Characterization of selected exotic jackfruit (Artocarpus heterophyllus Lam.) varieties

Abstract

The study entitled ‘Characterization of selected exotic jackfruit (Artocarpus heterophyllus Lam.) varieties’ was conducted at the Department of Fruit Science, College of Agriculture, Vellayani, Thiruvananthapuram, from November 2024 to July 2025. Fifteen exotic jackfruit varieties were identified from South Kerala, covering the districts of Thiruvananthapuram, Kollam, Alappuzha, and Kottayam. No systematic study has been conducted so far regarding the evaluation and morphological characterization of exotic jackfruit varieties under Kerala conditions. Keeping this in view, the present study is proposed with the aim of morphological characterization and evaluation of selected exotic jackfruit varieties grown in South Kerala. Observations were recorded on quantitative, qualitative, biochemical and organoleptic parameters. A preliminary survey was conducted in various locations across Thiruvananthapuram, Kollam, Alappuzha, and Kottayam districts to identify exotic jackfruit varieties. The preparations included contacting KVKs, research stations, various private and public nurseries and contacting farmers in order to collect information regarding the same. A traditional variety popular in Kerala, Muttom Varikka, was taken as control in order to compare the differences in characters with the exotic varieties. Seven of the exotic varieties were collected from Kollam, six from Thiruvananthapuram and each from Alappuzha and Kottayam district. Field observations for the selected exotic varieties were conducted by documenting the morphological characteristics of the tree, leaves, inflorescences, fruits, seeds, and other contributing traits, following the IPGRI (2000) descriptor for jackfruit. The incidence of pests, diseases, and other physiological disorders were also monitored and recorded. Regarding the important qualitative characters, most of the exotic varieties exhibited an irregular crown shape (40.00%) and irregular branching pattern (53.33%). All the exotic varieties were regular bearers, with 66.66% of them being early-bearing. Considerable variations were observed in qualitative, quantitative and biochemical characters of exotic varieties. Among the varieties, 26.66% exhibited a twisted flake shape, 20% each displayed obovate and rectangular shapes, 13.33% had

an irregular shape, and 6.66% each showed spheroid and cordate forms. 86.66% of the exotic varieties were sweet in taste, while 13.33% of them were insipid. Most of the varieties had yellow pulp color (40 %), followed by light yellow (33.33%), followed by coppery red (20 %) and creamy white (6.66%). An agglomerative hierarchical clustering was performed using 12 yield contributing quantitative parameters. The analysis classified the varieties into three clusters according to the similarities of these traits. The clustering results showed that the elite varieties with desirable traits were predominantly found in Cluster III. An agglomerative hierarchical clustering based on biochemical analysis was conducted using eight key biochemical traits that contribute to yield. The analysis classified the varieties into two clusters according to the similarities in these traits. The results indicate that the elite varieties with desirable characteristics were grouped in Cluster II. Principal component analysis (PCA) was performed using ten quantitative characters contributing to yield, including fruit length (FRL), fruit diameter (FRD), fruit weight (FRW), flake length (FLL), flake width (FLW), weight of flakes per kg of fruit (WFPKF), weight of fresh flake without seed (WFFWS), flake to fruit ratio (FFR), flake to seed ratio (FSR) and yield per tree (YPT). The PCA biplot results show that FFR, FRW, FRL, and FLL contribute positively to PC1. Gumless, White Jack, Red Jack, Thailand Red, J 33, and Dang Surya are found to have high values for these parameters. Similarly, FSR and YPT contribute positively to PC2 while FLW contributes negatively to PC2. Vietnam Super Early, Seedless are found to have high values for FSR but low values for FRL, FRD, FRW and FLW. Among the quantitative characters, J 13 had the longest fruit (57 cm), White Jack had the largest diameter (84.10 cm) and heaviest weight (14 kg). White Jack had the highest weight of flakes per kg of fruit (876 g), and Red Jack had the highest weight of fresh flake without seed (29 g). White Jack had the longest flake (8.50 cm) and the widest flake was present in Red Jack (11.10 cm). The highest yield per tree was recorded in the Gumless variety (326.80 kg). The traditional variety, Muttom Varikka taken as control, exhibited a fruit weight of 7 kg, fruit length of 58 cm, and fruit diameter of 70.50 cm.

