Thumbnail Image

Thesis

Browse

20181
Reset filters
Subject: Floriculture and Landscaping × Author: Ravneet Kaur × End date: 2018 × Start date: 2018 × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    ThesisItemOpen Access
    Combining ability analysis for growth and flowering characteristics in pansy (Viola × wittrockiana Gams.)
    (Punjab Agricultural University, Ludhiana, 2018) Ravneet Kaur; Dhatt, K. K.
    The present studies entitled "Combining ability analysis for growth and flowering characteristics in pansy (Viola × wittrockiana Gams.)" were undertaken at the Floriculture Research Farm of Punjab Agricultural University, Ludhiana during the year 2015-2018. Eight inbred lines of pansy were selected for crossing in half diallel fashion (8x8) to study the general combining ability effects of the parents and specific combining ability of the crosses. Twenty eight hybrids were grown along with their parents in Randomized block design. The results pertaining to the analysis of variance for experimental design and combining ability were highly significant for all the characters. Based on gca effects of parents, the parents Pa-64-1-5-14, Pa-62-4-12-18, Pa-63-1-7-25 and Pa-32-8-7-6 were best general combiners for most of the traits except stalk length and flower size which can be recommended for use in breeding programme to generate genetic variability in desirable direction. Studies on specific combining ability of the crosses indicated that the cross combinations viz.,Pa-64-1-5-14 × Pa-62-4-12-18, Pa-13-1-2-3 × Pa-47-1-3, Pa-11-1-3-7 × Pa-62-4-12-18, Pa-64-1-5-14 × Pa-63-1-7-25, Pa-11-1-3-7 × Pa-64-1-5-14, Pa-32-8-7-6 × Pa-63-1-7-25, Pa-64-1-5-14 × Pa-32-8-7-6 and Pa-11-1-3-7 × Pa-63-1-7-25 were the best specific combiner for most of the vegetative and floral characters viz., plant height, plant spread, branches number, days to flowering, duration of flowering, flowers per plant and pod setting (%). Combining ability analysis revealed that magnitude of gcavariance was greater than sca variance suggesting the predominance of additive gene action for the characters viz., branch count, flower size, days from bud initiation to flowering and flowers per plant. Specific combining ability (sca)variance was greater than gca variance for most of the characters viz., plant height at first flowering (cm), final plant height, plant spread, final plant spread, stalk length, days to flowering, flowering duration and pod setting (%) which indicated predominance of non-additive gene action in their inheritance and heterosis breeding would be the best option for improvement of these traits. Heterosis revealed that majority of the hybrids exhibited heterobeltiosis and mid-heterosis in desirable direction. The hybrids exhibiting high per se performance also showed high mid-heterosis. The hybrids exhibited heterosis over better parent for plant height, plant spread, branches count, stalk length, days from bud initiation to flowering, days to flowering, duration of flowering, flowers per plant were Pa-64-1-5-14 × Pa-63-1-7-25 , Pa-11-1-3-7 × Pa-47-1-3, Pa-32-8-7-6 × Pa-47-1-3, Pa-13-1-2-3 × Pa-47-1-3, Pa-11-1-3-7 × Pa-32-8-7-6, Pa-64-1-5-14 × Pa-32-8-7-6 and Pa-64-1-5-14 × Pa-62-4-12-18. High estimates of PCV and GCV were recorded indicating sufficient variability in the germplasm for most of the characters. PCV and GCV showed a range of variation from 14.25% to 67.50% and 14.10% to 67.29% respectively.High estimates of heritability ranges between 83.55% to 99.37% were obtained for different analysed characters and indicate that though the character was least influenced by the environmental effects. The estimates of genetic advance were varied from 2.25% to 336.80% and from 28.73% to 138.17% for genetic advance as % of mean. High heritability coupled with high genetic advance for the characters viz., number of flowers per plant, branch count and days from bud initiation to flowering were recorded and suggested the role of additive gene action in the inheritance of these characters. Hence, simple selection based on phenotypic performance of these traits would be more effective. The estimates of phenotypic and genotypic correlation revealed that flowers per plant was strongly and positively associated with the characters namely number of branches per plant, plant spread, final plant spread, final plant height and duration of flowering at phenotypic and genotypic level. The result of analysis of variance for F₂ indicated that mean sum of squares due to genotypes were highly significant for all the traits studied. PCV was higher than those of GCV for all the traits which indicated greater genotype x environment interactions for the expression of these characters. The estimates of heritability were more than 72.43 percent for all the characters studied for F₂ genotypes. High heritability along with high genetic advance as % of mean for F₂ population were observed for number of flowers per plant, number of branches per plant and days from bud initiation to flowering hence, amenable for simple selection. The different expected ratios were obtained among twenty eight cross combination of F₂ population of pansy for the inheritance of the flower colour.