under heat stress condition. The results indicated that both GCV and PCV estimates were high for photo thermal index, heat use efficiency and seed yield. High heritability coupled with moderate genetic advance as per cent of mean was recorded for photo-thermal unit and relative temperature depression indicated that involvement of both additive and non-additive type of gene action and possibilities of effective selection for improvement of these traits. Seed yield showed significant and positive association with days to maturity, growing degree days, relative temperature depression and heat use efficiency. Based on variability, association and path analysis; heat use efficiency, maturity, photo thermal index and growing degree days were found most contributing indices/ traits should be considered as selection criteria for discrimination of outstanding greengram genotypes under heat stress condition.

Genotypic variability and inheritance of iron, phosphorus, potassium and zinc contents in segregating generations of peanut (Arachis hypogaea L.)

Micronutrient malnutrition is a serious health issue affecting billions of people in developing countries. Peanut is rich in several mineral elements required for human nutrition. The objective of this study was to understand genetic variability and inheritance pattern of phosphorus (P), potash (K), zinc (Zn) and iron (Fe) concentrations in F2 and F3 generations of two peanut crosses namely Girnar-3 × FDRS-10 (Cross-A) and TG-37A × FDRS-10 (Cross-B). Pshell, Znshell, Kshell, Feshell, and Fekernel were positively skewed indicating additive gene action. Kurtosis formost of the characters moved in positive direction from F2 to F3 generation indicating a reduction in variation as generation advances.Phenotypic coefficient of variance (PCV) and genotypic coefficient of variance (GCV) revealed that traits were under genetic control and possessed substantial variability and hence a good scope for improving these characters. Both additive and non-additive types of gene actions were observed with the predominance of additive gene action for the inheritance of P, K, Fe and Zn in shell and kernels. Dominance variance (H) also played an important role in the inheritance of P, K, Fe and Zn in peanut. Average degree of dominance for most of the traits was greaterthan unityindicating over dominance forthese traits. Mineral elements had significant association among themselves but very few associations with pod yield. Selection and hybridization followed by pedigree breeding method are suggested in the later generations for genetic improvement to identify high yielding peanut genotypes rich in P, K, Fe and Zn.

GENETIC ARCHITECTURE OF RELATIVE CELL INJURY AND SOME YIELD RELATED PARAMETERS IN Gossypium hirsutum L.

Although cotton is sun loving crop but its production is adversely affected due to biotic and abiotic stress, heat stress contributed significantly in this loss around the globe. The present research work on heat tolerance in cotton is a step forward to understand the genetic basis of heat tolerance in upland cotton. The presence and identification of genetic variation for certain traits is one of the pre-requisite to start research work. There are several techniques for the screening of germplasm for heat tolerance. Relative cell injury was used for the identification of the most heat tolerant and susceptible cotton genotypes i.e. VH-259, VH-142 and DNH-40, VH-282 respectively. The identified genotypes were used for the development of F1, F2, BC1 and BC2 populations for genetic studies. The biometrical analysis revealed that selected traits i.e. relative cell injury, chlorophyll contents, boll shedding percentage, plant height, number of bolls per plant, number of seeds per boll, seed cotton yield were controlled by additive and non-additive type of gene action including epistatic effects. It is suggested that selection in these populations should be done in later generations for the development of new germplasm with enhanced heat tolerance.

Combining ability studies for grain yield other agronomic traits in maize (Zea mays L.)

The present study was aimed to investigate combining ability among twelve elite maize inbred lines in a complete diallel mating design for twelve yield and yield contributing traits. Twelve parents along with their 132 F 1 ’s including reciprocals were planted in a randomized complete block design with three replications. The analysis of variance indicated significant differences among parents for most of the traits studied except for ear diameter. Variance due to GCA and SCA were highly significant for the traits studied indicating importance of both additive and non-additive types of gene action. Preponderance of additive gene action was observed for most of the traits studied except for the grain yield plant -1 , number of kernel rows ear -1 , number of kernels row -1 and ear length which showed preponderance of non-additive gene action. Parent P10 was the best general combiner for grain yield followed by P9 and P1. Parent P9 was also found to be best general combiner for the all traits studied including grain yield. Parent P10 was also found to be best general combiner for early maturity, number of kernel rows ear -1 and 100 kernels weight. For the trait early maturity parent found to be best general combiners were P10, P3 and Parent P7. Total 79 cross combinations were possessing significant desirable SCA effects for grain yield. The top cross combinations possessing significant desirable SCA effects for grain yield were P2 x P6, P7 x P8, P3 x P7 and P7 x P9 which may be used for obtaining high yielding hybrids in maize.

