- I J Froneman en J Fivaz
- lnstituut vir Tropiese en Subtropiese Gewasse, Privaatsak X11208, Nelspruit 1200, Suid-Afrika
- 1996
Geleenthede bestaan vir die ontwikkeling van nuwe, verbeterde lietsjiekultivars deur gebruik te maak van gekontroleerde kruisbestuiwing. Voordelige eienskappe van indiwiduele kultivars kan sodoende gekombineer word in die geteelde nageslag. Metodes om gerigte/gekontroleerde kruisings te verkry, is gedurende die blomperiode van 1994 in die plaaslike lietsjieteelprogram gebruik. Skadunethokke met bye, die gebruik van ‘n stuifmeelbediener en handbestuiwings is op die proef gestel. ‘n Totaal van 921 sade afkosmtig van hierdie gekontroleerde kruisings is in ‘n kwekery gevestig. lso-ensiemtoetse sat aangewend word om kruising te bevestig.
Summary:
- Purpose of the study: The article discusses pollination techniques aimed at promoting targeted crossings in lychees (Litchi chinensis) to develop new and improved cultivars with combined desirable traits.
- Background: To date, lychee improvement has mainly been achieved through the selection of seedlings from open pollination, which allows limited control and involves long development phases. Traditional methods using open-pollinated seedlings are recommended to be replaced with controlled crossings where the parent plants are known.
- Pollination techniques:
- Three main methods were evaluated: shade-net cages with bees, a pollen applicator, and hand pollination.
- Shade nets are placed over two genotypes along with bees, limiting pollination to the selected lines.
- The pollen applicator uses bees to transfer selected pollen to chosen flowers.
- Hand pollination eliminates unwanted pollen and applies selected pollen using a brush.
- Results:
- 921 seeds from targeted crossings and 4,664 seeds from open pollination were planted in a nursery.
- Isoenzyme techniques are used to confirm the crossings.
- The new techniques have simplified hybridization and will form an integral part of future breeding programs.
- Implications:
- Targeted crossings enable systematic and planned breeding programs, leading to faster genetic improvement.
- Open pollination will be used less in the future as more material from targeted crossings becomes available.
- Key traits for cultivar selection: Traits such as earlier/later ripening, fruit quality, high yield, and disease resistance are focal points of the breeding program.
- Conclusion: Modern pollination techniques, such as hand pollination and the pollen applicator, provide practical solutions for the genetic improvement of lychees and are effective in achieving targeted crossings.