1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)

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Subject: search.filters.subject.Mechanism of dormancy

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    Genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.)
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Tessy Joseph; Namboodiri, K M N
    Investigations on genetic analysis of seed dormancy and productivity in groundnut (Arachis hypogaea L.) were carried out in the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara from 1992-95. The objective of the study was to find out the gene effects of biometric traits and seed dormancy in groundnut, so as to suggest appropriate breeding methodology and parental combinations to evolve domant, high yielding and early manuring varieties. The findings of the study are briefed below. Evaluation of 28 genotypes (14 domant and 14 non domant) for two seasons revealed that wide range of variability existed among them. Donors for specific traits were identified . The genotypes were also genetically diverse and could be grouped into four clusters. The line x tester analysis with three lines and five testers revealed that additive gene effects governed most of the characters except pod yield and number of mature pods , for which , non addictive gene effects were important. To harness both the types of gene effects pedigree method followed by selection in advanced generations will be fruitful.
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    Seed dormancy in groundnut
    (Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1992) Presanna Kumari, K T; Narayanan Namboodiri, K M
    The present investigation entitled "Seed dormancy in groundnut" was undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during 1987-1990 using the 419 genotypes received from ICRISAT, Hyderabad. The 419 genotypes possessed varying levels of dormancy at the time of harvest. Genotypes with varying degrees of dormancy were present in all the three botanical groups, viz., hypogaea, fastigiata and vulgaris. The dormancy period of genotypes ranged from 20 to 110 days. The hypogaea genotypes required longer period of rest. The nature of breakage of dormancy and the period of dormancy were found to be two independent phenomena. The factors for dormancy in groundnut were found to be residing in two distinct sites, the cotyledons and the seed coat (testa). Leaching improved the germinability of decoated seeds where as it failed to elicite germination in intact seeds. This indicates that germination inhibitors may be present in the cotyledons and testa retarded the removal of the same. Different genotypes responded differently to various presowing treatments. HgCl2 1, 1000 for five minutes was found to be the best treatment for breaking dormancy. The study of germinability of F1,F2 and F3(embryonic generation) seeds on the day of harvest indicated that dormancy was controlled by polygenes.