The trial was carried during 2011-2013 on the second experimental field of the Institute of forage Crops-Pleven, Bulgaria. Populations of P1, P2, F2 and F1 of the crosses Shtambovii × Pleven 10 and Rosacrono × Pleven 4 and their reciprocals were investigated. Heterosis for the investigated traits was found in the hybrids of F1 generations. The cross Rosacrono × Pleven 4 had the highest positive true heterosis for plant height (31.54%), height to first pod (15.44%) and pod length (17.11%); the cross Shtambovii × Pleven 10—for nods per plant (56.10%) and pod width (20.38%); Pleven 10 × Shtambovii—for 1000 seeds mass (14.65%) and Pleven 4 × Rosacrono—for number of seeds per pod. In F2 the plants from Rosacrono × Pleven 4 had the strongest depression for plant height (28.26%), height to first pod (27.74%) and pod length (18.13%); Shtambovii × Pleven 10—for 1000 seeds mass (32.22%) and number of seeds per pod (13.87%). The stability of the studied characters was determined. Their variation in F1 in the hybrid combination between Shtambovii andPleven10 was higher than F1 of Rosacrono and Pleven 4. For more traits in direct crosses variability was found to be lower in relation to the reciprocal crosses in both combination. The genetical part in phenotipycal expression for height to first pod (Pleven 10 × Shtambovii), pod length and number of seeds per pod (Pleven 4 ×
Field pea is an important crop among pulses in the country due to its multiple uses like vegetable, chola, besan, dal etc. Field pea plays an important role in improving protein in diet as its protein level reaches up to 40 per cent on dry weight basis. For achieving future improvement, there is a great need to develop high yielding culti- vars. The plant breeder depends upon variability present in the material for the improvement of quantitative and qualitative characters and their mutual association with seed yield [
Yield and production are affected by one or several major genes and also by multiple gene interactions, the separation of these effects is of great importance to understand the expression at the phenotypic level and to pre- dict the segregation of a cross evaluated in the field. This information is important to establish a crop strategy, in which a greater expression of the desired genes appears [
Genetic variation of phenological, morphological and yield traits, such as flowering, plant height and seed weight, can be the result of characteristic segregation coded by simple genes and also the interaction among multiple genes. The determination of genetic effects is of great importance to understand expression at the phe- notypic level and to predict the segregation of characteristics when a cross between contrasting individuals is carried out [
In populations, generated from a cross between two pure parents, different methods have been proposed for the identification of the effects of genetic components on quantitative traits using lineal models of mixed distri- bution generated from generation means, variances and likelihood based techniques [
The aim of the present investigation was to determine the character of inheritance, degree of gene interactions and genetic part in the phonotypical expression of some quantitative traits in forage pea populations by using genetic analysis with a view to the rational carry out of selection.
The experimental study was conducted during the 2011-2013 period in second expеrimental field of the Institute of Forage Crops, Pleven, Bulgaria. The parent-form used for crossing were from our collection: spring forms (Pisum sativum ssp. sativum)-Shtambovii and Pleven 4, winter types (Pisum sativum ssp. arvense)-Rosacrono and Pleven 10.
The characteristics of these varieties were reported in
Variety | Pleven 10 | Pleven 4 | Shtambovii | Rosacrono |
---|---|---|---|---|
Origin | Bulgaria | Bulgaria | Russia | Russia |
Vine type | long-prostrate | long semi-erect | short semi-erect | long semi-erect |
Flower position | axial | axial | terminal (with fasciation-fa, fac) | terminal (with fasciation-fa, Fac) |
Stipule type | normal | normal | double | double |
Leaf type | normal | normal | normal | normal |
Flower color | purple | white | white | pink |
Plant height, cm | 78d | 98c | 34a | 134b |
Height to first pod, cm | 65 d | 56b | 27a | 80c |
Nods per plant | 20.47ab | 12.68b | 4.2a | 11.64ab |
Pod length, cm | 5.94a | 5.61a | 5.37a | 5.78a |
Pod width, mm | 13ab | 10ab | 9a | 10ab |
1000 seeds mass (g) | 229.81 | 121.60 | 175.67 | 142.78 |
Number seeds per pod | 3.61b | 3.78 | 2.56a | 3.32 |
a, b, c, dstatistically proven differences in P = 0.05.
gression (Tn) in F2 [
All experimental data were processed statistically with using the computer software MS Excel for Windows XP.
