Relative Heterosis Research Articles

Comparison of residual heterosis in F2 and F3 segregating generations of Indian Mustard [Brassica juncea (L.) Czern & Coss.] crosses

Abstract The present investigation was undertaken to study the residual heterosis in F2 and F3 populations of Indian mustard [Brassica juncea (L.) Czern & Coss.]. The study material included eight parents and the 28 crosses of Indian mustard in two generations, namely F2 and F3. The experiment was conducted over two years at Uttar Banga Krishi Viswavidyalaya, Cooch Behar, West Bengal, during Rabi season 2020-21 and 2021-22. Out of the 28 crosses, three crosses namely, Npj-194 × DRMR-15-16, Npj-194 × RW- 85-59 (Sarma) and Npj-194 × SKJM-05 were found to show significantly positive residual standard heterosis over the standard variety (SKJM-05) for both the characters siliquae per plant and seed yield per plant. This provides us evidence that by improving siliquae per plant, the character seed yield per plant can be improved. The promising cross populations which have shown significant standard heterosis for seed yield in F2 and F3, can be utilized for the development of hybrid varieties, which would be very much beneficial to the marginal farmers of our country as they would be able to use the F2 and F3 seeds of the hybrid varieties without any compromise with seed yield. Keywords: Residual relative heterosis, Residual heterobeltiosis, Residual standard heterosis, Indian Mustard, Segregating generations

Assessment of Heterosis and inbreeding Depression for Yield, and its Associated Components Traits in Rice (Oryza sativa L.)

The present investigation entitled was carried out at Main Rice Research Centre, Navsari Agricultural University, Navsari during kharif-2023 with an objectives to obtain information on manifestation of heterosis and extent of inbreeding depression involved in the inheritance of various yield attributing characters in rice (Oryza sativa L.). This study comprised three crosses using four diverse lines. The experimental material comprised of five generations each cross of pair parents i.e. P1, P2, F1, F2 and F3 of three different crosses were conducted in Compact Family Block Design with three replications during kharif 2023. For grain yield per plant all the three crosses (IRBB 55 × Mahisagar, IRBB 55 × GR-11 and IRBB 55 × TN-1) exhibited significant and positive relative heterosis as well as heterobeltiosis. Among them the highest mid parent heterosis of 39.67% and heterobeltiosis of 7.56% were exhibited by cross IRBB 55 × GR-11. This hybrid showed positive and significant relative heterosis for all the four important characters viz., productive tillers per plant, panicle length, grains per panicle and 100 grain weight. While, the inbreeding depression was found significant and positive for all the three crosses which is not desirable for grain yield per plant. Here, all the three crosses exhibited positive heterosis followed by positive inbreeding depression indicated that trait is under influence of non-additive type of gene action and heterosis breeding would be found rewarding for improvement for grain yield per plant.

Heterosis and Inbreeding Depression Studies for Fibre Quality Traits in Upland Cotton (Gossypium hirsutum L.)

Cotton hybrids have its own advantage than varieties in yield and fibre properties. Heterosis breeding helps in identifying F1 hybrids and in creating variability. The chief intention of any hybridization programme is to combine all the desirable genes present in two or more parents into a single genetic background. This investigation helped in identifying the extent of heterosis in crosses among four families in upland cotton (Gossypium hirsutum L.) which was conducted at college Farm during kharif 2021-23. The all 4 hybrids were derived by generation mean analysis study which were analysed for fibre quality traits in a Compact Family Block Design. For traits like Ginning percentage, uniformity index, Upper Half Mean Length, Lint index, and Fibre strength, most of the crosses showed positive and significant relative heterosis. While, heterobeltiosis was also found positive and significant for ginning percentage, uniformity index, Upper half mean length and fibre strength for most of the crosses under study. Most of the crosses under study also showed little inbreeding depression for traits like ginning percentage, uniformity index and fibre strength. Thus, by exploiting the benefits of heterosis while mitigating risks associated with inbreeding depression may lead to the development of superior hybrid varieties with consistently improved fibre quality.

Estimation of heterosis on CGMS based pigeonpea

Thirty-five hybrids generated from seven cytoplasmic male sterile lines and five fertility restorer lines were tested for determining heterosis. All studied traits except pod length, number of seeds per pod, and leaf area showed significant variations between the parents indicating a sufficient variability amongthe parents (lines and testers). The mean sum of squares of the hybrids suggested high heterosis for studied traits except for test weight and number of branches per plant. The findings showed noteworthy and affirmative relative heterosis for eaj hybrid. Top three hybrids viz. CMS GT 1615 A × GTR 105 (28.34% and 38.97%), CMS GT 1615 A × GTR 18 (24.36% and 34.66%) and CMS GT 1615 × GTR 23 (22.23% and 32.35%) identified for seed yield and its contributing traits on the basis of standard heterosis against standard checks GTH 1 and GT 101, respectively. These can be exploited commercially for heterosis breeding in pigeonpea.

