Question

Garden asparagus, Asparagus officinalis, produces either staminate (male) or pistillate (female) plants in about equal numbers. Occasionally, stamens develop in pistillate flowers and pistils in staminate flowers. Although these latter pistels on the male plant are usually non-functional, they sometimes produce viable seed by self-fertilization. From self-fertilization, 198 such seed were obtained. Of these, 155 were male and 43 female.

1) Wht sex-determining system is most likely in these plants?

2) Which sex is the heterogametic sex? Explain

When 25 of the male plants were crossed with female plants, 8 gave male progeny only and 17 gave progeny in a 1 male to 1 female ratio

3) Wht further information does this give you?

Answer 1

Answer

1) qIn a small number of species, there is spatial separation of the sexual organs either as monoecy, where the male and female organs are carried on separate flowers on the same plant, or dioecy, where male and female flowers are carried on separate male (staminate) or female (pistillate) individuals. Sex determination systems in plants, leading to unisexuality as monoecy or dioecy, have evolved independently many times.

2) In dioecious species, such as asparagus, the male generally is the heterogametic (XY) sex.