INHERITANCE OF IMPORTANT TRAITS IN BREAD WHEAT OVER DIFFERENT PLANTING DATES USING DIALLEL ANALYSIS

Sarhad J. Agric. Vol. 23, No. 4, 2007 INHERITANCE OF IMPORTANT TRAITS IN BREAD WHEAT OVER DIFFERENT PLANTING DATES USING DIALLEL ANALYSIS Farhad Ahmad, Fida Mohammad, Muhammad Bashir, Saifullah and Hakim Khan ABSTRACT This experiment was conducted to study the inheritance pattern of yield and its related traits in eight bread wheat (Triticum aestivum L.) cultivars and their 56 F 1 s hybrids over three planting dates (early, normal and late) at the Experimental Farm of NWFP Agricultural University, Peshawar, Pakistan during 2002-04. The experiment was planted in randomized complete block design in three replicates. Data were collected on flag leaf area, plant height, spike length, grain yield and harvest index. The F- test declared significantly different means for all traits justifying diallel analyses. Genetic analyses for all traits were carried out. The adequacy model test revealed that additive-dominance model was appropriate for plant height, spike length and harvest index over all environments; grain yield plant -1 under normal planting and flag leaf area under late planting. Analyses of genetic components (Hayman, 1954b) indicated significant additive (D) and dominant (H) genetic variations for plant height, spike length and harvest index under early planting. Under normal planting, significant additive (D) and dominant (H) genetic components were observed for plant height, spike length and grain yield plant -1, while under late planting significant additive and dominance variations were found for flag leaf area and harvest index. Genetic analyses of traits confirmed the involvement of both additive and non-additive gene effects in governing the inheritance of these traits. Narrow sense heritability estimates were 69.74% and 82.15% for flag leaf area and plant height respectively, suggesting improvement through early generation selection, while the low narrow sense heritability estimates for spike length, grain yield plant -1 and harvest index favored selection at later stage. Keywords: Bread Wheat, Diallel Analysis, Inheritance, Planting Dates, Yield INTRODUCTION Wheat (Triticum aestivum L.) is the most widely cultivated crop among the cereals and is the principal food crop in most areas of the world. It is the leading grain crop of the temperate climates of the world, just as rice in the tropics. Although cultivated under a wide range of climatic conditions, the most extensive production of wheat is in areas where the winters are cool and the summers comparatively hot. Wheat production can be enhanced through the development of new cultivars with wider genetic base and better performance under various agro-climatic conditions. Genetic improvement in wheat is taking place, both by processes of nature and by the selective processes of human being since the earliest time of wheat cultivation. It is known that phenotypic expression of traits is highly influenced by environmental fluctuations (Allard and Bradshaw, 1964). Therefore, it is necessary to study the genetic mechanism of important traits across environments for selecting relatively stable phenotypes. Diallel mating design is the extensively used tool for genetic analyses by plant breeders to analyze mating system in which a set of varieties are intercrossed in all possible combinations. The technique includes diallel analysis of variance, computation of genetic components of variation, Wr,Vr (covariance, variance) graphs. Diallel analyses reveal presence or absence and magnitude of additive, dominant, nonallelic, maternal and reciprocal gene effects. Genetic analyses determine whether selection would be more effective in early segregating generation or at later stage. Additive gene effects for a trait favor early stage selection while dominant gene action supports selection at later generation. Additive gene effects for flag leaf area, plant height and harvest index were reported by Mehmood and Choudhry 2000, Soylu and Sade 2003, and Karam et al. 1996. Dominant gene action for spike length and grain yield were reported by Rajara and Maheshwari, 1996, and Dhayal and Sastry 2003. The objectives of this study were to i) determine gene actions, ii) estimate narrow-sense heritability, and iii) ascertain suitable planting date of selection for grain yield and other important traits in bread wheat. MATERIALS AND METHODS Eight cultivars of bread wheat, namely: Wafaq-2001, Takbeer, Tatara, Iqbal-2000, Margalla-99, Ghaznavi- 98, Khattakwal and Inqalab-91 were crossed in an 8x8 diallel fashion during 2002-03. Eight parental * ** *** Agricultural Research Station, Baffa, Mansehra - Pakistan Department of Plant Breeding & Genetics, NWFP Agricultural University, Peshawar - Pakistan Department of Plant Pathology, NWFP Agricultural University, Peshawar - Pakistan

