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Author: Anupama, T V × End date: 2006 × Start date: 2006 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Variability and propagation studies in pummelo (Citrus grandis(L.) osbeck)
    (Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 2006) Anupama, T V; KAU; Lila Mathew, K
    The present entitled “Variability and propagation studies in pummelo (Citrus grandis (L.). Osbeck.)” was conducted at the Department of Pomology and Floriculture, College of Horticulture, Vellanikkara during 2003-2005. The objectives of the study were to explore the variability in vegetative, flowering, fruiting characters of pummelo through a comprehensive survey in Thrissur, Ernakulam and Kottayam districts of Kerala and to standardize vegetative propagation techniques in pummelo. Variations were noticed in tree habit (upright, spreading and drooping), tree shape (ellipsoid, spheroid and ellipsoid-oblate), branch density (sparse, medium and high) among the 40 accessions surveyed. Leaf shape, length, width, length/width ratio, petiole wing shape, margin and aroma of crushed leaves showed variations. Flowering season started by March-April. Late flowering types (November- December) were also observed. AC. 16, 29 and 31 exhibited perpetual flowering habit. Flowers were both solitary and crowded. Variations were observed in number of flowers per inflorescence (four-12), flower length (1.40-3.37 cm), breadth (1.10-1.98 cm), pollen fertility (78-90 %) and pollen diameter (32.22-37.10 microns). The fruiting period was from September - February, with the peak in November- December. Variations were noticed in fruit shape (spheroid, pyriform, oblate and oblique), colour (yellow and greenish yellow), base shape (concave- collared, concave, truncate and convex), apex shape (depressed, truncate and convex) fruit skin surface (smooth and pitted), presence of oil glands (conspicuous and very conspicuous), mesocarp colour (white and light pink), carpel colour (pale yellow to red), juice colour (pale yellow to reddish), juice taste (poor and very poor) and juice flavour (moderate and strong). Biometric characters viz., fruit length (10.2 - 21.2 cm), width (9.8 - 24.8 cm), fruit weight (193.00 -1960.00 g), rind weight (50.00 - 997.00 g), number of segments (9.0 - 16.0), segment length (5.02 - 14.12 cm), segment width (2.54 - 5.20 cm), segment weight (12.00 - 78.00 g), juice content (18.1 - 75.3%), total segment weight- rind ratio (0.43 - 3.53) and yield of fruits per tree (48.25 - 255.00 kg) were varied widely. Significant correlation was observed between yield, fruit length, width, weight, rind weight, segment length, width and weight. Significant variations were noticed for bio chemical characters like TSS (5-110 brix), acidity (0.41-1.74 %), TSS/acidity ratio (3.86 to 22.22), total sugars (3.35- 6.73 %), reducing sugars (0.81- 3.09 %), non-reducing sugars (1.77 - 5.17 %) and ascorbic acid (16.0 - 95.0 mg per 100 g fruit). TSS was significantly correlated with total sugar and reducing sugar content. Sensory attributes viz., appearance, colour, taste, flavour, sweetness, juiciness and overall acceptability of fruits, showed wide variations. AC.11 and AC.12 excelled in sensory qualities. Seeded and seedless types were noticed among the collections. Seed characters varied with respect to the shape, number of seeds per fruit, length, width, weight, days for germination and germination percentage. Seeds had white cotyledons and exhibited monoembryony. Cluster analysis yielded three clusters and showed the existence of genetic divergence in pummelo. Principal component analysis was done using ten fruit parameters and a selection index was worked out. Sixteen accessions had selection index value greater than the standard. AC.2, 9, 11, 12, 14 and 26 can be selected for further evaluation and multiplication. Propagation methods viz., cutting, layering and budding were investigated in pummelo. Highest rooting percentage was obtained in cuttings treated with NAA at 1000 mg l-1 followed by NAA at 2000 mg l-1 and IBA at 1000 mg l-1 in the month of September. Soft wood cuttings showed lesser days for rooting and semi hard wood cuttings gave significantly higher number of roots, treated with NAA at 1000 mg l-1 treatment followed by NAA at 2000 mg l-1. The best medium for layering was sphagnum moss with more number of roots per layer and with lesser days for rooting. Second best medium was coconut fibre and saw dust was inferior to sphagnum moss and coconut fibre. August was the best month with lesser days for rooting and more number of roots per layer, followed by July, which showed the highest percentage of rooting. Patch budding and modified forkert budding, tried on pummelo and acid lime rootstocks, resulted in no bud take despite the different seasons.