Morphological , SSR and ISSR marker based genetic diversity assessment of mountain papaya germplasm in comparison with Carica papaya

The genetic diversity in papaya cultivars is essentially important as it provides the basis for varietal genetic diversity of the commercial Carica papaya cultivars in Sri Lanka and to introduce mountain papaya (Vasconcellea cundinamarcensis), one accessions of Carica papaya assessed by morphological, simple sequence repeat (SSR) and inter simple sequence repeat (ISSR) markers. A total of 33 per marker from 11 SSR and 2 ISSR markers. Morphological and molecular marker based cluster analyses revealed that C. papaya cultivars C. papaya accessions. Except three SSR markers, all the other markers C. papaya for both C. papaya and mountain papaya indicating the potential relatedness to C. papaya. This investigation revealed both the genetic diversity and the relatedness of mountain C. papaya so as to use it as a potential source for the improvement of C. papaya by hybridisation.


INTRODUCTION
Most of the Caricaceae species are considered as unexploited species except for Carica papaya for consumption as a fresh fruit and for use in drinks, jams, candies, etc. Papaya also has pharmaceutical and industrial values due to its proteins and alkaloids.Of these, papain is the most important industrially valuable green, unripe papaya fruits (Moussaoui et al., 2001).In Sri Lanka there are several C. papaya cultivars including introduced varieties from other countries, hybrid varieties and local-traditional cultivars.Currently 7,108 ha are under cultivation and the annual production is 84,606 mt (DOA, 2014).Caricaceae et al., 2015).Previously, the genus Carica the recommendation of Badillo (2000) Carica Vasconcellea genus Carica contains only one species, Carica papaya, Caricaceae

The family
The mountain papaya plant has been studied by important traits such as the potential for cold tolerance (Muthulakshmi et al., 2007) (Badillo, 2000).Both Carica and Vasconcellea are genetically diploids and share the same chromosome number, 2n = 18 (Storey, 1976

Morphological analysis
Phenotypic trait assessment of all examined C. papaya all qualitative traits assessed (Table 4).Out of all the female plants.All observed mountain papaya plants geographical area.
C. papaya accessions exhibited single stems.
C. papaya plants displayed light grey stems.The three main commercial C. papaya cultivars, Red Lady, Sinta and Rathne  C. papaya main clusters (Figure 2).One main cluster (cluster A) comprised all the mountain papaya genotypes collected

SSR primers resulting in monomorphic allele pattern had
Major allele frequencies of each SSR and ISSR locus for the 21 accessions are presented in Table 5. Monomorphic primers had the highest major allele ranging from 0.1 to 0.9.The highest major allele The polymorphism information content (PIC) value the average PIC of the 11 SSR and 2 ISSR loci in the and ISSR1  4).This result is described by the distinct C. papaya and mountain papaya accessions obtained from mCpCIR01, mCpCIR40, ISSR1 and ISSR2 primers.

DISCUSSION
The genetic improvement of any crop is dependent on modern breeding techniques.The assessment of genetic diversity at a given level is a requirement to select resistant and high yielding varieties (Mondini et al., 2009).In this study, the cluster analysis of morphological traits revealed that there is no distinct separation among the C. papaya due to the presence of unfavourable traits.Therefore, it is C. papaya as the recurrent parent to maximise the C. papaya genetic to the target loci of PRSV-P resistance inherited from

C
. papaya accessions.Their in the axils of the leaves.All C. papaya cultivars bear all papaya cultivars.Of all the cultivars, Red Lady and ribs from the base to apex of the fruit (Figure 1).The A a a Annealing temperature Table 4: peel colour of ripe C. papaya fruits ranged from light based on it could not be seen in C. papaya cultivars.C. papaya cultivars and they released a strong pleasant trait.

Figure 2 :
Figure 2: Dendrogram showing the relationships among Carica papaya and mountain
from the C. papaya accessions although LCL 04 and LCL 07, and one Red Lady cultivar (RDL 01) shared papaya accessions.Morphological markers alone are C. papaya and mountain papaya to examine the likelihood of intra-generic hybridisation.Therefore, the preferred method for diversity analysis among plant breeders.C. papaya and mountain papaya, and among C. papaya cultivars.Thirty three proving their ability to be used as polymorphic markers in both C. papaya and mountain papaya accessions.Although RAPD markers have been extensively used to assess some traits in papaya (Sondur et al., 1996; Jobin-Decor et al analysed by SSR and ISSR (Carrasco et al., 2009; de Oliveira et al the highest PIC value thereby indicating its usefulness in the screening of C. papaya accessions.DNA based cluster analysis also revealed that C. papaya cultivars due to sharing the same alleles in most of the SSR and ISSR markers.Results of the molecular analysis revealed that mountain papaya and C. papaya are genetically C. papaya and mountain papaya and hence, it can be assumed that mountain papaya could be more closely aligned to C. papaya et al. (1998) have reported the possibility the genus, Vasconcelleae and C. papaya, proving their close relationship.V. quercifolia and V. stipulata are considered as the major et al., 1998).Resistance to PRSV-P in C. papaya Vasconcellea species and C. papaya has yielded resistant hybrids indicating the possibility of donating PRSV-P resistant et al., 1998).

Table 1 :
Details of the papaya germplasm and their locations or common names ascribed to the individual accessions their local name (Table1).
District(Weerakoon et al., 2009)as an uncultivated papaya species.Mountain papaya is a sparsely branched herbaceous tree, habituated in the highest elevation mountain papaya accession in Sri Lanka has not been explained clearly and naturally hybridised genotypes have not been reported in Sri Lanka.

Table 3 :
Variation in morphological characters among papaya germplasm