Significant SCA Effects Research Articles

Combining Ability and Heterosis Analysis in Maize: Insights from Line × Tester Hybridization

Fifty hybrids were obtained by crossing twenty five lines with two testers and were evaluated to study heterosis and combining ability for kernel yield per plant and its components traits. The experiment was laid out in simple lattice design with two replications during kharif 2019 at Agricultural Research Station, Peddapuram, East Godavari District, Andhra Pradesh. Heterosis studies revealed that twelve out of fifty crosses exhibited significant positive heterosis over the mid-parent, five crosses showed significant positive heterosis over the better parent and one cross exhibited significant positive heterosis over the standard check, DHM117, for kernel yield per plant. The cross PDM1732 × BML6 recorded significant heterosis over mid parent, better parent and standard check in desirable direction for kernel yield per plant. Out of the 25 lines evaluated in the present investigation, the line PDM1733 for protein content and kernel yield per plant was found to be good general combiner in desirable direction and can be utilized as parent for production of good hybrids by crossing with other divergent lines and can also be employed in the development of synthetic varieties. None of the fifty crosses recorded significant sca effect for kernel yield per plant.

Combining Ability and Gene Action for Grain Yield and Attributing Traits in Maize (Zea mays L.) Subjected to Drought Stress

Background: Maize production is subdued by many impediments that cause yield minimization. Among various biotic and abiotic stress factors, one significant cause of yield reduction in maize is drought stress. Methods: A set of 15 inbreds which were crossed with 3 narrow base testers in line × tester mating design, and resulting 45 F1s along with the parent inbreds and 3 commercial checks were then, in RCBD, subjected to drought stressed and well-watered conditions to assess their genetic worth during spring 2021. Result: The ANOVA unraveled significant mean sum of squares due to lines, testers and line × tester in pooled analysis for all the ten traits. The inbred EI-2188-2 followed by EI-2448 and EI-03-3 contained fair per se performance and significant high GCA effects over the environments for grain yield/plant, proline content and cob length whereas the cross EI-2448-1 × EI-2156 was found most promising hybrid with significant and high SCA effects across the environments regarding grain yield/plant, proline content and cob girth. Prevalence of non-additive type of genetic variance in governing most of the traits suggests adoption of heterosis breeding will be rewarding for improving yield and drought tolerance. Heterotic pooling of the highlighted inbreds and utilization of the superlative hybrids in further breeding programmes for drought tolerance is proposed.

Study on gene action, combining ability and heterosis for different traits in Indian mustard (Brassica juncea L. Cxern & Coss)

Abstract Combining ability and heterosis was investigated in mustard hybrids obtained from 7 × 7 half diallel cross. Twenty one F1s along with seven parents were evaluated in Randomized Complete Block Design. The combined analysis of variance revealed very significant differences among the parents for all morphological variables with the exception of secondary branches and siliqua length, indicating wide diversity among the parental material used in the present study. Significant GCA and SCA variance indicated additive and non-additive gene action across all the characters. The SCA variance components were larger than the GCA variance components for most traits indicating the prevalence of non-additive gene effects. Jawahar mustard × PM-30, showed a significantly positive SCA and better parent heterosis for seed yield per plant whereas five hybrids (Kranti × PM-30, Gujarat Mustard-3 × Pusa Mahak, Jawahar Mustard × PM-30, Jawahar Mustard × Pusa Mahak and PM-30 × Pusa Mahak) exhibited significant positive SCA effect for number of siliqua/ plant. Jawahar Mustard × PM-30, Varuna×Jawahar Mustard, Gujarat Mustard-3 × PM-30, exhibited highly significant heterosis over the mid-parent. Keywords: Brassica juncea, GCA, SCA, gene action, Heterosis

Combining ability and gene action analysis in okra (Abelmoschus esculentus L. Moench)

