scholarly journals Assessing gene action for hypoxia tolerance in cotton (Gossypium hirsutum L.)

2019 ◽  
pp. 51-62
Author(s):  
Altaf Hussain ◽  
Zafar Ullah Zafar ◽  
Habib-Ur-Rehman Athar ◽  
Jehanzeb Farooq ◽  
Saghir Ahmad ◽  
...  

Introduction. The inheritance studies on hypoxia tolerance in cotton are very scanty. Objective. The objective of this work was to study the inheritance pattern of seed cotton yield, ginning out-turn, and fiber length under normal and hypoxia conditions. Materials and Methods. An 8•8 diallel mating system was employed in F1 generation of cotton. The experiment was conducted during the years 2011-2012 at Cotton Research Institute, Multan, Pakistan. Results. Analysis of variance revealed significant variation (P<0.01) for all the traits under both non-stress and flooding stress conditions. The value of regression coefficient b deviated significantly from zero but not from unity for all the traits which enabled further analysis of the data. The additive component (D) was significant for all the traits and this has more values than the values of dominance components H1 and H2, which clearly indicates the preponderance of additive genetic effects. Under normal and hypoxia conditions the estimates of narrow sense heritability were higher. Conclusion. Predominance of additive genetic effects, high heritability along with partial dominance under both conditions suggested that selection for these traits under hypoxic environment at early generation will be useful.

2015 ◽  
Vol 71 (1) ◽  
pp. 47-56
Author(s):  
Valiollah Rameeh

Abstract Six parents and their 15 F2 diallel progenies, totally 21 genotypes, were evaluated for genetic parameters of quantitative characteristics. The traits of interest were growing degree days (GDDs) from sowing to the flowering (DDF), to end of flowering (DDE), flowering period (DFP), to maturity (DDM) and seed yield (SY). Significant mean squares of general combining ability (GCA) was exhibited for DDF, DDE, DFP, DDM and seed yield indicating significant differences of GCA effects of parents for these traits. Significant mean squares of specific combining ability (SCA) for all the traits exhibited the importance of non additive genetic effects for the traits. Significant ratio of MS(GCA)/MS(SCA) and high narrow sense heritability estimates for DDF, DDE, DDM indicating the prime importance of additive genetic effects for controlling these traits. DFP was also less heritable than the other phonological traits, so the efficiency of selection for this trait will be low. All of the combinations with significant negative SCA effects for DDM had at least one parent with significant negative GCA effect for this trait. PF7045/91 with significant positive GCA effect of SY, was best combiner for improving SY. Significant positive correlation between DDM and each of two traits including DDF and DDE, indicating these traits can be used as indirect selection criteria for improving DDM.


2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SHAILESH CHAND GAUTAM ◽  
MP Chauhan

Line × tester analysis of twenty lines and three testers of Indian mustard (Brassica juncea L. Czern & Coss.) cultivars were used to estimate general combining ability (GCA), specific combining ability (SCA) effects, high parent heterosis and narrow-sense heritability estimate for plant height, yield components and seed yield. Significant variance of line x tester for the traits like pods per plant and seed yield indicating non additive genetic effects have important role for controlling these traits. Significant mean squares of parents v/s crosses which are indicating significant average heterosis were also significant for all the traits except seeds per pod. High narrow-sense heritability estimates for all the traits except seeds per pod exhibited the prime importance of additive genetic effects for these traits except seeds per pod. Most of the crosses with negative SCA effect for plant height had at least one parent with significant negative or negative GCA effect for this trait. For most of the traits except pods per plant, the efficiency of high parent heterosis effect was more than SCA effect for determining superior cross combinations.


Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 585 ◽  
Author(s):  
Seema Yadav ◽  
Phillip Jackson ◽  
Xianming Wei ◽  
Elizabeth M. Ross ◽  
Karen Aitken ◽  
...  

Sugarcane is a major industrial crop cultivated in tropical and subtropical regions of the world. It is the primary source of sugar worldwide, accounting for more than 70% of world sugar consumption. Additionally, sugarcane is emerging as a source of sustainable bioenergy. However, the increase in productivity from sugarcane has been small compared to other major crops, and the rate of genetic gains from current breeding programs tends to be plateauing. In this review, some of the main contributors for the relatively slow rates of genetic gain are discussed, including (i) breeding cycle length and (ii) low narrow-sense heritability for major commercial traits, possibly reflecting strong non-additive genetic effects involved in quantitative trait expression. A general overview of genomic selection (GS), a modern breeding tool that has been very successfully applied in animal and plant breeding, is given. This review discusses key elements of GS and its potential to significantly increase the rate of genetic gain in sugarcane, mainly by (i) reducing the breeding cycle length, (ii) increasing the prediction accuracy for clonal performance, and (iii) increasing the accuracy of breeding values for parent selection. GS approaches that can accurately capture non-additive genetic effects and potentially improve the accuracy of genomic estimated breeding values are particularly promising for the adoption of GS in sugarcane breeding. Finally, different strategies for the efficient incorporation of GS in a practical sugarcane breeding context are presented. These proposed strategies hold the potential to substantially increase the rate of genetic gain in future sugarcane breeding.


