Correlations and path coefficient analysis for vegetative traits guinea grass

摘要

An experiment comprising 36 clones, 8 parents and their 28 single crosses, was conducted to identify suitable cutting time for making the selection based on component traits for improving forage yield in Guinea grass (Panicum maximum Jacq.). Phenotypic correlation coefficients between green forage and dry matter yields, and also with their component traits, namely, tiller number, plant height, stem (culm) thickness, and leaf-stem ratio were studied in seven cuts-during 1988 and 1989. Green forage yield showed a positive and significant (Ps 0.01) phenotypic correlation coefficient (PCC) with dry matter yield in all cuts. Tiller number also showed a positive and significant (Ps 0.01) PCC with green forage yield and dry matter yield in all cuts. However, plant height showed a positive and significant PCC with dry matter and green forage yield in all cuts. Stem thickness and leaf-stern ratio showed non-significant PCC with green forage yield and dry matter yield in most of the cuts. Further, tiller number had the highest direct effect on green 'forage yield and also on dry matter yield, followed either by plant height or stem thickness, Cuts taken in October explained higher variation in forage yield than rest of the cuts in both years. Thus, selections to improve forage yield based on tiller number and plant height, done in October would be more gainful than at other times of the year.