Selected Thermotolerant Bivoltine Hybrids of Bombyx mori L. Exhibit Desirable Heterosis for Quantitative Traits under Beauveria bassiana Infection

Four thermotolerant bivoltine silkworm parents viz., B1, B4, B6 and B8 and their 12 hybrids viz., B1×B4, B1×B6, B1×B8, B4×B1, B4×B6, B4×B8, B6×B1, B6×B4, B6×B8, B8×B1, B8×B4 and B8×B6 were used in the experiments. One set of the parents and their hybrids were inoculated with Beauveria bassiana spore suspension (9.04 × 104 spores / ml), on the first day of the fifth instar before first feed and another set were exposed to high temperature (36 ± 1o C temp. & 85 ± 5 % RH) and their responses were studied in terms of heterotic expression of quantitative traits. Significantly highest positive relative heterosis under normal condition was recorded in B1×B4 hybrid for five characters (fifth instar larval weight, cocoon yield by weight, single cocoon weight, shell weight and filament length) and under muscardine inoculation significantly highest positive relative heterosis was recorded in the hybrid B4×B6 for ten characters (ERR, cocoon yield by number, fifth instar larval weight, cocoon yield by weight, single cocoon weight, shell weight, shell ratio, pupal weight, filament length and filament weight). Heterosis scoring over all the traits under muscardine inoculation revealed that the hybrid B4 × B6 scored high overall status of heterotic effects across the characters. Thus, B1 and B8 among parents and B1 × B8 and B4 × B6 among hybrids could be selected for dual stress tolerance against high temperature and muscardine disease.

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.

Genetic Components Derived Parameters and Heterosis in Okra under Saudi Arabia Conditions.

Four parental genotypes of okra were crossed in complete diallel design to study the direction and extent of relative heterosis and heterobeltiosis for yield and its associated traits for utilization of existing genetic diversity to develop heterotic F1 hybrids in okra. The additive genetic component (D) was significant in all studied traits except average pod weight. Nonadditive (H1 and H2) components were found to be significant in all studied traits. However, the values of the dominant effect (H1) were smaller than the D components for no. of nodes/plant, no. of pods/plant, weight of medium pods, weight of large pods, and total fresh pod yield. The maximum significant MP heterosis in the desirable direction (149.9%) was recorded for the weight of large pods/plot. The maximum significant heterobeltiosis in the desirable direction (120.1%) was recorded for the weight of small pods/plot followed by total fresh pod yield (107.4%), the weight of large pods/plot (104.9%), weight of medium pods/plot (92.1%), average pod weight (51.8%), number of pods/plant (38.4%), and plant height (34.3%). It could be concluded that plant height, average pod weight, and the number of branches could be considered for the development of elite hybrids (heterosis breeding) or inbred lines (pure line selection) in succeeding generations. Therefore, these parameters can be considered for selecting genotypes to improve the pod yield of okra. The superior crosses identified through heterosis analysis were Egyptian Balady × Line 4.1.18 (30.8 ton/ha), Line 4.1.18 × Egyptian Balady (29.8 ton/ha), Dwarf Green Long Pod × Line 4.1.18 (28.3 ton/ha), and Egyptian Balady × Dwarf Green Long Pod (27.6 ton/ha) as these crosses had high performance as well as significant and higher estimates of heterobeltiosis for fruit yield per plant and yield attributing other characters.

Study of heterosis for grain yield and its components in wheat (Triticum aestivum L. em. Thell.)

