Development of Genic Male-sterile Watermelon Lines with Delayed-green Seedling Marker

Abstract

<jats:p>Hybrid seed production can be facilitated by using male sterility coupled with a seedling marker. This research was initiated to combine the <jats:italic>ms</jats:italic> male sterility and <jats:italic>dg</jats:italic> delayed-green seedling marker into watermelon [<jats:italic>Citrullus lanatus</jats:italic> (Thunb.) Matsum. &amp; Nakai] lines. Male-sterile plants of the male-sterile line G17AB were crossed with plants of delayed-green breeding line Pale90, which has yellow cotyledons and pale-green, newly developed, true leaves. The double-recessive recombinants, male sterile and delayed green, from the F<jats:sub>2</jats:sub> population were backcrossed to the male-fertile plants of G17AB. The pedigree method was used for selection in the progenies. The segregation ratios obtained from F<jats:sub>2</jats:sub> and BC<jats:sub>1</jats:sub>F<jats:sub>2</jats:sub> populations suggest that the male-sterile and delayed-green traits are inherited independently and that delayed green is inherited as a single recessive nuclear gene. Two male-sterile watermelon lines with delayed-green seedling marker have been developed. These lines will provide a convenient way to introduce male sterility and the delayed-green seedling marker into various genetic backgrounds. These two lines can be used for testing the efficiency of a new, hybrid, watermelon, seed production system.</jats:p>

Inheritance and mapping of a yellow leaf mutant of carrot (Daucus carota)

“…Genetic studies of F 2 progenies and the corresponding F 3 families indicate that the yellow leaf (yel) locus is recessive, and is controlled by a single gene. This is in accordance with studies of various authors on other species such as Allium (Jones et al 1944), Lycopersicon (van der Biezen et al 1996), Solanum (Birhman et al 1994), Hordeum (Bossmann et al 1999), Cucumber (Zhang et al 1996) or Arabidopsis (Jacobsen and Olszewski 1993). Ryder (1992Ryder ( , 1996, and Ryder et al (1999) studied chlorophyll mutants of lettuce and postulated different genes, with either a recessive or epistatic inheritance.…”

“…Genetic studies often indicate a nuclear mutation at a single locus as being responsible for these phenotypes (van der Biezen et al 1996, Ryder 1996, Zhang et al 1996, De Jong et al 1998). However, chlorophyll synthesis is a highly complex biosynthetic pathway.…”

Development of Genic Male-sterile Watermelon Lines with Juvenile Albino Seedling Marker

“…Three chlorophyll-deficient seedling marker mutants have been described in watermelon (Rhodes, 1986;Zhang et al, 1996aZhang et al, , 1996b. Spotted (Sp) is a dominant mutant that produces yellow spots on the cotyledon, leaf, and fruit.…”

“…Juvenile albino (ja) is a recessive mutant in which chlorophyll deficiency is expressed under short-day conditions. No linkage relationships were found between ms and Sp (Murdock and Ferguson, 1992) or between ms and dg (Zhang et al, 1996a). Similarly, evidence of linkage between ms and ja was lacking in a breeding study population (unpublished).…”

“…The seedling marker is not used for distinguishing male-sterile and malefertile plants. The seedling marker is used to recognize inbreds in the hybrid population and to detect off-types in the parent line (Zhang et al, 1996a). Our report describes the introduction of the ja gene into genic male-sterile watermelon lines.…”