Morphological Traits in First Ratoon of Different Saccharum Species within the Diversity Panel of the World Collection of Sugarcane and Related Grasses.

The World Collection of Sugarcane and Related Grasses (WCSRG) located at the Subtropical Horticulture Research Station in Miami, FL is one of two diverse collections of Saccharum spp. and related genera. In 2013, a representative diversity panel selected from WCSRG based genotypic and phenotypic markers has been established. To understand the biomass yield components of this panel, pubescence ratings and measurements of stalk height, stalk diameter, internode length, and leaf width and length were taken in April 2014. The data was analyzed using mixed models in SAS PROC MIXED and the data was correlated using Spearman coefficients using SAS PROC CORR. The means of stalk diameter of the three major taxa [hybrid (20.98 mm), S. officinarum (19.66 mm) and S. spontaneum (7.49 mm)] were significantly different from each other. Pubescence ratings of hybrids (1.13) and officinarum (1.02) did not differ, but both were significantly less than the pubescence rating of spontaneum (1.72).On the other hand, the similar leaf widths of hybrids (3.56 cm) and officinarum (3.75 cm) were significantly greater than the leaf width of spontaneum (1.32 cm). Leaf length of hybrids (121.53 cm) was significantly more than the similar leaf lengths of spontaneum (108.22 cm) or officinarum (109.57 cm). The products of leaf length x leaf width did not differ significantly for hybrids (443.49 cm²) and officinarums (423.13 cm²), but these were significantly greater than this product for spontaneum (142.63 cm²). For spontaneum, internode length was moderately correlated (r² = 0.53) with stalk height and leaf width was moderately correlated (r² = 0.55) with stalk diameter. In officinarum, internode length (r² = 0.49) and leaf length (r² = 0.53) were correlated with stalk height; and stalk height (r² = 0.49), leaf width (r² = 0.51) and leaf length (r² = 0.50) were correlated with stalk diameter. The internode length (r² = 0.47) and leaf length (r² = 0.42) of hybrids were correlated with stalk height. Also for hybrids, leaf width (r² = 0.40) and leaf length (r² = 0.51) were correlated with stalk diameter. These results indicate differences among associations of traits that affect biomass between these different taxa.