Embryo Abnormality in Relation to Seed Sterility in Exotic Pine Species of Kumaon Himalayan Region

Abstract

Six exotic species were selected for the present study. Pre and post fertilization stages of embryo showed that in <i>Pinus patula. P taeda </i>and <i>P elliottii </i>degeneration was started mainly at the early stage of embryo development during cell division. In <i>P. thunbergii </i>and <i>P. greggii, </i>abnormal embryo was developed by uncontrolled division, which was unable to survive for a long period. In <i>P. echinata </i>and <i>P. palula </i>dead endosperm was found before fertilization and in some places it had been damaged during embryo development. Endosperm is a food reservoir for the embryo, hence absence of food supply caused death of embryo which ultimately produced sterile seeds. Abnormal archegonia were also seen in <i>P. patula </i>during the study which might be responsible for seed sterility.