Identification of superior parents for commercial watermelon seed production

Malaysia is a net exporter of watermelons. However the seeds are imported from Taiwan and U.S.A. This has become the major cost component in the cultivation of watermelons in the country. As such development of our own hybrid seeds is a major target in watermelon research. The procedure for the development of the new hybrids is through the pedigree method where superior genotypes are selected in successive segregating generations. Seeds of the locally adapted varieties which are usually F1 hybrids were imported. They are National Champion (NC), Olympia 1 (OLY 1), Olympia 2 (OLY 2), Olympia 3 (OLY 3), 6372, Goldin (GK), Bow Long (BL), New Dragon (ND), Ashahiyamoto (ASH), Crimson Sweet(CS), Champion (CH) and New Yellow Baby (NYB). Field assessments of the parental types were done. Selfing was done successively to generate F1, F2, F3, F4 and F5 generations resulting in the production of homozyqous individuals with definite family characteristics. Inbreeding depression were seen on general growth characters but there were improvement os specific characters such as brix % and fruit size. The combining ability of all the fifth level inbreds (F5) was tested using Crimson (CS), an open pollinated, popular and widely adapted variety. The performance of the resulted topcross hybrids were tested in Bukit Tangga, Telong, Kota Bhary adn Kluang. In Bukit Tangga all the selected topcross hybrids produced fruits bigger (6.7 kg - 8.2 kg) than the control (CS X CS). Hybrids CS x BL and CS x 6372 produced optimum fruit size i.e 7-8 kg/fruit, suitable for external market. Hybrids CS x CH x BL, and CS x 6272 has skin thickness above 1.4 cm. Hybrids CS x BL is the sweetest. All the hybrids recorded equal or higher brix values than the control i.e ≥ 10%. All hybrids were also given values for general appearance and acceptability. Hybrids CS x CH, CS x BL, and CS x 6372 have the highest ratings. Hybrid CS x BL was widely accepted as it had smooth and soft fresh. based on the general performances of the resulted top cross hybrids, F5 inbred seeds of 3 parents with red flesh (i.e Champion, 6372 and Bow Long) and 2 parents with yellow flesh (i.e Goldin and New Yellow Baby) needs to be produced for the production of promising commercial watermelon hybrids.