The present research was conducted in Okra to study combining ability and gene action in a set of 28 F1s developed by crossing seven lines and four testers. The experiment was laid out in a Randomized Block Design with three replications and observations were recorded on 12 traits viz. days to 50% flowering, days to first picking, number of internodes, number of branches plant-1, fruit length at maturity and harvest, number of fruits plant-1, number of seeds fruit-1, seed index, fruit weight, yield per plant and plant height. The results revealed that two lines viz., VRO-4 and Sel-2 were excellent general combiners for most of the traits in both positive and negative direction as per desirable traits. Cross VRO-6 x Varsha Uphar recorded highly significant SCA effects for eight traits and GAO-5 x GJO-3 for yield trait. Variance due to GCA was less than SCA, and the GCA/SCA ratio was less than unity indicating preponderance of non-additive gene action for all the traits. This suggested the feasibility of exploitation of heterosis. Keywords: Gene action, Fruit yield, Okra, GCA and SCA

Integrating Antixenosis Against Helicoverpa armigera (Lepidoptera: Noctuidae) and Micronutrition in Kabuli Chickpea (Cicer arietinum L.) Genotypes

ABSTRACTThe leguminous chickpea is a good source of protein, but its yield potential is frequently constrained by biotic stresses, primarily Helicoverpa armigera, a major havoc for cultivation of the crop. To develop host plant resistance for minimizing the losses due to the pod borer, five kabuli parents with desired traits for pod borer tolerance were crossed in diallel mating design to produce 10 crosses which were analysed for traits related to pod borer and nutrition. Based on correlation studies, trichome density was found positively correlated with phenol content, but both the traits were negatively associated with number of damaged seeds. Therefore, the tolerant genotypes were identified on the basis of phenol content, trichome density, number of damaged seeds and field rating. Among parents ICC 12197 was found superior in terms of yield and borer tolerance features with an intermediate pest resistance susceptible rating in addition to higher Fe content. However, significant sca effects for higher phenol content and seed yield in ICC 11764 × ICC 14190 were recorded with reduced number of damaged seeds in addition to higher Fe and Zn content. It was observed that the specific combination involved good and poor combiners for each trait. The same cross also showed significant standard heterosis in desirable direction for phenol content, trichome density, number of damaged seeds and seed yield. Additionally, the ratio of σ2 GCA to σ2 SCA revealed nonadditive gene action in controlling the expression of phenol content, trichome density, number of damaged seeds and Fe and Zn content. Thus, breeder may focus efforts on desirable cross utilizing selection in further segregating generations for higher phenol content, trichome density and Fe and Zn content in addition to yield‐related traits while lesser number of damaged seeds per plant to concentrate for development of pod borer resilient high yielding kabuli genotypes to combat micronutrient deficiency.

Combining Ability and Heterosis for Yield and Yield Attributing Traits in Bitter Gourd

A study was conducted during Rabi 2022 and Kharif 2023 at the Department of Horticulture, University of Agricultural Sciences, Bangalore to develop 49 F1 hybrids through the utilization of line × tester mating design. The parents and developed hybrids along with standard check (Pusa Hybrid 6) were evaluated in Randomized Complete Block Design) and Alpha lattice design, respectively, for yield and yield attributing traits. The combining ability analysis revealed that among 14 parents, Pusa Rasdar, Pusa Do Mausami, Pusa Vishesh, Hirkani and Pant Karela 4 were identified as best general combiners for most of the studied yield and yield attributing traits. The estimates of heterosis revealed that the hybrids, Konkan Karali × Pant Karela 4 (45.45%), Konkan Tara × Pusa Do Mausami (23.48%), Pusa Rasdar × Phule Green Gold (126.87%) and Hirkani × Pusa Do Mausami (46.20%) were top performing hybrids over standard check for fruit length, diameter, average weight and number of fruits per vine, respectively. Similarly, Pusa Rasdar × Pant Karela 4 (127.06%), Priya × Pusa Do Mausami (101.05%), Punjab 14 × Pusa Do Mausami (100.53%) and Pusa Rasdar × Pant Karela 3 (97.61%) were top performing hybrids over standard check for yield per vine. These hybrids also recorded highest significant sca effects hence, considered as good specific combiners.

