Abstract

Peanut is an indeterminate growth crop. Generally, peanut plant samples are randomly pulled out to evaluate maturity and harvest date by counting mature pods for more than 70% of total pods. This method may increase production cost and reduce yield from plant loss. Therefore, this research aimed to evaluate the pod maturity using growing degree days. Fifty-four peanut lines and five check cultivars (Khonkaen 5, Khonkaen 9, Kasetsart Koh Kae 40, Kasetsart ARDA.1 and Tainan 9) were planted at Lopburi Research Center, Faculty of Agriculture, Kasetsart University. The experimental design was Randomized Complete Block Design with three replications. Growing Degree Day (GDD; ºCd) and days after planting when the peanut plants reached 50% flowering and maturity stages were observed. Yield and yield components were evaluated. The results suggested to divide the peanut lines/cultivars into 3 groups according to maturity ages and GDD values: early-, intermediate-, and late-maturity groups. The early maturity was the group with 50% flowering days at 38 to 39 days after planting (GDD of 593.88 °Cd to 599.49 °Cd) and reached maturity at 110 days after planting (GDD of 2014.44°Cd). The medium maturity was the group with 50% flowering days at 38 to 40 days after planting (GDD of 593.88 °Cd to 621.86°Cd) and reached maturity at 111 days after planting (GDD of 2029.37 °Cd). The late maturity was the group with 50% flowering days at 38 to 42 days after planting (GDD of 593.88 °Cd to 639.28°Cd) and reached maturity at 112 to 113 days after planting (GDD of 2062.24°Cd to 2084.10°Cd). There were three peanut lines providing higher yields and yield components than those of other lines and check cultivars: KUP12BS022 (late maturity), KUP1288-4 (late maturity) and KUP11231-3 (early-maturity).