Plant Growth, Yield, and Fruit Size Improvements in ‘Alicia’ Papaya Multiplied by Grafting

Abstract

Papaya (Carica papaya L.) is one of the few fruit crops still propagated by seeds. However, its trioecious condition and the heterozygosity of the seedlings make urgent the development of reliable vegetative propagation procedures. In this experiment, we compared, in a greenhouse sited in Almería (Southeast Spain), the performance of plantlets of ‘Alicia’ papaya originated by seed, grafting, and micropropagation. Our results show that grafted papayas were more productive than seedlings papayas (7% and 4% for total and commercial yield), while in vitro micropropagated papayas were the least productive (28 and 5% less in total and commercial yield than grafted papayas, respectively). Root density and dry weight were both higher in grafted papayas, while the seasonal production of good quality, well-formed, flowers was also enhanced in grafted papayas. On the contrary, micropropagated ‘Alicia’ plants yielded less and lighter fruit despite these in vitro plants blooming earlier and setting fruit at desirable lower trunk height. Less tall and less thick plants and reduced production of good quality flowers might explain these negative results. In addition, the root system of micropropagated papaya was more superficial, while in grafted papayas, the root system was larger and had more fine roots. Our results suggest that the cost-benefit ratio does not favor the choice of micropropagated plants unless elite genotypes are used. On the contrary, our results encourage more research on grafting, including the search for suitable rootstocks for papaya.

Field performance of grafted, micropropagated, and own-rooted plants of three Italian hazelnut cultivars during the initial four seasons of development

“…This corresponds with the hazelnut data, where micropropagated plants showed higher growth rate than grafted and own-rooted plants, reaching, at the end of the trial, in the fourth growing season, similar canopy volumes to both grafted and own-rooted ones. Salinas et al (2023), comparing the performance of plantlets of papaya originated by seed, grafting, and micropropagation, found that in vitro micropropagated papayas were the least productive, even if they bloomed earlier and set fruit at desirable trunk height, because they were less tall and thick. Hernandez et al (1997) found in kiwifruit that commercial production first harvest was significantly higher in grafted plants, even if the following years plants obtained from cuttings showed greater vigor and higher cumulative and commercial yield.…”

Regulation of Embden–Meyerhof–Parnas (EMP) Pathway and Tricarboxylic Acid (TCA) Cycle Concerning Aberrant Chilling Injury Behavior in Postharvest Papaya (Carica papaya L.)

“…Papaya ( Carica papaya L.) originates from Central and South America but is cultivated in all tropical regions [ 1 ]. The total world papaya area has reached 468,731 hectares and global production of papaya is estimated to rise by 2.1 percent each year, up to 16.6 million tons in 2029 [ 2 , 3 ]. But papaya is a tropical fruit that is prone to physical damage and disease, which poses challenges for its storage and transportation [ 4 , 5 ].…”