Genotype Differences in Seed Germination and Growth, Pollen Fertility and Fruit Traits of Three Promising Papaya (Carica papaya L.) F1 Hybrids
Pablito M. Magdalita and Alangelico O. San Pascual
Papaya F1 hybrids are generally grown by many growers for their hybrid vigor, superior fruit characteristics and moderate tolerance to the Papaya ringspot virus (PRSV). A single-factor experiment conducted in completely randomized design (CRD) with three replications was done to test seed germination, assess seedling growth, and evaluate pollen fertility and horticultural characteristics of three promising papaya F1 hybrids – 5 648 x 336 (Liyag), 097 x 4 172 (Hirang), and 4 173 x 5 648 (Timyas). There were significant differences in percent seed germination and seedling height between the three papaya F1 hybrids. Hybrid 5 648 x 336 (Liyag) had the highest seed germination rate (92.20%) and the tallest seedlings (44.73 mm). In terms of root characteristics, there were significant differences between the hybrids in fresh and dry weights of roots, number and length of secondary roots. Hybrid 5 648 x 336 (Liyag) had the heaviest fresh and dry weights of roots and had the highest number of secondary roots while hybrid 097 x 4 172 (Hirang) had seedlings with the longest secondary roots. There were significant differences in pollen viability in the three hybrids. F1 hybrid 4 173 x 5 648 (Timyas) had the highest percent pollen viability (83.33%), and hybrid 097 x 4 172 (Hirang) the lowest (73.33%). Pollen viability and pollen germination were high for the six parental inbred lines of the three F1 hybrids, but no significant differences were found. In addition, there were significant differences between the three F1 hybrids in fruit weight, fruit length and flesh thickness. Hybrid 097 x 4 172 (Hirang) had red flesh, while hybrid 5 648 x 336 (Liyag) and hybrid 4 173 x 5 648 (Timyas) had yellow orange flesh. The three hybrids are moderately tolerant to PRSV similar to the control cultivar Sinta.