MSc

An investigation entitled "Evaluation of rose varieties for commercial cultivation under the warm humid tropics of Kerala "was conducted in a naturally ventilated polyhouse of Department of Floriculture and Landscaping during August 2017 to March 2018. The objective of the study was evaluate the performance of cut flower and loose flower rose varieties under polyhouse and to select suitable varieties of both types for commercial cultivation in the plains of Kerala. Ten cut flower varieties viz. Arka Ivory, Arka Pride, Arka Swadesh, Gold Strike, Noblesse, Revival, Taj Mahal, Corvette, Emma, Peach Avalanche and ten loose flower varieties viz. Arka Parimala, Sherba Gold, Mirabel, Vernish, Charisma, Jadiov, Star Light, Spray Orange, Spray Yellow and Red Varnish were evaluated for vegetative as well as floral and genetic parameters.
The variety Taj Mahal was superior in plant height (52.83 cm) at peak flowering stage. Highest number of sprouts (2.83) was observed in variety Gold Strike whereas varieties Revival (5.5) and Peach Avalanche (5) had highest number of branches. Variety Arka Ivory (38.67) was found to have highest number of leaves at peak flowering stage.
Stalk length, bud size, number of petals per flower and keeping quality are the important quality criteria for cut flowers in National and International markets. The highest stalk length was observed in variety Emma (30.48 cm) and Arka Pride (31.35 cm) whereas variety Taj Mahal (79.1) was superior in terms of number of petals. Length and diameter of flower bud was superior in varieties Arka Ivory (2.77 cm and 1.09 cm) and Taj Mahal (2.53 cm and 1.21 cm). Longest vase life was observed in varieties Revival (4.83 days), Noblesse (4.75 days) and Taj Mahal (4.75 days). Highest number of marketable flowers was observed in varieties Arka Ivory (8.45), Taj Mahal (8.28) and Revival (7.23).
Among the loose flower varieties the variety Arka Parimala was superior with respect to plant height (59.82 cm) and number of branches (6.67). Variety
Charisma had highest number of sprouts (4) whereas variety Star Light was superior with respect to number of leaves per branch (44.47).
Varieties varied significantly with respect to floral characters. Highest number of petals was observed in variety Star Light (101) and variety Arka Parimala was found to have longest flower bud (2.6 cm), highest flower diameter (6.7 cm) and strong fragrance whereas this variety was inferior with respect to number of petals (15.4). Yield of marketable flowers was highest for the varieties Arka Parimala (34.33 g), Mirabel (20.83 g), Vernish (28.39 g), Charisma (28.7 g), Spray Orange (26.93 g) and Red Varnish (29.28 g). Variety Star Light was found to be superior in terms of overall performance.
The marketable flower yield over the months of observation indicated that November – December is the best season for rose production after the October pruning. High temperature and low humidity along with severe incidence of thrips reduced marketable yield during Feruary – March.
Dendrogram based on D2 statistics indicated that there exists much diversity among the cut flower and loose flower varieties for both quantitative and qualitative characters.
The genetic estimates, GCV and PCV were found to be high for the characters viz. number of flowers per sprout (24.11 , 32.30), number of petals per flower (40.08, 43.56), yield of marketable flowers (27.71, 48.86) and fresh weight of the flower (21.19, 23.61) indicating wide variability for these characters among the ten cut flower varieties. The characters number of petals per flower (84.63,75.95), fresh weight of the flower (80.56, 39.18) and vase life (69.53, 26.96) exhibited high heritability coupled with high genetic advance indicating additive gene action in the expression of these characters and are highly inheritable while selection done based on these characters for cut flowers.
Among loose flowers, the genetic estimates GCV and PCV were found to be the highest for the characters number of flowers per sprout (42.25, 52.45), number of flowers per plant (26.93,34.43), number of petals per flower
(55.42,55.58), fresh weight of flower (61.69, 93.84), weight of petals per flower (83.81, 120.33) and flower diameter at fully opened stage (25.89, 28.71). High heritability coupled with high genetic advance were observed for the characters number of flowers per sprout (64.89,70.11), number of flowers per plant (61.19, 43.40), number of petals per flower (99.43, 50.12) and flower diameter at fully opened stage (81.32,48.10) indicating the existence of additive gene action and selection based on this characters will be effective.
Correlation and path analysis revealed that the characters viz. length of flower bud (1.041), number of flowers per plant (0.156) and number of petals per flower (1.045) were significantly and positively correlated with marketable yield per plant along with direct effect (1.131, 0.251, 0.285 respectively). Since, the characters number of flowers per plant and number of petals per flower had high GCV (%), PCV (%), high heritability (%) coupled with genetic gain (%) along with positive significant correlation and direct positive effect on marketable yield, these characters can be fixed as the selection criteria for loose flowers.