Sex Ratio in Hawaiian Papaya (Carica papaya L.) Variety ‘Solo’

Abstract

Fruits from hermaphrodite Hawaiian varieties are of medium size and preferred by consumers all over the world. Seeds obtained from the fruits of selfed hermaphrodite plants produce almost two third hermaphrodite plants and one-third pistillate plants. These plants can not be identified before the onset of flowering. However, there are conflicting reports in scientific literature on sex ratios obtained from selfed seeds from fruits of hermaphrodite plants. Sex ratios of hermaphrodite, pistillate and staminate plants were determined using seeds from selfed hermaphrodite fruits of a Hawaiian papaya (Carica papaya) variety ‘solo’. Bagging flowers on hermaphrodite plants during flowering season to avoid contamination from foreign pollen produced self-seeds. Seeds from fruits of many bagged hermaphrodite flowers were pooled together and grown in large plots. A total of 2633 plants were grown and evaluated for their specific sex at the onset of flowering. Of these 1838 were counted as hermaphrodite, 783 pistillate and only 12 staminate plants. This gave a ratio of 2.34 hermaphrodite plants : 1: pistillate plants ignoring 12 staminate plants. This obtained ratio is in disagreement with earlier reported ratio of 2 hermaphrodite plants : 1 pistillate : 1 non-viable zygotes. However, no viable male progeny was reported from hermaphrodite selfed seeds in earlier studies. One of the explanations for the observed changed ratio could be biased seed selection from the seed lot used for planting.