ASSESSMENT OF MORPHO-PHYSIOLOGICAL VARIATIONS IN TRADITIONAL AND IMPROVED CULTIVARS OF RICE (Oriza sativa L.)

Abstract

ABSTRACT A total of twenty two improved rice cultivars were collected from the National Cereals Research Institute (NCRI), Baddegi Rice Breeding unit and seventeen local cultivars collected from famers were examined for morhpo-physiological character variations, reaction to iron toxicity and African rice gall midge (AfRGM). The trials were conducted at National Cereal Research Institute (NCRI) Edozhigi substation for two years (2009 and 2010). Randomized complete block design (RCBD) was used in three replications. Eleven morpho-agronomic traits were used to characterize the experimental materials. Data collected were subjected to analysis of variance (ANOVA) using Genstat 5 (2004), Principal Component Analysis (PCA), Correlation, Euclidean distance with complete linkage and Cluster analysis. The analysis of variance showed that plant height, leaf width, gall midge count at 62 days after transplanting (DAT), iron toxicity score at 20 DAT and total yield per plot were significant at 1% probability level while gall midge count at 42 DAT, iron toxicity score at 40 DAT and 60 DAT showed no significant difference. In the second year, leaf length, panicle length, iron toxicity score at 20 DAT, 40 DAT, days to 50% flowering, leaf width and total yield per plot were significant at 1% probability level. The cluster analysis of the morphological character of two years combined produced three groups (GP) based on similarities with respect to varietal type. Group one had four local and two improved varieties. Group two comprises of twenty six varieties out of which twelve were local and fourteen improved. Group three had five out of which two are local while three are improved. From the correlation analysis of morphological traits for two years combined, result showed that panicle length and weight of 1000 grain, gall midge count and weight of 1000 grain, gall midge count and days to 50% flowering, gall midge count and leaf width were positively correlated while iron score and plant height, were negatively correlated. The result of Principal Component Analysis (PCA) of two years combined revealed that the first five principal components accounted for 65.4% of the total variation with phenotypic acceptability, weight of 1000 grains and leaf length contributing more to the variation. The scatted diagram indicates variations among the variables. The result showed that no cultivar was immune to African Rice Gall Midge (AfRGM), although Ndawodzufugi and Babawagi (Local) varieties showed resistant reaction at 62 DAT in the first year. Most cultivars react at a range of moderately resistant to moderately susceptible (3 to 5). In the same vain 3 to 5 score is the response of these entries to Iron toxicity. NERICA L36 and Mass varieties showed high level of variation amongst other entries and therefore could be good parents for breeding. Also Ndawodzufugi and Babawagi varieties could be subjected to further screening to ascertain their actual level of tolerance. This study separated cultivar into meaningful agronomic groups from which selection of varieties with uniform morphological characters could be made as parents for further rice improvement programs.