Genetic Evaluation of Heterosis and Combining Ability of Quality Protein Maize (Zea mays L.) Hybrids under Terminal Heat Stress Conditions

Background: The development of quality protein maize (QPM) hybrids tolerant to terminal stress environments has been an essential strategy for reducing the associated loss in grain yield. A study by Badu-Apraku et al., (2019) employed line × tester analysis in QPM breeding, highlighting its efficacy in selecting QPM hybrids. While QPM varieties resistant to disease, drought and environmental stresses have been developed conventionally, the adoption of improved QPM genotypes in farmers’ field is restricted mainly due to lack of proper team effort among maize breeders, farmers, agricultural extension workers and other relevant stakeholders. Methods: In line × tester mating design, six lines and three testers were crossed under heat stress environment and 18 F1s along with parental lines were evaluated along with check varietal during summer season, 2023, P.G research farm, CUTM, Paralakhemudi, Odisha. The objective of the current study was to evaluate parental lines and its crosses based on combining ability and heterosis. Result: ANOVA revealed significant to revealed significant differences for all the traits between parents, lines, testers and lines vs testers, except for cob height, chlorophyll content and canopy temperature. 𝛔2GCA/𝛔2SCA values for parents/hybrids recorded lower than unity for all the trait studied suggesting preponderance of non-additive gene action. Parental lines CML149, CML143 and CML330 are the best general combiners for early flowering, grain yield per plant and antioxidant status. Among eighteen crosses, two hybrids CML149 × CML330 and CML143 × CML193 recorded significant SCA effects for early flowering, grain yield per plant and antioxidant levels. Hybrids CML149 × CML330 (33.31%) and CML143 × CML193 (28.31%) noted significant standard heterosis for grain yield per plant over commercial check, HQPM-1. Hybrids CML149 × CML330 and CML143 × CML193 were resilient to terminal heat stress as they didn’t exhibit signs of leaf firing, tassel blast, root lodging and loss of yield.

Combining Ability and Hybrid Breeding in Tunisian Melon (Cucumis melo L.) for Fruit Traits

A half-diallel cross study of seven melon inbred lines was carried out. The seven parents and their 21 F1 hybrids were evaluated for precocity of maturity, average weight per fruit, and fruit quality (fruit size, rind thickness, and soluble solids). The Diallel analysis was investigated for breeding values of these melon genotypes via general and specific combining ability, relationships between general and specific combining ability, and heterosis for the evaluated traits. The analysis of variance of the traits evaluated indicated highly significant differences among genotypes, suggesting the presence of adequate genetic variation for breeding. Additive genetic effects were most important with respect to fruit weight, while genetic dominance and epistasis effects mainly controlled fruit quality traits (fruit size, rind thickness, and TSS). Parent 1 (P1) and parent 3 (P3) had significant positive general combining ability effects for fruit weight. Also, P3 had positive general combining ability effects for fruit length and diameter, and cavity diameter. P3 was found to show maximum significant GCA in the desirable direction for all the traits except for TSS. Evaluation of heterosis (%) revealed that hybrid P1 × P3 can be considered as the best-performing hybrid for average fruit weight, TSS, and precocity, which also exhibited the highest positive and significant SCA effect for these traits. These results suggested that, among the melon genotypes studied, there is the potential to generate superior new varieties in hybrid production.

ASSESSMENT OF COMBINING ABILITY FOR YIELD AND YIELD RELATED TRAITS IN SPRING WHEAT (TRITICUM AESTIVUM L.)

