Maize is one of the important cereal food crop in world agricultural economy (Morris et al., 1999) for humans, feed for animals and also a crop of industrial utilization (White and Johnson, 2003). It belongs to the family Poaceae and the tribe Maydeae. It is also known as miracle crop. It has very high yield potential as compared to other cereals and, that is why referred to as “queen of cereals”. In India, it is grown in an area of about 8.17 mha with an overall production of 19.73 million tonnes and productivity of 2415 kg/ha (Agriculture Annual Report, 2008-2009).
From time immemorial, since new breeding techniques have evolved, the hybrid cultivars have played a crucial role in augmenting the acreage and productivity of maize. The ultimate success of any programme aimed to produce inbreds for hybrid breeding depends upon the genetic potential of parental population. The actual value of an inbred line lies in its worth in combinations with other inbreds. The reason behind this can be ascribed to the exploitation of combining ability, which is the relative ability of a genotype to transmit its desirable performance to its crosses. Combining ability analysis is not only the quickest method of understanding the genetic nature of quantitatively inherited traits but also gives essential information about selection of parents which in turn throws out better segregants. The variance due to general combining ability (GCA) is usually considered to be an indicator of the extent of additive type of gene action, this was advocated by several workers as Ahmed et al., 2000; Al-Naggar et al., 2002; Alamnie et al., 2006; El–Badawy, 2006; Sedhom et al., 2007, whereas specific combining ability (SCA) is taken as the measure of non- additive type of gene actions in heterosis breeding (Dadheech and Joshi, 2007; Barakat and Osman, 2008; Irshad El–Haq et al., 2010). Akbar et al (2008) and Hefny (2010) reported that additive and non – additive gene effects were equally important in the genetic expression of yield and its contributing traits. The relative magnitude of general and specific combining ability helps in selecting appropriate breeding procedures for achieving maximum genetic advance (Hayman, 1954; Griffing, 1956). The present study was undertaken to estimate the combining ability of parents and hybrids, nature and magnitude of gene action for yield and yield components in maize by adopting Line×Tester analysis (Kempthorne, 1957).
Results and Discussion
Selection of any crop improvement programme is dependent upon selection of parents with superior combining ability used to develop superior hybrids thus helping the breeder in selection of appropriate breeding procedures. The analysis of variance revealed that variance due to treatments, parents, parents vs. crosses and crosses were highly significant for most of the traits studied. These results clearly showed that the treatment including parent and crosses differed among themselves for most of the traits. The highly significant variance due to parent vs. crosses for most of the traits clearly shows the existence of heterotic effect (Table 1; Table 2).
Table 1 Analysis of variance for parents and hybrids
|
Table 2 ANOVA for combining ability
|
The mean performance of fifteen lines showed that L11 (1.613) and L14(1.603) was highest yielder which also showed highest mean value for ear diameter. L8 showed highest ear length, L7 and L10showed highest mean value for number of kernels per row and number of rows per ear respectively, L6 had shortest days to tasseling and silking (Table 3; Table 4). Among testers, T1 was earliest in maturity, high yielding and superior for most of the other traits, therefore, can be used in breeding programme for exploitation of heterosis as it will be a high yielding parent. The effect of genetic diversity on parental lines in relation to hybrid performance was shown by several workers (Lonquist and Gardener, 1961 and Vidyasagar, 1970).
Table 3 Mean performance of inbred lines and testers for quantitative traits
|
Table 4 Mean performance of crosses for quantitative traits
|
The GCA effect of lines and testers were found to quite variable for eleven traits studied (Table 5). The following lines and testers were observed to be general combiner for various specific traits studied. Parental lines viz., L6, L7, L8 and L14 were good general combiner for earliness however, the lines L6, L2 and L3 were good general combiner for dwarfness, whereas, tester T1 was good for earliness and T3 for dwarfness. Lines L11 and L2 were good general combiner for yield and most of the other yield contributing traits, whereas, tester T2 was good general combiner for yield.
