Variation in photosensitivity of flowering in the world soybean mini-core collections (GmWMC)

Abstract

Photosensitivity of flowering is the main yield limiting factor for soybean production in tropical areas. Our objective was to evaluate the variation of photosensitivity in the world soybean mini-core collections (GmWMC) under controlled environment. Ten and 13 h were selected as short- and long- photoperiods. The days from emergence to first flower open (DEF) were 20–49 days under 13 h, whereas 20–31 days under 10 h photoperiods. The variation in DEF under short photoperiod might be caused by juvenile growth phase or post-inductive phase, because 10 h was the photoperiod which induction phase of most genotypes were minimized. Index of photosensitivity of flowering (IPF) varied from 0.00 to 0.47 and correlated positively with DEF under short photoperiod. However, some genotypes were found having higher IPF but shorter DEF, or lower IPF but longer DEF. Results provided the valuable information for soybean production in tropical areas. Abbreviations: DEF: days from emergence to first flower open; IPF: index of photosensitivity of flowering; JGP: juvenile growth phase; GmWMC: world soybean mini-core collections.