The data for plant height (
At the direct crosses the inheritance of this trait higher meaning play the domination, i.e. predominate the fa- ther’s components, which determinate longer stem. At the reciprocal crosses there were an epistatic gene effects (hp2 > hp1). Similar was the inheritance of height to first pod. Exception was Pleven 4 × Rosacrono, which was characterized with intermediate inheritance of the traits (hp1 = −0.01). In all hybrids there was plant’s depression (from 0.73% to 27.74%).
Epistatic gene effects prevail in nods per plant. All hybrids demonstrated high positive hypothetical heterosis. Especially for Shtambovii × Pleven 10 and its reciprocal, which true heterosis was also positive. Only Pleven 4 × Rosacrono is characterized with positive value of the parameter depression. Negative domination (hp1 > hp2) was for pod width in Pleven 4 × Rosacrono where dominate genes of variety Rosacrono. This cross reveal also the lowest negative heterosis. Positive were the heterosis behaviour of the hybrids of Shtambovii and Pleven 10 independently of the cross direction, which showed the highest depression also (from −1.17% to 8.57%). In the other hybrid combinations the inheritance was epistatic. The degree of dominance for pod length show, that the inheritance was negative dominant to over-dominant at Pleven 4 with Rosacrono and epistatic at Shtambovii with Pleven 10. The hybrids demonstrated positive heterosis and relative high depression for this trait with ex- ception of Shtambovii × Pleven 10 (−0.6%).
The character 1000 seeds mass was inherited semi-dominant at combination with the participation of Rosa- crono and Pleven 4. In the rest hybrids this trait was inherited positive dominant and over-dominant. Positive hypothetical heterosis effect (from 4.71% to 26.49%) as and depression were established in all hybrids. The combination Shtambovii with Pleven 10 was showed positive true heterosis. At almost all hybrids (without
Hybrids | F1 | F2 | Heterosis F1 (%) | Depression F2 (%) | Degrees of dominance | ||
---|---|---|---|---|---|---|---|
Hypothetical | Real | in F1 (hp1) | in F2 (hp2) | ||||
Plant height | |||||||
Shtambovii × Pleven 10 | 123.90* | 102.15 | 47.68 | −7.26 | 17.55 | 0.80 | 0.73 |
Pleven 10 × Shtambovii | 104.50 | 106.75 | 24.55 | −21.78 | −2.15 | 0.41 | 0.92 |
