Early detection of genetic variation in date palms propagated from tissueculture and offshoots by DNA fingerprinting.

摘要

Random amplified polymorphic DNA (RAPD) analysis was conducted to evaluate the genetic variation among the female (Khalas, Barhy and Sukkary) and male (Barhy and Sukkary) plantlets of date palm cultivars propagated from offshoots, seeds and tissue cultures (TC). The cultivars showed unique RAPD banding patterns. To facilitate RAPD analysis, the 13 DNA samples were divided into 2 sets of populations. In the first population, the amplification profiles of 6 DNA samples belonging to 2 offshoot-derived and 4 TC-derived plants of Khalas were compared with each other. Of the 18 primers screened, 13 detected polymorphism. Cluster analysis by unweighted pair group method with arithmetic mean resulted in 2 clusters. The genetic distances ranged from 0.634 to 0.825 in the similarity matrix based on Nei and Li's similarity coefficients. In the second population, 7 DNA samples belonging to male and female plants of Barhy and Sukkary derived from seedlings and offshoots, and to TC-derived plants of Barhy were compared. All 7 genotypes revealed a unique banding profile with 14 primers. The genetic distances ranged from 0.232 to 0.810. In this population, 2 clusters were also detected. Plants of Kalas derived from offshoots and TC showed low levels of polymorphism. However, TC-derived plants of Barhy showed higher levels of genetic variation compared with offshoot-derived and seedling-derived male and female Barhy plants. A significant level of genetic variation was also observed between Sukkary and Barhy. RAPD appears to be an efficient technique for the early detection of genetic variation in plants propagated from TC and offshoots.