Grain yield and other related characters were studied in 18 F1 generations along with nine parents (six lines and three testers) which were evaluated for combining ability with three replications in a randomized complete block design (RCBD). The results indicated that among various lines, line 9479 was identified as a good general combiner for the traits, viz., spike length, spikelet’s per spike, and 1000-grain weight, whereas, Line 9486 appeared as a good general combiner for the characters, flag leaf area, plant height, peduncle length, number of tillers per plant and 1000-grain weight. Line 9515 for flag leaf area, plant height, and spike length. Line 9519 for the number of tillers per plant, grain yield per plant, and plant height; line 9520 for peduncle length, number of tillers per plant, grains per spike, grain yield per plant and 9521 was identified as good general combiner for the characters spike length, spikelet’s per spike, number of grains per spike and spike density. Tester Punjab-11 emerged as a good general combiner for the traits; peduncle length, plant height, flag leaf area, and number of tillers per plant, whereas, Tester Ass-11 appeared as a good combiner for the spike length, peduncle length, 1000-grain weight, and flag leaf area. Tester Chakwal-50 identified a good general combiner for the number of tillers per plant, plant height, grains per spike, spikelets per spike, grain yield per plant, 1000-grain weight, and spike density. Out of 18 cross combinations, seven crosses viz. 9479 × Aas-11, 9486 × Aas-11, 9515 × Aas-11, 9519 × Chakwal-50, 9520 × Punjab-11, 9521 × Punjab-11, and 9521 × Aas-11 emerged with significant positive SCA effects for grain yield per plant. Thus, these crosses can be exploited for grain yield per plant by using biparental mating system.

Unearthing hybridization opportunities for augmenting biomass yield and harvest index in rajmash (Phaseolus vulgaris L.)

In present study, 21 F1 hybrids derived from crossing between seven female genotypes and three male testers following a line × tester mating design were evaluated for analyzing the component of genetic variation and heterosis of yield contributing traits. The components of variances due to gca and sca revealed the predominance of non-additive gene action for biomass and harvest index. The average better parent heterosis (BPH) and standard heterosis (SH) for Biomass yield (BY) was 43.71 and 114.67, respectively, and the average BPH and SH for the Harvest index (HI) was -13.04 and -20.45, respectively. The higher magnitude of the BPH and SH recorded for BY indicated that the scope for increasing the HI in Rajmash is limited and that further increases in productivity have to come mainly through enhanced BY. The parent RR21-01 and GR 1 were good general combiners for biomass, TRCR 3, TRCR 2, SKAU-R-19 and RKR 1033 for harvest index. Cross combinations IPR-277- 19 × HUR recorded positively significant sca effect for BY and IPR-277-19 × GR, TRCR 3 × GR 1, TRCR 2 × GR 1, IPR-205-19 × HUR, IPR-277-19 × GR 1, SKAU-R-19 ×RKR 1033, RR-21-01 × HUR and RR-21-12 × GR 1 for HI. These results demonstrate that the selection of parents should not only be based on per se performance but also on combining ability and heterosis for achieving genetic improvement in Rajmash,

Line×Tester Analysis for Heterosis and Combining Ability for Seed Yield and its Component Traits in Indian Mustard

Twelve advanced lines/varieties of Indian mustard (Brassica juncea L.) were selected for building the experimental material. It consisted of 8 lines and 4 testers, mated in Line × Tester design during rabi season 2018-19. These parents alongside with their 32 F1s were evaluated in RBD in rabi season 2019-20 for 13 traits including seed yield per plant (g), glucosinolate content (µmole/g) and oil content (%). Analysis of variance for combining ability showed that significant differences were present amid treatments for all the characters, except for siliqua length and seeds per siliqua. Line PAB 17-1 was identified as a good combiner on the basis of their GCA effect for seed yield, test weight; PAB 17-15 for number of primary branches, number of secondary branches, PAB 17-21 for plant height, length of main raceme, siliquae on main raceme, glucosinolate content and PAB 17-23 for oil content. Highest significant SCA effect was shown by cross-combination PAB 17-2×PHR-2 for seed yield per plant, PAB 17-23×NRCHB-101 for glucosinolate content and PAB 17-1×PAB-9511 for oil content. Cross combination PAB 17-2×PHR-2 showed highest heterobeltiosis (BP) for seed yield per plant followed by PAB 17-1 × PHR-2. The magnitude of heterosis over BP in the desired direction was quite high ranging from -36.18 to 160.14. Cross PAB 17-23×PHR-1 for oil content showed highest heterosis over BP. Cross combination PAB 17-15×PAB-9511 showed highest relative heterosis for seed yield per plant and PAB 17-20×PAB-9511 for oil content. Similarly PAB 17-2×PHR-2 showed highest economic heterosis for seed yield per plant.

