Further Investigation on the Orange Cotyledons in Pea (Pisum sativum L.)

Pea (Pisum sativum L.) is an important model plant for genetic as well as biochemical and physiological studies. A well-saturated map of pea consisting several morphological, biochemical and molecular markers has been constructed to date. Nevertheless, there are still several genes whose inheritance and map positions are not well understood. Orange cotyledon color in pea is an interesting characteristic whose precise nature of gene interactions is unknown. Genetic analysis using crosses between lines having orange cotyledon color and lines with yellow or green cotyledons revealed that the character is controlled by a single gene. It was also found that the gene i (producing green cotyledon color) shows an epistatic effect on the gene Orc (orange cotyledon color). Incomplete dominance and dominance were revealed in the loci Orc and I, respectively. Mapping analysis revealed that the gene Orc is located on linkage group 1 and 28.5 crossover units away from the gene Ans and 31.3 map units away from Idh. In addition, a significant linkage was detected between two genes Pur and Ans with an estimated distance of 9.9 map units. The distance between Orc and Pur was estimated as 38 map units.