Inheritance Mechanism of Some Morphological Characters in Hexaploid Wheat

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1 Scientia Agriculturae E-ISSN: X / P-ISSN: DOI: /PSCP.SA Sci. Agri. 7 (3), 214: PSCI Publications Inheritance Mechanism of Some Morphological Characters in Hexaploid Wheat Muhammad Wajid Pervez 1*, Ihsan Khaliq 1, Sajid Hussain 1, Saif Ali 2, Muzammal Rehman 2, Khalid Rehman 2, Muhammad Shahzad Khalid 2, Ghulam Aisha 3 and Saddam Hussain 3 1. Department of Plant Breeding and Genetics, University of Agriculture Faisalabad, Pakistan 2. Department of Agronomy, University of Agriculture Faisalabad, Pakistan 3. National Key Laboratory of Crop Genetic Improvement, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 437, China. *Corresponding author paragon286@yahoo.com Paper Information A B S T R A C T Efforts are being done since a long time in wheat breeding for its economic Received: 6 July, 214 traits to achieve maximum grain yield. This study of inheritance mechanism was carried out at the Department of Plant Breeding and Accepted: 27 August, 214 Genetics, University of Agriculture, Faisalabad-Pakistan during using 5 5 diallel crosses involving wheat varieties/lines viz.,, Published: 2 September, 214,, and to find the inheritance pattern of some quantitative traits like plant height, peduncle length, number of tillers per plant, 1-grain weight and grain yield per plant. Significant genotypic differences were observed for all the traits under consideration. The graphical analysis revealed over dominance type of gene action for grain yield per plant suggesting heterosis breeding might be fruitful for further improvement of these traits. Presence of additive gene action and as for dominance concerned which is partial type for plant height, peduncle length, number of tillers per plant, 1-grain weight and grain weight per spike emphasize that the pedigree selection procedure is a promising approach for further improvement of these traits. Absence of epistasis was found for all the characters. 214 PSCI Publisher All rights reserved. Key words: Inheritance pattern, Bread wheat, Diallel cross, Qantitative traits Introduction Wheat (Triticum aestivum L.) belonging to family Gramineae provides nutrition to a large world population. If we see the history then we will come to know that it goes parallel with the history of human civilization. One third population of the world gets more than half of their calories and proteins only from wheat. It is very good source of energy and gives 72% of calories and proteins by consuming the wheat products like breads, cakes, biscuits, chapattis, nans, pasteries (Heyne, 1987). It provides food for 36% of the world population and also gives 2% of food calories. Wheat is a self-fertilized annual crop and is grown in most parts of the world than any other crop. Wheat is staple food of Pakistan and outstandingly feeds humanities of urban and rural areas (Hussain et al., 213). Wheat contains an important chemical substance called gluten, with especial physical and chemical properties, through which risen loaf bread is produced. Hexaploid wheat is mainly used for production of bread around the world but it is also used to make numerous other food products namely cakes, pastries, cookies, noodles etc. Many agricultural scientists have done a lot of research on wheat in order to improve the grain yield per unit area. Regardless there remained an open field for wheat breeders to continue their efforts for improvement in genetic architecture of wheat plant to meet the feeding requirements of world. In spite of high production, bread wheat yield is low due to reasons namely unavailability of irrigation at the needed time, improper use of fertilizer, attack of diseases and weeds, late cultivation due to non-availability of fallow land and rain at the time of harvest (Hussain et al., 214; Fahad et al., 214). Because the majority of farmers have small land holdings and also suffer with scarcity of water, grain yield per unit area can only be improved with varieties containing desirable genes for high grain yield and its related traits under stressed conditions. Wheat grain yield is controlled by many quantitative genes which make it difficult to have a variety with high yield in all environments. By doing selection only on the basis of phenotype high yield barely can be improved unless the genetic mechanisms are known for the concerned traits. Therefore, the first step is the generation of knowledge regarding the genetic architecture and type of gene action. Thus, it is necessary to evaluate and study