PCA on biochemical parameters was carried out based on Total Soluble Sugars (TSS), acidity (AY), TSS-acidity ratio (TAR), ascorbic acid (AA), reducing sugars (RS), non-reducing sugars (NRS), total sugars (TS) and total carotenoids (TC). The PCA biplot shows that TSS, TS, TAR, RS and AA have positive contributions to PC1 while AY has a negative contribution to PC1. Exotic varieties such as J 33, Pink Jack, Dang Surya, Thailand Red and Cambodian Orange have higher values for TSS, TS, TAR, RS and AA, whereas J13, Seedless, Thailand Pink and Vietnam Early have higher values of AY. TSS peaked for the J33 variety (40.7 ºBrix) while maximum acidity was found in Thailand Pink and J13 varieties (0.64%). Vietnam Red and Pink Jack exhibited the least acidity (0.21). Pink Jack variety had the highest TSS-acidity ratio (167.62), followed by Vietnam Red (121.90) and ascorbic acid content was high in White Jack (20.19 mg/100g). Among the biochemical parameters, J33 had the highest percentage of non-reducing sugar (11.38 %) as well as total sugars (17.92%) and the Red Jack variety had the highest total carotenoid content (4430.13 μg/100g). For the identification of elite varieties based on the parameters, scoring was given based on the economic characters like tree vigour, fruit weight, pulp colour, flake to fruit ratio, TSS, acidity, carotenoid content, flake to seed ratio, number of fruits per tree and yield per tree. The elite exotic jack fruit varieties identified based on the study were Vietnam Super Early, J33, Thailand Red, Red Jack, Gumless, Cambodian Orange and Dang Surya. These elite varieties were compared with the traditional control variety, Muttom Varikka. The PCA analysis with traditional as well as selected elite varieties were done on 15 yield contributing quantitative and biochemical factors: fruit length (FRL), fruit diameter (FRD), fruit weight (FRW), flake length (FLL), flake width (FLW), weight of flakes per kg of fruit (WFPKF), weight of fresh flake without seed (WFFWS), flake to fruit ratio (FFR), flake to seed ratio (FSR), yield per tree (YPT), Total Soluble Sugars (TSS), acidity (AY), TSS- acidity ratio (TAR), ascorbic acid (AA), reducing sugars (RS), non-reducing sugars (NRS), total sugars (TS) and total carotenoids (TC). The PCA biplot showed that the traditional variety had comparatively higher values for FFR, WFPKF, FLL, FRL, FRD, while other parameters were found in higher values in exotic varieties.

The organoleptic assessment of the flake was done using a hedonic scale rating, ranging from 1 (indicating poor quality) to 9 (representing excellent quality), and underwent statistical analysis using Kendall's and Kruskal-Wallis tests. Red Jack had the highest rank for appearance (8.6), Dang Surya scored the highest for colour (8.8), Dang Surya and Thailand Red had the highest score for flavor (9). Texture scores were highest for Dang Surya (8.4). J33 scored 9 for taste. Overall acceptability scores were highest for Thailand Red and J33. Overall assessment revealed that exotic jackfruit varieties, Vietnam Super Early, J33, Thailand Red, Red Jack, Gumless, Cambodian Orange and Dang Surya were identified as elite types. The results of the study showed significant variation in both quantitative and qualitative traits, as well as biochemical and organoleptic parameters among the different exotic varieties. The findings indicate that exotic jackfruit varieties possess distinct advantages over traditional types, particularly in yield potential and fruit quality attributes. Further exploration and utilization of these varieties is essential for identifying superior genotypes, promoting commercial cultivation, conserving promising varieties, developing value-added products, and improving the economic potential of exotic jackfruit varieties.