2019 ◽  
Vol 4 (1) ◽  
pp. 591-598
Author(s):  
Valiollah Rameeh

AbstractHalf diallel crosses of eight spring genotypes of oilseed rape (Brassica napus L.) were considered to evaluate heterobeltiosis effects of plant height, yield component characters, seed yield and harvest index. Significant mean squares of general and specific combining abilities (GCA and SCA) were determined for all the traits except 1000-seed weight demonstrating prominence of additive and non additive genetic effects for the mentioned traits. Narrow-sense heritability estimates were high for siliquae on main raceme and 1000-seed weight representing the major importance of additive genetic effects for the characters. Most of the crosses with significant positive high parent heterosis for seed yield had also significant heterotic effects for siliquae per plant; therefore, this trait can be considered as indirect selection criterion for enhancing seed yield. Seed yield was significantly correlated with the traits including plant height, siliquae on main raceme and siliquae per plant based on mean performances of the traits and this result was confirmed with correlations based on heterobeltiosis. The crosses including L41×LF2 and L31×L401 with highly significant heterobeltiosis estimates of grain yield were superior combinations for breeding this trait. which proved good specific combiners for most of the traits.


2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Valiollah Rameeh

AbstractThe objectives of this research were to investigate the genetic structure of the 20 F1s rapeseed hybrids established from five female moderate maturing lines and four early maturing male testers, determine parents showing general combining ability (GCA) and assess crosses demonstrating specific combining ability (SCA). Significant mean squares of lines and testers determined GCA and confirmed the presence of additive genes that were influencing the traits, while the significance of line×tester interactions indicated the importance of SCA of parents and demonstrated the importance of dominance or non-additive genetic effects. Significant variance of parents vs. crosses revealed significant average heterosis for all the traits except first pod height and seeds per pod. High narrow-sense heritability estimates for number of branches and pod length indicated the importance of additive genetic effects for these traits. Significantly positive correlation was exhibited between GCA effects on pods on main raceme and seed yield and, therefore, the GCA effect on pods on main raceme can be used as indirect selection criterion for improvement of seed yield. The crosses L41×Foma2, Zafar×R42 and L22B×R38 recorded significant positive SCA effects and high mean values of seed yield of 3400, 3311.3 and 2904.2 kg ha-1, respectively.


2019 ◽  
Vol 2 (1) ◽  
pp. 314-320 ◽  
Author(s):  
Vinh Thi Nguyen ◽  
Luc Duc Do ◽  
Thinh Hoang Nguyen ◽  
Bo Xuan Ha ◽  
Mai Ngoc Hoang ◽  
...  

The association of the RNF4, RBP4, and IGF2 genotypes and their additive genetic effects with litter size in purebred Landrace and Yorkshire sows were studied. The results revealed significant associations between the RNF4 and RBP4 genotypes with the total number of piglets born (TNB) and number of piglets born alive (NBA) traits (P <0.05). The RNF4 CC genotype had greater TNB and NBA than the TT genotype in both breeds. The RBP4 BB genotype had greater TNB and NBA than the AA genotype in the Landrace breed. Significant additive effects of the RNF4 and RBP4 genes on the TNB and NBA were detected (P <0.05). No significant associations of the IGF2 genotypes and their additive effects with any reproductive traits were observed in both Landrace and Yorkshire sows (P >0.05). The results suggested that the RNF4 and RBP4 genes could be useful in selection for increasing TNB and NBA traits in pigs.