Rosacrono × Pleven 4 | 129.50* | 92.90 | 46.53 | 31.54 | 28.26 | 4.08 | 0.9 |
Pleven 4 × Rosacrono | 96.63 | 100.60 | 9.34 | −1.85 | −4.11 | 0.82 | 2.43 |
Height to first pod | |||||||
Shtambovii × Pleven 10 | 73.95 | 62.50 | 38.87 | −7.04 | 15.48 | 0.79 | 0.70 |
Pleven 10 × Shtambovii | 61.85 | 61.40 | 16.15 | −22.25 | 0.73 | 0.33 | 0.62 |
Rosacrono × Pleven 4 | 75.15* | 54.30 | 24.27 | 15.44 | 27.74 | 3.17 | −2.67 |
Pleven 4 × Rosacrono | 60.42 | 53.00 | −0.09 | −7.19 | 12.28 | −0.01 | −3.23 |
Nods per plant | |||||||
Shtambovii × Pleven 10 | 18.16 | 19.86 | 129.46 | 56.10 | −9.37 | 2.75 | 6.42 |
Pleven 10 × Shtambovii | 17.88 | 22.07* | 125.85 | 53.64 | −23.48 | 2.68 | 7.61 |
Rosacrono × Pleven 4 | 20.39 | 24.91* | 23.03 | −0.39 | −22.19 | 0.98 | 4.28 |
Pleven 4 × Rosacrono | 20.46 | 18.88 | 23.45 | −0.05 | 7.74 | 1.00 | 1.18 |
Pod width | |||||||
Shtambovii × Pleven 10 | 11.48 | 10.50 | 24.87 | 20.38 | 8.57 | 6.67 | 7.61 |
Pleven 10 × Shtambovii | 11.24 | 11.38 | 22.33 | 17.93 | −1.17 | 5.99 | 12.75 |
Rosacrono × Pleven 4 | 11.11 | 12.98* | −5.20 | −14.77 | −16.86 | −0.46 | 1.92 |
Pleven 4 × Rosacrono | 10.63 | 10.94 | −9.22 | −18.39 | −2.85 | −0.82 | −1.18 |
Pod length | |||||||
Shtambovii × Pleven 10 | 5.75 | 5.99 | 3.11 | −0.60 | −4.20 | 0.83 | 3.99 |
Pleven 10 × Shtambovii | 6.16 | 5.96 | 10.47 | 6.50 | 3.12 | 2.81 | 3.77 |
Rosacrono × Pleven 4 | 6.95 | 5.69 | 20.48 | 17.11 | 18.13 | 7.13 | −0.95 |
Pleven 4 × Rosacrono | 6.66 | 5.47 | 15.36 | 12.14 | 17.89 | 5.35 | −3.67 |
1000 seeds mass | |||||||
Shtambovii × Pleven 10 | 187.14 | 126.84 | 17.53 | 6.53 | 32.22 | 1.70 | −3.94 |
Pleven 10 × Shtambovii | 201.40 | 162.22 | 26.49 | 14.65 | 19.45 | 2.56 | 0.36 |
Rosacrono × Pleven 4 | 186.61 | 178.76 | 6.21 | −18.80 | 4.21 | 0.20 | 0.11 |
Pleven 4 × Rosacrono | 183.98 | 169.39 | 4.71 | −19.94 | 7.93 | 0.15 | −0.23 |
Number seeds per pod | |||||||
Shtambovii × Pleven 10 | 3.46 | 2.98 | 17.69 | 4.22 | 13.87 | 1.37 | 0.21 |
Pleven 10 × Shtambovii | 3.54 | 4.45 | 20.41 | 6.63 | -25.71 | 1.58 | 7.95 |
Rosacrono × Pleven 4 | 4.34 | 4.48 | 17.46 | 14.81 | -3.23 | 7.59 | 18.47 |
Pleven 4 × Rosacrono | 4.50 | 4.36 | 21.79 | 19.05 | 3.11 | 9.47 | 15.65 |
*Statistically proven differences between reciprocal crosses in P = 0.05.
Shtambovii × Pleven 10 positive over-dominance) number of seeds per pod was inherited under influence epi- static gene actions.
