Genetic variability in muskmelon for horticultural traits

Abstract

Muskmelon (Cucumis melo L.) is an important horticultural crop within the genus Cucumis and fruits are used as ‘dessert’. Seed kernel is also edible, tasty and nutritious, since it is rich in oil and energy. Great morphological variation exits in fruit characteristics such as size, shape, colour and texture, taste and composition, and muskmelon is therefore considered the most diverse crop of the genus Cucumis. Keeping in view the importance of the crop, a total of 20 germplasm of muskmelon were collected during 2013 from different places of Rajasthan. The segregating material has been purified through inbreeding exercising single plant selection for desirable traits viz., earliness, flesh thickness, flesh colour, rind thickness, size of seed cavity, yield and TSS. The resultant inbred lines were evaluated and characterized for different horticultural traits at ICAR-CIAH, Bikaner over the years. Observed wide variation among the genotypes for days taken to produce 50% pistillate flowers (47-51 days), node at which first pistillate flower appeared (2.40-4.60), days taken to first fruit harvest from sowing (74-79 days), fruit weight (0.55-1.05 kg), fruit diameter (7.16-11.28 cm), flesh thickness (1.60-4.04 cm), rind thickness (0.18-0.36 cm), size of seed cavity (5.58-7.10 cm), number of marketable fruits/ plant (2.60-4.00) and TSS (9.22-12.00%). The flesh colour was observed as white, light green, greenish white and salmon orange. Fruit shape was found to be ovate, elongated globe, oblate and obovate with or without sutures. The sex expression was andromonoecious in all genotypes except AHMM/BR-8 which expressed monoecious sex from. Further, these germplasm were also subjected to screening against pests and diseases. Significant differences were noted among antixenotic traits like length of ovary pubescence, fruit toughness, rind thickness and flesh thickness studied in relation to fruit fly infestation under field conditions. Among the genotypes, the minimum infestation of fruit fly was observed in AHMM/BR-1 (12.98%) followed by AHMM/BR-8 (15.72%). The per cent fruit fly infestation had negative correlation with fruit toughness, rind thickness, flesh thickness and length of ovary pubescence. Likewise against Fusarium wilt, per cent disease index (PDI) was recorded from 3.33 to 30.67. The minimum being in genotype AHMM/BR-41 and maximum in AHMM/BR-54. Based on overall performance, selected AHMM/BR-47 as promising line which produced first harvesting in 75-80 days after sowing and bear 3-4 fruits/ plant having 11-12% TSS. The average fruit weight of this line varied from 0.6-0.8 kg having netted and thick rind (0.3 cm) with small seed cavity (5.58 cm) and 2.8-3.1 cm thick flesh of salmon orange colour. It was found moderately resistant to Fusarium wilt under field conditions.