Genotype and substrate effects on moringa seed germination and plant growth in Tuscany (Italy)

Moringa is mostly propagated by seeds, hence plantations are not uniform and the end products show a wide variation in terms of commercial characteristics. In this paper the effect of moringa seed origin on seed germination and seedling growth in standard and unconventional substrates is studied. Seeds collected from four different geographic areas (India, Pakistan, Mozambique and Paraguay) and stored at ambient conditions were sown in a germination substrate (50% v/v peat based commercial substrate and 50% v/v perlite) (Trial A) and transplanted after two months in a peat based commercial substrate (control, TS0) and in two unconventional substrates (pure - TS100 - and 50% v/v mixed remediated marine harbour dredged sediment with peat based commercial substrate - TS50) (Trial B). Plants were grown in pots placed in open air from May to September 2018 and located on the campus of the University of Florence, Sesto Fiorentino (FI), Italy (43°48'31.55”N, 11°12'10.46”E; 42 m a.s.l.). Germination rate and mean germination time (MGT) were assessed in the first trial. Stem diameter, plant height and number of internodes were monitored on all the growing seedlings in both Trial A and B. Very significant statistical differences were observed in seed germination rate, with seeds from Paraguay and India showing the highest values, while more homogeneous results were observed for MGT. Plant growth parameters were significantly affected by origin, with plantlets from Paraguayan and Pakistani seeds showing the highest values for plant height (27.8±4.8 and 25.0±5.3 cm, respectively) at transplant time. Results from Trial B showed significant effects of plant genotype, growing substrates and their interactions. The tallest plants were obtained from seedlings of Pakistani origin grown on TS100 (74.14±12.0 cm) and TS50 (72.81±11.4 cm) and on Paraguayan seedlings (72.83±9.1 cm) on the peat based commercial substrate. Conversely, the lowest height values were observed on seedlings of Indian origin grown on the pure treated sediment (TS100) and those from Mozambique on the commercial substrate (TS0).