Phenotype
The 
phenotype of a plant is of great agricultural and economic importance, as it represents the coordinated set of traits and performance characteristics that are manifested by an individual variety over a range of environments. Phenotypes that are important to crop production include yield, disease resistance, abiotic stress tolerance, flowering time, plant stature, grain quality and many other use-related traits . To begin clarifying the relationship between phenotype and genotype, we collected data on 10 yield-related characteristics and 37 additional traits in the panel of 400 diverse cultivated rice varieties selected for study. The phenotyping team at the DBNRRC evaluated yield components, including the number of seeds/plant, number of seeds/panicle (inflorescence), number of panicles/plant, number of primary branches/panicle, etc., and other characteristics important for rice cultivation, including days to heading, plant height, leaf length and leaf width (histograms of phenotypic values in O. sativa (10 traits) [PDF]).
We also evaluated ancestral populations of O. rufipogon for a set of phenotypic traits. These traits relate to plant development and plant architecture—flowering time, plant height, plant type, number of tillers, seed length and seed width. Knowing the variation in these traits is important for the selection of wild accessions to use in making interspecific crosses between cultivated rice and its wild ancestor (histograms of phenotypic values in O. rufipogon (5 Traits) [PDF]).
The phenotypic data on diverse O. sativa varieties from field-grown plants was collected at the Dale Bumpers National Rice Research Center (DBNRRC) in Stuttgart, Arkansas (phenotyping team). We recorded measurements on six plants for each of the 400 rice varieties in two locations over two years, evaluating a total of more than 4,800 plants during 2006 and 2007. Phenotypic data on greenhouse-grown O. rufipogon plants was collected at both Cornell University and at the DBNRRC. To keep track of the data, we created a bar-coding system that allows us to enter measurements for each plant directly into a database.