scholarly journals Genetic parameters assessment of siliquae associated with stress indices in rapeseed cultivars

2012 ◽  
Vol 67 (4) ◽  
pp. 35-44
Author(s):  
VALIOLLAH RAMEEH

The objective of the present study was to determine the genetic control and heritability of siliquae per plant at two places including without and application of nitrogen (Pp and Ps) and its related stress tolerance indices based on half diallel crosses of six spring rapeseed varieties. Significant mean squares of general combining ability (GCA) were detected for Pp and Ps and also the other related stress indices except tolerance index (TOL) and stress susceptibility index (SSI), indicating the importance of additive genetic effect. Significant mean squares of specific combining ability (SCA) were observed for all the studied traits except TOL indicating the importance of non additive genetic effects for them. Low narrow sense heritability estimates for Pp and Ps and also other associated stress indices except geometric productivity (GMP) indicated the prime importance of non additive genetic effects for these traits except GMP. Most of the crosses had significant SCA effects of siliquae per plant at non application of nitrogen condition, therefore selection of combinations based on SCA effect of Ps will be more efficient than SCA effect of Pp. The variations of SCA effects of the crosses for mean productivity (MP) and GMP are higher than the other stress indices, so selection of the crosses based on this two stress indices will have sufficient gain. High parent heterosis effects of TOL, STI and SSI were more variated than SCA effects, therefore selection based on high parent heterosis effects will be more efficient than SCA effects.

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.


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.


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.


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.


Agricultura ◽  
2017 ◽  
Vol 14 (1-2) ◽  
pp. 9-16
Author(s):  
Valiollah Rameeh

AbstractInformation on estimates of combining ability of the promising lines of breeding material is important for evolving higher yielding varieties of oilseed rape (Brassica napus L.). An experiment was conducted to quantitatively examine the genetic parameters of phenological traits, plant height, pods on main raceme, pods per plant and seed yield for eight oilseed rape genotypes using a half-diallel crosses. The result of the diallel analysis revealed significant mean squares of general and specific combining abilities (GCA and SCA) for all studied traits, indicating the importance of additive and non-additive genetic effects for these traits. On the other hand estimation of high narrow-sense heritability estimates for days to flowering, duration of flowering and pods on main raceme, indicated the prime importance of additive genetic effects for these traits. L420 and L401 with significant negative GCA effects for days to flowering and days to maturity were suitable for yielding early maturity combinations. L41, Zafar and L22 with significant positive GCA effects for seed yield were superior parents for increasing seed yield. The crosses with significant positive SCA effects for seed yield had at least one parent with significant positive GCA effects for this trait. The crosses including L41×L22, L41×LF2, Zafar×L22 and Zafar×L420 with seed yield of 3421.7, 3400, 3348.1 and 3311.3 kg ha-1 could be promising for determination of superior recombinants for high seed yield coupled with other growth characters in advanced generations of segregation.


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.


1999 ◽  
Vol 22 (3) ◽  
pp. 451-456 ◽  
Author(s):  
Cleso Antônio Patto Pacheco ◽  
Cosme Damião Cruz ◽  
Manoel Xavier dos Santos

The objective of the present work was to provide a methodology to study the inheritance of adaptability and stability through the breakdown of Eberhart and Russell regression coefficients and regression deviations in effects due to the mean and additive genetic effects (gi's and gj's) as well as dominance effects (sij's) of Griffing´s methodology, when the diallel is conducted in several environments. It was concluded that the adaptability and stability parameters are determined in the same manner as are genetic effects. So an F1 cross inherits half the general combining ability (GCA) mean effect from each parent, while the effects due to specific combining ability (SCA) are subjected to the same considerations relative to sij's, i.e., they are dependent on specific 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.


1990 ◽  
Vol 115 (5) ◽  
pp. 829-834 ◽  
Author(s):  
R.L. Bell ◽  
Jules Janick

Narrow-sense heritability estimates were computed for five fruit quality characteristics and their weighted total index. Grit content and skin russeting were moderately heritable traits, while flesh texture, flavor, appearance, and the weighted total score were of relatively low heritability. Within sub-populations of crosses, defined by the species ancestry of the parents, the relative magnitudes of heritabilities for each trait varied, but were in general agreement with those for the entire population. The general combining ability variances were 4.5 to 12.0 times those for specific combining ability, although both were statistically significant for all traits and the weighted quality index. The species ancestry of a parent had no effect on its general combining ability rank. While selection of individual seedlings on the basis of their own phenotype will result in genetic improvement for grit and russet, selection based on a combination of full-sib family means and individual phenotypes is recommended for flavor, texture, appearance, and overall fruit quality.


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