Farhad Ahmad et al. Inheritance of important traits in bread wheat 956 cultivars and their resulting 56 F 1 s were grown in a randomized complete block design with three replications under early, (E 1 -October planting), normal (E 2 -November planting) and late (E 3 - December planting) sown conditions at the experimental farm of Department of Plant Breeding and Genetics, NWFP Agricultural University, Peshawar during 2003-04. Plant to plant and row to row spacing were kept 15 and 30 cm, respectively. One healthy seed was planted per site. Each treatment comprised a single row of three meters length having 20 healthy plants. Five plants from each treatment were randomly selected for recording data on five traits viz., flag leaf area, plant height, spike length, harvest index and grain yield plant -1 under each environment. The mean of each treatment was used for statistical analysis. Data were analyzed statistically using analysis of variance technique (Steel and Torrie, 1984) and significant differences among the genotypes were further analyzed using diallel analysis techniques (Hayman, 1954a,b; Mather and Jinks, 1982). Genetic Components of Variation Genetic components of variation were obtained using the procedures described by Hayman (1954a) and Mather and Jinks (1982) and adopted by Singh and Choudhry (1985). Formulae for genetic components are given as under: i. Additive variation (D), ii. Variation due to dominant effect of genes iii. (H 1 ) Variation due to dominant effect of genes correlated for gene distribution (H 2 ). iv. Relative frequency of dominant and recessive alleles (F). If F was positive dominant alleles are more than the recessive and if F is negative vice-versa is true. v. Overall dominance of heterozygous loci (h 2 ). vi. Environmental variance (E). vii. Average degree of dominance (H 1 /D) 1/2. viii. Proportion of genes with positive and negative effects in the parents i.e. uv over all loci u=frequency of increasing alleles and v=1-u = frequency of decreasing alleles. This ratio is equal to 0.25. When u=v at all loci (H 2 /4H 1 ). ix. Proportion of dominant and recessive genes in the parents (4DH 1 ) 1/2 +F/(4DH 1 ) 1/2 -F. Heritability 0.5D + 0.5H 1-0.25H 2-0.5F Heritability (BS) = 0.5D + 0.5H 1-0.25H 2-0.5F + E 0.5D + 0.5H 1-0.5H 2-0.5F Heritability (NS) = 0.5D + 0.5H 1-0.25H 2-0.5F + E RESULTS AND DISCUSSION Pooled analysis of variance showed significant differences among the genotypes for all traits (Table I). The genotypes by environment interactions were significant for all traits, suggesting that genotypes performed differently across environments. Significant F-test for all traits justified the genetic analyses and heritability estimation for these traits. Significant genotypes by environment interactions for all traits necessitated analyses on each environment basis.the analysis of individual environment also declared significant differences among genotypes for all traits (Table II). Two scalling tests were applied following Mather and Jinks (1982) for testing the validity of additivedominance model. First test was the joint regression coefficient test followed by analysis of variance of Wr+Vr and Wr-Vr for the confirmation of absence of non-allelic gene interaction. Additive-dominance model was found adequate for plant height, spike length and harvest index across three plantings, for grain yield plant -1 under normal planting, while for flag leaf area under late planting (Table IV). Flag Leaf Area Significant additive (D) and dominant (H) components under late planting indicated presence of both additive and dominance gene actions (Table V). Unequal values of H 1 and H 2 suggested that positive and negative alleles were unequal among parent cultivars. Average degree of dominance indicated partial dominance. This was also supported by the ratio of H 2 /4H 1 (0.15) which was less than 0.25. Under late planting, significant and positive value of F revealed the important role of dominant genes which was also supported by the ratio of dominant to recessive genes (2.09). Over all dominance effect due to heterozygous loci (h 2 ) was significant. Influence of environment (E) was non-significant. These results are in accordance with those of Mehmood and Choudhry (2000) and Choudhry et al. (1994), who also reported additive gene action for this trait. Narrow sense heritability estimate (69.74%) for flag leaf area under late planting indicated greater proportion of additive genetic variation (Table V), suggesting possible improvement in early generations. The wider range for flag leaf area among F 1 hybrids (39 to 71 cm 2 ), than parent cultivars (41 to 61 cm 2 ) under early planting date

