Correlations Between Stability Statistics of Forage Production in Elephant Grass

Elephant grass (Pennisetum purpureum Schum.) is an important forage plant in the tropics and the potential of genotypes depends on the genotype × environment interaction effects. The objective of this study was to evaluate and compare different stability methods of forage production of 53 elephant grass genotypes, in Campos dos Goytacazes, Rio de Janeiro State, Brazil. The experiment lasted two years, a total of ten cuts with randomized block experimental design with two replications. The analysis of variance was applied to data from dry matter production (DMP), subjected to stability analysis using the following methods: Yates and Cochran, Plaisted and Peterson, ecovalence Wrickie, Kang and Phan, Lin and Bins, and Annicchiarico. The Yates and Cochran method showed more stable genotypes but being less productive. Plaisted and Peterson and ecovalence Wrickie methods presented a Spearman correlation equal to 1, so it is not recommended to implement them concurrently. Lin and Bins showed a strong negative correlation with the average being a method that indicates the genotype also very stable and productive. This method correlates with Annicchiarico, which also indicates productive genotypes by the confidence index. The genotypes most stable among the methods were: Pusa Napier 2, Taiwan A-143 and Merckeron Comum.