Identification of Potential Tropical Maize Inbred Lines with Early Maturity for Drought-Prone Environments

The present study was undertaken during October, 2020–January, 2021 at Maize Research Centre, Professor Jayashankar Telangana State Agricultural University, Rajendranagar, Hyderabad, Telangana state, India to identify potential inbred lines and hybrids with early maturity and high yield through combining ability analysis and heterosis. Six lines and four testers were crossed in L×T design to obtain 24 crosses. Evaluation of these crosses and their parents for combining ability revealed significant differences due to lines, testers and their crosses indicating the existence of wider variability among the material used in the study. Maize line MGC 434 (91 days), two testers GP-170 and PFSR-56 (91 days), and one hybrid MGC-445×PFSR-132 (83 days) were identified as early duration genotypes. Four lines MGC-444 (-3.13), MGC-440 (-2.71), MGC-439 (-1.96) and MGC-445 (-0.46) with significant negative GCA effects were identified as best general combiners for early maturity. Eight hybrids, MGC-439×BML-14 (-4.99), MGC-445×PFSR-56 (-4.65), MGC-461×PFSR-56 (-3.65), MGC-445×PFSR-132 (-3.60), MGC-434×BML-14 (-2.32), MGC-439×GP-170 (-2.10), MGC-440×PFSR-56 (-2.07) and MGC-440×GP-170 (-1.01) with significant negative SCA effects were considered as best cross combinations with early maturity. The inbred parents and cross combinations with early maturity identified in the study can be utilized for development of hybrids suitable to drought prone environments.

Combining Ability Studies for Yield and Yield Attributes in Bajra

In this study combining ability and gene action were studied in eight quantitative attributes in pearl millet using seven male sterile lines and three restorers which were crossed in Line x Tester design. Analysis of variance for combining ability revealed significant differences among mean squares for lines, testers and lines x testers for all the characters except for spike girth, lines for spike length and lines x testers for days to maturity. These results are indicative of importance of both additive and non-additive genetic variances in the expression of these traits. The ratio of GCA variance and SCA variance indicated the predominance of non-additive gene action for all the eight characters studied, i.e. days to 50% flowering, days to maturity, plant height, number of productive tillers per plant, spike length, spike girth, dry fodder yield and grain yield. Among the lines, ICMA12222 and ICMA 94444 and the tester ICMR 07555 displayed high GCA effect for grain yield per plant. Significant and positive SCA effect for grain yield per plant was displayed by the cross ICMA 12222 x ICMR 07666 followed by ICMA 98444 x ICMR 07555, ICMA 98111 x ICMR 07555 and ICMA 88006 x ICMR 08111. These crosses have been identified as best combiners to give higher grain yield hybrids and could be further evaluated to confirm their stable superior performance.

Combining ability analysis of Cucurbita moschata D. in Côte d'Ivoire and classification of promising lines based on their gca effects.

