ASSESSMENT OF GENETIC DIVERSITY AMONG RICE GENOTYPES USING AGRO-MORPHOLOGICAL TRAITS IN ABAKALIKI, EBONYI STATE NIGERIA

The research was carried out with 61 rice genotypes, that comprised landraces, inbred lines, released varieties adapted to area and introduced varieties to study the genetic diversity and their relationship based on agronomic and morphological traits. The field experiment was carried out during the cropping season of 2012 and 2013 at the Rice Research Field of the Biotechnology Research and Development Centre, Ebonyi State University, Abakaliki, Nigeria. The experiments were laid out in a Randomized Complete Block Design (RCBD) with three replications. The rice seedlings were transplanted to a plot of 2 m x 1 m with spacing of 20 cm x 20 cm at twenty-one (21) days after seeding. Data were collected from seventeen agro-morphological traits to study the diversity pattern among them. The traits were analysed using cluster analysis and principal component analysis (PCA).The results indicated a considerably high level of variations among the studied genotypes; the landraces produced mainly late heading and maturing, tallest plants and longpanicles, while the exotic genotypes were mostly early and intermediate heading and maturing, short and medium in height. High yielding genotypes were observed among both landraces and exotic genotypes. The result of the cluster analysis showed the existence of wide variation among the rice genotypes and were grouped into four clusters independently of their origin, based on the average performance of each of the genotypes used in the study. The local (landrace) genotypes were distributed in all the clusters, while the exotic including IRRI lines, Indonesian varieties, IWA (inbred) lines and released varieties were limited to two and three clusters respectively. The clustering pattern revealed highest level of genetic diversity among the landraces compared to the exotic varieties or inbred lines indicating that landraces are indeed good sources of variability and as such should not be allowed to go into extinction. Moreover, principal component analysis identified primary traits to be looked out for in rice breeding programmes to include leaf area and leaf area index, panicle length, plant height, days to flowering, days to maturity and paddy yield