YIELD ATTRIBUTING TRAITS IN PARENTS VERSUS HYBRIDS IN FCV TOBACCO (Nicotiana tabacum L.)

Transcription

1 Sarhad J. Agric. Vol. 30, No. 2, 2014 YIELD ATTRIBUTING TRAITS IN PARENTS VERSUS HYBRIDS IN FCV TOBACCO (Nicotiana tabacum L.) QAIZAR AHMED and FIDA MOHAMMAD* Department of Plant Breed & Genetics, The University of Agriculture Peshawar, Pakistan *Corresponding author: ABSTRACT This research was conducted to compare the performance of parent cultivars versus hybrids in Flue Cured Virginia (FCV) tobacco (Nicotiana tabacum L.). Seven varieties were crossed in all possible combinations at the Tobacco Research Sub Station, Mansehra during 2007 to generate a full diallel set of progeny. Forty-two F 1 hybrids along with their parent cultivars were planted at the Tobacco Research Station, Mardan (plain) and the Tobacco Research Sub Station, Mansehra (hilly) during 2008 and Both experiments were planted in a randomized complete block design with four replications. Data were recorded on days to flowering, plant height, leaves plant -1, internodal length, leaf area, green leaf weight, cured leaf weight, number of green leaves kg -1, number of cured leaves kg -1, yield, grade index (%), percent nicotine and percent reducing sugars. Analysis of variance revealed significance (P<0.01) among genotypes and their interactions with environments for all traits. Hybrids exhibited higher mean performance than parent cultivars in the expression of days to flowering, leaf area, number of green leaves kg -1, number of cured leaves kg -1 and percent nicotine. Ranges in hybrids were higher than parent cultivars for days to flowering, plant height, leaves plant -1, internodal length, leaf area, green leaf weight, number of green leaves kg -1, percent nicotine, and percent reducing sugar which indicates hybrid vigour for all traits. Performance of F 1 hybrids across environments was environment-specific. Based on mean performance, the parent cultivars Spt G 126, Spt G 28 and KHG21 had higher yield across environments. The parent cultivar Spt G 28 had the highest performance for grade index, percent nicotine and percent reducing sugars. The desirable F 1 hybrids for yield were Spt G 28/Spt G 126 and Spt G 126/KHG24. Key word: Flue cured Virginia tobacco, hybrids, environments, Percent nicotine Citation: Ahmed. Q. and F. Mohammad Yield attributing traits in parents versus hybrids in FCV tobacco (Nicotiana tabacum l. ). Sarhad J. Agric. 30(2): INTRODUCTION Tobacco (Nicotiana tabacum L.) crop belongs to family Solanaceae and it generates revenue higher than any other crop (Federal Board of Revenue, Pakistan). It is one of the major sources of income in government revenues due to worldwide acceptance by growers and users. According to old chronicles of the Moghul period, special levies were imposed in areas where tobacco cultivation was concentrated. The British East India Company also made this a legally excisable commodity. When tobacco became a potential source of government revenue it gained importance compared to other agricultural crops. Tobacco is grown as cash crop worldwide due to high economic return. In Pakistan, during , tobacco was planted on 51,300 hectares with a total production of 102,800 tonnes. In Khyber Pakhtunkhwa province, tobacco was planted on 32,500 hectares. Raw Exports of tobacco and cigarettes were worth million rupees. The tobacco industry generated 58.3 billion rupees as indirect taxes (Khan et al., 2011). The history of tobacco in the sub-continent traces back to the reign of Great Moghul Emperor Akbar in 16th century where people were accustomed to inhale the smoke of burning herbs. The introduction of tobacco to the subcontinent people quickly turned to use as a relaxing agent (Ahmed, 1978). Tobacco has a long history of use by medical herbalists as