Changes in growth performance and fecundity of Eucalyptus camaldulensis and E. tereticornis during domestication in southern India

Abstract

Bulk seedlots of two unpedigreed multiprovenance seed production areas (SPAs) each of Eucalyptus camaldulensis and Eucalyptus tereticornis and one pedigreed seedling seed orchard (SSO) of E. tereticornis were planted in genetic gain trials at three southern Indian trial sites. At the time of seed collection, fewer than 30% trees flowered in these orchards, except in one E. camaldulensis SPA where 73% of the trees flowered, which had an estimated outcrossing rate of 86%. The E. tereticornis SSO was dominated by pollen from five highly fecund families of the Indian Mysore gum land race, which contributed 59% of the fruits produced. The SPA and SSO seedlots were compared with a bulked natural-provenance seedlot of E. camaldulensis (Morehead, Laura, and Kennedy Rivers, Queensland), another natural-provenance seedlot (Petford, Queensland), commercial eucalypt clones at two sites, and a Mysore gum seedlot at one site. At 3 years, progeny from all the four SPAs displayed good survival (79-93%) and performance similar to that of the natural provenances and the commercial clones. Progeny from the E. tereticornis SSO had significantly lower growth (at two sites) and lower survival at all three test sites. The Mysore gum seedlot displayed high fecundity and lower growth but better survival than the SSO progeny. Seed orchard genetic composition and flowering contributions thus affected progeny performance and the extent to which orchard genetic diversity was captured in the progeny. SPA progeny displayed greater fecundity than the natural provenances, indicating a response to selection for fertility.

A comparison of the effect of genetic improvement, seed source and seedling seed orchard variables on progeny growth in Eucalyptus nitens in South Africa

“…This is supported by findings in previous E. macarthurii (Swain et al 1999) and E. nitens genetic gain trials (Jones, pers. comm 1 ) in South Africa and in E. camaldulensis genetic gain trials in India (Varghese et al 2009), where bulks of the same nominal level of improvement did not differ significantly from each other.…”

Hybrid purity assessment in Eucalyptus F1 hybrids using microsatellite markers

“…Reports on controlled inter-specific hybrid eucalypts production and their importance in genetic improvement were available since 1960 in India for the commercially important species like Eucalyptus camaldulensis , Eucalyptus tereticornis and Eucalyptus grandis (Venkatesh and Kedharnath 1965; Venkatesh and Sharma 1977, 1979). However, eucalypts breeding program in India mainly focused on improvement of pure species (Varghese et al 2009) which is obviously a prerequisite for hybrid development. Many earlier hybrid selections in Congo and Brazil were from sporadic hybrids identified from open pollinated seed orchards and later shifted to planned attempts for production of inter-specific hybrids (Potts and Dungey 2004).…”

Combining genetic gain and diversity under an individual selection method in a selected provenance of Eucalyptus cladocalyx

“…However, in relation to the flower intensity or abundance, Butcher et al (2009) found little flowering in the populations of E. camaldulensis in the arid regions of Australia, whereas Varghese et al (2009) found inter-species differences in the fertile trees and fecundity percentages in the south of India. Mora et al (2007) found that the Cowell provenance exhibited an early flowering that was higher than other populations from Australia.…”