Genetic variability, association and diversity analysis in upland Rice (Oryza sativa L)

SAARC J. Agri., 12(2): 40-51 (2014) GENETIC VARIABILITY, ASSOCIATION AND DIVERSITY ANALYSIS IN UPLAND RICE (Oryza sativa L) R. Khare, A. K. Singh, S. Eram and P. K. Singh* Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221005, India ABSTRACT High heritability coupled with high to moderate phenotypic and genotypic coefficient of variation and genetic advance as per cent of mean was recorded for grain yield per plant, plant height, test weight, fertile spikelet per panicle, total grains per panicle and number of effective tillers per plant. Positive and significant association were observed for days to 50 per cent flowering, days to maturity, plant height, panicle length, fertile spikelet per panicle, total grains per panicle and spikelet fertility with grain yield per plant at both genotypic and phenotypic level, while highest positive direct effect on grain yield was recorded by fertile spikelet per panicle, total number of grains per panicle, plant height and days to 50% flowering. Based on ten quantitative traits the accessions were clustered into seven groups, the cluster III contained highest 14 accessions, followed by clusters I comprised 11 accessions and cluster VI, VII, V, IV and II have 9, 8, 7, 6 and 5 accessions, respectively. The first four principal components accounted for 77.13% of total variation of all the traits. Key words: Correlation, Path analysis, Variability and Upland rice. INTRODUCTION Rice (Oryza sativa L.) is a highly domesticated crop, and domestication processes are reported to be accompanied by genetic erosion, which causes a reduction in genetic diversity among traditional varieties and gradual loss of landraces from the fields (Brush, 2000). Modern rice cultivars have been developed through the hybridization of elite lines and subsequent selection for yield and quality traits. The genetic potential and magnitude of heterogeneity are still present in local landraces need to characterize in available upland rice germplasm. Grain yield is dependent on many yield contributing traits as well as on the environmental influence. Genetic variability of yield contributing traits and * Corresponding author email: Received: 21.04.2014 DIVERSITY ANALYSIS IN UPLAND RICE 41 interrelationship among them and their relation with yield are necessary for a successful breeding program. Knowledge of heritability is essential for selection based improvement. Before placing strong emphasis on breeding for yield improvement trait, the knowledge on the association between yield and yield attributes will immense help the breeder in the improvement of yield. The correlation coefficient may also help to identify characters that have little or no importance in the selection programme. The existence of correlation may be attributed to the presence of linkage or pleiotropic effect of genes or physiological and development relationship or environmental effect or in combination of all (Oad et al., 2002). Path coefficient analysis proposed by Wright (1921) help the partition the total correlation into direct and indirect effects of various causes. The spectrum of variability in segregating generation for grain yield traits depends on the genetic diversity of the combining parents. Hence, estimation of genetic diversity for yield traits among accessions is important for planning the future crossing programmes. Thus, the present investigation was undertaken to assess the genetic variability, association among the traits, their path coefficient and diversity analysis for grain yield and other traits. MATERIALS AND METHODS Panicles of sixty upland rice germplasm accessions were collected from natural habitat of Eastern India and DBT Networking Project, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi during wet 2008-09 and their seeds were multiplied during next wet season 2010. The accessions were evaluated in randomized block design with three replications during kharif 2011 and 2012. Twenty days old single seedlings were transplanted with a spacing of 20 x 15 cm in 3.0 x 1.5 m plot. The recommended packages of practices were followed to raise a healthy crop. Where are fertilizer dosages? The source of upland rice germplasm accessions are presented in table 1. The observations were recorded on days to 50% flowering, days to maturity, plant height, panicle length, effective tillers per plant, fertile spikelet per panicle, total number of grains per panicle, spikelet fertility percentage, test weight and grain yield per plant. Randomly ten plants are selected from each replication in each germplasm excluding border rows. Ten randomly selected plants in each accession in each replication were tagged for recording observation. The panicles of accessions showing shattering characteristics were observed daily and fertile spikelets were plucked one by one before shattering and stored. The mean value of both years were pooled over and used for statistical analysis. The data was analyzed for variability as per procedure given by Panse and Sukhatme (1985). The genotypic and phenotypic coefficients of variability were worked out as per Burton and De-Vane (1953); heritability and genetic advance were estimated as per formula given by Allard (1960). Estimates of correlation coefficient 42 R. Khare et al. were worked as per Al-Jibouri et al. (1958) and path analysis given by Dewey and Lu (1959). Cluster and principle component analysis (PCA) were carried out by using SPSS 16.0 version software. RESULTS AND DISCUSSION Variation and genetic parameters among accessions The analysis of variance revealed highly significant difference among the germplasm accessions for all the traits indicating a large amount of variability was present in the set of material for effective selection (Table 2). The magnitude of phenotypic coefficient of variations was higher for yield and yield attributing traits but the difference is very less indicates the presence of environmental influence to some degree in the phenotypic expression of the traits (Table 3). Similar results were reported by Subudhi et al. (2011). The highest estimate of PCV and GCV were observed for fertile spikelet per panicle, total grains per panicle, grain yield per plant and number of effective tillers per plant, while the lowest in days to maturity and days to 50 per cent flowering . Similarly, Bhadru et al, (2012) reported high PCV and GCV for number of grains per panicle, fertility percentage and grain yield per plant in rice. The estimate of heritability were high for test weight (98.30%), plant height (97.83%), grain yield per plant (96.52%), days to 50 per cent flowering (94.50%) and days to maturity (93.94%) due to genetic causes rather only by environmental effects. High heritability does not always indicate high genetic gain; heritability coupled with high genetic advance should be used in predicting the ultimate effect for se (...truncated)