Selection index based on phenotypic and genotypic values predicted by REML/BLUP in Papaya

Abstract

Selection of superior genotypes based on the simultaneous responses to different characteristics is a fundamental strategy in plant breeding. This study aimed to compare the efficiency of four selection index constructed using phenotypic and genotypic values in a segregating population of the cultivar Rubi Incaper 511. Eight morpho-agronomic variates and the severity of black-spot and phoma-spot were evaluated under field conditions. The classical selection index were calculated based on non-standardized phenotypic means (NSM), standardized means (SM), and genotypic values predicted by REML/BLUP (GVP), using predetermined economic weights. Additionally, the rank sum (RS) was obtained on the basis of the classification of individuals in these three selection index. For ten characteristics, the selected individuals showed a higher mean than did the original population. The best selection differential values were obtained by SM, however, the highest degree of coincidence among the selected individuals was obtained between GVP and RS (80%). The index used were efficient at selecting individuals with higher soluble solids and lower diseases severity evaluated. Therefore, for the papaya breeding programs, different selection index need to be evaluated to maximize genetic gain.

Use of the REML/BLUP methodology for the selection of sweet orange genotypes

“…Individual heritabilities of low magnitude have also been observed for other perennial crops, with values of: 0.08% for physic nut (Jatropha curcas L.) (Cardoso et al, 2018), 0.07% for coffee (Coffea arabica L.) (Pereira et al, 2013), 0.01% for guava (Psidium guajava L.) (Almeida, 2017), and 0.1% for papaya (Carica papaya L.) (Moreira et al, 2019), confirming the results of the present study.…”

Use of an index based on best linear unbiased prediction value for the selection of superior papaya lines for multiple traits

“…The low heritability estimates may be attributed not only to environmental circumstances but also to the structure of the population being evaluated (Barros et al 2017;Falconer and Mackay 1989;Moreira et al 2019;Pinto et al 2013;Resende et al 2016). The F 5 lines showed the lowest expectations of response to selection for FF, FLF, and SSC, given that this population was derived from a biparental cross belonging to the same heterotic group and that there is probably low allelic variability for the physical-chemical traits concerned.…”

“…Another important point is genetic assessment based on REML/BLUP has received special attention because of the potential for outstanding genetic progress and great accuracy in the selection process (Lima and Silva et al 2017). This way, the genetic-statistical procedure of mixed models via REML/BLUP has been a strategy adopted to rank genotypes considering the predicted genotypic values of various traits (Alves et al 2019;Imai et al 2016;Lima and Silva et al 2017;Moreira et al 2019;Pinto et al 2013). The most indicated practice in papaya breeding programs is, however, the use of selection indexes, which, together with the predicted genotypic values (BLUP), are more efficient as a strategy to obtain genotypes with favorable responses to the maximum number of traits in a combined selection (Cortes et al 2019;Ramos et al 2014).…”

Selection gain and interrelations between agronomic traits in wheat F5 genotypes

“…Among the indexes, Mulamba & Mock (1978), and Smith (1936) and Hazel (1943) are the most commonly used. The efficiency of using selection indexes for crop breeding has also been highlighted by Moreira et al (2019) and Smiderle et al (2019).…”