Table 5 Estimation of general combining ability effects (GCA) of lines and testers for quantitative traits
|
The SCA effect of different crosses (Table 6) for different traits varied significantly from each other. The cross L6×T1 followed by crosses L8×T1, L14×T2, L10×T3 and L12×T2 showed high SCA effect for yield. The line×tester with good combining ability for yield contributing characters like ear girth and ear length (Table 7; Table 8; Table 9) will also improve yield in cross combinations as advocated by Singh and Singh (1998). Sinha and Mishra (1997) and Daret al (2007) also reported that significant differences existed among lines and lines×testers for all the traits.
Table 6 Estimation of specific combining ability (SCA) effects of crosses for quantitative traits
|
Table 7 Lines and testers with good general combining ability
|
Table 8 Elite specific combinations for yield and its components
|
Table 9 Elite specific combinations for maturity traits
|
In the experimental hybrids, L5×T3, L1×T2, L3×T1 and L6×T2 exhibited negative and significant estimate of SCA effect for maturity traits however, the hybrids L10×T1 and L6×T2 showed negative and significant SCA effect for height trait. The crosses L6×T1, L8×T1 and L14×T2 recorded positive and significant SCA effects for yield/plot. The crosses L7×T1, L14×T2 and L2×T1 recorded positive and significant estimates of SCA effect for ear length and L7×T1 and L14×T2 for ear diameter. However, crosses L7×T1, L11×T1 and L5×T3 showed highest positive significant SCA effect for rows per ear.
Any combination among parents may produce hybrid vigour over parents which might be due to dominant, over dominant or epistatic gene action (Moll and Stuber, 1974). So, the crosses showing desirable SCA effects can be used in future breeding programmes. The inbred lines selected for high GCA can be used for the development of synthetic varieties. Lines showing high SCA values can be used in hybrid breeding programmes.
Materials and Methods
The parental material for present investigation comprised of 15 inbred lines viz., HUZM-55, HUZM-68, HUZM-69, HUZM-70-1, HUZM-77, HUZM-78, HUZM-79, HUZM-91-1, HUZM-175-2, HUZM-210-2, HUZM-211-1, HUZM-217, HUZM-221, HUZM-227-1-1 and HUZM-329 designated as L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14 and L15 respectively, 3 testers viz.,CM-119, HKI-1105 and HKI-323 designated as T1, T2 and T3 respectively along with 3 checks. These were selected on the basis of wide diversity for different metric traits. The inbred lines were developed and maintained at the centre of AICMIP, B.H.U., Varanasi, whereas, testers for investigation viz., T1 were collected from maize research stations at Hyderabad, T2 and T3 from Karnal.
The F1 hybrids were developed during Kharif 2008-2009 involving 15 lines and 3 testers along with 3 checks following Line×Tester mating design. These were sown in a Randomized Complete Block Design with three replications in Rabi 2008-2009 at Crop Research Centre of Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, (Table 10). Each genotype was planted in a single row plot of 4 m length having a uniform inter and intra row spacing of 60 cm and 20 cm respectively. Two seeds per hill was planted and later on one plant was thinned (if necessary) from each hill to maintain the optimum plant population. Border rows were planted to avoid border effect.
Table 10 Description of maize genotypes involved in experiment
|
Prior to tasseling five plants in each plot was randomly selected and tagged to record the observation for height and yield traits. However, data on days to 50% tassel, days to 50% silk and grain yield/plot was recorded on plot basis. The pre-harvest observations recorded were days to tassel (50%), days to silk (50%), plant height (cm) and ear height (cm), and the post-harvest observations taken were ear length (cm), ear diameter (cm), number of kernels/row, number of kernel rows/ear, 100 kernel weight (g), yield/plant (g) and yield/plot (kg). The data was subjected to the following statistical analysis: (1) Analysis of Variance (Panse and Sukhatme, 1967); (2) Mean performance of Lines, Testers and Crosses; (3) Combining ability analysis (Kempthorne, 1957).
