SCA Variance Research Articles

Combining ability analysis and correlation studies for yield and mineral nutrients in ridge gourd (Luffa acutangula)

The current study was carried out to determine combining ability and association of yield and yield components in 7 × 7 half-diallel crosses of ridge gourd (Luffa acutangula Roxb.) at ICAR-IARI, New Delhi in the year 2016. Twenty one F1 hybrids along with seven parental lines were grown in randomized block design in three replications. The mean square due to GCA and SCA were highly significant for all the characters indicating the importance of additive and non-additive genetic components for the traits under study. Further, SCA variance was more than GCA variance for all the characters which suggested the importance of non-additive variance for the improvement of these characters. The parental lines Pusa Nutan, DRG-7, DRG-71 and Pusa Nasdar were good combiners for most characters under study including yield and mineral nutrients. The hybrid combination of Pusa Nutan × Arka Sujat, Pusa Nasdar × Co-1 and Pusa Nasdar × Swarna Uphar were found to be most promising combinations for earliness, yield, mineral content and other economic traits of interest. Significant positive correlations were observed between yield and fruit length, average fruit weight and number of fruits per plant. The results indicated the importance of heterosis breeding for effective utilization of non-additive genetic variance in ridge gourd.

Genetics of quantitative traits in barnyard millet (Echinochloa frumentacea (Roxb.) Link) – an underutilized crop

With an objective to identify potential parents and crosses for quantitative and nutrient related characters and to understand the gene action for different traits for further improvement, an investigation was carried out in barnyard millet with diallel analysis involving five parents (CO 2, ACM 145, ACM 161, ACM 331 and ACM 332). Five parents and twenty crosses were evaluated for thirteen quantitative and four nutrient traits. The GCA, SCA and RCA variances were significant for almost all the characters suggesting the importance of both additive and non-additive gene action with pre-ponderance of non-additive gene action and significant reciprocal differences indicating the inter action between cytoplasm and the nuclear gene effects. However, for single plant yield the gene action was additive as the ratio of GCA to SCA variances was more than one. In the evaluation of parents, taking per se performance and gca effects as criteria the parents in the order ACM 145, ACM 161 and CO 2 were identified as the best general combiners. The crosses ACM 145/CO 2 and ACM 145/ACM 161 were selected as superior over others based on per se performance, SCA effects and heterosis percent together and are suggested for utilization in heterosis breeding. Non-significant SCA effect was possessed by CO 2/ACM 145 and CO 2/ACM 161 and they could be used for improvement of grain yield by recombination breeding to isolate useful segregants.

Inheritance pattern of genes for morpho-physiological and yield traits in wheat (Triticum aestivumL.)

In order to study the inheritance pattern of morpho-physiological traits in bread wheat, a 10×10 diallel cross, excluding reciprocals was made and grown in a randomized complete block design (RCBD) with three replications. Observations were recorded on Days to 75% flowering (DF), Days to maturity (DM), Duration of reproductive phase (DRP), Plant height (cm) (PH), Effective tiller/plant (TLS), No. of spikelets per spike (SLS), No. of grains per spike (GS), Grain weight per spike (g) (GW), Spike length (cm) (SL), Biological yield per plant (g) (BY), Harvest index (%) (HI), 1000-Grain weight (g) (TGW), Spike density (SD), Canopy temperature depression (°C) (CTD), Chlorophyll intensity (%) (CI), Chlorophyll fluorescence (Fv/Fm) (CF), Protein content (%) (PC), Grain yield per plant (g) (GY). Highly significant differences were observed among the genotypes for all traits. The resulted 45 F1s and their F2s used for study the nature of gene for grain yield and its contributing traits in bread wheat. The result indicated that considerable gene action and average degree of dominance respond to achieving significant result for grain yield and its component traits. In both the generations F1s and F2s, grain yield per plant (g) was governed by non-additive gene action based on combining ability analysis, (σ2 g/σ2 s)0.5 [GCA and SCA variance ratio] and (H1/D)0.5 [Degree of dominance] were exhibited over dominance type average degree of dominance for grain yield and its component traits in both generations. Genetic analyses of the traits confirm the involvement of both additive and non-additive gene effects in governing the inheritance.