a relaxant. They are used externally in the treatment of rheumatic swelling, skin diseases and scorpion stings. Wet tobacco leaves can be applied to stings in order to relieve the pain. They are also a certain cure for painful piles. A homeopathic remedy is made from the dried leaves. Some of the species such as Nicotiana sylvestris and Nicotiana alata are grown for ornamental purposes. Extracts from tobacco had been used in insecticides, but it got diminished with the passage of time and hence nowadays it is not preferred. The agro-climatic conditions in Pakistan are suitable for growing various types of tobacco. Production practices and curing management produce multiple tobacco products. At the time of independence in 1947, there were many tobacco types present but no cigarette type tobacco was produced in Pakistan. In 1948, a humble beginning was made with a trial plantation of 20 acres of flue-cured Virginia tobacco. Since then, the production of cigarette type tobacco has expanded. Realizing the importance of tobacco the Pakistan Tobacco Board, an autonomous body of the

2 Qaizar Ahmed and Fida Muhammad, et al. Yield attributing traits in parents versus hybrids 194 Ministry of Commerce, was established in 1968 with the responsibility to take all possible measures to improve production, quality and marketing of tobacco. In any crop, pace of variety development determines the speed of improvement. No varieties have been developed in Pakistan resulting in reliance on introduced varieties. Consequently, a single variety with modest yield and quality with no resistance against diseases has been in cultivation. At present there is a need to establish an objectives-based tobacco breeding program in the country. A local tobacco breeding program would focus on the development of end use-specific varieties, thus promoting production, quality and disease resistance. The diallel cross technique, a conventional approach and introduced by Schmidt (1919), involves crossing a set of parental lines in all possible combinations including their reciprocals. Tobacco is grown for its leaves i.e., vegetative portion. Greater leaf yields depend on number of harvestable leaves, leaf length, breadth and weight. Leaf quality is also measured by grade index and quantities of nicotine and reducing sugar contents. Phenotypic expressions of quantitative traits are genotype and environment specific. Keeping in view the need and importance of the tobacco industry, this study was initiated with the objectives to: i) generate hybrids and provide a sound base for a breeding program in FCV tobacco, and ii) compare parent cultivars versus hybrids for several production traits. MATERIALS AND METHODS The present study was conducted to determine performance of F 1 s in relation to parent cultivars for various agronomic and biochemical traits in flue-cured Virginia tobacco (Nicotiana tabacum L.). Table 1. Seven tobacco varieties and their characteristics S# Variety/line Pedigree Main features 1 NC 606 NC729/NC 82 Good cured-leaf quality Tall plants with about 30 leaves and longer internodal length. 2 K 399 (Coker139x Coker 319) and NC 95 3 Spt. G 126 K 326 x Speight G-96 4 Spt, G 28 (Coker 139 x Oxford 1-181) and NC 95 5 KHG 21 Locally selected accession 6 KHG 22 Locally selected accession 7 KHG 24 Locally selected accession Dwarf plants with about 26 leaves. Somewhat late flowering. Broader leaves. Produces average yields of less than average quality Produces nearly 20 to 25 leaves on a stalk of average height Flowers later than most varieties and good holding ability. The recommended variety for last 30 years in Pakistan. Moderate yield and medium quality tobacco. Short plants having more than 25 leaves. Flowers medium to late. Based on long-term data it has tall plants, more than 30 