2 the genetic variation as it is the basic requirement of any crop improvement program as well as the inheritance patterns of different plant parameters to start an efficient breeding program. Proper choice of parents needs utmost care because they should not only manifest the mandatory traits but should also be capable of producing hybrids with superior performance when crossed with other lineages. Using eight doubled haploid Ojaghi and Akhundova (21) reported that plant height to be inherited through partial dominace and gene action was additive and similar results were reported by Kashif et al. (23) by using 8 8 diallel crosses. With their studies on peduncle length, Ajmal et al. (211), found that it is inherited by partial dominance with additive type of gene action. Bakhash et al. (24) concluded that number of tillers is inherited by many additive genes and partial dominace was also observed. Over dominance gene action was observed for yield per plant (Heidari et al. 26; and Gurmani et al. 27). The present studies were designed using five parents in a diallel cross to understand the genetic basis of some polygenic characters of spring wheat. Ten imperative polygenic characters would be studied in order to determine the gene action involved in their inheritance. Information so derived might be efficiently exploited to design suitable strategies for sustained genetic improvement of this essential food crop. Materials and Methods The present research work on gene action studies for various plant morphological traits was carried out in the experimental area of the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad-Pakistan. In this experiment five wheat varieties/lines of spring wheat (Triticum aestivum L.) viz.,,,, and and their F 1 crosses were used. The sowing of these varieties/lines was completed during Rabi season (Mid November Mid March) and using diallel scheme. The sowing of hybrid seeds including reciprocals and parents was carried out on November 15, 212, under a randomized complete blocks design and three replications were used. Each replication had 2 crosses and 5 parental lines, each plot of 3m length. The distance between plants and rows was 15 and 3 cm, respectively. The sowing was done using a dibble. Three seeds per hole were sown and then thinning was carried out and only one seedling was kept in one hole for allowing better growth. After full maturity of crop ten plants were taken out randomly and data were collected for plant height, peduncle length, number of tillers per plant, 1-grain weight and grain yield per plant. The data were subjected to Analysis of variance (Steel et al., 198). Significant differences in existing data were determined by Hayman (1954a, b) and Jinks (1955) techniques. The variance () of family mean within an array and covariance () of array with parental means were calculated: Xi 2 ( Xi) 2 /n i = Where, i = Variance of the ith array Xi 2 =Sum of square of ith array Xi = Sum of the ith array n = number of observation Covariance of these means with non-recurrent parents mean was calculated by using following formula: XiYi ( Xi)( Yi)/n i = Where, i = Covariance of the ith array Xi = Sum of the ith array Yi = Sum of the parental mean XiYi = Sum of the product of ith array and parental means n = Number of observation By plotting covariance () of each array against the respective variance (), information about the gene action was obtained. Regression coefficient was computed by the formula: b = cp/. S. S. Where, XiYi ( Xi)( Yi)/n Cp (Covariance product) =

3 XiYi = Product of ith array Xi = Sum of the ith array Yi = Sum of ith array covariance with parents Xi 2 ( Xi) 2 /n Var. (vr) = Var. (vr.) = Variance of the ith array variances Xi 2 = Sum of squares of ith array variances Xi = Sum of the ith array variances Significance of b from unity was checked by t-test: 1-b t = S.E (b) The slope and position of the regression line fitted to the array points within parabola indicates the degree of dominance and presence or absence of gene interaction. Regression line was drawn by plotting of covariance of each array (along y-axis) against the respective variances (along x-axis) inside parabola limits. ei were calculated to draw regression line; ei = bvr + bvri Where = Mean covariance of the ith array with parents mean = Mean variance of ith array b = Regression coefficient i = Variance of ith array The points of parabola limits were computed as under; ii = Where ii = Parabola limits Vp = Parental variance i = Variance of ith array The regression line touches wr-axis at the point known as intercept a which can be estimated as under; a= b.. Where = Covariance mean b = Regression coefficient = Variance mean a= Point of interception The intercepts provide a measure of average degree of dominance. If the line of a unit slope (b=1) passes through origin (zero intercept), complete dominance is indicated. The movement of the line upward and downward denotes decrease and increase dominance respectively. If the line intercepts -axis below the origin (Negative intercept), it shows over dominance type of gene action. If line cuts -axis above the origin (positive intercept), it exhibits partial dominance. When regression line is almost tangent to the parabola, then additive type of gene action is reflected. The position of array points on the regression line indicates the distribution of dominant and recessive genes among the common parents. Array points close to origin hold maximum dominant genes while those far away from origin carry maximum recessive genes. Results and Discussion Different traits studied in different varieties show the presence of dominant and recessive genes in respective traits and also it was also inferred from recent studies that different lineages have different combining ability for different traits. So good general combiners and specific combiners could be used in hybridization or variety development programs and these derived information might be used. 152

