Rubber tree ortet-ramet genetic correlation and early selection efficiency to reduce rubber tree breeding cycle

• There is reliability that the most productive ortets selected in nursery stage will originate more productive ramets, reducing the rubber tree breeding cycle.
• The superior magnitudes for progenies mean heritability indicates that selection on progenies level is recommended.
• The genetic variance for dry rubber production (DRP), bark thickness (BTS) and number of latex vessel rings (NVR) remained higher when compared with the values ​​of residual variance, even after selection.
• The superiority of genetic coefficient of variation resulted in high relative coefficient of variation for all the studied traits, indicating a favorable situation to selection in the clonal population.

The present study aimed to correlate the performance of rubber tree [Hevea brasiliensis (Willd. ex. Adr. de Juss.) Muell-Arg] ortets selected in progenies tests and the performance of their respective ramets in the clonal test. In the progenies tests three early measurements were carried out for the traits early rubber yield (ERP), number of vassel latex rings (NVR) and bark thickness (BKT). Using the HMMm (Hamaker Morris-Mann modified) test the best ortets were selected based on rubber yield and cloned to set the clonal test. In the clonal test the same traits were studied, but the dry rubber production (DRP) was assessed in the normal tapping (from the seventh year of age). Statistical analyses were carried out using the REML/BLUP (restricted maximum likelihood/best linear unbiased prediction) method. After studying the progenies and clonal tests, the correlation between the performance of ortets and ramets was estimated and the performance of the ortets in the second and third early tests (ERP2 and ERP3) has proven to be reliable, since the observed estimate of the correlation coefficient with its ramets was significant. The study showed that if taken into account the second and/or third early test, there is reliability that the most productive ortets selected in nursery stage will originate more productive clones. It is efficient to select rubber tree based on the early rubber production, thus reducing the long rubber tree breeding cycle.