Effects of Pollination Season and Relative Humidity on Seed Setting Potential in Zingiber mioga Roscoe, and Variations in the Number of Chromosomes of Self-pollinated Progenies

Abstract

Zingiber mioga Roscoe (2n=55), a condimental vegetable, rarely sets seed. To activate a breeding project, the effects of the pollination season and relative humidity on the seed setting potential were examined under long day (16 hr) conditions. The variation in the number of chromosomes of self-pollinated progenies was also investigated.
In the spring of 1987, only five seeds set in four ovaries obtained from 190 florets pollinated with fresh pollens. In the winter of 1988, 84 seeds set in 26 ovaries obtained from 184 pollinated florets. In the spring of 1989, the seed setting capacity of plants was compared between those grown in a fully open, plastic house under natural humidity and those grown in a partially open, humidified plastic one. In the latter, high relative humidity was maintained with a humidifier. No seed set in any of 45 florets pollinated under natural humidity conditions, whereas 73 seeds set in 23 ovaries obtained from 121 florets pollinated under humidified conditions. Embryos were excised from 73 and 69 seeds obtained in the winter of 1988 and in the spring of 1989, respectively. These embryos were cultured on MS medium containing 30 g/liter sucrose from which 106 plants were raised. Of the 67 plants examined, the chromosome number varied from 2n=46 to 2n=60.