The extent of wheat heterosis was determined by synthesizing 45 hybrids in a 10×10 diallel method, eliminating reciprocals, to determine how widespread it is. The 57 entries that made up the experimental material—10 parents, 45 crosses and 2 checks (HD 3086 and UP 2628), were assessed over the course of rabi 2018–19 using a Randomized Block Design (RBD) with three replications, and observations were made for 12 characters. For yield and its component traits, analyses of heterosis over mid parent, better parent and two standard checks were conducted. ANOVA exposed that there was a high significance existed among all the genotypes for all the characters studied. Yield and its contributing traits have been evaluated for their maximum heterotic range. One cross i.e., CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2* KAU2/6/...×PBW 692 showed positive significance for relative heterosis, heterobeltiosis and standard heterosis over both checks for grain yield per plant. In terms of the number of productive tillers per plant and the number of grains per spike, UP 2901×QLD 73 was found to be a superior heterotic F1. By displaying a negative significant standard heterosis over both checks, the cross between CAL/NH//H567.71/3/SER1/4/CAL/NH//H567.71/5/2*KAU2/6/...×UP 2901 demonstrated its earliness. The desired significant relative heterosis, heterobeltiosis and standard heterosis for spike length were present in HD 3234×UP 2762. The finest heterotic cross combinations for harvest index were determined to be CAL/NH//H567.71/3/SER1/4/CAL /NH//H567.71/5/2* KAU2/6/...×UP 2762 and VORB/SOKOLL×QLD 73. Higher heterotic crossings may be used to identify transgressive segregants that will increase bread wheat production and yield-contributing characteristics.

Heterosis and combining ability for nutritional quality in bottle gourd (Lagenaria siceraria)

The study was carried during kharif 2021 and zaid 2022 at Vegetable Research Centre of G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand to investigate the nutritional properties of bottle gourd [Lagenaria siceraria (Molina) Standl] across various genotypes and hybrid combinations. Bottle gourd, a versatile crop with nutritional benefits, was analysed for traits like dry matter content, ascorbic acid, reducing sugar, non-reducing sugar, total sugar and total soluble solids. Promising parent genotypes, P6, P1 and P4 were identified based on their per se performance. The hybrid combination P2 × P7 exhibited exceptional results considering relative heterosis, heterobeltiosis and standard heterosis. Parent P3 demonstrated strong general combining ability for several traits. Notably, specific combining ability analysis identified hybrids like P2 × P6, P5 × P6, and P1 × P4 as promising for multiple traits. The prevalence of significant σ2SCA values over σ2GCA values highlighted the dominance gene action's role in governing these traits, suggesting the potential of hybrid breeding for genetic enhancement. In conclusion, the study emphasizes the importance of nutrient quality and presents strategies for harnessing hybrid breeding to improve these traits in bottle gourd.

Studies on Heterosis and Combiing Ability for Yield and Quality Attributing Traits in Chilli (Capsicum Annum L.)

Seven lines and four testers were crossed in line x tester mating design to evolve twenty-eight hybrids. These hybrids were studied along with their eleven parents for estimation of relative heterosis, heterobeltiosis and standard heterosis for Fruififteen characters. Observations were recorded on fifteen economically important traits viz., days to 50 percent flowering, plant height at maturity, plant spread, fruit length, fruit width, fruit pedicel length, placenta length, number of fruits per plant, fruit weight, number of seeds per fruit, 1000 seed weight, fruit yield per plant, ascorbic acid content, capsaicin content and capsanthin content. The hybrids L4 x T3 (LCA 625 × G-4) is the best hybrids followed by L7 x T4 (Pant C-1 × LCA 678) and L7 x T2 (Pant C-1 × K1) recorded significant standard heterosis for fruit yield per plant. Selection of hybrids for heterosis breeding based on per se performance, sca effects and standard heterosis will be more effective. It may be concluded that based on all the three criteria, the following three hybrids L4 x T3 (LCA 625 × G-4) and L7 x T4 (Pant C-1 × LCA 678) and L7 x T2 (Pant C-1 × K1) were identified as the superior hybrids, among the twenty-eight hybrids evaluated.

Interpretation of Mean Values and Extent of Heterosis Bottle Gourd [Lagenaria siceraria (Mol.) Standl.