leaves per plant and intermediate internodal length. It has more leaf area than KHG 22and KHG 24. Based on long-term data, it possesses an average of 24 leaves per plant with intermediate leaf area. It has more internodal length than KHG21 and KHG 24. Based on long-term data, it has an average of 25 leaves per plant with intermediate internodal length. It is dwarf, having smaller leaf area than KHG21 and KHG 22. Seven tobacco varieties/lines with contrasting traits (Table 1) were crossed in all possible combinations to generate a 7 7 diallel set at the Tobacco Research Sub-Station, Pakistan Tobacco Board, Mansehra in Seed of 42 F 1 hybrids was collected and stored for planting during 2008 and In 2008 and 2009, all F 1 hybrids along with their parent cultivars were planted in a randomized complete block design with four replicates at the Tobacco Research Station Mardan (plain) and Tobacco Research Sub Station Mansehra (hilly). Hereafter the experiments conducted at Mardan during 2008, Mansehra during 2008, Mardan during 2009 and Mansehra during 2009 will be referred to as Environment-1 (E -1), Environment-2 (E -2), Environment-3 (E -3) and Environment-4 (E -4), respectively (Table 2). Individual plants were spaced 60 cm apart within each row and rows were 90 cm apart. Each entry was planted in a one row plot 6 m in length. Cultural practices including weeding, hoeing, earthing-up, fertilizer application, etc. were applied according to local production practices. Collection of Data Five random chosen plants in each plot were used for morphological, yield and biochemical parameters. Days of flowering were counted from the date of transplantation to the date of 90% flowering. At button stage of inflorescence topping of each treatment is a standard practice in FCV tobacco. After topping, plant height was measured from ground level to the cut tips. Internodal length was calculated by dividing plant height with number of

3 Sarhad J. Agric. Vol. 30, No. 2, leaves plant -1. Leaves plant -1 were counted as the number of leaves after topping. Length and broadest width of the 5 th, 10 th and 15 th leaves were averaged for leaf area (cm 2 ). Mean value was further adjusted as proposed by Suggs et al. (1960). Leaves were picked according to maturity five or six times. The maturity starts from bottom leaves towards middle and top on the plant. Total weight of mature leaves at all harvest phases was recorded. Leaves were picked from field, tied to sticks and transferred to the flue-curing barn. After curing the cured leaves were weighed. Number of green leaves kg -1 was recorded as leaves in one kilogram at harvest. Number of cured leaves kg -1 was taken as leaves in one kilogram after curing. Yield was recorded as weight of leaves after curing. FCV tobacco is graded according to its colour and texture, assessed visually. Different grades fetch variable prices. Grade index (%) was assessed visually as per standard procedure, prevailing in the market. Nicotine and sugar contents were determined in a composite sample of all pickings as outlined by Shmuk (1954). Table 2. Description of the experimental environments. E-1 E-2 E-3 E-4 Altitude (meters) Annual Rainfall (mm) Rainfall during March to August (mm) Mean annual temperature (Min and Max o C) Mean temperature, March to August (Min and Max o C) Soil texture Silt loam Silt loam Silt loam Silt loam Soil ph chemical nature Chlorides % Soil nutrients Statistical Analysis N % P % K % Organic matter % Analyses of variance for various traits across environments were worked out to know the significance of genotype by environment, using the following format of ANOVA Table. Source of variation Df MS F Value Environments (e-1) = 3 En Ms En Ms/EMS Rep (Env.) e(r-1) = 12 EMS - Genotypes (g-1) = 48 GMS GMS/EMS G x V (g-1) (e-1) = 