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Title: Development of heterotic groups for hybird production in tomato
Authors: Gillani, Syed Muhammad Waqas
Keywords: Biological Sciences
Issue Date: 2019
Publisher: Pakistan Institute of Engineering & Applied Sciences, Islamabad.
Abstract: Tomato ranked as the 2nd most cultivated and consumed vegetable crop round the globe. Regular consumption of tomato can decrease the risk of different chronic and heart related diseases because of antioxidants like lycopene, carotenoids and vitamin C. Aim of the first study was to estimate heritability, genetic advance correlation between yield and yield components and fruit quality parameters in 50 tomato genotypes to establish the selection criteria. Analysis of variance showed significant mean square for all that traits indicating scope of improvement in tested genotypes. High heritability and high genetic advance was observed in cluster per plant, plant height, fruit weight, vitamin C and protein contents proposed additive the gene action and early improvement of those traits via selection. Yield/plant had significant and positive correlation with plant height, fruit weight, fruit width and fruit length suggesting improvement in yield via those traits. Flowers per cluster had highest direct positive effect on yield followed by fruit width, fruit length, plant height, fruit firmness and total carotenoids. So, keeping in view the results of heritability, genetic advance, correlation and path analysis yield can be increased by number of flowers, plant height, fruit width and length, fruit firmness, total carotenoids and vitamin C. Assessment of diversity in the germplasm can provide a baseline to screen out the parental line in a framework of breeding program. Second study was designed with an objective to describe antioxidant and biochemical potential of diverse tomato germplasm including backcross populations, modern and vintage cultivars, open pollinated varieties, hybrids and introgression lines to generate useful information for breeders to devise a breeding scheme for enhancing quality of tomatoes. Hence, fruits were collected at fully ripened stage from the experiment having completely randomized block design (RCBD) in triplets and then fruits were subjected to analysis for different antioxidants and biochemical compounds. Introgression lines of S. Pennillii possessed maximum total phenolic contents (T.P.C) (806.7 mg/kg F.W.), total carotenoids (172.66 mg/kg F.W.), lycopene (83.58 mg/kg F.W.) total oxidant status (151.28 μM/g F.W.) and reducing sugar (78.82 μg/g F.W.). while backcross population had maximum amount of total chlorophyll, chlorophyll a and chlorophyll b (159.09 μg/g F.W., 59.24 μg/g F.W., and 96.85 μg/g F.W. respectively). Commercial and elite hybrids showed least mean value of all studied antioxidants and phytochemicals except peroxidase activity (POD) among all the tested classes of tomatoes. Results indicated that Introgression lines of S. pennellii, can be elucidated as good genetic resources to device a judicious breeding program for quality improvement in tomato. In third study 24 hybrids along with 10 parental genotypes were analyzed for different genetic components, analysis of vaiance, general combining ablitiy, specific combining ablity and all type of heterosis. Analysis for the mean preformance of hybrids revealed that Vendor × V48 had maximum No. of cluster/plant (95.3), No. of flowers/cluster (9.0), fruit weight (58.3), fruit width (45.1) and fruit yield per plant (3.8) among hybrids. However, LA4141 × WV-63 have 6.0 kg/f fruit and 84.2 cm, fruit firmness and plant height respectively. In case of days to maturity (151), number fruits per cluster (7) and vitamin c contents (4131.4), Lyp-1 × LA4157 preformed best among the hybrids for the said traits. LA4141 × V48 has highest protein contents (316.3), while LA4141 × 21354 has maximum carotenoids (20.6) and lycopene (11.4) contents among the hybrids. ANOVA indicated the presence of genetic variability and wide scope of improvement in yield, yield related and quality parameters in the tested hybrids and parents. Moreover, Variance of σ2SCA was greater than that of σ2GCA all yield related and all the quality related traits. Variance of σ2SCA represents SCA of the presents, while σ2GCA variance of GCA of the parents. Magnitudes of σ2SCA and σ2D were higher than their corresponding σ2GCA and additive σ2A components for all the characters except fruit firmness. High [h2(b.s)] and accoupled with GA on the high side was recorded for number of cluster per plant, fruit weight, fruit length, fruit firmness, carotenoids, lycopene and protein contents. High heritability [h2(b.s)] acoupled with moderate genetic advance (G.A) was noted in case of fruit width and plant height. High [h2(b.s)] accoupled with less G.A was identified for days to maturity and vitamin C contents. Moderate [h2(b.s)] with moderate genetic advance was noted for number of flower per cluster, while moderate [h2(b.s)] with high genetic advance was recorded for no. of fruits per. While [h2(b.s)] represents heritability in broad sense. However, estimates of general combining ability revealed Vendar a female parent had desirable GCA effect for most of the yeild related paramters like number of cluster per plant (12.74), days to maturity (-1.76), number of flower per cluster (0.48), single fruit weight (6.18), fruit width (1.77), fruit firmness (0.35), plant height (3.25), and fruit yeild per plant(0.18). While, B-L-35 a female line which can be elucidated as a desirable parent for most of the qaulity parameters like total carotenoids (3.32), lycopene (1.31) and protien contents (15.44). Among tester Wv-65 was considered as best general combiner for many different traits which are under investigation in this study. Estimates SCA effects reavelad that Vendor x V48, Lyp-1 x LA4157 and B-L-35 x LA4157 might be rated as best specific combiner for most of the yield related components and yield. While, LA4097 x V48 and LA4097 x WV-63 were rated as best specific combiner for quality attributes. Vendor x V48, Lyp-1x LA4157 and B-L-35 x LA4157 were the best hybrids considering heterosis expressions for yield and its contributing different factors.while, LA4141 × V48 and LA4141 × 21354 were elucidated as best hybrids while taking account of all three types of heterosis for quality related traits. Molecular confirmation of the hybrids were carried out in forth study to confirm true hybrids. DNA was extracted from the young seedlings using CTAB mehtod. Different DNA based markers systems such as RADP, SSR , URP.s and SCAR were used to detect polymorphism in the F1 hybrids. Molecular analysis revealed that OPU-3 a RAPD primer confirmed 6 recombinants hybrids Viz; H-24 × V48, Lyp-1 × V48, LA4097 × V48, LA4141 × V48, Vendor × V48 and B-L-35 × V48. All these hyrids had a male specific band of V-48. Another RAPD primer UBC-840 showed a male parent specific band in LA4157 confirming the true recobination of hybrids that were H-24 × LA4157, Lyp-1 × LA4157, LA4097 × LA4157, LA4141 × LA4157, Vendor × LA4157, B-L-35 × LA4157. UBC-840 a RAPD primer detected a male parent specific band in LA415. Thus hybrids, H-24 × LA4157, Lyp-1 × LA4157, LA4097 × LA4157, LA4141 × LA4157, Vendor × LA4157 and B-L-35 × LA4157 were confrimed using this primer. LA4157 a male parent showed polymorphism using OPW-04 primer six hybrids (H-24 × LA4157, Lyp-1 × LA4157, LA4097 × LA4157, LA4141 × LA4157, Vendor × LA4157, B-L-35 × LA4157) had the male specific band in their genome confirming them as true hybrids. In this study URP’s, SSR and SCAR markers did not effectivley detect polymorphism in F1 recombinants. Hence, all the hybrids used in this the study were confirmed as true recombinants containing the male DNA part in their genome. So, the phenotypic/morphological expresssions of the hybrids were beacause of the recombinant genome of these hybrids not only due to environmental factors.
Gov't Doc #: 19340
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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