Trifolium alexandrinum (Egyptian clover) is a widely cultivated winter annual fodder. Present work deals with inheritance of the seed coat colour in segregating progenies of the interspecific cross between T. alexandrinum and T. apertum. Although, both the parent species possessed yellow seed coat, the F1 seeds were black coloured in the reciprocal cross (T. apertum × T. alexandrinum). Seeds borne on individual F2 plants and the advancing generations segregated in yellow and black seed coat colour, which confirmed xenia effect. F2 seeds collected from individual F1 plants exhibited nine black and seven yellow segregation ratio. The segregation of the seed coat colour recorded from F3 to F5 generations revealed that yellow seed coat was true breeding (i.e. non-segregating) in this interspecific cross (including the reciprocal crosses). However, the black seeded progenies were either true breeding or segregated in nine black: seven yellow ratio or three black: one yellow ratio suggesting a complementary gene interaction or duplicate recessive epistasis. It indicated that the seed coat colour is controlled by complementary gene interaction along with xenia effect in interspecific crosses between T. alexandrinum and T. apertum. Occurrence of the complementary genes across the species could suggest T. apertum to be the progenitor of T. alexandrinum. Inheritance of seed coat colour in reference to its importance in Egyptian clover breeding is also discussed.

中文翻译：

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互补基因相互作用和 xenia 效应控制三叶草和 T. apertum 种间杂交种皮颜色

Trifolium alexandrinum（埃及三叶草）是一种广泛栽培的冬季一年生饲料。目前的工作涉及分离 T. alexandrinum 和 T. apertum 种间杂交后代中种皮颜色的遗传。尽管两种亲本都具有黄色种皮，但 F1 种子在互交中呈黑色（T. apertum × T. alexandrinum）。单个 F2 植株上的种子和后代以黄色和黑色种皮颜色分离，这证实了 xenia 效应。从单个 F1 植物收集的 F2 种子表现出 9 个黑色和 7 个黄色分离比例。从 F3 到 F5 世代记录的种皮颜色的分离表明黄色种皮在这个种间杂交（包括互惠杂交）中是真正的繁殖（即非分离）。然而，黑色种子后代要么是真正的繁殖，要么以九黑：七黄比例或三黑：一黄比例分离，表明互补基因相互作用或重复隐性上位。这表明种皮颜色受互补基因相互作用以及T. alexandrinum 和T. apertum 种间杂交中的xenia 效应控制。跨物种互补基因的出现可能表明 T. apertum 是 T. alexandrinum 的祖先。还讨论了种皮颜色的继承及其在埃及三叶草育种中的重要性。这表明种皮颜色受互补基因相互作用以及T. alexandrinum 和T. apertum 种间杂交中的xenia 效应控制。跨物种互补基因的出现可能表明 T. apertum 是 T. alexandrinum 的祖先。还讨论了种皮颜色的继承及其在埃及三叶草育种中的重要性。这表明种皮颜色受互补基因相互作用以及T. alexandrinum 和T. apertum 种间杂交中的xenia 效应控制。跨物种互补基因的出现可能表明 T. apertum 是 T. alexandrinum 的祖先。还讨论了种皮颜色的继承及其在埃及三叶草育种中的重要性。