Despite, that settled positive true heterosis, its value between separately hybrids very high (from 4.22% in Shtambovii × Pleven 10% to19.05% in Pleven 4 × Rosacrono), which results are different level of depression. In Pleven 10 × Shtambovii and Rosacrono × Pleven 4, it was the lowest and negative. From of the negative values for degree of transgression (
Crosses/Indicators | Gene parameters | ||||||
---|---|---|---|---|---|---|---|
Tn | H2 | h2 | N | E | Pp | ||
Plant height | |||||||
Shtambovii × Pleven 10 | −27.10 | 0.47* | 0.31* | 0.74 | 0.48 | −0.25 | |
Pleven 10 × Shtambovii | −20.17 | 0.37* | 0.25* | 61.25 | −15.95 | −5.65 | |
Rosacrono × Pleven 4 | −18.44 | 0.03ns | 0.01ns | 55.09 | 10.18 | 0.25 | |
Pleven 4 × Rosacrono | −13.72 | 0.003ns | - | 62.10 | −15.58 | −4.42 | |
Height to first pod | |||||||
Shtambovii × Pleven 10 | −28.09 | 0.38* | 0.26* | 0.61 | 0.43 | 0.09 | |
Pleven 10 × Shtambovii | −27.42 | 0.39* | 0.26* | 2.76 | −1.25 | 0.32 | |
Rosacrono × Pleven 4 | −36.83 | 0.24* | 0.18* | 50.12 | 10.96 | −0.22 | |
Pleven 4 × Rosacrono | −46.44 | 0.44* | 0.29* | 14.25 | 4.06 | −0.02 | |
Nods per plant | |||||||
Shtambovii × Pleven 10 | 69.11 | 0.52* | 0.33* | 40.44 | −10.76 | −3.36 | |
Pleven 10 × Shtambovii | 74.43 | 0.72* | 0.41* | 173.63 | −41.88 | −13.81 | |
Rosacrono × Pleven 4 | −5.39 | 0.15* | 0.11* | 14.76 | −4.28 | −0.36 | |
Pleven 4 × Rosacrono | −39.46 | 0.14* | 0.10* | 3.97 | −1.72 | −1.59 | |
Pod width | |||||||
Shtambovii × Pleven 10 | −7.60 | 0.04ns | 0.01ns | 1.33 | −0.77 | 0.67 | |
Pleven 10 × Shtambovii | −6.76 | 0.03ns | 0.01ns | 0.14 | -0.19 | 0.71 | |
Rosacrono × Pleven 4 | −36.72 | 0.01ns | 0.01ns | 99.48 | 18.94 | 0.41 | |
Pleven 4 × Rosacrono | −38.95 | 0.12* | 0.08* | 38.58 | −9.25 | −0.89 | |
Pod length | |||||||
Shtambovii × Pleven 10 | 7.39 | 0.38* | 0.26* | 13.44 | −4.00 | −0.37 | |
Pleven 10 × Shtambovii | 7.82 | 0.34* | 0.24* | 6.51 | −2.32 | −0.08 | |
Rosacrono × Pleven 4 | −35.08 | 0.001ns | - | 710.88 | −147.95 | −26.50 | |
Pleven 4 × Rosacrono | −44.40 | 0.40* | 0.27* | 1.75 | 0.91 | 0.23 | |
Number seeds per pod | |||||||
Shtambovii × Pleven 10 | 9.53 | 0.02ns | - | 0.13 | −0.13 | 0.24 | |
Pleven 10 × Shtambovii | 32.37 | 0.21ns | 0.05* | 21.49 | −5.91 | −0.88 | |
Rosacrono × Pleven 4 | 23.62 | 0.20* | 0.15* | 7.90 | −2.67 | −0.12 | |
Pleven 4 × Rosacrono | 22.94 | 0.14* | 0.11* | 2.78 | −1.26 | 0.18 | |
*P = 0.05; ns: not significantly different.
