Genetic diversity among papaya accessions

Abstract

Genetic diversity studies provide fundamental information for characterization, conservation and utilization of available genetic resources in plant genetic improvement programs. To evaluate the genetic divergence among papaya accessions, 17 morphoagronomic variables from 59 accessions of the active germplasm bank were evaluated in an experiment at Santa Teresinha Farm, belonging to Caliman Agrícola S/A, in Linhares-ES, Brazil. The experiment was conducted in a randomized block design with two replicates. The divergence between the accessions was estimated using the Tocher optimization method and the agglomerative hierarchical approach based on the Unweighted Pair-Group Method Using an Arithmetic Average. (UPGMA). There was significant difference for all the variables evaluated, showing variability among the accessions. The variables plant height, first fruit insertion height, greatest thickness of fruit pulp, fruit diameter, and fruit length had heritability above 80%, indicating expressive gains in the simple process of selection. Genetic variability was found among the accessions, and Americano, short-peduncle-STZ-03 and Califlora 209 were the most divergent. The optimization methods Tocher and hierarchical based on UPGMA were partially concordant for the formation of heterotic groups of papaya accessions. The variables fruit mass, fruit diameter and plant height contributed the most to the genetic diversity.

Assessment of Genetic Divergence by Using Multivariate Analysis for Physico Chemical Characters of Mango Table and Juicy Cultivars Grown in Telangana Region

“…Therefore, these characters should be given greater importance for the improvement of quality in further selection of segregants and choice of parents during hybridization programmes in mango. Similar studies were also carried out by Singh (2005), Rajan et al (2009), Rufifni et al (2011, Barhate et al (2012), Majumder et al (2013, Barholia and Sangeetha (2014) and Sandra et al (2013) in mango; Clemilton et al (2017) in papaya, and Singh et al (2003) in pomegranate.…”

Obtaining and Evaluating New Hybrids of Papaya Tree

“…In the study of 59 accessions of the active Papaya germplasm bank, Silva et al (2017) also observed great variability in fruit size, the American access of the "Formosa" group presented the highest fruit length (39.00 cm) and the STZ 03 Petiole-short access from the "Solo" group presented (11.00 cm) for this characteristic.…”

“…An alternative and feasible solution to incorporate these characteristics is the knowledge and exploration of the variability existing in active germplasm banks of papaya (Carica papaya L.) (Silva et al, 2017), and resorting to expanding the genetic base through programs by using hybridizations.…”

Assessment of genetic divergence using Mahalanobis D2analysis in mango

“…Characters such as tree height (0.00 %), tree girth (0.00 %), tree spread (0.00 %), leaf length (0.00 %), leaf width (0.00 %), chlorophyll content (0.00 %), number of male flowers per panicle (0.00 %), number of perfect flowers per panicle (0.00 %), fruit drop percentage (0.00 %), stone weight (0.00 %) and non-reducing sugar (0.00 %) had no contribution towards total divergence. Clemilton et al (2017) reported that the fruit mass (16.88%), fruit equatorial diameter (11.32%) and greatest thickness of fruit pulp (11.01%) showed the greatest contribution to genetic diversity. On the other hand, yield (2.26%), stem diameter (1.17%) and first fruit insertion height (0.66%) showed the smallest relative contribution in papaya which is in correspondence with the results of the present study.…”