Cucurbita moschata varieties grown in Africa have very low yield. They have been neglected, and totally ignored in agricultural research programs. However, interest in their fruits, seeds, flowers and leaves is growing nowadays due to their nutritional and medicinal potentials. That growing interest has prompted plant breeders and agronomists to develop research programs for their improvement. A complete diallel cross analysis of four parental lines, Long, Zouan-H, Oval, and Soubre and their twelve F1 hybrids, was carried out in a farming environment at the University Nangui Abrogoua, Abidjan, Côte d'Ivoire. The four parental lines and the F1 hybrids were evaluated for their general performances, combining abilities, potency ratio and heterosis effects. The investigated traits included plant height, and eleven fruit- and seed-related characters. The analysis of variance showed significant differences for all traits studied. In addition, the diallel model yielded highly significant gca effects of the female parents. The gca effects of the male parents were significant for all traits except plant height, length of the fruit, width of the fruit and length of the seed. Highly significant sca effects were observed in the crosses for all the traits. Strong maternal effects were observed for the weight and diameter of the fruit, weight of the pulp, number of seeds per fruit, weight of the fresh seeds and 100-seed weight. The general predictive ratio approached the value 1 for all the traits except weight of the fresh seed and width of the dry seed. Most of the characters under this study are predominantly determined by the effects of additive genes. But, weight of the fresh seed and width of the dry seed may be controlled by non-additive genes. Mid-parent heterosis was significant for all measured traits in the crosses, except the length of the fruit. And better-parent heterosis was significant for all traits except plant height, number of fruits per plant and length of the fruit. Gene expression is described by a super-dominance for many traits, and partial dominance for some other traits in all twelve F1 hybrids. Classification of the parental lines based on the effects of their general combining ability grouped the Soubre lines as promising contributors to fruit yield. The parental lines Long and Oval formed another group likely on the basis of the small size of their fruits, the small pulps, the smaller number of fruits per plant and the large number of seeds per fruit. However, Long would be a candidate parent for the development of cultivars with longer vegetative growth. The parental line Zouan-H formed the third group and it was mostly characterized by its large number of seeds per fruit and relatively large fruits.

Gene Effect Analysis for Grain Yield, Yield Components and Physiological Characters in Bread Wheat Under Water Limited Conditions of Bundelkhand Region

The present study was conducted during rabi, 2019-20 and 2020-21 with 08 bread wheat diverse parents and their 28 F1s (half diallel, excluding reciprocals) to study gene effects and heterosis for grain yield, yield attributes and physiological traits. Days to heading and days to maturity had general mean values of 89.8 days and 130.4 days, respectively. The parent GW 322 showed early heading in 88 days, while the genotype DBW 110 exhibited early maturity in 128 days. The hybrid NW 5054×PBW 723 (13.45 cm) had the highest spike length, followed by HD 3086×NW 5054 (13.40 cm) and PBW 723×NIAW 34 (13.25 cm). The grain yield per plant ranged from 17.37 g to 21.85 g in parents and 14.99 g to 23.41 g among hybrids. The cross HD 3086×K 1006 (23.41 g) and the parent HD 3086 (21.85 g) depicted the highest grain yield per plant. The parent NIAW 34 and the hybrid HD 3086×NIAW 34 showed the highest chlorophyll fluorescence. All three key physiological traits showed significant and positive associations with grain yield and harvest index. All the seventeen characters showed high GCA effects than SCA effects and indicated for preponderance of additive gene effects for yield, its components and physiological traits. An appraisal of GCA effects found that HD 3086 was a good general combiner for the majority of characters, while the crosses, HI 1544×NIAW 34, HI 1544×GW 322 and NW5054×PBW723 with significant SCA effects were found promising under water limited conditions of Bundelkhand region.

Combining ability and gene action studies in castor (Ricinus communis L.)

The present study of combining ability and gene action studies will be helpful in identifying better combiners to yield superior hybrids along with selection protocol for the trait of interest. Analysis of variance studies revealed that significant variation exists in the material understudy. Higher estimates of SCA variance were observed than the GCA variance except for seed yield indicating preponderance of non-additive gene action in governing the traits. Significant gca effects were observed in SKP-84 and ICS-142 for seed yield and PPL-1001, SKI-215, DCS86, PCS-327 and Kiran for oil content. Significant sca effect was observed for the crosses viz., M-574 x Kiran, PPL1001 x SKI-215 and SKP-84 x JI-244 for total yield.

