A first physiological assessment of latex clonal metabolic typology and rubber yield potential of "CMS" rubber tree clones

Tapped trees from 19 clones (CDC56, CDC308, CDC3 l 2, CDC429, FDR446 l, FDR4575, FDR5240, FDR5283, FDR5597, FDR5665, FDR5788, FDR5802, MDFl80, MDX607, MDX608, MDX624, PMB 1, SIAL893 and TP875) showing good tolerance to SALB (South American Leaf Blight) have been studied for their latex physiological parameters from 2007 to 2011 on Plantation Michelin Da Bahia (PMB). Igrapiuna, Brazil. Main latex physiological parameters (sucrose latex content, inorganic phosphorus latex content, reduced thiols latex content and latex DRC) have been recorded from 3 large scale clone trials, with or without ethephon stimulation. Without stimulation, latex analysis results show clear discrimination between the clones for their latex metabolic types, from very low to high latex metabolism. The clones showing the most interesting physiological characteristics (medium to high metabolism together with higher latex sucrose content) are FDR4575, FDR5788 and PMB l. These 3 clones are likely to obtain the highest yield potentials among the selection. 3 other clones (MDX608, CDC308 and FDR446 l) show high metabolism with lower sucrose content, showing typical quick sta1ter profiles. Finally, 5 other clones (FDR5240, TP875, CDC429, CDC3 l 2 and FDR5665) show typical medium metabolism profiles. Ali other clones show some physiological limitations due either to their low latex metabolism, either to their low latex sugar content. With stimulation, latex parameters variability among clones is greatly reduced, making it difficult to discriminate clones profiles. This confirms that ethephon stimulation is not helping in the evaluation of clonal latex physiological characteristics. From this early clonal physiological characterization, a tentative optimum stimulation range can be proposed for each of the 19 clones tested in these trials. (Résumé d'auteur