Fruit quality of grape (Vitis vinifera L.) cv. Muscat in response to plant growth regulator application.
Year: 2010
Type: article
Abstract: Field experiments were conducted at Tamil Nadu Agricultural University, Coimbatore to elucidate the response of grape cv. Muscat to growth regulator application with respect to their quality in the summer and winter seasons. The quality characters such as total soluble solids (TSS), total sugars and anthocyanin content were found to be better in the treatment combination Gibberellic acid (GA)+ Brassinosteroids (BR) + Pink Pigmented Facultative Methylobacteria (PPFM). The season had profound effect on colour development while grapes harvested in the winter recorded more anthocyanin content compared to summer. INTRODUCTION Grape (Vitis vinifera L.) is one of the earliest fruits known to mankind and is grown for its juicy and tasty berries. Grape is considered to be one of the most delicious, refreshing and nourishing fruits and a rich source of carbohydrate (15-25%) particularly rich in glucose and fructose with traces of minerals (0.2-0.6%). Over the past two decades, usage of plant growth regulators has gained considerable importance in the field of horticulture. Several chemicals have been tried for cluster thinning, hastening maturity, improving berry size and controling the vegetative growth in grape vines. Gibberellic acid (GA) came into prominence for its beneficial effect on increasing berry size of grapes. In grapes, application of GA is known to reduce the bunch compactness and improve the size and quality of berries. Brassinosteroids (BR) are the sixth group of plant hormones with significant growth promoting activity (Clouse and Sasse, 1998). Exogenous BR levels are associated with ripening in grapes (Symons et al., 2006). Brassinolides are considered as hormones with pleiotropic effects, as they influence varied developmental processes like growth, flowering and senescence. Pink Pigmented Facultative Methylobacteria (PPFM) is a microbial culture, which is a cytokinin rich source used as a growth regulator instead of synthetic cytokinin. Bacteria of the genus Methylobacterium are well-studied examples of facultative 1 Department of Fruit Crops, Horticultural College and Research Institute, Tamil Nadu Agricultural University, Coimbatore 641 003, India 2 Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore 641 003, India 3 Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore 641 003, India Response of Grapes to Plant Growth Regulators 219 methylotrophs. Methylobacterium strains are commonly found in soils, as well as on the surfaces of leaves of a wide variety of plants (Corpe, 1985). Considering the need for optimizing the growth regulator, an attempt was made to study the bio-efficacy of growth regulators to improve fruit quality of grape cv. Muscat in summer and winter seasons. MATERIALS AND METHODS Field experiments were conducted at Kupanoor village of Thondamuthur Panchayat by Horticultural College and Research Institute Tamil Nadu Agricultural University, Coimbatore during 2007-2008. The investigation was laid out in a Factorial Randomized Complete Block Design (FRCBD) with three replications. Irrigated crop with three year old vines having uniform canopy size were selected for the study. Pandhal system of training was followed. In each experimental plot, vines were labeled and tagged before calyptra fall stage. The labeled vines were thoroughly sprayed with the respective treatment solutions. The treatment details are given below. After full ripening of berries, the labeled bunches were harvested separately and used for biochemical studies. As per the treatment details, growth regulators were sprayed three times, at pre flowering, flowering and fruit setting stages. Pink Pigmented Facultative Methylobacteria (PPFM) spraying was given to each bunch early in the morning (between 6.00 am and 7.00 am) as per the treatment detail. After that, the treated bunches were left for about two hours. Subsequently, GA and BR were sprayed along with teepol as per the treatment schedule. Biochemical analysis The total soluble solids (TSS) were determined by using Carl-Zeiss hand refractrometer and the results expressed as Brix at 21C. The titrable acidity as per cent citric acid was estimated following the method of A.O.A.C. (1975). Total sugars were estimated by the method of Somogyi (1952) and expressed as percentage. The sugar acid ratio was calculated by dividing total sugar content with acidity. The total anthocyanin was estimated by pH differential method (Giusti and Wrolstad, 2001) and expressed as mg per 100g. The statistical analysis of the observations recorded was performed according to the method suggested by Panse and Sukhatme (1985). Treatments T1 : Control (Water spray) T2 : 25 ppm Gibberellic acid (GA) T3 : 1 ppm Brassinosteroid (BR) T4 : Pink Pigmented Facultative Methylobacteria (PPFM) @10ml/l T5 : 25 ppm GA+ PPFM @10ml/l T6 : 1 ppm BR+ PPFM @10ml/l T7 : 25 ppm GA + 1 ppm BR T8 : 25 ppm GA + 1 ppm BR + PPFM @10ml/l
Source: Tropical Agricultural Research
Authors: V. Jegadeeswari, T.N. Balamohan, R.M. Vijayakumar, S. Mohandass, S. Kuttalam
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W2175246408