- P J Robbertse, Elsie M A Steyn and J Fivaz
- Margaretha Mes Institute for Seed Research, University of Pretoria, Pretoria 0002
- 1993
This report supplies information about the longevity of litchi pollen under different storage conditions. The best results were obtained where the pollen was dried and stored at 4 °C. A misinterpretation about the relation between aril development and the obturator, as was published in a previous report by the authors, is brought up to date. Preliminary results of fruit-set, after self- and reciprocal cross-pollinations between the cultivars Mauritius and Madras are also supplied.
Summary:
Litchi pollen longevity was studied under different storage conditions; the best viability was obtained when pollen was dried and stored at 4°C, maintaining some viability up to six weeks.
Pollen viability significantly drops over time in cold storage, and after 40 weeks no viable pollen remains.
Experiments with organic solvents showed that xylene treatment was least damaging to pollen viability after 24 hours.
Hand-pollination trials with Mauritius and Madras cultivars showed higher fruit set with inter-cultivar crosses compared to self-pollination, suggesting litchi naturally prefers outcrossing for better fruit production.
Open-pollination in commercial orchards showed 95% of flowers were pollinated but only about one-third had pollen tubes reaching ovules, indicating pollen tube growth could limit fruit set.
The pistil structure supports competition among pollen tubes, possibly favoring cross-pollen over self-pollen, though more research is needed.
A previous misunderstanding about aril development was corrected: aril develops from the basal part of the young seed about seven weeks post-fertilization, independent of the obturator which disintegrates after fertilization.
The study highlights the complexity of fruit set in litchi, with factors beyond pollination impacting success, and calls for further research on pollen donors and reproductive biology.
The research aims to assist breeding programs and enhance fruit set via better understanding of pollen viability and compatibility.