Impact of Fertility Variation on Gene Diversity and Drift in two Clonal Seed Orchards of Teak (Tectona grandis Linn. f.)

• Published in: New forests 2006-05, Vol.31 (3), p.497-512
• Main Authors: Varghese, M, Nicodemus, A, Nagarajan, B, Lindgren, D
• Format: Article
• Language: English
• Subjects: clones; Crop production; Fertility; Flowers; forest nurseries; forest trees; Fruits; Genetic diversity; Genetic drift; genetic improvement; genetic variation; Offspring; Orchards; plant fertility; Population number; Seed orchards; seed productivity; Seeds; Tectona grandis
• ISSN: 0169-4286; 1573-5095
• DOI: 10.1007/s11056-005-2178-8

CSO-II), respectively, selected mostly from moist forests of Western Ghats (latitude 10° N) in southern India, were evaluated for fertility, offspring diversity, and genetic drift. The orchards differed in fertility of clones as well as flower and fruit production per ramet. Fertility was highly skewed in CSO-II, where one clone (originating from higher latitude -17° N, in Eastern Ghats of peninsular India) produced 55% of the fruits and 68% of the flowers in the orchard, in contrast to a similar contribution from four most fertile clones in CSO-I. Fertility variation, measured as 'sibling coefficient' (1.7 in CSO-I and 8.3 in CSO-II), was high in CSO-II resulting in high coancestry and low effective population size (3 times lower than CSO-I) in the seed crop. In CSO-I, 58% of the clones contributed effectively to seed production compared to only 12% effective contribution resulting in eight times higher genetic drift in CSO-II. Placing limits on how much seed can be collected per clone might be useful in restricting over representation of highly reproductive clones thereby increasing genetic diversity in the seed crop.