Methods of breaking seed dormancy for ornamental passion fruit species

Thalita Neves Marostega,Leonarda Grillo Neves,Petterson Baptista Da Luz,Armando Reis Tavares,Severino De Paiva Sobrinho

doi:10.14295/oh.v23i1.982

Thalita Neves Marostega, Leonarda Grillo Neves + Show 3 more

Open Access

https://doi.org/10.14295/oh.v23i1.982

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Abstract

The Passiflora L. genus covers a diversity of wild species with ornamental potential, especially due to the intrinsic beauty of its exotic flowers, flowering more than once a year and the lush foliage. However, Passiflora seeds present dormancy complicating seed germination and the establishment of commercial plant production with species with high ornamental potential. This study was conducted to determine the best pre-germination treatments to overcome seed dormancy for Passiflora quadrangularis, P. nitida, P. foetida, P. eichleriana, P. alata, P. cincinnata, P. mucronata, P. micropetala, P. suberosa, P. morifolia and P. tenuifila. The experimental design was completely randomized, with five treatments and four replicates, with 25 seeds per plot. Pre-germination treatments were: seeds soaked in 1,000 mg L- 1 GA3 (gibberellic acid) for 6 hours, seeds soaked in 0.2 % KNO3 (potassium nitrate) for 24 hours, seeds soaked in 1 % KNO3 for 24 hours, partial seedcoat scarification with sandpaper number 120 and control (seeds untreated). Percentage of germination, germination velocity index and radicle length were evaluated for all species. The results showed that GA3 was effective to overcome seed dormancy in P. suberosa (86%), P. morifolia (68 %) and P. tenuifila (54%). KNO3 1% had significant effect on overcoming dormancy in seeds of P. eichleriana (66%) and scarification with sandpaper increased seed germination of P. micropetala (38%).

Highlights

Passion fruit can be propagated by asexual reproduction as cuttings, grafting, layering or tissue culture (FERREIRA, 2000)
GA3 was able to overcome seed dormancy in P. suberosa, P. morifolia and P. tenuifila and 1% KNO3 was effective for P. eichleriana
P. tenuifila is very important specie for passion-flower breeding given the importance of the species due to its resistance/tolerant for soil diseases, there is a lack of information in the literature regarding overcoming its dormancy (FALEIRO et al, 2005)

Summary

Introduction

Passion fruit can be propagated by asexual reproduction as cuttings, grafting, layering or tissue culture (FERREIRA, 2000). Seed propagation is recommended for rootstock formation and plant breeding programs focused on disease-resistant and drought-tolerant hybrids with ornamental or medicinal use (JUNQUEIRA et al, 2001). Several authors had reported that the period for passion fruit germination is from ten days to three months, with low germination rate and irregular seedling formation (DELANOY et al 2006; FOWLER and BIANCHETTI, 2000; DOIJODE, 2001). The period of seed viability for the majority of Passiflora species is unknown (FALEIRO et al, 2005), and the long period of natural or induced dormancy make seed germination slow and unevenness, restricting the commercial use of promising materials (DOIJODE, 2001)

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