Original Research Article
Year: 2015 | Month: September | Volume: 2 | Issue: 9 | Pages: 527-535
Estimation of Genetic Variability and Trait Association in Nitrogen Use Efficiency of Upland Rice Varieties in North Western Ethiopia
Taddesse Lakew
Fogera National Rice Research and Training Center, P.O.Box, 1937, Bahir Dar, Ethiopia.
ABSTRACT
Use of nitrogen efficient genotypes is an important complementary strategy in improving rice yield and reducing cost of production in subsistence farming. A field experiment was conducted at Woreta, South Gondar Zone of Western Amhara Region during the 2009 main cropping season. The objectives were to investigate genetic variability in nitrogen use efficiency of upland rice genotype, to identify genotypes with best nitrogen use efficiency and to assess nature of association of nitrogen use efficiency and yield traits. Twelve upland rice genotypes (6 released and 6 pipelines) with two nitrogen levels (0 and 64 kg N ha-1) were evaluated in a factorial randomized complete block design of three replications. Analysis of variance revealed significant differences among genotypes for yield, nitrogen use efficiency, uptake efficiency and utilization efficiency traits. Differences were significant between nitrogen levels for number of filled spikletes per panicle, grain yield, and biomass yield and nitrogen use efficiency component traits. Genotype × nitrogen interaction effect was not significant for all traits. Grain yield ranged from 2852.9 (Getachew) to 5437.7(NERICA-3) kg ha-1. Nitrogen uptake, nitrogen utilization and nitrogen use efficiency varied from 21.87 to 48.43%, 21.46 to 53.4 kg kg-1 N and 6.47 to 17.58 kg kg-1 N respectively. Superica-1, NERICA-3, Andassa and NERICA-4 had the highest nitrogen use efficiency values. Grain yield, harvest index, grain nitrogen yield, nitrogen harvest index, nitrogen uptake efficiency, nitrogen utilization efficiency and nitrogen use efficiency had high genotypic and phenotypic coefficient of variation and high broad sense heritability estimates. Grain yield showed significant and positive correlation with grain nitrogen yield, and nitrogen harvest index. Grain nitrogen concentration had significant and positive correlation with nitrogen uptake efficiency and nitrogen use efficiency. The results suggested that varieties including Superica-1, NERICA-3, Andassa and NERICA-4 were relatively nitrogen efficient and could be used for cultivation and/or used as parents in future breeding program to produce better nitrogen use efficiency varieties.
Key words: N uptake, grain yield, yields component, heritability.