144 G x E MS G x E MS/EMS Error e(r-1) (g-1) = 576 EMS - Total 783 As genotypes by environment interaction were significant, analyses of variance over individual environment were carried out, using the statistical model of Steel and Torrie (1980). In case of significant mean squares of genotypes least significance difference test was conducted (Steel and Torrie, 1980) to compare means of best parent and F 1 s. RESULTS AND DISCUSSION Test of Significance Data recorded on seven FCV tobacco varieties and their 42 F 1 hybrids for various traits over four environments were subjected to combined analysis of variance (Table 3). Genotypes and GEI were significant (P <0.01) for all traits. Significant GEI implies that response of genotypes to various environments was different and thus it necessitated considering analysis of genotypes in individual environments. Analyses of variance revealed significant differences among genotypes for all traits in four environments (Table 3). Days to Flowering Early flowering is desirable in FCV tobacco as it provides more time for leaf development, biochemical processes and ultimately yield (Sastri, 1974 ; Chaudhry and Fareed, 1982). Statistical analysis revealed significant (P <0.01) differences among genotypes for days to flowering (Table 1). Data for days to flowering ranged from 65 to 81; 57 to

4 Qaizar Ahmed and Fida Muhammad, et al. Yield attributing traits in parents versus hybrids ; 72 to 79 and 80 to 84 days among hybrids in four environments, respectively. Crosses like Spt G 126/KHG24, KHG22/KHG21, Spt G 8/KHG22 performed best. The range for the parent cultivars was 68 to 75; 55 to 74; 74 to 79 and 81 to 85 days in the same four environments, respectively (Table 4). KHG22 took least days to flowering in all environments studied. Mean days to flowering of parent cultivars was greater than the hybrids, but the range for days to flowering is wider in progeny, indicating that hybrid progeny had plants with a higher range for this trait. Significant differences among hybrids for days to flowering reflected that selection for early maturing plants could be made. Hashmi et al. (2004) and Sadeghi et al. (2012) also reported significant differences for days to flowering in tobacco. Plant Height (cm) Taller plants with longer internodes are desirable as it facilitates light and air circulation for leaf development and biochemical processes in FCV tobacco. Statistical analysis revealed significant (P <0.01) differences among genotypes for plant height (Table 3). Data for plant height ranged from 106 to 119 cm; 84 to 105 cm; 106 to 124 cm and 93 to 103 cm among hybrids in the four environments, respectively (Table 4). Parent cultivars ranged from 106 to 111 cm; 88 to 96 cm; 110 to 121 cm and 94 to 104 cm for plant height in four environments respectively (Table 4). Parent cultivars KHG22 and NC606 produced tallest plants in all four environments while crosses KHG22/K399, NC606/Spt G 126 and KHG21/KHG24 produced plants taller than above mentioned parents. The range among hybrids was greater than parent cultivars, indicating plants with a wider range of plant height. This reflected that favourable selections could be practiced. Significant differences for plant height in the tobacco crop have been reported by Kara and Esendal (1997), Butorac et al. (2004) and Sadeghi et al. (2012). Leaves Plant -1 Analysis of variance showed significant (P<0.01) differences for leaves plant -1 among genotypes Table 3. Data for leaves plant -1 ranged from 16 to 22; 18 to 24; 14 to 19 and 18 to 24 for hybrids in the four environments, respectively, while values for the parents ranged from 17 to 21; 17 to 22; 15 to 19 and 19 to 22, respectively, in the same four environments, (Table 4). Range among the hybrids was greater than among the parent cultivars