Abstract

Growth and development of peanut (Arachis hypogaea L.) are affected by different uncontrollable environmental conditions. The objective of this work was to investigate the effect of different planting dates, thermal temperatures (growing degree days, GDD) and daily sunshine duration on morphological and agronomic traits of three commercial peanut cultivars (Gazipasa, Florispan, and NC-7) and a local cultivar. Experiments were carried out at four different planting dates in the Aegean region of Turkey during 2004 and 2005. The experimental design was a split-plot design with three replications. Planting date affected emergence, beginning of flowering, beginning gynophore formation, primary branch number, primary branch length, days to maturity and pod yield. Pod yield was significantly correlated with the primary branch length, GDD, sunshine radiation during gynophore formation, time to maturity and days from emergence to flowering. The Aegean climate has a long growing period and is a suitable environment for peanut growth. Peanut cultivars are exposed to suitable temperature regimes and sunshine during the vegetative and reproductive growth stages in the early and normal planting dates in the Aegean region. On the contrary, the peanut cultivars planted in the late planting stage were negatively affected in the vegetative and reproductive growth stages. The peanut cultivars were stressed in the late planting because of the shortened growth period and unsuitable growing conditions. Early planting, ranging from May 5 – 20, provided the essential 1450 and 1600°C GDD and 893 – 978 h of sunshine during the reproductive stage for peanuts grown in the Aegean region. The best suitable planting date was May 20 and GazipaÅŸa and the Local cultivar were the most promising cultivars for conditions typical of the Aegean region. 

Key words: Peanut, growing degree days, morphological and agronomic traits.

Abbreviation

GDD, growing degree days; LSD, least significant difference.