Aims: To Study the mean values and heterosis for fruit yield with associated traits of bottle gourd.
 Study Design: Randomized block design.
 Place and Duration of Study: The seeds of F1 hybrids were produced during summer 2021 at Potato Research Station, S. D. Agricultural University, Deesa.
 Methodology: The experimental material consisted of twelve parents, their 35 Line × Tester crosses and one standard check (ABGH 1).
 Results: The study was undertaken to reveal mean and per cent heterosis level in bottle gourd [Lagenaria siceraria (Mol.) Standl.]. An examination of mean data of parents with (F1) hybrids for fruit yield and associated traits revealed that DBG 5 amongst females and ABGS 11-17 amongst males, while NDBG 132 × PUNJAB LONG, LOCAL × ABGS 14-25, and LOCAL × ABGS 11-17 amongst hybrids exhibited higher mean value for fruit yield per plant with some of its associated traits. The significant relative heterosis, heterobeltiosis and standard heterosis were perceived in many hybrids for different component traits. The F1 hybrids, NDBG 132 × PUNJAB LONG (75.30, 53.04 & 21.64 %), LOCAL × ABGS 14-25 (34.99, 27.77 and 20.71 %) and LOCAL × ABGS 11-17 (31.82, 23.49 and 19.27 %) manifested significant and positive heterosis over mid parent, better parent and the standard check ABGH 1 for fruit yield per plant. These crosses were also given best mean performance, hence hold promising for commercial exploitation.
 Conclusion: The analysis of variance revealed that significant differences among the parents for all traits. This indicated a sufficient variability in the parents (i.e., lines and testers) for studied trait. The best heterotic crosses NDBG 132 × PUNJAB LONG, LOCAL × ABGS 14-25, LOCAL × ABGS 11-17 and GPBG 108 × ABGS 11-24 for fruit yield per plant revealed significant positive heterosis over mid parent, better parent and standard check.

Estimation of Magnitude of Heterosis for Grain Yield and Related Traits in Sesame (Sesamum indicum L.)

Sesame (Sesamum indicum L.) is an important oilseed crop which is native to India and cultivated in around 2.3 million ha across its several states. India stands way below in terms of productivity compared to several other countries across the globe. Being an often-cross pollinated crop, heterosis even in a marginal magnitude could be exploited in sesame in varietal development. Hence, the present study was performed with the objective of estimating the extent of relative heterosis, heterobeltiosis and standard heterosis in eight cross combinations for important yield attributing traits in sesame in order to select promising cross combinations for utilization in heterosis breeding and/or selection of superior segregants in segregating generations. Eight cross combinations derived out of crossing high yielding parents viz., TMV (Sv) 7 and VRI (Sv) 2 as female and E8, DSS 9, DS 5 and Prachi as male in L × T fashion were utilized for the analysis considering TMV (Sv) 7 as the Standard parent. The analysis showed significant differences between the genotypes for all the characters studied. The hybrids showed Relative/ Mid parental heterosis ranging from 2.02 to 26.05 per cent; heterobeltiosis from -4.55 to 15.85 per cent and standard heterosis from -11.27 to 15.85 per cent for grain yield /ha. Mid Parental Heterosis (RH) was found to be positive and significant for the characters no. of branches/plant, no. of capsules / plant, grain yield (kg/ha) in all the hybrid combinations except VRI (Sv) 2 / Prachi. Based on heterobeltiosis, the hybrids TMV (Sv) 7 / E 8, TMV (Sv) 7 / DSS 9, TMV (Sv) 7 / DS 5, VRI (Sv) 2 / DS 5 could be selected since they showed significant heterobeltiosis for important yield contributing characters viz., no. of branches / plant, no. of capsules /plant and grain yield. With respect to the Standard heterosis for grain yield and contributing characters like no. of branches/plant, no. of capsules/plant and grain yield/ha the hybrids viz., TMV (Sv) 7 / E 8, TMV (Sv) 7 / DS 5 and TMV (Sv) 7 / DSS 9 showed positive and significant heterosis. Considering all the three types of heterosis, the hybrids TMV (Sv) 7 / E 8, TMV (Sv) 7 / DS 5 and TMV (Sv) 7 / DSS 9 may be selected for yield enhancement in Sesame.

Studies on Promising Restorer Lines for Yield and Yield Components in Rice (Oryza sativa L.)

The present investigation was carried out at Regional Agricultural Research Station, Maruteru with a set of 30 experimental hybrids developed by crossing three male sterile lines with 10 testers in Line × Tester mating design during kharif, 2022. The resultant 30 hybrids were evaluated in Randomized Block Design with two replications along with the parents and hybrid check, HRI-174 during rabi, 2022-23. Analysis of variance for yield and yield components revealed significant differences among the genotypes, parents, hybrids and parents vs. crosses for most traits, indicating significant differences among parents and hybrids, in addition to significant levels of heterosis for the traits studied. In general, the hybrids had recorded higher grain yield per plant, compared to the lines and were observed to be early and relatively tall with a more number of productive tillers per plant and increased panicle length compared to the parents. The hybrids, APMS 15A×RGL 5613, APMS 15A×MTU 1213, APMS 17A×RGL 5613 and APMS 17A ×MTU 2055had recorded significant and positive relative heterosis, heterobeltiosis and standard heterosis of more than 25 per cent for grain yield per plant and were identified as promising heterotic combinations for further evaluation and commercial exploitation.