for leaves plant -1 over all environments, indicating that hybrids with higher number of leaves could be selected. Crosses like KHG22/KHG21, Spt G 28/KHG21 and K399/Spt G 28 produced more leaves than best performing parents like NC606, K399, KHG22 and KHG24. Findings of the current study for leaves plant -1 in FCV tobacco confirmed the results of Kara and Esendal (1997), Butorac et al. (2004) and Sadeghi et al. (2012). Internodal length (cm) Larger internodes facilitate light and air circulation for leaf development and bio chemical processes in FCV tobacco. Mean squares revealed that genotypes were significant (P <0.01) for internodal length Table 3. Data for internodal length ranged from 5.1 to 6.8 cm; 3.6 to 5.6 cm; 6.1 to 8.3 cm and 4.4 to 5.5 cm among hybrids across the four environments, respectively, while internode length for the parent cultivars ranged from 5.1 to 6.4 cm; 4.1 to 5.7 cm; 6.3 to 8.1 cm and 4.6 to 5.4 cm, respectively, across the same four environments Table 4. Parents like KHG22 and KHG24 performed best for the trait. Among the hybrids Spt G 126/KHG24 and KHG24/K399 were bearing larger internodes than best performing parents. Means with ranges in Table 2 for intermodal length indicated that plants with longer internodes existed among hybrids. This reflected that selection for larger internodes could be made. Leaf Area (cm 2 ) Analysis of variance showed significant (P<0.01) differences for leaf area among genotypes Table 3. Data for leaf area ranged from 1229 to 1683; 842 to 1305; 640 to 789 and 740 to 847 cm for hybrids in 4 environments respectively, while 1194 to 1407; 917 to 1266; 676 to 773 and 748 to 861 cm for parents in 4 environments, respectively (Table 4 ). Mean leaf area in hybrid populations was greater than the mean leaf area for parental cultivars in E-1 and E-2 (Table 2). About 14 hybrids produced larger leaf area than maximum range of parents in E- 1. KHG21/KHG22 and NC606/KHG21 were best among them. In E-2 and E-3 crosses like Spt G 126/KHG22 and KHG21/Spt G28 performed higher in magnitude for the trait. Green leaves weight (kg) Significant (P<0.01) differences were observed in genotypes for green leaves weight (Table 3 ). Data for green leaves weight varied from 2.3 to 3.7 kg; 1.9 to 2.8 kg; 1.0 to 1.4 kg and 1.3 to 1.9 kg for hybrids in four environments respectively while 2.5 to 3.5 kg; 2.0 to 2.4 kg; 0.9 to 1.4 kg and 1.3 to 1.8 kg for parents in four environments respectively (Table 4). Hybrids like Spt G 28/K399, Spt G 28/Spt G 126 and KHG22/KHG21

5 Sarhad J. Agric. Vol. 30, No. 2, exhibited wider range of plants with green leaves weight in all environments except E-3, suggesting that plants with heavier green leaves could be selected in all environments except E-3. Gopinath et al. (1967) also reported significant mean squares for green weight of leaves in tobacco. Cured Leaves Weight (kg) Analysis of variance declared significant (P<0.01) differences among genotypes for cured leaf weight (Table 3 ). Data for cured leaf weight ranged from 356 to 449 g; 310 to 433 g; 162 to 229 g and 205 to 292 g for hybrids and 373 to 450 g; 325 to 415 g; 169 to 240 g and 202 to 299 g for parent cultivars over four environments, respectively (Table 4). Spt G 28/Spt G 126 was the cross exhibiting more weight of cured leaf than any of parent in E-2. Based on the data, selection for increased cured leaf weight was possible in E-2 only. This is in agreement with findings of Gopinath et al. (1967). Number of Green Leaves (kg -1 ) Significant (P<0.01) variation was observed in genotypes for number of green leaves in FCV tobacco (Table 3). Minimum number of green leaves is desirable to get heavier leaves. Data for green leaves varied from 10.3 to 14.5; 14.4 to 20.3; 19.8 to 33.3 and 21.8 to 27.9 for hybrids and 10.0 to 15.1; 