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Title: Genetic analysis of agronomic traits in Oryza sativa X O. sativa Cross
Authors: Kamara, Nabieu
Issue Date: 4-Apr-2016
Abstract: The objectives of this experiment were to study the inheritance of agronomic traits, determine the inheritance of aroma, estimates the heritability of important quantitative traits in rice (Oryza sativa L.). Six generations viz., P1, P2, F1, F2, BCP1 and BCP2 of a cross between IET6279 and IR70445-146-3-3 were used in present study. The experiment was laid out in a randomized complete block design (RCBD) with three replications at the CSIR- Crops Research Institute, Kumasi Ghana during 2014/2015 minor cropping season. Genotypes differed significantly at (p>0.001) for all the traits studied, which implies that the genotypes constitute a pool of germplasm with adequate genetic variability. Generation mean analysis suggested that additive effects had a major role for the expression of plant height, number of tillers, number of panicles, panicle length, culm length, leaf length, flag leaf width, grain width, number of spikelet per panicle, number of spikelet per plant. Spikelet fertility per cent and grain yield per plant, suggested that phenotypic selection was appropriate at an early stage. Epistasis effect was significant in most of the characters. Among interactions additive x additive and additive x dominance effects were important, but additive x dominance is more important than additive x additive effect, while dominance x dominance was less important than other genetic effect in the inheritance of traits. Both additive and non-additive gene action were important for the expression of days to 50% flowering, days to maturity, leaf width, flag leaf length, grain length, 100 grain weight, number of fertile spikelet per panicle and number of fertile spikelet per plant. Therefore, selection for these characters would be fruitful, if delayed till epistasis effects are reduced to minimum. The inheritance pattern of aroma in rice was carried out in the cross among one non-aromatic and one aromatic varieties. All the F1 and BCP1 plants of the cross were non-aromatic indicating that the gene controlling aroma in the donor parent was recessive. The segregation ratio of aromatic to non-aromatic plants was 1:3 in F2 and 1:1 in BCP2 plants confirming the monogenic inheritance of aroma. High broad sense heritability estimates (63 – 83%) was observed for characters viz. plant height, culm length, grain length, grain width, days to 50% flowering, days to maturity and 100 grain weight suggesting that the traits are primary under genetic control. Low estimates of broad sense heritability (27 - 49%) for number of tillers, number of panicle, panicle length, leaf length, leaf width, flag leaf length, flag leaf width, number of spikelet per panicle, number of spikelet per plant, number of fertile spikelet per panicle, number of fertile spikelet per plant, spikelet fertility per cent per plant and grain yield per plant, indicating environmental influence on this traits.  
Description: A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the award of the Degree of Master of Philosophy in Agronomy (Plant Breeding), 2015
URI: http://hdl.handle.net/123456789/8471
Appears in Collections:College of Agric and Natural Resources

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