Author : Pramote Klib-ngern

Summary : The effect of photoperiod and plant growth regulators on flower initiation and development of winged bean varieties UPS 22, Batangas medium, and Pangasinan long were studied. Under short-day condition of 9 hrs. light, 100 percent flowering of the 3 varieties was observed, but not under long-day condition of 15 hrs. light and natural daylength of 12.89 hrs. Critical daylength for UPS 22 was around 12.58 while Pangasinan long was 11.80. However, under an average daylength of 12.89 hrs., 28 percent of UPS 22 plants initiated 1-2 floral buds/plant, but these abscissed before anthesis. Under a daylength of 12.75 hrs., UPS 22, Batangas medium and Pangasinan long required 5, 7, and 11 short-day cycles, respectively, for floral buds to be initiated and developed. Lesser than this, floral buds were initiated but eventually abscissed. However, even if the plants were exposed to the required number of short-day cycles if exposed to long-day afterwards, no flower develop to anthesis. Exposure to 10-20 short-day cycles and later to a long-day 15 hrs. effected 100 percent flower initiation of Pangasinan long but not enough for flower development. A continuous flower initiation and fast development was obtained from a continuous short-day treatment. Under a daylength of 12.58 hrs. three levels of concentration of GA (subscript 3) and ABA used did not induce flowering in Pangasinan long. ABA significantly hastened flowering of UPS 22 while GA (subscript 3) delayed it. Application of GA (subscript 3) resulted to significantly longer plant vines in both UPS 22 and Pangasinan long.