Sarhad J. Agric. Vol. 23, No. 4, 2007 957 compared to other planting dates indicate better chances of selection under this planting date (Table III). Plant Height Both additive (D) and dominant (H) components were found significant under early, normal and late plantings (Table V). However, dominance component (H) was greater in magnitude in normal and late plantings. Unequal values of H 1 and H 2 suggested that positive and negative alleles were unequal among parent cultivars. Average degrees of dominance (1.04) indicated over-dominance type of gene action under early planting, while under normal and late planting average degrees of dominance (0.73 and 0.61) indicated absence of dominant gene effects. This was also supported by the ratio of H 2 /4H 1 (0.19, 0.16 and 0.16 respectively) which was less than 0.25. In early planting, value of F was positive and significant indicating the important role of dominant genes for plant height. This was also supported by the ratio of dominant to recessive genes (2.52) which was more than one. In normal and late planting values of F were negative and nonsignificant but ratios of dominant to recessive genes (0.40 and 0.45 respectively) exhibited that the recessive genes were more frequent. In all the three plantings, values of h 2 were significant showing a substantial role of dominance effects due to heterogeneity at loci. Non-significant E under early, normal and late plantings indicated absence of environmental effects. These results are in accordance with those of Taleei and Beigi (1996), Meena and Sastry (2003) and Soylu and Sade (2003) who also reported additive gene action for this trait. High narrow sense heritability estimates under early, normal and late plantings (82.15, 90.96, 92.76%, respectively) indicated large additive proportion in the total genetic variation (Table V). Selection strategies for plant height under early, normal and late plantings would be effective in early generation. Soylu and Sade (2003) reported high broad sense heritability for plant height (95%) while narrow sense heritability estimate was very low (8%). Mehta et al. (1998) reported moderate heritability estimates for plant height. The wider range for plant height among F 1 hybrids (72 to 136 cm) compared with parent cultivars (73 to 126 cm) under early planting date in comparison to other planting dates indicated better chances of selection under early planting (Table III). Spike Length Genetic components of variations revealed that both additive (D) and dominant (H) variations were significant under early, normal and late plantings (Table V). Average degrees of dominance (1.19 and 1.08) depicted an over dominance type of gene action under early and normal planting, however average degree of dominance (0.62) under late planting displayed the absence of dominance. Dominant gene distribution among parent cultivars under early, normal and late plantings was unequal, which was also evident from H 2 /4H 1 ratios (0.17, 0.20 and 0.23) which were less 0.25. Under early planting F was positive and significant indicating the greater proportion of dominant genes, while under normal and late planting F was positive and nonsignificant. The ratio of dominant to recessive genes (2.61, 1.81 and 1.02) also indicated that the dominant genes were more frequent. These results are in accordance with those of Khan and Ali (1998) who reported both additive and non-additive gene effects for this trait, while Rajara and Maheshwari (1996) reported only non-additive gene effect for spike length. Low narrow sense heritability estimates (32.63% and 33.72%) under early and normal planting indicated non-additive genetic variation, while under late planting high narrow sense heritability estimate (73.65%) indicated additive genetic variation in the total heritable genetic variation (Table V). The wider range for spike length among F 1 hybrids (10 to 15 cm) than parent cultivars (11 to 14 cm) under early planting date compared to other planting dates indicated better chances of selection under early planting (Table III). Harvest Index Components of genetic variation under early and late planting indicated significant additive (D) and dominant (H) variation. However, under normal planting both these components were non-significant (Table V). Unequal values of H 1 and H 2 supported by the ratios of H 2 /4H 1 (0.22 and 0.18) under early and late planting indicated unequal distribution of positive and negative alleles among parent cultivars, while under normal planting equal values of H 1 and H 2 supported by the ratio of H 2 /4H 1 (0.26) indicated equal distribution of positive and negative alleles among parent cultivars. Average degrees of dominance (1.77, 1.25 and 1.51) showed an overdominant gene actions under early, normal and late plantings. Value of F was non-significant under early

Farhad Ahmad et al. Inheritance of important traits in bread wheat 958 and normal planting, while significant under late planting. Ratios of dominant to recessive genes (1.48 and 2.13) also suggested preponderance of dominant genes in the parent cultivars under early and late planting, while under normal planting this value is less than 1, indicating the importance of recessive genes for the trait. Values of h 2 were non-significant under early, normal and late plantings. Significant values of E depicted the influence of environment on harvest index under early, normal and late plantings. These results are in accordance with those of Karam et al. (1996) who reported additive gene effects for harvest index. Low narrow sense heritability estimates (21.91%, 30.75% and 30.63%) under early, normal and late plantings indicated preponderance of non-additive genetic variations (Table V). Selection for harvest index will be effective in later generations. The wider range for harvest index among F 1 hybrids (20 to 42%) than parent cultivars (24 to 36%) under early planting date compared to other planting dates indicated better chances of selection under early planting (Table III). Grain Yield Plant -1 Under normal planting both additive (D) and dominant (H) variations were significant (Table V). Unequal values of H 1 and H 2 supported by the ratios of H 2 /4H 1 (0.15) indicated unequal distribution of positive and negative alleles among parent cultivars. The value of F was positive and significant indicating the important role of dominant genes for yield plant -1. This was also supported by the ratios of dominant to recessive genes (3.95). Average degree of dominance (2.16) displayed an over dominant gene action. The value of h 2 was non-significant. Significant value of E depicted the influence of environment on grain yield plant -1. These results are in accordance with those of Dhayal and Sastry (2003), Karam et al. (1996), Mann et al. (1995) and El-Hennawy (1996) who also reported non-additive gene effects for grain yield plant -1. error mean squares under early planting that genotypes exhibited wider genetic variation for plant height and grain yield plant -1 compared to normal and late plantings. The greater ratios of genotypes to error means square emphasize that selection for these traits would be effective in early planting. Under normal planting, greater ratios of genotypes to error mean squares for flag leaf area reflected higher genetic variability indicating better chances of desirable selection. Similarly, greater ratios of genotypes to error mean squares under late planting for spike length and harvest index displayed higher genetic variability presenting more choices for selection. Additive gene effects and high heritability estimates for flag leaf area and plant height suggested that these traits could be improved effectively through early generation selection, while the dominance gene effects and low heritability estimates for spike length, grain yield plant -1 and harvest index favor delayed stage plant selection. Parent cultivars Takbeer, Inqalab and Margalla gave maximum grain yield plant -1 under early, normal and late plantings. These parent cultivars can be incorporated in future wheat breeding programmes for development of high yielding and early maturing wheat varieties. Best crosses identified for yield and other morphological traits under early planting were Khattakwal x Tatara, Inqalab x Khattakwal, Khattakwal x Takbeer, Ghaznavi x Wafaq and Wafaq x Khattakwal for grain yield plant -1, flag leaf area, plant height, spike length and harvest index respectively. Under normal planting best crosses identified were Margalla x Tatara, Tatara x Inqalab, Inqalab x Margalla, Takbeer x Khattakwal and Wafaq x Takbeer for grain yield plant -1, flag leaf area, plant height, spike length and harvest index respectively. Similarly, under late planting best crosses were Wafaq x Tatara for grain yield plant -1 and flag leaf area, Iqbal x Margalla for plant height, Inqalab x Margalla for spike length and harvest index. These crosses may yield transgressive segregants in subsequent generations. Low narrow sense heritability estimate (10.13%) under normal planting indicated non-additive genetic variation (Table V). Selection for this trait will be effective in later generations. The wider range for grain yield among F 1 hybrids (26 to 83g) than parent cultivars (22 to 66g) under early planting date compared to other planting dates indicated better chances of selection under early planting (Table III). CONCLUSIONS It can be inferred from greater ratios of genotypes to

Sarhad J. Agric. Vol. 23, No. 4, 2007 959 Table-I: Characters Pooled analysis of variance for the characters studied under early, normal and late plantings (Mean squares). Env. (df=2) Reps. (Env) (df=6) Genotypes (df=63) Geno x Env (df=126) Pooled error (df=378) Flag leaf area 32199.65 112.16 200.60 ** 107.39 ** 3.45 Plant height 5722.69 86.64 2017.58 ** 117.77 ** 2.59 Spike length 99.91 7.45 3.82 ** 2.25 ** 0.42 Grain yield plant -1 30442.70 13.71 331.28 ** 224.32 ** 12.66 Harvest index 2093.45 26.98 60.35 ** 42.61 ** 10.47 ** P 0.01 Table-II: Analysis of variance for the characters studied under early, normal and late plantings (Mean squares). Characters Reps. (df=2) Early Normal Late Genotypes (df=63) Error (df=126) Reps. (df=2) Genotypes (df=63) Error (df=126) Reps. (df=2) Genotypes (df=63) Error (df=126) Flag leaf area 99.58 965.50 ** 3.41 135.02 688.32 ** 1.54 25.32 599.30 ** 2.81 Plant height 12.57 3.02 ** 0.23 7.80 2.44 ** 0.70 1.97 2.86 ** 0.34 Spike length 115.32 135.22 ** 29.82 69.66 106.26 ** 3.41 155.50 173.89 ** 2.40 Grain yield plant -1 5.32 592.72 ** 20.72 4.81 109.89 ** 12.52 31.01 77.32 ** 4.76 Harvest index 38.39 65.34 ** 13.32 34.75 30.68 ** 12.02 7.80 49.56 ** 6.07 ** P 0.01

Farhad Ahmad et al. Inheritance of important traits in bread wheat 960 Table-III: Mean values of parents and F 1 ranges for flag leaf area (cm²), plant height (cm), spike length (cm), harvest index (%) and grain yield plant -1 (g) under early, normal and late plantings. Genotypes Flag leaf area Plant height Spike length Harvest index Grain yield plant -1 WAFAQ 61.30 99.00 13.70 36.00 47.13 TAKBEER 45.00 85.67 13.30 32.00 66.87 TATARA 47.00 95.00 11.30 34.67 30.63 IQBAL 43.30 73.33 14.00 28.33 22.10 MARGALLA 49.70 96.00 14.00 34.00 43.13 GHAZNAVI 43.30 76.00 12.30 30.67 26.00 KHATTAKWAL 49.30 126.67 11.70 24.67 57.03 INQALAB 41.00 87.33 14.00 33.00 60.00 F 1 (Ranges) 39-71 72-136 10-15 20-42 26-83 LSD at 1% 4.55 2.50 1.02 7.79 9.72 C.V % 4.25 1.90 3.61 11.93 9.68 Early Normal WAFAQ 49.00 93.67 14.00 28.33 37.37 TAKBEER 46.70 80.00 13.70 33.00 38.07 TATARA 48.30 86.00 13.30 29.33 39.93 IQBAL 46.70 83.33 15.30 29.67 27.90 MARGALLA 39.70 87.33 13.30 24.67 34.63 GHAZNAVI 37.70 73.67 12.30 31.00 38.47 KHATTAKWAL 48.00 126.00 12.30 26.33 40.80 INQALAB 36.70 84.00 14.30 24.67 45.10 F 1 (Ranges) 31-57 72-127 10-15 21-37 24-51 LSD at 1% 3.94 2.65 1.78 7.40 7.55 C.V % 4.18 1.32 5.97 12.41 9.72 WAFAQ 37.70 85.67 12.30 24.33 28.33 TAKBEER 32.00 73.00 11.00 25.67 25.33 TATARA 15.30 73.67 10.30 25.67 15.20 IQBAL 41.00 77.00 12.30 22.00 15.80 MARGALLA 24.70 93.33 12.30 28.00 30.80 GHAZNAVI 17.00 68.33 11.30 20.00 19.23 KHATTAKWAL 29.30 117.33 13.30 19.00 26.87 INQALAB 26.70 76.33 14.00 18.33 20.20 F 1 (Ranges) 13-41 71-118 11-15 16-31 11-33 LSD at 1% 3.31 3.58 1.25 7.39 4.66 C.V % 6.12 1.93 4.68 10.26 9.96 Late

Sarhad J. Agric. Vol. 23, No. 4, 2007 961 Table-IV: Test of adequacy of additive-dominance model for 8x8 diallel cross of wheat sown under early, normal and plantings. Early planting Characters Regression analysis Analysis of array variance Remarks b=0 b=1 wr+vr wr-vr Flag leaf area NS * ** ** Both tests suggested inadequacy of the model. Plant height ** NS ** ** Regression analysis indicated adequacy of the model but analysis of arrays invalidates the model, thus it was Spike length NS * NS * Regression analysis invalidates the model but analysis of arrays suggests the model to be adequate, thus it was Grain yield plant -1 NS * ** ** Both tests suggested inadequacy of the model. Harvest index NS * NS NS Regression analysis invalidates the model but analysis of arrays suggests the model to be adequate, thus it was Normal planting Flag leaf area NS * ** ** Both tests suggested inadequacy of the model. Plant height ** NS ** ** Regression analysis indicated adequacy of the model but analysis of arrays invalidates the model, thus it was Spike length * * NS ** Both tests suggested adequacy of the model. Grain yield plant -1 * NS ** ** Regression analysis indicated adequacy of the model but analysis of arrays invalidates the model, thus it was Harvest index NS ** NS NS Regression analysis invalidates the model but analysis of arrays suggests the model to be adequate, thus it was Late planting Flag leaf area ** NS ** ** Regression analysis indicated adequacy of the model but analysis of arrays invalidates the model, thus it was Plant height ** NS ** ** Regression analysis indicated adequacy of the model but analysis of arrays invalidates the model, thus it was Spike length ** NS NS NS Both tests suggested adequacy of the model. Grain yield plant -1 NS ** * ** Both tests suggested inadequacy of the model. Harvest index * NS NS NS Both tests suggested adequacy of the model. * = Significant ** = Highly significant NS = Non-significant.

Farhad Ahmad et al. Inheritance of important traits in bread wheat 962 Table-V: Components Estimates of genetic components of variation for various traits. Flag leaf area Plant height Spike length Grain yield Harvest index Late Early Normal Late Early Normal Late Normal Early Normal Late D 80.48±5.94 * 275.64±25.97 * 252.40±13.78 * 252.56±13.55 * 1.08±0.23 * 0.74±0.15 * 1.33±0.06 * 20.95±5.66 * 9.18±4.07 * 4.81±2.57 ns 10.63±2.11 * H 1 65.16±13.72 * 300.58±59.97 * 133.08±31.82 * 92.83±31.28 * 1.54±0.53 * 0.86±0.36 * 0.51±0.15 * 97.70±13.07 * 28.86±9.40 * 7.49±5.92 ns 24.23±4.87 * H 2 40.55±11.93 * 220.10±52.18 * 86.12±27.68 * 58.72±27.22 * 1.07±0.46 * 0.69±0.31 * 0.48±0.13 * 60.39±11.37 * 25.61±8.18 * 7.70±5.15 ns 17.60±4.24 * F 50.98±14.10 * -165.37±61.65 ns -158.26±32.71 ns -116.32±32.16 ns 1.15±0.55 * 0.46±0.37 ns 0.01±0.15 ns 53.93±13.44 * 6.27±9.66 ns -0.78±6.09 ns 11.58±5.01 * h² 26.75±7.98 * 96.18±34.91 * 89.13±18.52 * 49.86±18.21 * 0.12±0.31 ns 0.53±0.21 * 0.64±0.08 * 5.94±7.61 ns 2.74±5.47 ns -1.04±3.45 ns 4.31±2.84 ns E 1.60±1.99 ns 1.64±8.70 ns 1.21±4.61 ns 1.05±4.54 ns 0.14±0.08 ns 0.27±0.05 * 0.12±0.02 * 4.13±1.89 * 4.57±1.36 * 4.13±0.86 * 2.03±0.71 * (H 1/D) ½ 0.90 1.04 0.73 0.61 1.19 1.08 0.62 2.16 1.77 1.25 1.51 H 2/4H 1 0.15 0.18 0.16 0.16 0.17 0.20 0.23 0.15 0.22 0.26 0.18 (4DH1) ½ +F (4DH 1) ½ -F Heritability (ns)% Heritability (bs)% 2.09 0.55 0.40 0.45 2.61 1.81 1.02 3.95 1.48 0.88 2.13 69.74 82.15 90.96 92.76 32.63 33.72 73.65 10.13 21.91 30.74 30.63 95.88 99.48 99.52 99.51 76.83 59.66 86.60 80.69 67.47 52.77 78.08 * Value is significant when it exceeds 1.96 when it is divided by its std.error ns non-significant. D measures additive effect, H 1 and H 2 measures dominance effect, F determines frequencies of dominant to recessive alleles in parents, h² determines the overall dominance effect due to heterozygous loci, E shows environment effect, (H 1 /D) ½ measures average degree of dominance, H 2 /4H 1 determines proportion of genes with positive and negative effects in the parents, (4DH1) ½ +F/(4DH 1 ) ½ -F measures proportion of dominant and recessive genes in the parents.

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