4 Plant height Plant height showed the presence of partial dominance and additive gene action was involved because the regression line cuts co-variance () axis above the origin (positive intercept) (Fig.1). As regression line did not vary from unity so the assumption of absence of non-allelic interaction seemed to be satisfied. Similar findings were reported by Lonc and Zalewski (1996) and Ojaghi and Akhundova (21). From array means (Table 1) genotype was found to be the excellent general combiner contains highest array mean of cm while genotype was proved to be lowest performer with a lower array mean value of 83.7 cm. The array points on the regression line clarify that genotype being near to origin contains most dominant genes for plant height whereas genotype being far away from origin carry maximum recessive genes for plant height. Therefore, it can be concluded from the results plant height can be fixed by gradual selection in early generations. Table 1. Mean performance of the parent wheat varieties for various characters Character Plant height(cm) Peduncle length(cm) No. of tillers per plant 1-grain weight(g) Grain yield per plant(g) Peduncle Length Peduncle length was controlled by additive type of gene action with partial dominance as the regression line cuts the -axis above the origin (Fig. 2). The assumption of the absence of non-allelic interaction appears to be satisfied as the regression line following the unity. The results are in conformity with the findings of Bakhsh et al. (24). The investigation of array means (Table 1) revealed that genotype was good general combiner having maximum array mean value of 34.8 cm while showed minimum value 31.4 cm. Distribution of varietal points along the regression line showed that as compared to other varieties/lines, had maximum number of dominant genes and has maximum number of recessive genes for parameter under discussion (Fig. 2). As the additive type of gene action with partial dominance was operative for this trait suggesting that gradual selection in early generations would be useful to fix the trait Figure1. / graph for plant height. Number of tillers per plant 153

5 The graphical analysis revealed that the intercept of regression line on the axis is above the origin, showing partial dominance type of gene action with additive effects (Fig. 3). The assumption of the absence of non-allelic interaction appears to be satisfied as the regression line following the unit slope. Current results are in accordance with the observation of Inamullah et al. (26) and Gurmani et al. (27). Perusal of array means (Table 1) revealed that genotype was good general combiner among series of crosses having an array mean value of 8.8 while the genotype had poorest performance with an array mean value of The pattern of distribution of varieties/lines along the regression line indicates that has maximum number of dominant genes while has maximum number of recessive genes for this character. So it can be concluded from the present study that improvement of this trait is possible through recurrent selection in early generations Figure2. / graph for peduncle length 1-grain weight The inheritance of 1-grain weight in the selected genotypes was governed by partial dominance type of gene action as the regression line intersected the covariance axis above the point of origin (positive intercept) (Fig. 4). The assumption of the absence of non-allelic interaction appears to be satisfied as the regression line following the unit slope. The current observation of partial dominance type of gene action are in conformity with the findings of Sheikh et al. (2) and Subhani and Chowdhry (2). The perusal of array means (Table 1) indicated that among series of crosses the variety Millat- 11 expressed maximum mean value of 6.34 g closely followed by the genotype with mean value of 6.18 g considered to be the best performers while the variety showed minimum array mean value of 53.8 g appeared poor general combiner. The scattered array points along the regression line indicate the diversity among parents. The parents and carry maximum dominant genes as both are in the vicinity of origin while genotype contains most of recessive genes being far away from the origin. As 1-grain weight is inherited by partial dominance so selection must be done in early generations to fix this character. 154