2012 ◽  
Vol 57 (3) ◽  
pp. 111-120 ◽  
Author(s):  
Valiollah Rameeh

To estimate the general and specific combining ability (GCA and SCA) effects of plant height, yield components, seed yield and oil content, three testers and six lines of spring type of rapeseed varieties were crossed using line ? tester fashion. Significant mean squares of parents and crosses for all the traits indicated significant genetic variation among the parents and their F1 crosses. Significant mean squares of parents vs crosses revealed significant average heterosis for all the traits except seeds per pod, 1000-seed weight and oil content. High narrow-sense heritability estimates for all the traits except seeds per pod, indicating the importance of additive genetic effects for these traits. Due to more importance of additive genetic effects for most of the traits, only a few of the crosses exhibited significant SCA effects. A significant positive correlation between seed yield and some of yield components including pods on main axis, pods per plant and 1000-seed weight indicates that these traits can be used as suitable selection criteria for improving of seed yield. The crosses including Opt ? R01, RG06 ? R01, RG06 ? R08 and RGS3 ? R08 with 3241.91, 3213.68, 3334.28 and 3237.45 kg ha-1 of seed yield detected as prior combinations for improving of this trait and all of these combinations had also positive SCA effect for this trait.


2012 ◽  
Vol 12 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Sebastião Márcio de Azevedo ◽  
Wilson Roberto Maluf ◽  
Marcos Ventura Faria ◽  
Juliano Tadeu Vilela de Resende ◽  
Cícero Beserra de Menezes ◽  
...  

Two watermelon genotypes were used as parental in crosses designed to study the inheritance of resistance to PRSV-W: the cultivar Crimson Sweet (susceptible) and the accession 'PI 595201'(resistant). Plants of the generations P1, P2, F1, F2, BC11 e BC12 were inoculated with a Brazilian isolate of PRSV-W and were evaluated by recording symptoms. Genetic and phenotypic parameters of PRSV-W resistance were estimated and tests based on hypothesis of monogenic inheritance and maximum likelihood methods were performed. The additive component [a] of resistance was higher than the non-additive [d]. The estimates of the broad-sense heritability (0.80) and of narrow-sense heritability (0.67) indicated that the genetic variance was greater than the environmental, allowing higher genetic gains in selecting more resistant plants in segregating populations. The inheritance is more complex than a typical monogenic inheritance. The importance of the additive genetic effects in the expression of resistance to PRSV-W was evidenced.


2013 ◽  
Vol 58 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Valiollah Rameeh

Although an average plant height is more preferable in most of agronomic crops, less reduction of this trait in stress condition makes yield components and seed yield sustainable in rapeseed varieties. Combining ability, heterosis and heritability of plant height at application and non-application of nitrogen environments (Hp and Hs, respectively) and its related stress tolerance indices were detected in half F2 diallel crosses of six spring rapeseed varieties. Significant mean squares of general and specific combining abilities (GCA and SCA) were detected for Hp, Hs, mean productivity (MP), geometric mean productivity (GMP) and stress tolerance index (STI), indicating the importance of additive and non-additive genetic effects for them. A high narrow-sense heritability estimate was exhibited for STI, emphasizing the prime importance of additive genetic effects for this stress tolerance index. A significant correlation among Hp, Hs, MP, GMP and STI showed the efficiency of these stress indices for improving plant height in plant breeding programme. In comparison to SCA effects, most of the crosses had significant high parent heterosis for Hp, Hs and all the stress indices. RGS003 with a significant positive GCA effect of Hs was considered as a suitable parent for improving this trait and most of the combinations of this genotype had significant negative SCA effects.


Genetika ◽  
2010 ◽  
Vol 42 (3) ◽  
pp. 575-583 ◽  
Author(s):  
Radisa Djordjevic ◽  
Bogoljub Zecevic ◽  
Jasmina Zdravkovic ◽  
Tomislav Zivanovic ◽  
Goran Todorovic

The aim of the present study was to estimate, on the basis of diallel crossing, superior-parent heterosis, components of genetic variability and trait heritability for three yield components in tomato, and to perform the VrWr regression analysis. Six different tomato inbred lines originating from local and introduced breeding material were selected for the study. The hybrids expressed greater mean values for the majority of the traits than the inbred lines. The value of additive component of variance (D) was higher than the value of the dominant variance (H1 and H2) for the number of fruits per plant and the average fruit weight, while the value of the dominant component of variance was higher for the fruit weight per plant. Positive values of additive x dominant genetic effect interaction (F) for the observed traits point to a greater participation of dominant alleles in the inheritance of these traits, which was confirmed by the coefficients H2/4H1 (0.208-0.228) and by the ratio KD/KR being greater than unity (1.129-1.536). The values of the average degree of dominance H / D 1 , lower than unity for the number of fruits per plant and the average fruit weight, indicate that these traits were inherited by partial dominance. Furthermore, values of the degree of dominance greater than unity for the fruit weight indicate that this trait was inherited by dominance or superdominance. These conclusions were also confirmed by high values of the broad- and narrow-sense heritability that varied from 98.88% to 99.44%, i.e., from 45.06 to 87.51%, respectively, as well as, by the VrWr regression for the observed traits in the F1 generation.


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