Increasing Your Nut Crop: Diversity Is Key

When choosing a macadamia nut variety to plant, farmers could be tempted to stick with one variety throughout the farm to make management easier. However, diversity is key to obtaining a superior nut crop, as cross-pollination between varieties can lead to a yield increase. Lindi Botha reports.

- Lindi Botha

FAST FACTS

Macadamia nut orchards are under-pollinated due to a lack of diversity in cultivars.

Inbreeding occurs when there is a monoculture of varieties.

Substantial yield increases can be gained from better pollination.

Better pollination in macadamia nut orchards is key to improving yields and increasing kernel recovery. While bees play a crucial role in pollinating these crops, obtaining maximum pollination is an issue that most farmers grapple with.

Coupled with this is the underestimated role that cross-pollination between different macadamia nut varieties plays in getting maximum pollination and nut set. For this reason, it is not uncommon to find whole farms consisting of a single variety.

Looking into the exact role that monoculture plays in pollination, an ongoing study in Australia has revealed that not only are macadamias under-pollinated for the most part, but improving this one aspect could add 1t/ ha of nut-in-shell (NIS) to yield. At current nut prices, this equates to around R65 250.

Prof Helen Wallace from the Agricultural Ecology Department at Griffith University in Queensland, Australia, has been a macadamia researcher for more than 20 years and is part of a team investigating pollination in macadamias. Debunking myths on how pollination in orchards works, she clarifies that bees and other insects are primarily responsible for pollination.