Inheritance of some Seed Quality and Assessment of Soluble Protein Profiles in Five Pea (Pisum sativum L.) Cultivars

A half diallel set of five- parents of pea (Pisum sativum L.) was used to study the inheritance of four seed quality traits in addition to the differences in soluble protein patterns. The studied traits included 100 green seed weight, sugar percentage, starch percentage and protein content. The variances of SCA were higher in magnitude than those of GCA for total sugar and starch contents which indicated that non-additive effects were higher than the additive effects for these characters. Both additive and non-additive effects were important in controlling protein content. Meanwhile, the variance of GCA exceeded SCA by 50 folds in 100 green seed weight indicated the predominance of additive effects in the inheritance of such trait than non-additive effects.

Combining ability effects for fibre quality traits in first and ratoon crops of cotton interspecific hybrids (G. hirsutum × G. barbadense)

The combining ability effects were evaluated through line x tester analysis for the identification of best general combiners and specific combiners for fibre quality traits in 30 novel hybrids. The results revealed the presence of considerable genetic variation with respect to various fibre quality traits and significant differences for all the traits except elongation percentage and fibre fineness in both first and ratoon crops and indicated that the sca variances were higher than the gca variances for all the studied traits. The ratio of σ2 gca/σ2 sca was less than one for all the traits indicating the preponderance of dominant gene action, which plays an important role in the exploitation of heterosis through hybrid breeding. Parents AFRICAN I-2 and SVPR 4, KC 3 and SURABHI were found to be good combiners for fibre length and elongation percentage. The parent SUVIN was good combiner for fibre fineness. The sca effects revealed the best specific combinations viz., (i) the hybrids KC 3 x TCB 209, SVPR 4 x CCB 36 and SVPR 4 x TCB 209 for fibre length; (ii) AFRICAN I-2 x DB 3 for uniformity ratio; (iii) COD 5-1-2 x DB 3, KC 3 x DB 3 and SURABHI x TCB 26 for fibre fineness.

Combining Ability and Heterosis for Yield and Related Traits in Chili (Capsicum annuum L.)

Introduction:An experiment was conducted to study combining ability and heterosis for yield and related traits in chili during November 2015 to September 2017.Materials and Methods:The experimental material consisted of six parents and their fifteen F1’s developed by half diallel mating design. Analysis of variance for combining ability exhibited significant General and Specific Combining Ability (GCA and SCA) effects for all the characters studied.Results:The SCA variance was higher than GCA variance for all the traits except ten fresh fruit weight, fruit length and fruit width indicating the predominance of non-additive type of gene action. The parents P1and P6were identified as the best general combiners and the hybrids P1×P6, P1×P4and P2×P5were identified as the best specific combinations for fresh fruit yield per plant and related traits. The hybrids P1×P6, P1×P4and P3×P6showed significant average heterosis and heterobeltiosis for fresh fruit yield per plant and its related traits. (H1/D)0.5ratio indicated partial dominance effect of genes for all the traits.Conclusion:Therefore, it may be possible to take advantages of better heterotic effects to be fixed in the later generations to facilitate further selection and best specific combinations for development of the hybrid variety of chili which can help to increase the total production in Bangladesh.

Diallel analysis of yield and its important components in aromatic rice (Oryza Sativa L.)

Eight parents of aromatic rice were crossed in half diallel mating design without reciprocal including parents. The parents were evaluated for eleven different characters. Genetic analysis was done through Griffing’s Method II Model I. Analysis of variance revealed highly significant differences among parents and their crosses for all the characters. Combining ability analysis revealed that gca and sca variance were highly significant for most of the characters studied in F1 generation. Amongst the parental lines, Basmati Kasturi was a good general combiner for plant height at maturity, total number of spikelets per panicle, total number of filled grains per panicle and grain yield per plant in F1 generation while the most promising specific combiners for grain yield per plant were Basmati x Chakhao Angangba and Basmati Kasturi x Basmati 370.

Combining ability analysis for quantitative traits in China aster [Callistephus chinensis (L.) Nees

A line x tester analysis was carried out involving 11 divergent genotypes (6 lines and 5 testers) and 30 F1 hybrids of China aster for assessing the combining ability for 13 economic traits, during 2017. The genotypes Matsumoto White and Phule Ganesh Violet among lines and testers, showed good general combining ability for most of the economical traits. The cross combinations Matsumoto Scarlet x Phule Ganesh Violet, Matsumoto White x Phule Ganesh Violet and Matsumoto Red x IIHRJ3-2 showed best specific combining ability for various traits. The variance of sca was the highest for all the traits except for plant spread and days to first flowering which indicated the dominance of additive gene effects. Hence, it was inferred that specific combining ability can be exploited for the creation of novel flower colours and phenotypes.

