Abstract
The objective of this work was to estimate the genetic parameters, genotypic and phenotypic correlations, and direct and indirect genetic gains among and within rubber tree (Hevea brasiliensis) progenies. The experiment was set up at the Municipality of Jaú, SP, Brazil. A randomized complete block design was used, with 22 treatments (progenies), 6 replicates, and 10 plants per plot at a spacing of 3x3 m. Three‑year‑old progenies were assessed for girth, rubber yield, and bark thickness by direct and indirect gains and genotypic correlations. The number of latex vessel rings showed the best correlations, correlating positively and significantly with girth and bark thickness. Selection gains among progenies were greater than within progeny for all the variables analyzed. Total gains obtained were high, especially for girth increase and rubber yield, which were 93.38 and 105.95%, respectively. Young progeny selection can maximize the expected genetic gains, reducing the rubber tree selection cycle.
Highlights
Rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell
Twenty‐two half‐sib progenies, obtained from 22 parental clones phenotypically selected from a H. brasiliensis population from Asia, established at the Centro Experimental Central (CEC) of Instituto Agronômico (IAC), SP, Brazil, were used
The effects of mean squares were significant at 1% probability for all the variables evaluated (Table 2), indicating that the progenies showed genetic variability that led to genetic gain, allowing for the selection of the best progenies
Summary
Arg.] genetic breeding has a very long selection cycle, which can reach up to 30 years. It is important to carry out studies on young plants using early analysis methods in progeny tests. These studies can be used to predict the genetic variability and selection gains of the studied population and as a basis for future breeding programs to reduce the breeding cycle of the species. Selecting traits in the juvenile stage may be an efficient method to reduce the breeding cycle and to maximize genetic gains (Adams et al, 2007). Information on gain selection can be used to orient
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