Agronomy
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Item Genetic variability for and tolerance to anaerobic germination in rice (Oryza sativa L.)(Taylor & Francis, 2021) Asante, M. D.; Ipinyomi, S. O.; Abe, A.; Adjah, K. L.; Aculey, P.; Bam, R. K.; Manneh, B.Poor germination and seedling establishment under flooded conditions is a major bottleneck in the direct-seeding system of rice. The objectives of this study were to determine the genetic variability for traits associated with anaerobic germination and identify tolerant genotypes. One hundred rice genotypes were screened. Data were collected on survival percentage, shoot length, root length, length of plant above water, and seedling vigor index. Six clusters, which were generally related to the ability of the genotypes to tolerate anaerobic germination, were detected. The first two principal components accounted for 91.1% of the total variation, with survival percentage, seedling vigor index and shoot length being the main discriminatory traits. Genotypic coefficient of variation ranged from 18.21% for shoot length to 50.89% for seedling vigor index. Shoot length and seedling vigor index recorded high broad-sense heritability estimates (>60%), with accompanying high genetic advance as percent of mean (>20%); the latter ranged from 23.12% for root length to 82.21% for seedling vigor index. The high heritability, along with high genetic advance, particularly for shoot length and seedling vigor index, indicated that selection for these traits should be effective in improving tolerance to anaerobic germination. Five tolerant genotypes (OBOLO, ART68-12-1-1-B-B, ART64-31-1-1-B-B, CRI-1-21-5-12, and CRI-Enapa) with high survival percentage (≥70%) under anaerobic conditions were identified. These genotypes could be used to improve commercial rice varieties for tolerance to anaerobic germination.Item Genetic variability, heritability and correlations for milling and grain appearance qualities in some accessions of rice (Oryza sativa L.)(Springer, 2020-06) Adjah, K. L.; Abe, A.; Adetimirin, V. O.; Asante, M. D.Poor milling and grain appearance is a common feature of locally produced rice (Oryza sativa L.) in West Africa. Development of genotypes with high yield and uniform milled grain size will enhance the market for the locally produced rice. One hundred rice accessions were evaluated to assess genetic variability, heritability and correlations for 11 milling and appearance quality traits and grain yield. The field was laid as a 10 9 10 alpha lattice design with three replications following standard cultivation practices. ANOVA revealed significant differences for the traits studied. The genotypic and environmental variances showed significant differences for all characters studied. Phenotypic coefficient of variation was greater than its corresponding genotypic coefficient of variation for each studied trait. Heritability at broad-sense varied from 14.1% for milling degree to 73.8% for milled grain length-to-width ratio (L/W). Genetic advance as percent of mean ranged from 2.2% for brown rice recovery to 129.6% for percentage of grain with chalkiness (PGWC). In general, genotypic correlations ranged higher than their corresponding phenotypic correlations. Brown rice recovery had significant positive phenotypic and genotypic correlations with milling recovery and head rice recovery. Consequently, brown rice recovery, milling recovery and L/W could be used as selection criteria for the improvement of head rice recovery. Genotypes BETIA and CRI-AMANKWATIA had the desirable PGWC and degree of chalkiness, therefore, they are recommended for the improvement of high yielding varieties with high amount of chalkiness.