Heterosis and combining ability for yield and its related traits in ridge gourd [Luffa acutangula (L.)Roxb.

Line × Tester analysis involving three lines and four testers was carried out in ridge gourd [Luffa acutangula (Roxb.) L.]. Significant variation was noticed in the mean performance of the parents and hybrids for all the characters studied except for vine length and fruit girth. The results from GCA and SCA variance indicated the predominance of non-additive gene action for all the traits except fruit girth. Significant heterosis of 177.78% over standard check, Arka Sumeet for fruit weight per plant was expressed by the cross GARG-1 × CO-1. The best general combiners were GARG-1 and Pusa Nutan among the lines, and Jaipur long and CO-1 among testers. Best specific combining ability effects for fruit length and yield (t/ ha) were recorded by the crosses Pusa Nasdar × Arka Sumeet and GARG-1 × CO-1.

Heterosis and combining ability for yield and its related traits in ridge gourd [Luffa acutangula (L.)Roxb.

Line × Tester analysis involving three lines and four testers was carried out in ridge gourd [Luffa acutangula (Roxb.) L.]. Significant variation was noticed in the mean performance of the parents and hybrids for all the characters studied except for vine length and fruit girth. The results from GCA and SCA variance indicated the predominance of non-additive gene action for all the traits except fruit girth. Significant heterosis of 177.78% over standard check, Arka Sumeet for fruit weight per plant was expressed by the cross GARG-1 × CO-1. The best general combiners were GARG-1 and Pusa Nutan among the lines, and Jaipur long and CO-1 among testers. Best specific combining ability effects for fruit length and yield (t/ ha) were recorded by the crosses Pusa Nasdar × Arka Sumeet and GARG-1 × CO-1.

Combining ability analysis over environments in bread wheat

Thirty-eight genotypes of wheat including 8 parents, their 28 F1s and 2 checks evaluated in 4 different environments i.e. early sown, normal sown, late sown and very late sown conditions was undertaken to study the combining ability in bread wheat for grain yield and its component traits. From pooled analysis, it was found that mean square due to GCA and SCA were significant for all characters which revealed difference between parents for GCA and difference between crosses for SCA. Significant mean square for GCA x E and SCA x E for proline content, chlorophyll content, chlorophyll stability index and heat injury was observed. In addition, SCA x E for grain yield was also significant. This suggested that additive and non-additive genetic components were sensitive to environments. Variance for GCA was higher than their respective SCA variance for grain yield per plant, leaf canopy temperature, proline content and chlorophyll stability index which suggested that additive component was less stable over the environment than dominant component. Parents HD 2987 was good general combiners for grain yield over different environments. Cross HI 1544 x HD 2987 was the best specific combiner for grain yield per plant followed by HI 1544 x RAJ 4079.

Combining ability studies for yield and quality traits in aromatic genotypes of rice (Oryza Sativa. L.)

The present investigation was aimed to study the general combining ability of eight aromatic genotypes of rice and specific combining ability of all possible crosses for grain yield and quality traits in 28 F1’s obtained by 8x8 on way Diallel mating design. The estimates of SCA variance were revealed greater than GCA variance for all the characters except days to 50% flowering, days to maturity, plant height, effective tillers/plant and kernel length after cooking. It showed that both the additive as well as non-additive genetic variance exhibited importance for expression of the characters studied. The Parents, Pusa -2517-2-51-1and Pusa Sugandh-5 studied were identified as best general combiner for both yield and quality traits for most of the characters. Crosses, Pusa-2517-2-51-1×Type-3 showed non additive effects for yield traits only. However, the cross Ranbir Basmati x Pusa Basmati-1 showed non additive effects for quality traits. Cross combination viz., Pusa Sugandh-5 x Pusa Basmati-1, Ranbir Basmati x Kasturi Basmati, Kasturi Basmati × Pusa-2517-2-51-1 and Pusa Sugandh-3 x Type-3 showed non additive gene action for most of the yield as well as quality traits. For those traits which showed high performance were under the control of dominance and dominance × dominance gene effects, heterosis breeding would be most effective. Thus, present study aims to develop hybrids performing better for both yield as well as quality traits.

