Crop Effects on Genetic Relationships Among Sugarcane Traits
1990
Milligan, S. B. | Gravois, K. A. | Bischoff, K. P. | Martin, F. A.
Genetic correlations are commonly considered in the development of selection strategies. Previously reported correlations between sugarcane (Sacdmrum spp.) yield components may be of questionable value because they were obtained either from small populations or from a restricted range of environments. The effect of crop age on trait relationships has not been reported. Thistady's objective was to examine crop age effects on the geneticorrelations among sugarcane traits using path coefficient analysis. A population was planted in 1983 and 1984 at five locations in Louisiana. Harvest data were collected for three crops. Results indicated that cane yield (TCH) was the most important determinant of sucrose yield (SPH) and became increasingly important in determining the SPH in older ratoon crops (rₛₚₕ,ₜcₕₕ = 0.91). Stalk number (SNO) was the primary determinant of TCH and became more important in determining TCH in older ratoon crops (rₜcₕ,ₛₙₒ = 0.77). Stalk diameter (DIA) was more important than stalk length (LEN) and stalk density (DEN) in affecting stalk weight (WT) regardless of crop age (rwₜ,dₗₐ = 0.70 vs. rwₜ,ₗₑₙ = 0.52 and rwₜdₑₙ = 0.33). Brix and juice parity were highly correlated with sucrose content and with each other, and were not affected by crop age. The results indicated that selection for SPH should emphasize TCH with concentration on SNO, particularly in ratoon crops. The results also indicated that development of selection strategies of sugarcane should consider crop age in weighing the importance of yield components that affect SPH. Approved for publication by the Director of the Louisiana Agric. Exp. Stn. as manuscript no. 89-09-3378.
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