Selection of inbreds with better combining ability is instrumental in developing CMS-based heterotic hybrids in tropical carrot (Daucus carota L.)

Abstract Carrot is an important vegetable crop worldwide valued for its fleshy edible roots of varied colours. Owing to its highly cross-pollinated nature and small flower size, cytoplasmic male sterility (CMS) is being utilized for hybrid development. Among different types of male sterility, petaloid CMS is widely used for hybrid carrot breeding globally. This study aimed to develop selection criteria for parents in developing heterotic F1 hybrids using CMS lines. A large number of agro-morphological traits and Simple Sequence Repeats (genomic-SSRs) were used to assess the diversity among parental lines. We developed 60 F1 hybrids by crossing four petaloid CMS lines and 15 testers in line × tester mating design and evaluated them in replicated randomized block design trial for four vegetative and 11 economic traits. The mean squares of all the traits in line × tester interactions were significant. The estimates of genetic components of variance indicated predominance of non-additive gene action except for root maturity, root length and core diameter. The hybrids with highest per se performance also had significant positive specific combining ability effects. The root yield and root weight showed highest heterosis percentage (33%). The best performing heterotic hybrids were DCatH-5392, DCatH-700 and DCatH-9892. Correlation between genetic distance and relative heterosis of economic traits indicated no significant association and thus genetic distance could not be used to predict heterosis. As most of the yield-related traits were controlled by non-additive gene action, heterosis breeding could be potentially used along with combining ability analysis to reduce time in selection of best parents and crosses in tropical carrot.

Estimation of Heterosis for Seed Yield and Yield Contributing Characters of Desi x Desi Crosses of Chickpea (Cicer arietinum L.) under Late Sown Condition

Aims: To estimate the relative heterosis & heterobeltiosis for seed yield and it’s contributing characters in chickpea. The study was conducted in chickpea for the evaluation of genetic makeup of chickpea genotypes and their further use in chickpea improvement program, information regarding their mean performance and heterosis is very helpful.
 Study Design: Randomized block design (RBD) was followed.
 Place and Duration of Study: The experiment was conducted at research farm, Rajasthan Agricultural Research Institute, Durgapura (SKNAU, Jobner, Jaipur, Rajasathan) during rabi2019-2022.
 Methodology: An investigation consisted of eight chickpea genotypes viz., RSG-888, CSJD-884, RSG-963, RSG-973, RSG-974, CSJ-515, Avrodhi and HC-5 and crossed in all possible combinationswere raised inrandomized block design (RBD) with three replications in late sown condition December, 2021.
 Results: The ANOVA (Analysis of Variance) for different characters revealed that the significant mean square due to generations and parents for all the studied characters under study.The maximum relative heterosis over mid-parent was observed as 49.99 per cent (CSJ-515 × HC-5). Similarly, maximum heterosis over better parent was observed as 35.46 per cent (RSG-973 × HC-5). Therefore, these crosses were observed more heterotic as well as heterobeltiotic for seed yield per plant under late sown environment.
 Conclusion: In this study additive and non additive type of gene actions were important in governing all traits studied resulting in high heterosis in selected cross combinations for seed yield per plant and attributed traits.

Studies on the Expression of Heterosis in Interspecific Hybrids of Sesame (Sesamum indicum L.)

The present study was undertaken to develop superior hybrids for yield and its component traits in Sesamum indicum L. through interspecific hybridization by utilizing S. malabaricum as one of the parents. Direct and reciprocal crosses were attempted using eight cultivated varieties and S. malabaricum, which evaluated a total of fifteen interspecific hybrids. Highly significant and positive heterosis was observed in a few hybrids for the vegetative traits. For single plant yield, the number of seeds per capsule, 100 seed weight, highly significant and negative heterosis was observed. The hybrid SVPR 1 x S. malabaricum had expressed significantly negative relative heterosis for days to first flowering, days to maturity, and plant height. The cross S. malabaricum x TMV 3 had shown highly significant and positive relative heterosis for the number of primary and secondary branches the number of capsules on the main stem and branches.