that in decompose generations from the available homozygous genotypes higher percent will be lower from ini- tial forms and with more narrow pods. At Pleven 4 × Rosacrono among homozygous plants probably will pre- vail these with height typical for parents. For number nods per plant only at Shtambovii × Pleven 10 and Pleven 10 × Shtambovii (69.11% and 74.43%) can expect homozygous genotypes with higher values for these traits. This probably was due of the rich inheritable base of the parent’s forms. As regards of pod length only Shtam- bovii × Pleven 10 and its reciprocal exhibit positive degree of transgression and in follow generations can obtain plants with longer pods. For seeds per pod in all hybrids can expect homozygous plants with increased number seeds. The part from common variability conditioned from genetic differences was determined through using coefficient of heritability-broad-sense (H2) and narrow (h2). The inheritance is characterization of the relative part of the genetic differences and these which are result of the action of the environment in the phenotypic di- versity. At change of genotype or the environment follow and variation of the assessment for inheritability. For all investigated traits (
The quantitative traits determine the productiveness characterize with continuous variability due of the fact that the parent’s varieties used that the parent’s varieties use in hybridization scheme contain alleles of different genes of given polygene series. As much as contrasting initial forms in their phenotype, the hybrids will com- bine more different alleles of genes from respective polygene series. In all hybrids, the variability of the fol- lowed traits was tested by VC%, characterizing the phenotypic diversity (
The variation was considered low, if VC was 10%, medium, if VC was between 10% and 20%, and high, if VC was higher than 20%, respectively. The CV values varied in a different way depending on crosses and traits. The level of variability of the traits in F1 in hybrids between Shtambovii and Pleven 10 was higher (from 10.40% for height to first pod to 34.34% for number nods per plant) than F1 of the other hybrid combination (from 7.19% for plant height to 18.05% for height to first pod). At direct crosses the variability was lower in relation with re- ciprocals and in both hybrids combinations with exception for nods per plant in Pleven 10 × Shtambovii. In the second generation F2 highest range of the variability was established for nods per plant and number seeds per pod in all hybrids exception Pleven 4 × Rosacrono (10.74%). Positive values of the coefficients for effectiveness of selection were established for height plant (0.25) at Rosacrono × Pleven 4, height to first pod at Shtambovii × Pleven 10 and reciprocal (0.09; 0.32), pod length at Pleven 4 × Rosacrono (0.23), number seeds per pod at Shtambovii × Pleven 10 (0.24) and Pleven 4 × Rosacrono (0.18) and for pod width at all hybrids with exception of Pleven 4 × Rosacrono.
The obtained experimental data were in agreement with published results by other authors [
Obtained values for coefficients of heritability confirm results by other authors [
According them comparatively low difference between the coefficient of heritability in narrow and broad sense probably indicates that the genetic diversity for these traits is strongly inheritable and that the selection by phenotype may be effective and in follow generations could separate consolidate forms with desired trait’s pa- rameters.
The coefficients of heritability and of effectiveness of selection for height to first pod at Pleven 10 × Shtam- bovii, pod length and number seeds per pod at Pleven 4 × Rosacrono were relative high, which give reason to suppose that realy probability for selection of homozygous genotypes on their phenotype is high. The mass selection at these hybrids for pointed traits can start more in F2 - F3. As sub-regard values of the gene parameters for the other traits as and the established coefficients can expect better results if at these traits through mass se- lection choose desired genotypes in later hybrid generations (F6 - F7) or through used of individual selection (pedigree procedure).
In the hybrids from first generations F1 was found activities of heterosis for the investigated traits. With the highest positive true heterosis were characterized Rosacrono × Pleven 4 for plant height (31.54%), height to first pod (15.44%) and pod length (17.11%), Shtambovii × Pleven 10 (56.10%) for nods per plant and pod width (20.38%), Pleven 10 × Shtambovii for 1000 seeds mass (14.65%) and Pleven 4 × Rosacrono for number seeds per pod. In F2 with the strongest depression were plants from Rosacrono × Pleven 4 for plant height (28.26%), height to first pod (27.74%) and pod length (18.13%), Shtambovii × Pleven 10 for 1000 seeds mass (32.22%) and number seeds per pod (13.87%). The stability of the studied characters was determined. Their variation in F1 in the hybrid combination between Shtambovii and Pleven 10 was higher than F1 of Rosacrono and Pleven 4. For more traits in direct crosses variability was found to be lower in relation to the reciprocal crosses in both combination. The genetical part in phenotipycal expression for height to first pod (Pleven 10 × Shtambovii), pod length and number of seeds per pod (Pleven 4 × Rosacrono) was relative high and existed probability for selec- tion of homozygous genotypes in the generation F2 and F3. The mass phenotype selection for other traits can implement and will be more effective if it starts in later hybrid generations (F6 - F7) or through individual selec- tion. Were selected perspective hybrid forms (Pleven 10 × Shtambovii and Pleven 4 × Rosacrono) with new morphological and physiological characteristic. In the future, the selection will be evaluated their suitability for using as green forage and seed yield.