MSc

India is the largest producer of jackfruit in the world (APAARI, 2012). A wide range of genetic and morphological variation has been reported in jackfruit (Ullah and Haque, 2008). In Kerala also rich genetic diversity is reported (Muthulakshmi, 2003; Amma and Kumaran, 2011). Hence it is essential to characterize the accessions at morphological and molecular levels for knowing their identity, genetic relatedness and for exploitation in future breeding programmes.

The study on ‘Morpho-molecular characterization of jackfruit (Artocarpusheterophyllus L.) accessions’ was carried out at College of Horticulture, Vellanikkara, Kerala from August 2013 to June 2015. The main objective of the study was to characterise the selected accessions/varieties of jackfruit based on morphological and molecular analysis. Twenty types/accessions of jack fruit maintained in the College orchard and in the Pineapple Research Centre, Vellanikkara along with the MuttomVarikka,Sindoorand Thamarachakkavarieties were used for the study. All the accessions/varieties were studied for morphological, physico-chemical and organoleptic properties. Molecular characterization of the selected accessions/varieties was carried out using standard procedure and subjected to ISSR techniques.

All the accessions/varieties showed variability in tree characters,inflorescence characters, fruit characters and fruit quality. At the similarity coefficient status of 30 percent, grouping of accessions was done based on tree characters,which resulted in 6 non-overlapping clusters.Tree characters viz.,tree height (4.50 m to 18.00 m), trunk girth (76.00 cm to 270.00 cm), crown shape (pyramidal, broadly pyramidal, spherical, oblong, semi-circular, elliptical and irregular), branching pattern (erect, opposite, verticillate, horizontal and irregular), leaf blade shape (obovate, elliptic, broadly elliptic, narrowly elliptic, oblong and lyrate (wavy)), leaf apex (acute, acuminate, retuse and obtuse) , leaf base shape (oblique, rounded, cuneate and shortly attenuate) , leaf length (12.34 cm to 18.02 cm) and breadth ( 6.37 cm to 9.43 cm) were observed.

The accessions were grouped at the similarity coefficient status of 75per cent based on inflorescence characters, which resulted in 5 non-overlapping clusters.Time of flowering, female inflorescence density, female and male inflorescence positions, bearing habit (regular) and secondary flowering (no secondary flowering) were recorded.

At the similarity coefficient status of 26 per cent, grouping of accessions was done based on fruit characters, which resulted in 5 non - overlapping clusters. Variation was observed with respect to fruiting season, fruit clustering habit, fruit number (21 to 135) , shape, surface, fruit weight (1.65 kg to 20.00 kg ), fruit yield (41.25 kg/ plant to 1593 kg/ plant), shelf life ( 3 to 5 days ), latex exudation, rind colour and thickness, core length (10.20 cm to 50.50 cm ) and thickness (2.50 cm to 13.90 cm), number of flakes (bulbs) per kg of the fruit (12.61 to 71.15), weight of flake (16.69g to 33.91g), flesh thickness ( 1.26 mm to 7.8 mm), bulb diameter (6.08 cm to 10.11 cm), shape, pulp flavour, colour and consistency, number of seeds (44 to 482), 100-seed weight (240g to 800g) and rind, flake and seed ratio (2.30 to 7.31).

Sensory evaluation viz.,taste, flavour, colour, texture, sweetness and appearance were recorded on basis of 9 point hedonic scale. At the similarity coefficient status of 7 per cent, grouping of accessions was done based on biochemical characters, which resulted in 14 non - overlapping clusters.The percentage of moisture (29 to 74 %), TSS (20.30 0 Brix to 33.80 o Brix), reducing sugars (6.61 to 13.16 %) and non-reducing sugars (5.16 to 13.29 %) and β carotene (0.99 to 12.94 mg/100g) were estimated.

In molecular characterization five main clusters were formed at 77 per cent similarity. The first cluster grouped four accessions (Acc. 1, Acc. 3, Acc. 5, Acc. 4). The second cluster consists of Sindoor. Third cluster consists of Thamarachakka, fourth cluster consists of Acc. 2 and MuttomVarikka and the fifth cluster consist of five accessions (Acc. 15, Acc. 17, Acc. 18, Acc. 19, and Acc. 16). First cluster included the firm fleshed jackfruit accessions whereas Cluster V included all the soft fleshed accessions.
Thus in the present investigation, evaluation and characterization of twenty accessions and three varieties namely Sindoor, MuttomVarikka and Thamarachakka have been made to understand the extent of genetic diversity and similarity with the help of morphological, biochemical and molecular characters for identifying superior types for further selection. Sindoor and MuttomVarikka are the two firm fleshed varieties widely accepted in Kerala and suited for homestead cultivation. The morphological and fruit quantity and quality parameters of accessions 1, 3, 5, 7, 10, 14 and 15 are compared with the above varieties. But for specific purposes, desirable traits are to be employed for selection. Further studies are also required to confirm the results. Molecular markers- ISSR markers could be successfully employed in determining the texture of the jackfruit flakes (firm/soft flesh types) and also for knowing the genetic relatedness.