Combining ability analysis for yield and it’s contributing characters in Indian mustard

Fifteen F1 crosses of Indian mustard [Brassica juncea (L.) Czern & Coss] obtained by half diallel fashion using six parents (excluding reciprocal) and evaluated along with parents and checks to study the combining ability. The parent NRCHB-101 and Pusa Mustard-31 were recorded as good general combiners for seed yield and it attributing characters. The crosses NRCHB-101 × Pusa Mustard-31 and Pusa Mustard-31 × Kranti both showed significant negative SCA effects for seed yield and most of its contributing characters and also exhibited significant mean for most of yield contributing characters. These crosses can be forwarded to next generation for producing genotypes of inherent superiority by blending and mixing maximum favorable following by simple selection methods.

Combining ability, heterosis and gene action for yield and its component traits incastor (Ricinus Communis L.)

An investigation on combining ability, heterosis and gene action for yield and its component traits in castor was carried out at AICRP Castor, UAS, Bangalore involving fifty hybrids developed from five pistillate lines as females and 10 testers as males. Analysis of variance revealed significant differences among parents and crosses for all yield attributing traits. The line YRCP-1 and tester RG-3160 showed significant positive effect for seed yield. The cross MCP-1×RG- 3160, expresses significant SCA effect for earliness, spike lengths, capsules on primary spike and seed yield/plant. Hybrids MCP-1 × RG-2787 (157.50 g) and DPC-22 × RG-2787 (186.77 g) involving poor performing parents produced high magnitude for seed yield/plant and yield attributing traits like 100 seed weight and oil percent (%).

Diallel Crosses of Cotton (Gossypium hirsutum L.)—Enhancement of Fiber Properties in Future Cultivars for Burkina Faso

The market value of cotton in exporting countries, such as Burkina Faso, depends on the quality of major fiber properties. A lack of variation among the genetic resources available in Burkina Faso hinders breeding progress to meet fiber quality demands in future cultivars. F1 populations from a half diallel crossing scheme between lines developed at Texas A&M AgriLife cotton breeding program at Lubbock and germplasm accessed from Burkina Faso were evaluated for fiber property enhancement. Crosses exclusively within common origin materials did not result in highly enhanced hybrids. Hybrids within American materials expressed significant SCA effects undesirable for future cultivars in Burkina Faso. Five hybrids within the Burkina Faso material expressed significant SCA effects: two of them implicating FK37 as the better parent in transmitting superior targeted fiber traits to its progenies. Hybrid FK37xE9 significantly enhanced UHML, Str, UI and SFI but not Mic and Rd. Inter-program hybrids with at least one significant SCA effect were crosses with female American lines and male Burkina Faso parents. Hybrids E53x16-2-216FQ, E53x15-10-610-7 and E32x15-10-610-7 showed significantly improved Str and UI for the most economically important traits, which also include Mic, UHML, SFI, Rd and +b. Together, the GCA and SCA effects, heritability and correlations showed more additive than non-additive gene actions. Therefore, knowledge of the best combiners and hybrids could be used in the cultivar development process to enhance value with improved fiber characteristics.

Combining ability analysis for seed yield and its attributes in Indian mustard [Brassica juncea (L.) Czern and Coss

The hybrids were developed by adopting diallel mating design excluding reciprocals involving ten diverse Indian mustard genotypes during rabi 2007-08. The resultant 45 hybrids along with their parents were evaluated in a Randomized Block Design with three replications under four environments viz., timely sown at Sardarkrushinagar (E1) and Ladol (E2), and late sown at Sardarkrushinagar (E3) and Ladol (E4), during rabi 2008-09. Combining ability analysis on pooled basis, revealed importance of both additive and non-additive genetic variances for the control of various traits. However, the ratio σ2 gca/σ2 sca indicated preponderance of non-additive gene action for days to 50% flowering, days to maturity, seed yield/plant and oil content, while additive gene action was preponderant for rest of the traits. The parents RK 9501, GM 1 and GM 2 were good general combiners, whereas, the crosses 'RK 9501 x GM 2', 'GM 1 x GM 3' and 'GM 3 x SKM 139' were found to be the best specific combinations for seed yield/plant and some of the important yield contributing traits. However, on the basis of per se performance, exploitable heterosis and significant sca effects for seed yield/plant and some of its important components, the above hybrids were considered to be the most promising for exploitation of heterosis.