16.5 to 21.3; 24.5 to 31.0 and 22.7 to 28.1 for parent cultivars across four environments, respectively (Table 4). KHG22/KHG21, KHG24/K399 and KHG21/KHG24 were hybrids showing improved leaf number in E-2, E-3 and E-4 respectively. In the current study selection of plants with a minimum number of green leaves in tobacco could be effective in all four environments except E-1. Number of Cured Leaves (kg -1 ) Genotypes had significant (P<0.01) differences for number of cured leaves (Table 3). Data for number of cured leaves varied from 74 to 99; 93to 127; 122 to 185 and 134 to 176 for hybrids while 70 to 102; 81 to 120; 144 to 171 and 131 to 171 for parent cultivars in E-1, E-2, E-3 and E-4, respectively. Minimum number of cured leaves is desirable for heavier leaves. Six hybrids in E-3 performed in higher magnitude than best parent for the trait. Among them KHG24/K399 and KHG22/Spt G 126 performed best. In remaining 3 environments the desirable limit of range of parents could not be crossed by crosses obtained. Yield (kg ha -1 ) Significant (P<0.01) variation was observed in genotypes for yield in FCV tobacco (Table 3). Data for yield varied from 3566 to 4486 kg; 3102 to 4329 kg; 1623 to 2289 kg and 2054 to 2918 kg for hybrids and 3731 to 4500 kg; 3250 to 4150 kg; 1694 to 2404 kg and 2019 to 2994 kg for parent cultivars in E-1, E-2, E-3 and E-4, respectively (Table 4). Yield could be improved over highest performing parent by the cross Spt G 28/Spt G 126 in E-2. In the current study for yield, selection of plants with higher yield in tobacco could be effective in E-2 only. Pathak et al. (1996), Patel and Pathak (1996) and Sadeghi et al. (2012) reported significant differences for yield in their breeding material which is in agreement with the findings of this study. Grade Index (%) Statistical analysis revealed significant (P<0.01) differences for grade index among ge notypes (Ta ble 3). Data for grade index ranged from 60 to 74%; 61 to 76%; 67 to 82% and 64 to 81% for hybrids and 64 to 78%; 65 to 80%; 64 to 86% and 65 to 81% for parent cultivars across four environments, respectively (Table 4). The parent cultivars KHG21, Spt G 28 and Spt G 126 were best in grade index in the four environments. None of the hybrids exceeded parent cultivars for grade index. Sheng (2007) also advocated for presence of genetic variability for grade index in tobacco. Percent Nicotine Genotypes were significantly ( P<0.01) different for percent nicotine (Table 3). Percent nicotine varied from 1.4 to 2.4%; 2.1 to 3.1%; 1.4 to 2.4% and 2.1 to 3.0% for tobacco hybrids and 1.3 to 1.8%; 1.7 to 2.5%; 1.4 to 1.8% and % for parents in E-1, E-2, E-3 and E-4, respectively (Table 4). The hybrids means for nicotine were greater than parental means in all four environments for nicotine which expressed high intensity of plants with higher nicotine content. Almost 17 hybrids exceeded in nicotine contents than best performing parent in E-1. Thirteen, eleven and ten hybrids performed better than best performing parent in E-2, E-3 and E-4 respectively. KHG22/NC606 and KHG22/K399 performed in highest magnitude for the trait in the four environments. Kara and Esendal (1995) and Pathak et al. (1996) also recorded genetic variability for nicotine in tobacco.