​Combining Ability and Heterosis Analysis for Seed Yield and Yield Related Traits in Table Pea [Pisum sativum (L.) var. hortense

Background: A study was carried out to estimate the general and specific combining abilities, as well as heterosis for seed yield and yield associated traits in pea lines. Methods: Twenty-eight cross combinations were generated using half-diallel mating design with eight parental lines. The mean values of seed yield and its contributing traits of parental lines and their offspring for each replication were used for statistical analysis viz., GCA, SCA and Heterosis. Result: The GCA and SCA were significant and indicating the presence of both additive and non-additive types of gene actions. AP-3, VL-7, Kashi_Nandini and PC-531 were identified as promising parents due to significant GCA effects on seed yield and other traits. Among the crosses Kashi_Nandini x PC-531, VL-7 x PMR-53, Arkel x Vl-7 and VL-7 x Kashi_uday hybrids were the most promising, with significantly higher SCA effects for seed yield and yield related traits. Seed yield showed significantly high heterosis ranged from -2.00% to 8.77 % (AP-3 x PC-531 and Arkel x PMR-53, respectively) and relative heterosis ranged from -0.75% to 14.10% (Kashi_uday x PC-531 and Arkel x PMR-53 respectively) significantly exhibited positive heterosis for seed yield over better parent and mid-parent.

Genetic Variance, Heterosis and Correlation for Yield and Fibre Quality in Four F1 Cotton Hybrids

The extent of phenotype and genotype variances, traits correlation and Principal components were investigated in F1 inter-varietal hybrid cotton. The F1 crosses were evaluated alongside their F2s, the eight involved parents and a single standard check. All the hybrids demonstrated positive and significant Relative Heterosis and Heterobeltiosis for sympodial branches and seed cotton yield per plant. Cross IV recorded the highest value for inbreeding depression of 61.7% in Seed cotton yield per plant. Days to first bursting recorded high heritability in narrow sense in IV while number of seeds per boll had same in Cross I. Cross I also recorded high genetic advance for Plant height, number of seeds per boll, seed cotton yield per plant, lint index, number of sympodia per plant and bundle strength, suggesting the effects of additive and dominant genes and absence of epistasis. Meanwhile, 87% of the accumulative variability was accounted for by the principal component 1, 2 and 3; the variability was mostly associated with plant height, seed cotton yield per plant, number of monopodia per plant, days to 50% flowering and bolls weight. The results revealed adequate genetic variability which can be exploited in a selection program for the traits. The positive and significant heterobeltiosis and standard heterosis exhibited in the F1 hybrids can be harnessed for commercial purposes after further evaluation.

Per se Performance and Heterosis in Relation to Gene Action for Seed Yield and Yield Related Traits in Chickpea

Background: The productivity of chickpea needs to be increased significantly to exploit the maximum benefit from the increasing world market demand for this crop. Hence, the objective of this study was to find suitable heterotic cross combinations for yield and yield related traits in chickpea. Methods: The present study on chickpea was conducted at Norman E. Borlaug Crop Research Centre, GBPUAT, Pantnagar, Uttarakhand, during rabi season of 2018-2019. It comprised a half-diallel set of seven diverse parents viz. PG5 and PG170 and five ICRISAT chickpea collections viz. ICC13124, ICC14778, ICC14815, ICC16348 and ICC16349 and their 21 F1 crosses were used for heterosis studies through 7×7 diallel analysis with respect to seed yield and other yield contributing traits. Result: Variance components of combining ability revealed that both additive and non-additive gene actions were important for yield and yield related traits. The parent ICC13124 was best general combiner for yield and related traits. It was also one of the parents in best specific combinations for seed yield. The crosses viz. PG170×ICC16349 (7.15), ICC13124×ICC14815 (3.22) and ICC13124×ICC14778 (3.00) were the best specific cross combinations for seed yield. The highest heterosis for seed yield was observed in cross PG170×ICC16349 (73.14%) followed by ICC13124×ICC14815 (43.17%) and ICC13124×ICC14778 (41.09%). The results showed direct association between the specific combining abilities of the crosses and heterotic response indicating the involvement of additive × additive type of interactions causing heterosis. Hence, the GCA, SCA and per se performance of the crosses should be given equal importance while selecting for heterotic combinations.

Study of Heterosis for Grain Yield and its Components Traits in Single Cross Derivatives of Maize (Zea mays L.)

The 45 F1 hybrids obtained by crossing in line x tester fashion were evaluated in three different environments along with parents and checks for grain yield traits and its component to harness the heterotic information over better parent and standard check. the number of hybrids depicted significant positive heterobeltiosis and relative heterosis on pooled basis were 38 and 40 respectively, for grain yield per plant. The estimates of standard heterosis for grain yield and its attributing traits showed that hybrid L14×T3 exhibited maximum estimates of significant positive standard heterosis suggesting that hybrid may be exploited before commercial release for confirmation of its superiority.