Comparative greenhouse study of Eucalyptus grandis in vitro plantlets and half-sib seedlings, II. Dry matter accumulation and relative distribution

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Warrag, Essam I.
Lesney, M.S.
Rockwood, D. L.
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In vitro directly micropropagated plantlets from three ire-C-Eed five-year-old Eucalyptus grandis Hill ex. Maiden hybrids were compared to their related half-sib seedlings for growth and growth pattern par-ameters under greenhouse conditions used for opera-tional seedling production. The oven dry weights were determined from stem, leaf, and root samples collected every 40 days for four times. Relative growth rate, net assimilation rates and shoot:root ratio were calculated. Survival was 98% and 95% for plantlets and seedlings, respectively. Significant differences were observed between parents in terms of shoot and root dry weights and their ratios with sim-ilar ranking among plantlets and seedlings, suggest-ing genetic control over these traits. Plantlets started with significantly higher root: shoot ratios and stem, leaf, root, and total dry weight. Although seedlings had higher relative growth and net assimi-lation rates, all the initial differences decreased sharply over time.
greenhouse, seedlings