In vitro Flowering and Pod Setting of Non-symbiotically Germinated Pea

Abstract

To establish a method of accelerating generation turn-over in In vitro cultured pea (Pisum sativum L.), the effects of cultural conditions on the flowering and pod setting were investigated. 1. The percentage set of flower and pod (seed set) in early maturing, short internodal cultivars, such as 'Misasa', were 100%, whereas those of late maturing, long internodal cultivars, such as 'Kishu-usui', were lower. 2. The flowering and pod setting percentages were highest, when a φ 30×200mm test tube and cotton stopper were used, in both 'Misasa' and 'Kishu-usui'. 3. At 25°C, 'Misasa' flowered and set pods faster than it did at 20°C. Under 10, 000lx, the flowering and pod setting percentages were higher and the days to flowering were shorter than they were at 3, 000lx, in both cultivars. Under a 24-hr photoperiod, the flower and pod set in 'Kishu-usui' were higher and the days to flowering were fewer than those under a 16-hr photoperiod. 4. More pod set in 'Kishu-usui' in a hormone-free MS medium containing 3% sucrose or if the medium was supplemented with 0.5mg·liter^-1 of NAA. 5. The addition of 10mg·liter^-1 uniconazole to the medium reduced plant height, internode length and the number of nodes, but advanced flowering and increased pod set. Ancymidol, likewise, caused dwarfing of seedlings but did not increase flower or pod set.