EVALUATION OF GENETIC DIVERSITY IN PEARL MILLET [Pennisetumglaucum (L.) R. Br.] GENOTYPES FOR DROUGHT TOLERANCE USING RAPD TECHNIQUE
EVALUATION OF GENETIC DIVERSITY IN PEARL MILLET [Pennisetumglaucum (L.) R. Br.] GENOTYPES FOR DROUGHT TOLERANCE USING RAPD TECHNIQUE
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Date
2014-11
Authors
OGECHI, NWEKE
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Abstract
Drought is one of the environmental factors that have adverse effects on farming in Nigeria, and is a global problem constraining crop production. This has necessitated research for the improvement of crops that are tolerant to drought. Pearl millet is an important staple food crop that adapts to growing in areas characterised by drought, low soil fertility and high temperature. Although, it can be grown in areas where other cereals crops would not survive it produces poor yields in areas with unpredictable rainfall. Hence, there is a need to exploit genetic diversity of this crop, to enhance its yield. Random amplified polymorphic DNA (RAPD) analysis was applied on some pearl millet genotypes, to assess the degree of polymorphisms and also investigate the genetic diversity. Ten (10) genotypes were evaluated, DNA was extracted and polymerase chain reaction for RAPD amplification was carried out using 10 different primers. Bands obtained after agarose gel electrophoresis was scored as „1‟ for presence of a band and „0‟ for absence of a band. The primers revealed scorable polymorphism and therefore recommended for further evaluation in pearl millet breeding programme. A total of 48 distinct fragments were produced. Of these, 44 (91.6%) were found to be polymorphic. P16 (TCGGCGGTTC), P18 (TGAGCCTCAC), P20 (CTGCGCTGGA), P27 (CCGTGCAGTA), P29 (GGCTAGGGGG) and P30 (TACGGTGCCG) primers produced the highest number of polymorphic bands, with 100% polymorphism, while P26 (ATCGGGTCCG) produced the least number of polymorphic bands (66.7.%). A 600bp fragment was amplified in varieties suspected to be drought tolerant and absent in others e.g. COMPOSITE, SOSAT C88, DMR-15, EX-BORNO and JKBH 778. Polymorphic PCR products (unique and shared) were compared and similarity coefficients were generated using Nei‟s analysis. The similarity coefficients were employed to construct a dendrogram showing genetic relationships using unweighted paired group method with arithmetic averages (UPGMA). The analysis indicates a highest similarity (73%) between ZANGO and PEO 5984 varieties while lowest similarity (3%) was observed between COMPOSITE and PEO 5684. These varieties with low similarity can be selected and crossed to obtain drought tolerant varieties in pearl millet improvement programmes. The use of RAPD technique was effective and helpful in determining the genetic relationship among the 10 pearl millet genotypes and identifying markers that may be associated with drought tolerance.
Description
A THESIS SUMMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA, NIGERIA IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF MASTERS OF SCIENCE DEGREE IN BIOCHEMISTRY
Keywords
EVALUATION,, GENETIC,, DIVERSITY,, PEARL,, MILLET,, Pennisetumglaucum,, GENOTYPES,, DROUGHT,, TOLERANCE,, USING,, RAPD,, TECHNIQUE.