Analysis of Combining Ability and Genetic Parameters for Yield and Other Quantitative Traits in Black Gram [Vigna mungo (L.) Hepper

Combining ability analysis was studied in an 8 × 8 diallel set of black gram genotypes. Variance due to general combining ability (GCA) among the parents for all the traits, and due to specific combining ability (SCA) among the crosses was deduced. Combining ability analysis is an important tool to find out gene actions and it is frequently used by plant breeder to choose parents with high GCA and hybrids with high SCA effects. GCA is associated with additive genetic effects, whereas SCA is taken as the measure of non-additive type of gene actions, arising largely from dominance and epistatic deviations with respect to certain traits. GCA is attributed to additive and additive gene effects epistasis and is theoretically fixable on the other hand; SCA attributed to non-additive gene action due to dominance or epistasis or both and is non-fixable. The presence of non-additive genetic variance is the primary reason for initiating the hybrid programme. GCA variance (σ 2 gca ) was invariably lower than SCA variance (σ 2 sca ) for almost all characters indicating preponderance of non-additive gene action. The percentage of heritability in broad sense was highest with days to maturity (94.78%) followed by days to 50% flowering (94.67%). The gca effect ranged from -0.16 to 0.25. OBG-31 (0.25) had maximum significant positive gca effect followed by Keonjhar Local (0.24). OBG-17 (-0.16) and TU-94-2 (-0.16) witnessed the maximum negative gca effect for yield/plant followed by B-3-8-8 (-0.14). For yield the range of sca varied from -0.64 to 1.02. Among the 28 F 1 hybrids B-3-8-8 × PU-30 (1.02) had the highest sca effect followed by PU-35 × LBG-17 (0.71) and PU-30 × OBG-31 (0.48) for yield/plant. The mean yield per plant was recorded highest in PU-35 × LBG-17 (6.19) followed by OBG-31 × Keonjhar Local (6.16), LBG-17 × OBG-31 (6.15) and B-3-8-8 × PU-30 (6.14). Among 28 cross combinations 11 crosses exhibited positive sca effect (9 were significant) for this character whereas 17 crosses exhibited negative sca effect (13 were significant).

Genetic architecture of quantitative traits in barley (Hordeum vulgareL.)

The nature and magnitude of gene effects for yield and its component traits were studied in barley using generation mean analysis in five crosses. In general, magnitude of dominance effect (h) has a greater value than additive effect (d) in all the traits. It is obvious that non-fixable gene effects (h), (j) and (l) were higher than the fixable (d) and (i) in all the crosses in all the characters, indicating greater role of non-additive effects in the inheritance of all the characters. The study revealed the importance of non-additive type of gene action for most of the traits, thereby suggesting that selection at later segregating generation could provide better results.

Genetics of Fruit Quality in Okra (Abelmoschus Esculentus) under Waste Water

A field experiment consists of five genotypes of okra was conducted in the research area of the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad during crop season 2010-2011.All possible crosses were made to obtain F1seed following diallel analysis design. The F1 seed along with their parents was evaluated. The experiment was laid out in randomized complete block design. Data was collected for some quality traits as protein content, dietryfiber content and carbohydrates. The numerical approaches demonstrated that dietary fiber contents and carbohydrate contents under wastewater irrigation were ruled by over-dominance with non-additive type of gene action while partial dominance was observed in protein contents under wastewater irrigation, dietary fiber contents and carbohydrates under normal irrigation water which suggested that early selection might end up in improving these genotypes. Non-allelic interaction or epistasis was absent for all the traits studied. It indicated thatselection in early generations for these traits would be difficult.

English

Thirty six (36) genotypes (eight parents and 28 F1 diallel crosses) were grown in randomized complete block design with two replicates during 2006 at Mandura, North western Ethiopia. The experiment was executed to study the inheritance of two primary yield component traits: number of seeds per pod and 1000 seed weight. Statistical significant difference was observed between genotypes, parents and crosses for the traits considered. The mean square due to general combining ability was significant for the two traits. However, specific combining ability mean square was significant only for number of seeds per pod. Thus, both additive and non-additive types of gene actions were important in the inheritance of number of seeds per pod. Significant b1 component was obtained for number of seeds per pod. The b2 and b3 components however, were insignificant, suggesting the absence of gene asymmetry. From Wr/Vr graph, inheritance of seeds per pod was governed by partial dominance with additive gene action. Key words: Diallel crosses, general combining ability, Phaseolus vulgaris L., specific combining ability.

THE UTILIZATION OF CYTOPLASMIC MALE STERILE (CMS) AND RESTORER LINES IN THE DEVELOPING OF HYBRID RICE.