Ahmed M.A., El–Sheikh M.H., and Shamarka S.A., 2000, Diallel analysis of yielding ability and earliness in maize (Zea mays L.)., J. Agric. Sci. Mansoura Univ., 25: 3717-3726
Akbar M., Saleem M., Azhar F.M., Ashraf M.Y., and Ahmed R., 2008, Combining ability analysis in maize under normal and high temperature conditions,J. Agric. Res., 64: 27-38
Al–Naggar A.M., Radwan M.S., and Atta M.M.M., 2002, Analysis of diallel crosses among ten maize populations differing in drought tolerance, Egypt J. Plant Breed., 6: 179-198.
Alamnie A., Wali M.C., Salimath P.M., and Jagadeesha R.C., 2006, Combining ability and heterosis for grain yield and ear characters in maize, Karnataka J. Agric. Sci., 19: 13-16
Barakat A.A., and Osman M.M.A., 2008, Evaluation of some newly developed yellow maize inbred lines for combining ability in two locations, J. Agric. Sci. Mansoura Univ., 33: 4667-4679
Dadheech A., and Joshi V. N, 2007, Heterosis and combining ability for quality and yield in early maturing single cross hybrids of maize (Zea mays L.), Indian J. Agric. Res., 41:210-214
Dar S.A., Ali G., Rather A.G. and Khan M.N., 2007, Combining ability for yield and maturity traits in elite inbred lines of maize (Zea mays L.), Int. J. of Agricul. Sci., 3: 2, 290-293
El–Badawy M.E.M., 2006, Genetical analysis of diallel crosses in maize (Zea mays L.) over two years, J. Agric. Sci. Benha Univ., 44: 911-922
Griffing B., 1956, Concept of general and specific combining ability in relation to diallel crossing system, Australian J. Biol. Sci., 9: 463-493
Hayman B.I., 1954, The theory and analysis of diallel crosses, Genetics, 30: 789- 809
Irshad–El–Haq M., Ajmal S.U., Munir M., and Gulfaraz M., 2010, Gene action studies of different quantitative traits in maize, Pak. J. Bot., 42: 1021:1030
Jayakumar J., and Sundaram T., 2007, Combining ability studies for grain yield and other yield components in maize (Zea mays L.), Crop Research (Hisar), 33: 1-3, 179-186
Kempthorne O., 1957, An introduction to genetical statistics. John Willey and Sons Inc., New York, pp. 323-331
Morris M.L., Risopoulos J., and Beck D., 1999, Genetic changes in farmer – recycled maize seed: A review of the evidence, CIMMYT Econ, Working Paper No. 99–07. Mexico, D.F., CIMMYT. pp. 1
Panse V.G., and Sukhatme P.V., 1967, Statistical Method for Agricultural Workers. ICAR, Pub. New Delhi.
Prasad S.K., and Kumar P., 2003, Line×tester analysis for combining ability in maize, J. Res. (RAU), 13: 68-72
Sedhom A.S., El–Badawy M.El.M., Morsy A.M., El–Hosary A. A. A, 2007, Diallel analysis and relationship between molecular polymorphisms and yellow maize hybrid performance. J. Agric. Sci. Benha Univ. 45: 1-20
Singh D.N. and Singh I.S., 1998, Line×tester analysis in maize (Zea mays L.), Journal of Research, Birsa Agricultural University,10 (2): 177-182
Sinha A., and Mishra S.N., 1997, Combining ability analysis in varietal crosses of maize, Indian J. of Genetics & Plant Breed., 57(2): 149-153
Subramaniyan A., and Subbraman N., 2006, Combining ability analysis for yield and its contributing traits in maize, Indian J. Agric. Res., 40: 131-134
Vidyasagar, 1970, Heterosis and combining ability for yield and other quantitative traits in exotic varieties of Maize, Agron J., 141: 197-199
Vijayabharathi A., Anandakumar C.R., and Gnanamalar R.P., 2009, Combining ability analysis for yield and its components in popcorn (Zea mays var. everta Sturt.). Electronic J. Plant Breed., 1: 28-32
White P.J., and Johnson L.A., 2003, Corn: Chemistry and Technology, 2nd Edn., American Association of Cereal Chemists, St. Paul, M. N. USA., ISBN – 13: 9781891127335, Pages:892