6 Figure3. / graph for number of tillers per plant Figure4. / graph for 1-grain weight Grain yield per plant The grain yield per plant was inherited by over dominance as the regression line intersected the covariance axis below the point of origin (Fig. 5). The assumption of the absence of non-allelic interaction appears to be satisfied as the regression line following the unit slope. The present study is in harmony with the observations of Heidari et al. (26) and Kashif and Khan (28). From array means (Table 1) it is obvious that among series of crosses genotype was proved to be the 155

7 leading general combiner expressing highest array mean of g whereas the variety showed weak performance on account of showing minimum array mean value of g. A look on regression line tells about different distributed points that genotype and genotype being closer to origin contain most of the dominant genes for grain yield per plant while the genotype being distant from origin carries maximum of recessive genes. The present study suggests that selection for desirable transgressive segregates would not be possible through selection in early generations. Figure5. / graph for grain yield per plant References Ajmal S, Khaliq I, Rehman A.211. Genetic analysis for yield and some yield traits in bread wheat (T. aestivum L.). J. Agric. Res. 49(4): Bakhsh A, Hussain A, Ali Z.24. Gene action study for some morphological traits in bread wheat. Sarhad J. Agric. 2(1): Fahad S, Nie L, Khan FA, Chen Y, Hussain S, Wu C, et al Disease resistance in rice and the role of molecular breeding in protecting rice crops against diseases. Biotechnology letters, Gurmani RR., Khan SJ, Saqib ZA, Khan R, Shakeel A, Ullah M.27. Genetic evaluation of some yield and yield related traits in wheat. Pak. J. Agri. Sci. 44(1): Hayman BI.1954a. The theory and analysis of diallel crosses. Genetics 39: Hayman BI.1954b. The analysis of variance diallel crosses. Biometrics, 1: Heidari B, Rezai A, Mirmohammadi SAM, Maibody.26. Diallel analysis for the estimation of the genetic parameters of grain yield and grain yield components in bread wheat. J. Sci. and Technol. Agric. Natur. Resour. 1(2): Heyne EG Wheat and wheat improvement. 2 nd edition. American Society of Agronomy, Crop Sciences Sodety of America, Soil Science Society of America, Madison, WI, USA. pp Hussain S, Khaliq A, Matloob A, Fahad S, Tanveer A.214. Interference and economic threshold level of little seed canary grass in wheat under different sowing times. Environmental Science and Pollution Research, 1-9. Hussain S, Khaliq A, Matloob A, Wahid MA, Afzal I.213. Germination and growth response of three wheat cultivars to NaCl salinity. Soil and Environment, 32(1): Inamullah HA, Mohammad F, Siraj-ud-Din, Hassan G, Gul R.26. Diallel analysis of the inheritance pattern of agronomic traits of bread wheat. Pak. J. Bot. 38(4): Jinks JL A survey of the genetical basis of heterosis in a variety of diallel crosses. Heredity 9: Kashif M, Ahmad J, Chowdhry MA, Perveen K.23. Study of genetic architecture of some important agronomic traits in durum wheat (Triticum durum Desf.). Asian J.Pl. Sci. 2(9): Kashif M, Khan AS.28. Combining ability studies for some yield contributing traits of bread wheat under normal and late sowing conditions. Pak. J. Agric. Sci. 45(1): Lonc W, Zalewski D Diallel analysis of quantitative traits of winter wheat F 2 hybrids. Biuletyn Instytutu Hodowli-i-Aklimatyzacji Roslin 2: Ojaghi J, Akhundova E.21. Genetic analysis for yield and its components in doubled haploid wheat. Afr. J. Agric. Res. 5(4): Sheikh S, Singh I, Singh J.2. Inheritance of some quantitative traits in bread wheat (T. aestivum L. em. Thell). Annals Agri. Res. 21(1): Steel RGD, Torrie JH, Dickey DA Principles and procedures of statistics. A biometrical approach. 3rd ed. McGraw Hill Book Co. New York. Subhani GM, Chowdhry MA.2. Genetic studies in bread wheat under irrigated and drought stress conditions. Pak. J. Biol. Sci. 3(11):