Genotypic and Phenotypic Correlations between Leaf-Rust Disease and Leaf Morphology and its Ratio in Arabica Coffee

  Selection parameter in coffee breeding for leaf rust (Hemeleia vastatrix) resistance is very important. Breeders used leaf-rust severity and leaf-rust incidence as parameters of direct selection. However, scientific proof is not yet available whether leaf morphology can be used as a parameter of indirect selection. The objective of this research was to seek the possibility of leaf morphology parameter and its ratio to be used as selection criteria through analyses of genotypic and phenotypic correlations of parameter of rust disease and parameter of leaf morphology and its ratio. The result revealed that genotypes showed significant variations in leaf-rust severity (5.21–25.84%), leaf morphology, and leaf-morphology ratio. Leaf length to leaf width ratio, leaf length to leaf area ratio, and leaf width to leaf weight ratio were not affected by the environment. Leaf-rust severity performed highly significant positive genotypic and phenotypic correlations the ratio of with leaf length to leaf area. For selection criteria, leaf-rust severity could be better used rather than leaf-rust incidence and branch-rust incidence. The ratio of leaf length to leaf area could also be used as an indirect selection criterion because the ratio showed a highly significant genotypic correlation with leaf-rust severity (rGab = 0.254**). However, the ratio of leaf length to leaf area is even better chosen for selection criteria rather than leaf-rust severity because the ratio was not affected by the environment.   Keywords: fungus, Hemeleia vastatrix, indirect selectio

Morphological Variation in Arabica Coffee (Coffea Arabica L.) Growing in North Sumatra Indonesia

Genetic variation is important in plant breeding. However, information on the genetic variability of Arabica coffee especially in coffee field of North Sumatra was not yet available. Magnitude of morphological variation, genotypic variation, phenotypic variation, heritability, genetic advance, genetic correlation, and phenotypic correlation of plant vigors and yield components of 28 genotypes were evaluated using nested design. This research showed morphological and genetic variations of the genotypes in the field. Based on the research locations as operational taxonomic unit, the genotypes were separated into three clusters. Most of the parameters had low to moderate genotypic variation, while phenotypic variation was moderate to high. Heritability and genetic advance were low, moderate, and high. Several plant vigors and yield components had a positive significant genetic and phenotypic correlation one another, and several had negative ones. Coffee berry borer infestation (CBBI) had a highly significant negative genetic correlation with leaf width (rG = -0.309**), leaf weight (rG = -0.671**), fruit diameter (rG = -0.320**), and bean length (rG = -0.175**). CBBI showed a significant positive genetic correlation with mesocarp pH (rG = 0.134*). To reduce CBBI, selection for higher leaf weight is better. Selection on lower pH of mesocarp could be considered to decrease CBBI

Saepo Modi and Correlation among Statistical Methods for Measuring of Phenotypic Stability

A stabile phenotype is desired. Many statistical methods are available to measure stability. So far, the choice of parameter of stability depended on the perception on the interaction of genotype and environment or ease of counting. The goal of this research was to study correlation among stability parameters. In total of 16 stability parameters were used in this research. Saepo modi (SMsp) as a stability parameter was also used. Branch rust incidence, leaf rust incidence, and leaf rust severity on Arabica coffee were used as variables. This research result showed that none of the parameters of stability correlated significantly with all parameter of stability. It coud be concluded that if someone want to use only one stability parameter, it is preffered to make use of regression and deviation from regression (D2i). In the case a researcher needs to use several of parameters of stability, Saepo modi (SMsp) might be exercised

Morphological Variation in Arabica Coffee (Coffea arabica L.) Growing in North Sumatra Indonesia

ABSTRACTGenetic variation is important in plant breeding. However, information on the genetic variability of Arabica coffee especially in coffee field of North Sumatra was not yet available.  Magnitude of morphological variation, genotypic variation, phenotypic variation, heritability, genetic advance, genetic correlation, and phenotypic correlation of plant vigors and yield components of 28 genotypes were evaluated using nested design.  This research showed morphological and genetic variations of the genotypes in the field. Based on the research locations as operational taxonomic unit, the genotypes were separated into three clusters. Most of the parameters had low to moderate genotypic variation, while phenotypic variation was moderate to high. Heritability and genetic advance were low, moderate, and high. Several plant vigors and yield components had a positive significant genetic and phenotypic correlation one another, and several had negative ones. Coffee berry borer infestation (CBBI) had a highly significant negative genetic correlation with leaf width (rG = -0.309**), leaf weight (rG = -0.671**), fruit diameter (rG = -0.320**), and bean length (rG = -0.175**). CBBI showed a significant positive genetic correlation with mesocarp pH (rG = 0.134*).  To reduce CBBI, selection for higher leaf weight is better. Selection on lower pH of mesocarp could be considered to decrease CBBI.Keywords: cluster analysis, genetic correlation, genetic heritability, variability<br /

Variability of organoleptic quality of Arabica coffe

Beverage quality of coffee is the most important for consumers. The objective of this research was to determine the genotypic and phenotypic variability of Arabica coffee (Coffea arabica L.). Nested design with three factors was used. The organoleptic quality of 28 genotypes was analyzed. This research revealed that most of the organoleptic qualities had low genotypic and phenotypic variations. Fragrance/aroma, flavor, aftertaste, acidity, body, uniformity, balance, sweetness, overall and total score showed low heritability and low genetic advance