Intrapopulation recurrent selection by mixed models in papaya of the formosa group

Fabíola Lacerda De Souza Barros,Karin Tesch Kuhlcamp,Alyce Carla Rodrigues Moitinho,Sarah Ola Moreira,Moises Zucoloto

doi:10.1590/0100-29452018870

Abstract

Abstract Few cultivars of papaya from the Formosa group are available to producers, and the development of new genotypes is indispensable. Thus, the use of effective selection strategies to obtain more productive cultivars and better quality fruits is also necessary. The aim of this study was to select of half-sib families (HSF) of papaya using the methodology of mixed models. Nineteen HSFs from the Incaper’s papaya breeding program were evaluated in a randomized block design with five replicates and nine plants per plot. The selection was made based on fruit mass (FM), pulp thickness (PT), soluble solids content in pulp (SS) and number of fruits (NF). The genetic parameters and genotypic values were estimated by the REML/BLUP procedure. The selected HSFs increased FM by 26.1%; the PT in 10.5%; the SS in 7.5% and; the NF in 13.0%. The additive heritability within the progenies and the individual variation coefficient obtained indicate that the selection between and within the HSFs can provide greater genetic gains. The selection based on the REML/BLUP methodology was efficient to obtain simultaneous genetic gains for all variables under study despite the negative correlation between them.

Highlights

Brazil is the second largest producer and exporter of papaya (Carica papaya L.) with cultivated area of approximately 32 thousand hectares, production of about 1.6 million tons year -1 and productivity around 50 t ha-1 (FAOSTAT, 2017)
In a similar manner to the characteristics described above, the soluble solids content was lower, as it is influenced by temperature, precipitation, pest and disease incidence, light exposure and fruit maturity at harvest time (LUZ et al, 2015)
The NF of this experiment does not reflect the total number of fruits of the plant during the whole production period, justifying the average lower than that reported by Cattaneo et al (2010)

Summary

Introduction

Brazil is the second largest producer and exporter of papaya (Carica papaya L.) with cultivated area of approximately 32 thousand hectares, production of about 1.6 million tons year -1 and productivity around 50 t ha-1 (FAOSTAT, 2017). For the papaya tree there are two heterotic groups - Solo and Formosa - that differ mainly in relation to fruit size and commercial uses. The fruits of papaya from the Formosa group weigh more than 1 kg and are more used by the industry and hotel chain. Despite the large area of production and consumption, few cultivars of papaya from the Formosa group are available to producers, which can cause the genetic vulnerability of the crop, limiting its genetic progress. The development of new cultivars can contribute to reduce this risk, besides increasing productivity and improving the quality of papaya fruits. This study will be facilitated by the use of efficient methods of genetic parameters estimation and the selection of genotypes of interest (PINTO et al, 2013)

Objectives

Methods

Results