Abstract
The objective of this study was to evaluate the stigma morphoanatomy and receptivity in ten promising papaya accessions, to expand knowledge useful for genetic improvement of the culture. The morphoanatomy was analyzed by light and scanning electron microscopy, and the stigma receptivity was investigated by application of hydrogen peroxide and α-naphthyl-acetate with fast blue B salt, in pre-anthesis, anthesis and post-anthesis. The papaya accessions presented dry stigma surface, presence of one to six erect stigmatic lobes, with structures joined to the upper base of the style and covered with numerous elongated unicellular tubular papillae, distributed on both faces of the epidermis. The morphoanatomy had a similar pattern in all the accessions, differing only in the timing of floral development. The stigma receptivity in some accessions occurred even before floral opening, continuing with greater intensity in anthesis and post-anthesis. Pre-anthesis is the stage least propitious for controlled hybridizations due to the weak or absent stigmatic receptivity. The results obtained provide information on the floral stage that is most propitious for fertilization, as well as supporting future investigations of the botanical morphology of the species.
Highlights
Carica papaya L. is the only species of Caricaceae Dumort. that produces marketable fruit
We evaluated 10 papaya accessions of the species Carica papaya L., four of the ‘Solo’ type (CMF020, CMF-026, CMF-070 and CMF-123) and six of the ‘Formosa’ type (CMF-022, CMF-055, CMF-075, CMF-142, CMF-245 and CMF-247), belonging to the Papaya Active Germplasm Bank (Papaya AGB) of Embrapa Mandioca e Fruticultura, located in the municipality of Cruz das Almas, Bahia, Brazil
The stigmas from hermaphrodite flowers in floral anthesis were collected from each accession and immediately fixed in modified Karnovsky’s solution (Karnovsky 1965) (2% glutaraldehyde, 2% paraformaldehyde, Cacl2 0.001 M and sodium cacodylate buffer 0.05 M) with pH adjusted to 7.2, for a period of 48 hours
Summary
Carica papaya L. is the only species of Caricaceae Dumort. that produces marketable fruit. Programs for genetic improvement of papaya are focused on obtaining new varieties that are resistant both to biotic and abiotic factors and that meet the requirements of the domestic and external markets as well as of farmers (Dantas & Lima 2001, Ruggiero et al 2011). Understanding the reproductive biological aspects of different accessions of a species helps to identify potential parents for use in future crosses and/ or hybridizations (Bernardello et al 2001, Souza et al 2017). Knowledge of the morphoanatomy and stigma receptivity of different accessions of C. papaya has been important to support actions involving controlled pollinations. Studies of these aspects improve understanding of the compatibility between pollen grains and stigmas, influencing the fertilization rate and formation of fruits and seeds (Galen et al 1987, Lenzi & Orth 2004)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