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).

Heritability, genetic gain and detection of gene action in hexaploid wheat for yield and its related attributes

Selection of promising genotypes from a diverse genetic pool and their utilization for hybridization is an important strategy for wheat crop improvement. The data from ten parents and their F1 progenies using line × tester mating scheme were analyzed to assess the effects of combining ability for yield and its cognate characters using randomized complete block design with three replications. Data were taken for grain yield and its associated characters like plant height, peduncle and spike length, flag leaf area, per plant tillers, spikelets spike−1, grains spike−1, spike density, thousand-grain weight and grain yield plant−1. Analysis of variance was used to statistically analyze the data. Line × tester analysis was used to find out association among traits and to estimate the effects of GCA and SCA. Highly significant differences were found among parents (lines, testers) and their F1 hybrids for all the parameters under study. Among parents, Line 9796 and tester 107 manifested as best general combiners and exhibited significant GCA effects for almost all the mentioned traits. In the case of F1 hybrids, 9793 × 118 and Punjab-2011 × 108 were recognized as best specific combiners exhibiting significant SCA effects. A higher value of SCA variance than the variance of GCA revealed the preponderance of non-additive genetic action. The degree of dominance revealed the involvement of both type of gene action for the traits under investigation. The deviations among total variation were mainly due to genotypes. Most of the yield associated traits were highly heritable with more than 80% heritability. These findings were confirmed by genetic gain. Thus, potential homozygous lines can be selected from transgressive segregants to improve yield and these crosses will be beneficial for commercial exploitation to heterosis.

Combining Ability, Heterosis and Gene Action Estimation by Using Line X Tester Analysis in Bread Wheat (Triticum astivum, L)

In order to investigate the combining ability, gene action and heterosis morphological, yield and its components traits in wheat F1 crosses using line x tester analysis. Experiment was conducted with sixty three genotypes consisting of fifteen lines, L1,L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15.and three testers namely; Gemmeiza 9 (T1), Giza 171 (T2) and Gemmeiza 11 ((T3) and heir forty five crosses made in line x tester mating at experimental Research Farm, Faculty of Agric., Tanta University during the winter successive growing seasons 2014/15 and 2015/16. A significant difference was found among lines, testers and line x testers for all the studied traits. Analysis of genetic revealed that GCA and SCA variances were significant for all traits, indicating the importance of both additive and non-additive components in the inheritance of thesis traits. The non-additive was more important for all the studied traits except days to heading and No. of grains/spike in which the additive was more important.The best general combining ability for earliness (Number of days to heading and maturity) were L5, L7, L9, L10 and L14for short plant were L2, L6, L10, L12 andL13 for spikes numbers/plant, grains numbers/spike and grain yield/plant were the parental lines L11 and L12. The best crosses for heterosis relative to mid parent and better parent were T1 x L7 and T1 x L9 for number of days to heading and maturity, while the cross T3 x L11 for spikes numbers/plant, grains number/spike and grain yield/plant.Heritability in broad sense were greater than the corresponding values of narrow sense for all the studied traits. Higher value for narrow sense 10.22% was obtained for days to maturity, while the lowest value 3.96 was detected for No. of grains/spike. The lines had higher contribution to the total variance than both testers and lines x testers, also the line x testers contribution were higher than the testers for all the studied characters excluding number of days to heading.

Line × Tester analysis for kernel yield and component traits in maize (Zea mays L.)

Line × Tester analysis performed using 10 female and 4 male parental lines and their 40 hybrids in yellow maize. The analysis of variance showed that the enormity of sca variance was higher than the gca variance for all the traits except for days to tasseling, days to silking and ASI. The ratio of σ2gca/σ2sca was less than unity for all the characters except days to silking, which indicated predominance of non-additive gene action in the inheritance of these traits. Based on general combining ability (gca) effects, none of the parents was good general combiners for all the characters. Parental line IMR-33 was good general combiner for cob yield per plant, kernel yield per plant, plant height, ear height and cob length, while it was average for rest of the traits except days to dry husk. The cross combination VL-1032 × WNC 40218 exhibited highest significant positive sca effects for cob yield per plant (63.08) and kernel yield per plant (49.09). The cross BLD-329 × BLD-270 exhibited highest heterobeltiosis and standard heterosis for both cob yield per plant and kernel yield plant.

