Performance and genetic assessment of rubber tree clones in Southern Thailand

Abstract

Thailand is the world leader in the production of latex extracted from the rubber tree (Hevea brasiliensis). However, the most cultivated clone RRIM 600, is highly susceptible to diseases, and there is economic incentive to develop new rubber tree clones. Four rubber tree clones (T2, SK1, NK1 and SK3) that have high latex yield potential from plantations in Southern Thailand were selected for this study. Yield performance, latex biochemical parameters and anatomical characteristics of bark were monitored for two years, using RRIM 600 clones in the same fields as paired controls. The average yields of the clones SK1, NK1 and SK3 were 129.3, 74.2 and 53.9 g per tree per tapping, respectively, surpassing the paired RRIM 600 controls (94.3, 49.9 and 43.9 g per tree per tapping in matching order). There was a difference in girth increment of SK1, SK3and T2 clones when compared with RRIM 600, whereas the clones SK1 and T2 had higher renewed bark thickness than the paired RRIM 600. The anatomical measurements showed that the diameter of the latex vessels and density of latex vessels mm −2 were the highest in clone NK1, which also had the best latex biochemical parameters. This indicates NK1 is superior, and supports its use inHevea breeding programs to improve latex yield. Our genetic characterization and assessment of the four clones selected used Random Amplified Polymorphic DNA (RAPD) and Simple Sequence Repeats (SSR). Seventeen recommended rubber clones were included as references. The clones SK3 and SK1 were closely related to RRIM 600 with similarity coefficients of 0.891 and 0.809, while NK1 and T2 were closely related to RRIT 250 (0.836) and RRIC 110 (0.864), respectively.

Carbon Footprints of Rubber Products Supply Chains (Fresh Latex to Rubber Glove)

“…A survey of Thai rubber farmers during 2014-2016 gave 381 small farmers (total area 819 ha), 253 medium farmers (total area 2,512 ha) and 22 large farmers (total area 1,007 ha) accounting for 0.14% of the total rubber wood plantation area in Thailand (total Thai plantation area was 3,138,169 ha in 2016 cultivated clone RRIM600 which is highly susceptive to diseases and economic incentive to develop new rubber tree clones (Pethin et al, 2015). Details of the plantations are shown in Table 1.…”

Genetic diversity and structure in ex situ conserved populations of Hevea brasiliensis

“…Molecular markers have been used to assess genetic diversity through indices such as expected and observed heterozygosity and fixation index, among others. Some studies have quantified the genetic diversity of rubber trees using these markers (CUBRY et al, 2014;PERSEGUINI et al, 2012;PETHIN et al, 2015), offering significant potential for genetic studies involving the species (SOUZA et al, 2009).…”

Genome-Wide Identification and Characterization of MADS-box Family Genes Related to Floral Organ Development and Stress Resistance in Hevea brasiliensis Müll. Arg.

“…To meet the growing demand for NR, it is necessary to expand the planting area of rubber trees. However, the rubber tree originates from the Amazon rainforest, so the planting area must be located in sub-tropical to tropical zones [4]. At present, 95% of rubber trees in the world are now mainly cultivated in South-East Asia, so the regions suitable for planting rubber trees are very limited.…”