The present investigation was conducted to determine the magnitudes of combining ability and heterosis obtained from hybrids three produced by utilization of CMS, maintainer and restorer lines in rice. The experiment was carried out during the two growing seasons of 2010 and 2011 at Rice Research and Training Center (RRTC) Farm, Sakha, Kafr El-Sheikh, Egypt. Twelve F1 hybrids were obtained from crossing three CMS lines as female parent with four restorer lines. These hybrids were evaluated along with their parents for genotypic variances. The analysis of variance revealed highly significant differences among genotypes, parents, parents vs. crosses for days to heading (day); plant height (cm); panicles plant-1; panicle length (cm); filled grains panicle-1; spikelets fertility% and grain yield plant-1 except parents vs. crosses for panicle length (cm). The variance among males (testers) were either significant of highly significant for all studied traits. The variances among crosses due to males and females (lines x testers) interactions, showed highly significant SCA effects for all the studied traits except for plant height (cm). The estimated values for variance of general combining ability (σ²GCA) were less than specific combining ability variance (σ²SCA) for all studied traits except plant height (cm). This result indicated the preponderance of non-additive gene action. It was supported by the ratio of (σ²GCA/ σ²SCA) which was less than one for all studied traits except for plant height (cm), indicating that the non-additive type of gene action played a major role in the inheritance of these traits. Heritability estimates in broad sense (h2b%) were high for all studied traits. However, heritability estimates in the narrow sense (h2n%) were moderate for days to heading (day) (44.58%), plant height (cm) (45.81%) and filled grains panicle-1 (53.80%) and low for the other traits. Three parental lines viz.; IR69625A; G46A and GZ9057-6-1-3-2 were identified as good general combiners for grain yield plant-1(g). Hybrid combinations as G46A x Giza178; IR69625A x GZ6296-12-1-2-1-1 and Large stigma A x GZ9057-6-1-3-2 showed high mean performances due to the presence of SCA effects.

English

Information on the availability of genetic variability and mode of gene action are critically important for choosing effective breeding methods that result in appreciable improvement in performance under drought stress. The objectives of this study were to estimate the gene action for drought resistance of quantitative traits and also to estimate the components of variance and heritability of drought resistance in common bean. Field experiment was carried out using six generations of two populations made of crosses between pairs of drought resistant and susceptible genotypes (Roba-1 &times; SER-16; Melka-Dima &times; SAB623). The treatments were laid in a split plot design with three replications, where watering regime was assigned to the main plot and generations to the sub-plot. Drought stress was initiated at flowering stage by withholding application of irrigation water. Scaling test and generation mean analysis brought out that individual crosses greatly differed for the gene action and on an overall basis all the types of gene action, additive, dominance and epistasis were important for drought resistance in common bean. Both additive and non-additive types of gene action were important in governing the inheritance of the traits considered. However, additive types of gene actions were important in the inheritance of number of pod per plant in Roba-1 &times; SER-16 and above ground biomass in Melka-Dima &times; SAB-623 under drought stress. Medium to high broad and narrow sense heritability were found for most of the traits under both watering regimes. Evidences have unfolded that chances to find stress tolerant breeding material in segregating populations of the two crosses were promising. The presence of significant amount of all types of gene action for the important traits imply that methods which can utilize all of them such as recurrent selection and multiple cross could be employed in breeding beans for drought environments. &nbsp; Key words:&nbsp;Common bean, drought resistance, gene action, generation mean analysis, heritability, scale test.

Line × Tester Mating Design Analysis for Grain Yield and Yield Related Traits in Bread Wheat (Triticum aestivumL.)

Nine bread wheat (Triticum aestivumL.) genotypes were crossed in a line × tester mating design. The 20 F1's and their parents were evaluated in a randomized complete block design with three replications at the Field Crop Institute-Agricultural Experimental Station of Setif (Algeria) during the 2011/2012 cropping season. The results indicated that sufficient genetic variability was observed for all characters studied. A899 × Rmada, A899 × Wifak, and A1135 × Wifak hybrids had greater grain yield mean than the parents. A901line and the tester Wifak were good combiners for the number of grains per spike. MD is a good combiner for 1000-kernel weight and number of fertile tillers. HD1220is a good general combiner to reduce plant height; Rmada is a good general combiner to shorten the duration of the vegetative growth period. A901 × Wifak is a best specific combiner to reduce plant height, to increase 1000-kernel weight and number of grains per spike. AA × MD is a best specific combiner to reduce duration of the vegetative period, plant height and to increase the number of kernels per spike. A899 × Wifak showed the highest heterosis for grain yield, accompanied with positive heterosis for the number of fertile tillers and spike length, and negative heterosis for 1000-kernel weight and the number of days to heading.σgca2/σsca2, (σD2/σA2)1/2low ratios and low to intermediate estimates of h2nssupported the involvement of both additive and nonadditive gene effects. The preponderance of non-additive type of gene actions clearly indicated that selection of superior plants should be postponed to later generation.