6 Qaizar Ahmed and Fida Muhammad, et al. Yield attributing traits in parents versus hybrids 198 Percent Reducing Sugars Significant (P<0.01) differences were recorded for percent reducing sugars among genotypes (Table 3). Hybrids ranged from 15.6 to 24.6%; 15.3 to 24.7%; 15.2 to 24.6% and 14.6 to 24.2% for nicotine while the parent cultivars gave a range of 14.0 to 22.2%; 15.7 to 22.4%; 15.5 to 21.5% and 15.4 to 22.0.% in E-1, E-2, E-3 and E-4, respectively (Table 4). The hybrids KHG21/Spt G 28 and KHG21/NC606 exhibited highest values of reducing sugars in all four environments. Mean values for percent reducing sugars among the hybrids were greater than parental means in E-1 and E-3 which indicates potential for effective selection for this trait. Kara and Esendal (1995) and Pathak et al. (1996) also recorded genetic variability for reducing sugars in their breeding material. CONCLUSION AND RECOMMENDATIONS Tobacco is one of the cash crops which substantially add to the revenue of government of Pakistan. However, there has been no locally based breeding program in tobacco and the industry relies on introduced genotypes for cultivation. Consequently, susceptible tobacco varieties with modest yield and quality are cultivated. Establishment of a local tobacco breeding program would promote the tobacco industry significantly. The prime objective of the current study is to provide sound basis to a tobacco breeding program in the Pakistan. Seven tobacco cultivars were crossed in all possible combinations to generate material for studying parents versus hybrids for economical production traits. This study indicated that forty-two hybrids along with their parent cultivars had significant differences and genotype by environment interactions. Selection for days to flowering, green leaves weight, cured leaf weight, number of green leaves kg -1, cured leaves kg -1 and yield would be environment-specific. This study identified crosses like Spt G 126/KHG24, KHG22/KHG21, Spt G 8/KHG22 performing best for days to flowering. Crosses KHG22/K399, NC606/Spt G 126 and KHG21/KHG24 produced tallest plants, crosses like KHG22/KHG21, Spt G 28/KHG21 and K399/Spt G 28 produced more leaves. Hybrids Spt G 126/KHG24 and KHG24/K399 were having larger internodes. For leaf area KHG21/KHG22, NC606/KHG21, Spt G 126/KHG22 and KHG21/Spt G 28 performed highest. Hybrids like Spt G 28/K399, Spt G 28/Spt G 126 and KHG22/KHG21 produced highest green leaves weight. Spt G 28/Spt G 126 was the cross exhibiting more weight of cured leaf. The leaf number per kg could be improved by crosses KHG22/KHG21, KHG24/K399 and KHG21/KHG24. Crosses KHG24/K399 and KHG22/Spt G 126 were identified for desirable most number of cured leaf per kg. Yield was shown best by cross Spt G 28/Spt G 126. None of crosses produced better grade index than parents. Nicotine can be improved by crosses like. KHG22/NC606 and KHG22/K399 and reducing sugars were higher in crosses like KHG21/Spt G 28 and KHG21/NC606. Hence, these hybrids are recommended for further investigation.

7 Sarhad J. Agric. Vol. 30, No. 2, 2014 Table 3 Mean squares for different agronomic and biochemical traits in 7x7 diallel of FCV tobacco of 2008 & Source Df DTF PH LP IL LA GW CW GLN CLN YLD GI NC RS Combined analysis in 4 environments Environment ** ** ** ** ** ** ** ** ** ** ** 30.27** 27.6** Rep (Env.) Genotype ** 54.2** 8.502** 1.144** ** 0.175** ** 13.39** 439.3** ** 193.6** 0.76** 69..3** G x E ** 46.2** 4.678** 0.584** ** 0.127** ** 13.36** 445.5** ** 44.5** 0.01** 2.7** Error CV % E-1 Block ** ** ** Genotype ** ** 0.72** ** 0.307** ** 5.58** ** ** 75.03** 0.192** 18.11** Error CV % E-2 Block ** ** 98.01** ** ** ** 18.59** Genotype ** 80.28* 6.84** 0.69** ** 0.12** ** 10.04** ** ** 79.09** 0.239** 20.65** Error CV % E-3 Block * 0.67** Genotype ** 65.83** 4.83** 1.21** ** 0.059** ** 28.22** ** ** 77.57** 0.187** 19.88** Error CV % E-4 Block ** 1.71** ** ** ** ** 3.50** Genotype ** 15.95* 4.52** 0.26** ** 0.070** ** 9.66** ** ** 95.31** 0.171** 18.79** Error CV % * and ** : P < 0.05 and P< 0.01, respectively DTF: days to flowering; PH: plant height; LP: leaves plant -1 ; IL: internodal length; LA: leaf area; GW: green leaves weight; CW: cured leaves weight; NGL: number of green leaves kg -1 ; NCL: number of cured leaves kg -1 ; YLD: yield; GI: grade index, NC: nicotine and RS: reducing sugars.

