ABSTRACT
Broad-sense heritability and genetic advance value were computed for flag leaf area, flag leaf weight, specific flag leaf area, specific flag leaf weight, plant height, tillers per plant, spike length, spikelets per spike, grains per spike, 1000-grains weight and grain yield per plant involving six bread wheat crosses viz., WLRG-6 x 5039, WLRG-7 x 5039, WLRG-6 x LU26S, WLRG-1 x LU26S and WLRG-1 x 5039. Most of these traits showed moderate to high estimates of heritability with appreciable genetic advance values. Crosses WLRG-7 x LU26S, WLRG-1 x 5039 and WLRG-7 x 5039 are of considerable interest showing high heritability estimates for all the characters studied.
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DOI: 10.3923/ajps.2003.495.497
URL: https://scialert.net/abstract/?doi=ajps.2003.495.497
INTRODUCTION
Wheat being the major food gain of Pakistan invites the attention of breeder/researcher and grower to raise the level of production so that hungry bellies of increasing population be filled and farmer could grow it economically. Wheat is the most widely grown crop in the world and approximately one sixth of the total arable land in the world is cultivated with it. In Pakistan wheat is grown over the area of 8.18 million hectors with production of 19.02 million tons with average yield of 2325 kg per hectare (Anonymous, 2002). It is dietary main for millions of people. The concerned breeders and geneticists have always been making efforts to improve its population to the level of self-sufficiency. However, the success of any breeding programme depends on the presence of genetic variation in the breeding material. High heritable character can easily be fined with simpler selection procedure resulting in quick progress. Heritable, character can easily be fined with simpler selection procedure resulting in quick progress. Heritability of a character describes the extent to which it is transmitted from one generation to the next generation. The knowledge of heritability thus guides the plant breeder to predict the behavior of the succeeding generation, making describable selection and accessing the magnitude of genetic advance improvement which is possible through selection. Considerable research on this aspect has already been reported by many researchers. High heritability with high genetic advance have been reported for plant height, tillers per plant, spikekets per spike, grains per spike (Kisana et al., 1982; Masood et al., 1986), 1000-grain weight, grain yield per plant, spike length and flag leaf area. (Chowdhry et al., 1993; Awaad et al., 1996). While moderate to high heritability and genetic advance were observed for plant height, grain yield per plant, spikelets per spike, spike length, 1000-grain weight and grain per spike (Pathak and Nema 1985; Chowdhry et al., 1997), flag leaf weight, specific flag leaf area and specific flag weight (Riaz, 1990; Rehman, 1995).
MATERIALS AND METHODS
F1 seeds of six crosses involving five strains/varieties of bread wheat namely WLRG-6 x 5039, WLRG-7 x 5039, WLRG-6 x LU26S, WLRG-1 x LU26S, WLRG-7 x LU26S and WLRG-1 x 5039 alongwith their parents were space planted in the experimental area of the University of Agriculture, Faisalabad to which the F2 population during the crop season 2001-2002. The seed were sown with a dibble keeping plant to plant and row to row distance of 15 and 30 cm, respectively. At maturity 200 plants from each F2 population of each cross and 20 plants from each parent were taken randomly and data were recorded on flag leaf area (cm2), flag leaf weight (mg), specific flag leaf area, specific flag leaf weight, plant height (cm), tillers per plant, spike length (cm), spikelets per spike, 1000-grain weight(g) and grain yield per plant(g).
Heritability estimates in broad-sense were calculated by using the formula proposed by Mahmud and Kramer (1951). Genetic advance was computed by the following formula at 10 percent selection intensity.
GA | = | SDF2 x h2 x I |
GA | = | The genetic advance |
SDF2 | = | The phenotypic standard deviation of F2 population |
h2 | = | The estimates of broad-sense heritability in fraction |
I | = | Constant value that reflects the selection intensity |
I | = | 1.775 in this study at 10% selection pressure |
RESULTS AND DISCUSSION
Heritability estimates and genetic advance are given in Table 1. It is obvious from the table that the highest heritability (92.22%) occurred in cross combination WLRG-7 x LU26S with highest genetic advance (12.17) while the lowest heritability estimates (64.64%) alongwith lowest genetic advance (5.73) was observed in the cross WLRG x LU26S for flag leaf area. Moderate to high heritability and genetic advance in F2 population showed that an appropriate cross combination and new strain may be developed by possessing desired level of flag leaf area. The results given in the table are also in agreement the findings of Mornhinweg (1985) and Chowdhry (1997). For Flag leaf weight the highest heritability estimates (76.35%) coupled with highest genetic advance (42.61) was recorded in the cross WLRG-1 x 5039 while the lowest heritability estimates (51.79%) coupled with low genetic advance (20.57) was noted in the cross WLRG-1 x LU26S. Flag leaf weight plays an important role in proper grain development and filling. High heritability for this trait shows that effective selection can be made from the F2 population and new strains may be developed with desired level of flag leaf weight. These results are in accordance with the results of Riaz (1990) and Rehman (1995). Moderate to high heritability estimates in F2 population varying from 52.39 (WLRG-6 x 5039) to 83.96 percent (WLRG-1 x LU26S) were calculated for specific flag leaf area. However the values of genetic advance ranged from 0.044 to 0.10 for the crosses WLRG-1 x 5039 and WLRG-1 x LU26S, respectively. The highest heritability and genetic advance values were recorded for the cross combination WLRG-1 x LU26S which reflects that effective selection in possible for this character. Similar results were obtained by Raiz (1990) and Rehman (1995). In case of specific flag leaf weight highest value of heritability 88.41 percent with genetic advance 2.99 was exhibited by the cross WLRG-1 x 5039 whereas lowest heritability 28.12% alongwith genetic advance 0.43 was observed in the cross WLRG-7 x 5039. Low to high heritability indicate that variability as present in much extent for this trait and though appropriate combinations improvement is possible for this character. Rehman (1995) also reported similar results. It is clear from the table that heritability estimate (91.94%) coupled with genetic advance 25.09 was obtained from the cross WLRG-1 x 5039 while lowest heritability value (57.24%) along with genetic advance (6.69) was found in the cross WLRG-6 x 5039. Transgressive segreation with high heritability and genetic advance for plant height in most crosses indicate that genetic variability was present in the F2 populations and different high levels can be selected from those crosses. These results are in conformity with those of Masood et al. (1986), Awaad (1996) and Fida et al. (2001).
For tillers per plant the heritability values ranged from 36.07 to 73.83% with genetic advance ranging from 1.51 to 3.87, for the crosses WLRG-6 x 5039 and WLRG-7 x LU26S, respectively. Heritability and genetic advance were moderate for most of the crosses and their magnitude showed that considerable progress is possible. The present results are in closely agreement with the findings of Pathak and Nema (1985) and Chowdhry et al. (1997).
Table 1: | Estimation of heritability and genetic gain of some metric traits in six hybrid populations of spring wheat |
As regard the spike length heritability estimates in broad-sense ranged from 61.81 (WLRG-6 x LU26S) to 85.46% (WLRG-7 x 5039). These crosses indicated the genetic advance of 1.01 to 1.97, respectively. The results indicated moderate to high heritability for most of the crosses for spike length. So that spike length can be exploited for selecting high yieldin genotypes of bread wheat. Similar results have also been reported by Khan et al. (1985), Chowdhry (1997) and Thakur et al. (1999).
Highest values of heritability were observed for number of spikelets per spike which ranged from 72.81 to 85.14% coupled with genetic advance 2.15 to 2.79 for the crosses WLRG-6 x 5039 and WLRG-7 x LU26S, respectively. Number of spikelets per spike is a character of great interest for wheat breeder as it determined the yield. High heritability showed that there is a scope for improvement in this trait with appropriate cross combination. Results obtained are in conformity with the findings obtained by Kisana et al. (1982), Pathak and Nema (1985), Maseed et al. (1986), Singh et al. (1999) and Riaz (1990). I n case of grains per spike broad sense heritability estimates varied from 46.53 to 82.42% and genetic advance ranged from 6.67 to 15.96 for the cross combinations WLRG-1 x 5039 and WLRG-7 x LU26S, respectively. High heritability coupled with genetic advance values indicated that effective selection for grains per spike can be through an efficient hybridization programme. The results of the present study regarding grains per spike are supported by the findings of Khan et al. (1985), Subhani et al. (1995) and Fida et al. (2001). As regards 1000-grain weight moderate heritability (67.88%) alongwith genetic advance 6.15 observed for cross WLRG-7 x 5039. The heritability estimates for 1000-grain weight ranged from 30.30 to 67.88 and genetic advance 2.04 to 6.15. These findings are in accordance with those of Ansari et al. (1991) and Gupta and Verma (2000). The heritability estimates in broad-sense ranged from 15.35 to 65.67% and genetic advance varied from 1.51 to 6.87 for grain yield per plant. Grain yield per plant is a character of prime importance and special interest to the plant breeds. Moderate heritability with genetic advance indicate that effective selection is possible for the improvement in this character. The present results are in collaboration with the findings of Fida et al. (2001). The crosses of F2 population WLRG-1 x LU26S, WLRG-7 x LU26S, WLRG-1 x 5039 and WLRG-7 x 5039 are of considerable interest showing interest showing high heritability estimates and high genetic gain for almost all the characters. It is concluded that varieties/lines like WLRG-1, WLRG-7, LU26S and 5039 posses high heritable characters for almost all traits. So these varieties/lines should be give due importance in future breeding programme.
REFERENCES
- Chowdhry, M.A., M. Raiz, I. Khaliq and N. Ahmad, 1993. Transmissibility index in spring wheat. J. Agric. Res., 31: 139-144.
Direct Link - Gupta, S. and S. Verma, 2000. Variability, heritability and genetic advance under normal and rainfed conditions in durum wheat (Triticum durum Desf). Indian J. Agric. Res., 34: 122-125.
Direct Link - Kisana, N.S., A.R. Chowdhry, M. Tahir and M.A. Chowdhry, 1982. Heritability of some quantitative characters in five crosses of wheat (Triticum aestivum). Pak. J. Agric. Res., 3: 211-214.
Direct Link - Masood, M.S., M.Y. Mujahid, N.S. Kisana and N.I. Hashmi, 1986. Variability studies in wheat under rainfed conditions. Pak. J. Agric. Res., 7: 244-247.
Direct Link