Implications of Gene Actions for Different Qualitative and Quantitative Traits in Linseed (Linum usitatissimum L.)

The ninety crosses were evaluated for 27 qualitative and quantitative traits to study the different gene actions, genetic variances, heritability and genetic advances involved in parents and in their off springs. The analysis of variance showed highly significant differences present among all the treatments for all quantitative and qualitative traits. The estimates of genetic component of variances together with related genetic parameters indicated that the magnitude of SCA variances was more pronounced than their corresponding GCA variances for majority of the traits for all testers and lines in both generations which suggested the role of non-additive gene action in the inheritance of these traits. The information obtained from the present study exhibited most of the traits had high value of σ2s than σ2g and over dominance gene action so, it is necessary to maintain the heterozygosity in the population for the improvement purposes. The non-additive genetic variability is non-fixable in nature thus the breeding methods such as biparental mating followed by recurrent selection may accelerate the genetic improvement for the traits sought to be improved.

Heterosis and combining ability in cucumber (Cucumis sativus L.)

The objective of this work was to evaluate four parental lines of cucumber which included: ‘Zeina’ (Zna), ‘Beit Alpha’ (BA), ‘Straight 8’ (Strght 8) and ‘Calypso’ (Capso) and six F1s generated by diallel cross, using randomized complete block design with three replications to study heterosis and combining ability for yield and yield component traits. Estimated heterosis showed that cross ‘Zna × Capso’ had the highest Better Parent (BP) heterosis in total fruit yield/ha while ‘BA × Capso’ had the highest Mid Parent (MP) heterosis in the same trait. Significant general (GCA) and specific (SCA) combining ability variances were obtained in all the traits implying that both the additive and non-additive gene effects operated in the genetic expression of the traits. Relative magnitude of GCA and SCA variances indicated preponderance of additive gene action for all the traits. ‘Beit Alpha’ and ‘Straight 8’ are best general combiners while ‘BA × Capso’ and ‘Capso × Strght 8’ were the best specific combiners for total fruit yield.

Combining ability and gene action of some tomato genotypes under low light condition

Limitations in access to electricity in rural areas and substantial cost of supplemental lightning necessitate breeding as response to low light conditions. Seven inbred lines of tomato ( Solanum lycopersicum L.) and their F1 hybrids, including reciprocals, developed through a 7×7 full diallel cross were evaluated under two different levels of light. Mean square for light (L) effect was significant for total yield, average fruit weight and days to first flower. Variation attributable to Genotypes and genotype × light (G×L) interaction had significant effect on all studied traits except days to ripening for which G×L interaction was not significant. Diallel analysis across two environments indicated that general (GCA), specific (SCA) and reciprocal combining ability (REC) were significant for all characters implying importance of additive and non-additive gene action along with cytoplasmic effects on genetic expression of yield, yield components and earliness. Ratio of SCA variance to SCA variance and estimates of narrow sense heritability (h2n.s) demonstrated higher weight of additive effects in inheritance of yield, fruit number and days to ripening, while indicating predominance of non-additive effects for fruit weight and early flowering. Interactions GCA×L and SCA×L were significant for almost all studied features. A particular genotype could not be recommended for all traits, but variation among genotypes in response to ambient light was promising for feasibility of plant breeding for non-optimal light intensity and duration.

Genetic Control on Yield and its Attributing Traits in Rice withn Combining Abilities of the Parent for the Traits

Eleven genotypes of rice were evaluated for different yield and its attributing characters. Out of these eight parents were chosen as female and three parents were considered as male. These lines and tester were combined following Line × Tester crossing design to estimate combining abilities (gca effect) of Parentts and crosses (sca effect). Line × Tester analysis confirmed the influence of sca variance on most of the yield related characters which predicted that some characters were predominantly controlled by dominance gene actions with substantial amount of epistatic gene interactions. Some genotypes were found to be high general combiners for yield plant-1 with number of yield related characters like number of grains plant-1 and number of grains panicle-1.