More systematic exploration and collection of pine germplasm was done in Central America and Mexico between the late 1950s and the early 1970s, focusing on Pinuscaribaea, Pinusmaximinoi, Pinusoocarpa, Pinusgreggii, Pinustecunumanii and P. patula.
Subsequently, P. caribaea and P. oocarpa, for example, have been introduced to 79 and 34 countries, respectively ( Table 1). The past germplasm PI3K inhibitor transfer patterns of tropical hardwoods are more diverse when compared to the above-discussed categories of species. Some tropical hardwoods were introduced for production purposes outside their natural ranges several hundred years ago, long before systematic R&D efforts started. More recently, however, germplasm of several tropical hardwoods was first transferred for R&D, and the results of this work then created interest and demand for further transferring germplasm for production purposes. Tectona grandis is a well-known example of the first category of tropical hardwoods. The large-scale transfer of its germplasm from Asia to other continents started more than one hundred years ago. Today, the species is estimated to be planted in a total
of 65 countries outside of its native range ( Table 1). Transferred germplasm of T. grandis originated from multiple sources and this contributed to the development of landraces in Africa and Central America. The origins of selleck compound these landraces are poorly understood, but historical records and genetic studies have shed some light on the possible routes of introduction, and the likely sources of germplasm. In Africa, it appears that T. grandis was first introduced to Tanzania at the end of the 19th century, and from there to other countries in East and (later) West Africa. The African landraces are reported to originate from multiple and rather diverse seed sources in India, Myanmar and possibly Java ( Wood, 1967). These landraces have a relatively high level of genetic diversity ( Kjaer and Siegismund, 1996). Phospholipase D1 No clear genetic relationship with T. grandis populations in South India has
been found ( Fofana et al., 2008), but Verhaegen et al. (2010) indicated that North India may have been an important seed source for many African introductions. Several other studies on the genetic diversity of T. grandis (e.g., Kertadikara and Prat, 1995, Shrestha et al., 2005 and Sreekanth et al., 2012) have also increased our understanding of the African landraces, but they have not been able to reveal their exact origins. In Central America, the first introductions of T. grandis occurred in Trinidad, where the seed probably originated from Myanmar and India ( Keogh, 1980). In the early 20th century, T. grandis was also planted in Panama using a small seed lot presumed to originate from India ( Keogh, 1980).