8 Sarhad J. Agric. Vol. 30, No. 2, 2014 Table 4 Means with ranges of parent cultivars and F 1 hybrids for various traits across 4 environments. DTF PH LP IL LA GW CW NGL NCL YLD GI NC RS (days) (cm) (#) (cm) (cm 2 ) (kg) (g) (#) (#) (kg ha -1 ) (%) (%) (%) E-1 Minimum of parents Maximum of parents Mean of parents Minimum of F 1 hybrids Maximum of F 1 hybrids Mean of F 1 hybrids Lsd (P<0.05) E-2 Minimum of parents Maximum of parents Mean of parents Minimum of F 1 hybrids Maximum of F 1 hybrids Mean of F 1 hybrids Lsd (P<0.05) E-3 Minimum of parents Maximum of parents Mean of parents Minimum of F 1 hybrids Maximum of F 1 hybrids Mean of F 1 hybrids Lsd (P<0.05) E-4 Minimum of parents Maximum of parents Mean of parents Minimum of F 1 hybrids Maximum of F 1 hybrids Mean of F 1 hybrids Lsd (P<0.05) DTF: days to flowering; PH: plant height; LP: leaves plant -1 ; IL: internodal length; LA: leaf area; GW: green leaves weight; CW: cured leaves weight; NGL: number of green leaves kg -1 ; NCL: number of cured leaves kg -1 ; YLD: yield; GI: grade index, NC: nicotine and RS: reducing sugars. REFERENCES Ahmed, M Production of tobacco in Pakistan. An analytical study of past, present and future trends. Pak Tob. II(1): Butorac, J., J. Beljo and J. Gunjaca Study of inheritance of some agronomic and morphological traits in burley tobacco by graphic analysis of diallel cross. Plant Soil Environ. 50(4): Chaudhry, G. A. and M. Fareed Association of yield components in tobacco (Nicotiana tabacum L.). Pak. J. of Agri. Res. 3 (2): Gopinath, D.M., R. Lakshminaray and C.L. Narayana The mode of gene action in flue-cured tobacco. Euphytica. 16(2):

9 Sarhad J. Agric. Vol. 30, No. 2, Hashmi, E.A., G. Woras, F. Karim, M. Shahid and S.A. Shah Comparative study of different flue-cured Virginia (FCV) tobacco varieties in NWFP, Pakistan. Pak Tob. 23(1): Kara, S.M. and E. Esendal Heterosis and combining ability analysis of some quantitative characters in Turkish tobacco. Tob. Res. 21(1-2): Kara, S.M. and E. Esendal Diallel analysis of some quantitative characters in tobacco (Nicotiana tabacum L.). Anadolu Journal of Aegean Agricultural Research Institute. 7(1): Khan, A., A. Gohar and A. Wahab Statistical Bulletin, Pakistan Tobacco Board, Ministry of Commerce, Government of Pakistan. Patel, D.A. and H.C. Pathak Gene effects for yield and quality in rustica tobacco Nicotiana rustica L. Tob. Res. 22(1): Pathak, H.C., J.N. Patel, G.C. Jadeja, R. Lakshminarayana and S.B. Patel Line X tester analysis for yield and quality in tobacco (Nicotiana tabacum L.). Tob. Res. 22 (1): Sadeghi, S.M., E. Amin and M. Ashouri An investigation of gene action on different traits of tobacco under irrigated and drought stress environment. African J of Biotech. 11(21): Sastri, A. B Path analysis of yield components in Natu Tobacco. Ind. J. of Gen. Pl. Br. 34(1): Sheng, H.R Genetic studies on heterosis of flue cured tobacco ms hybrids. PhD Thesis. Hunan Agric. University. Schmidt J., La valeur de l'individu à titre de génratéur appréciée suivant la méthode du croisement dialléle. C. R. Trav. Lab. Carlsberg 14(6): Shmuk, A.A The chemistry and technology of tobacco. Vol. 3, Pishchapremizdat, Publishing Company, Moscow. Steel, R.D.G. and J.H. Torrie Principles and procedures of statistics. McGraw Hill Book Co. Inc., New York, USA. Suggs, P.W., J.E. Beeman and W.E. Splinter Physical properties of green Virginia types tobacco leaves in relation to length and breadth of leaf area. Tob. Sci. 4: