Genetic variation of flower characteristics in a population derived from a cross between the chrysanthemum cultivars ‘Falcao’ and ‘Frill Green’

Abstract

Chrysanthemum is a major floriculture species and a breeding goal is to develop cultivars with unique flower forms and colors. This study was conducted to investigate the genetic basis of six flower traits including petal color, flower shape, ray floret length, the level of ray floret twisting, the shape of the ray floret tips, and the attitude of the basal part of the ray florets. A pseudo-testcross population derived from a cross between the ‘Falcao’ and ‘Frill Green’ cultivars was used. The female parent ‘Falcao’ is a popular pompon type that has an orange-pink color and lacks twisted ray florets. The male parent ‘Frill Green’ is a single type with green twisted ray florets. For color, six different colors were observed in 130 progeny: white, yellow, green, orange, orange-pink, and pink and 52 (40%) and 52 (40%) progeny showed green and yellow colors, respectively. The progeny was grouped into 4 classes based on flower form. The semi-double class was the most frequent (70%) in the population, suggesting an incomplete dominance for the double and single flower. Among four ray floret traits, the shape of the ray floret tips seems to be controlled by a single gene, while the level of twisting of the ray floret showed a significant deviation from the expected 3:1 or 1:1 ratio (p < 0.05). The progeny were divided into three classes in terms of the attitude of the basal part of the ray florets (ascending, descending, and horizontal). Four and three progeny for green pompon or green double flowers were selected, respectively. Two of the four green pompon selections have twisted ray florets. These results will help breeders for developing new chrysanthemum cultivars with unique flower forms and colors.