Growth Stage Identification in Mungbean (Vigna radiata (L.) Wilczek)

Abstract

               Growth stage descriptions were developed for Mungbean (Vigna radiata (L.) Wilczek) based on measurements and visual observations of Mungbean plants grown in four successive experiments conducted from May 1986 to November 1978 at Chainat Field Crop Research Center, Department of Agriculture and Department of Agronomy, Kasetsart University.

                It is proposed that the growth stages of Mungbean be defined in terms of vegetative (V) and reproductive (R) stages. The V stages are numbered V_(o) – V_(n), and are determined by counting the number of developed nodes on the main stem, beginning with the cotyledonary node as zero. The last node counted must have its trifoliate leaf sufficiently expanded so that leaflets are unfolded and flat in appearance. The R-stages proposed are R1 (first open flower), R2 (first pod), R3 (start of seed growth), R4 (full seed), R5(first mature pod), R6(1^st harvest) and R7 (2^nd harvest). The V and R stages can be measured separately and concurrently and apply to a population, or to single plants.

                 When Mungbean cultivars, Kamphaeng Saen 1 (KPS-1), Kamphaeng Saen 2 (KPS-2), Uthong 1 and Chainat 60 were grown in a randomized complete block design at Chainat Field Crop Research Center (Chainat FCRC) in May and August 1986. Also at Kasetsart University (KU) cultivars KPS-1, KPS-2, and U-thong 1 were grown in May and August 1987. It was found that, cultivars, KPS-1, KPS-2 and U-thong 1 grown at KU matured in 86 and 78 days at May and August planting. At Chainat, cultivars KPS-1, KPS-2 and U-thong 1 matured in 58 days regardless of planting dates, while Chainat 60 matured in 51 and 52 days for May and August planting respectively. At all locations tested, all mungbean cultivars at least completed their vegetative growth up to V6 before shifting to R1. In many cases, the plants extended their vegetative growth up to V, before flowering depending on genotypes, planting dates and locations. To complete its life cycle, the mungbean plants consequently exhibited R1 up to R2 growth stages.

                 The propose growth stage description of mungbean should be potentially useful and facilitate a common understanding among researchers and extension personnels and should provide a more precise basis for scheduling cultural practices for mungbean.