Variability and Heritability of Yield and Yield Components of Various Rice (Oryza sativa L.) Varieties in Port Harcourt, Nigeria

Field experiments were conducted at the Rivers State University Teaching and Research Farm Nkpolu, Port Harcourt, during the 2019 planting season under rainfed condition and complimented by irrigation in two different planting dates to access the genetic variability and heritability in yield and yield components of twenty-five rice varieties. The experiments were laid out in a randomized complete block design with three replications. Data were collected on eleven yield and yield components. Results from the analysis of variance indicated significant differences (P < 0.01 < 0.05) among the varieties for all parameters except plant height and tiller number in planting date one. Combined analysis of variance across planting dates showed that there was significant variation (P < 0.01) among the rice varieties for all parameters evaluated. The varietal mean performance for phenological parameters showed significant differences (P < 0.05) for all parameters except tiller number in planting date one. Variability evaluation of varieties for yield parameters showed significant differences (P < 0.05) for all parameters evaluated except for 100-grain weight in planting date two. The pooled mean values of the varieties differed significantly (P < 0.05) for all yield parameters evaluated. The highest grain yield per stand was recorded in UPIA 2 with 7.41 g/stand, and was significantly different from FARO 67 with the least (1.70 g/stand). The estimate of variance components showed that phenotypic variance (Vp) and phenotypic coefficient of variation (PVC) were higher than their corresponding genotypic variance (Vg) and genotypic coefficient of variation (GCV) for all the parameters studied. Heritability estimates in broad sense were found to be moderate for majority of the parameters, except leaf area (68.12%), panicle number (63.41%), spikelet fertility (50.23%) and grain yield per stand (55.87%) that had high heritability estimates and tiller number (15.93%) which had a low estimate. However, only leaf area, panicle number and grain yield per stand had high heritability estimates which were accompanied by high genetic advance. There was considerable variation among the 25 rice varieties evaluated. UPIA 2 and FARO 44 had the best agronomic performance. However, UPN 324, UPN 228, FARO 61 and 66 could be selected for onward improvement programme. Keynote: Grain yield, heritability, Oryza sativa, variation, yield components DOI: 10.7176/ALST/86-04 Publication date:March 31st 202

Character Association of Yield and Yield Components of Various Varieties of Rice (Oryza sativa L.)

Yield and yield attributing parameters are the most widely targeted traits in rice improvement programmes. The relationship between yield and yield attributing traits are important for direct and indirect selection of traits which contribute to yield. Information on the extent of association between yield and yield components is important in the simultaneous improvement of correlated traits. This study was carried out to determine the direct and indirect contributions of yield components to yield of rice and the level of association. Path Coefficient Analysis was used to evaluate the character association of yield and yield components of twenty-five rice varieties at the Rivers State University Teaching and Research Farm, Port Harcourt, during the 2019 planting season under rainfed condition and complimented by irrigation in two different planting dates. The experiments were laid out in a randomized complete block design. Data were collected on yield and yield components. Leaf area, plant height, panicle length, panicle number, panicle weight, 100-grain weight and spikelet fertility correlated positively and significantly with grain yield per stand. The path coefficient analysis indicated that panicle number (0.265) and spikelet fertility (0.219) had the highest positive direct effect on grain yield per stand. Conversely, number of grains per panicle (-0.128), days to 50% flowering (-0.114), tiller number (-0.095) and panicle length (-0.056) exerted negative direct effect on grain yield per stand with 0.674 residual effects. Therefore, direct selection for leaf area, plant height, panicle number, panicle weight, 100 grain weight, and spikelet fertility will effectively improve yield in rice. Keywords: Grain yield, Character Association, Oryza sativa, variation, yield components DOI: 10.7176/JNSR/13-8-02 Publication date: April 30th 202