Hybrid cocoa tree adaptability and yield temporal stability in Rondônia State, Brazil

Abstract

Hybrid cocoa tree (Theobroma cacao L.) adaptability and yield temporal stability were studied to screen agronomically superior varieties for yield, bean quality and resistance to witches’ broom under the ecological conditions of Ouro Preto do Oeste County, Rondonia State, Brazil. Assessments were based on yield component measurements evaluated at maturity in a randomized complete block experiment. Additionally, the possibility of early hybrid selection, at the initial fructification phase, was investigated. For this, the results obtained from both periods was compared. At maturity, the SCA 6 x ICS 1, PA 150 x SIC 328 and IMC 67 x BE 8 hybrids were superior in the simultaneous analysis of total number of healthy fruits (TNHF), total weight of fresh beans (TWFB) and mean weight of fresh beans per fruit (MWFBF). Using Eberhart and Russell’s methodology, PA 150 x SIC 328 had general adaptability and highly predictable performance for TNHF. The SCA 6 x ICS 1 hybrid also had general adaptability, in spite of indicated low predictability. The IMC 67 x BE 8 cross was adapted to unfavorable environments and had high predictability for TNHF. The SCA 6 x ICS 1 and PA 150 x SIC 328 hybrids behaved similarly for TWFB, showing adaptability to favorable environments and high predictability. IMC 67 x BE 8 showed general adaptability and high predictability for this trait. The three hybrids showed general adaptability and high predictability for MWFBF. On the base of mean performance (or i P values of Lin and Binn’ methodology), hybrid selection was also successful using measurements taken at the initial fructification phase. On the other hand, the Eberhart and Russel’s adaptability and stability parameters depended on the period evaluated.